270. Oscillatory building blocks underlying perceptual decision making

Hesham Elshafei1, Ying Joey Zhou1, Saskia Haegens1

1Donders Institute

270. Objectives and research question Neural oscillations in different frequency bands are currently being linked to various cognitive functions e.g. theta with memory and alpha with attention. Instead, we propose that the role of neural oscillations is to control communication by providing building blocks, or low-level operations, that can be employed for these higher-level cognitive functions. In this study, we targeted three rhythms: delta/theta, alpha and beta. Materials and methods We recorded MEG data from 33 healthy young participants who performed a match-to-sample paradigm where they were required to match either orientation or spatial frequency of two visual gratings (target and probe). The to-be-matched feature was indicated by a visual cue occurring either before (pre-cue) or after (retro-cue) target presentation. Results First, we demonstrated that inter-trial coherence following the probe in the delta/theta range (in parietal and occipital sensors) negatively correlated with reaction times i.e. the more consistent was the phase of these oscillations during probe presentation, the faster the participants were to correctly compare it to the target. Second, we demonstrated that alpha power preceding cue presentation correlated negatively with reaction times and positively with accuracy i.e. participants were faster and more accurate in trials with low alpha power. Finally, using multivariate pattern analyses we demonstrated that activity in the beta (and alpha) band maintains several task information e.g the attended target feature and the cue condition. In addition, activity in the beta rhythm contained information about the participants’ decision outcome after probe presentation i.e. we were able to decode participants’ decision to provide a matched and accurate response. Conclusion In this study, we targeted three specific rhythms: delta/theta, alpha and beta. We tested and provided evidence to our proposed framework of oscillatory building blocks where slow rhythms optimally sample task-relevant input, while the alpha rhythm suppresses irrelevant input, and the beta rhythm recruits task relevant circuits that maintain input information in working memory, as well as circuits that hold the decision outcome.

376. Dissociation of perception and associative learning in rat hippocampal sub-regions by neuronal synchronization

Kim Kayon1, MS Nokia, JM Palva, S Palva 1Neuroscience Center, HiLIFE, University of Helsinki

376. Recent studies found that hippocampus is involved not only in learning or memory formation, but also in perceptual process of sensory stimulus. Yet, little is understood how perception of sensory stimuli are represented, which is the prerequisite for learning of stimulus associations in hippocampal circuit. In this study, we recorded local field potential (LFP) from rat dorsal hippocampus while rats were performing classical eyeblink conditioning task to investigate how hippocampal oscillations reflect the representation of stimulus-response mapping of sensory stimuli and are related to the learning of the stimuli association. We found distinct spatio-temporal dynamics during the task that are related to either perception or learning. Our results further suggest that associative learning underlies neuronal synchronization that involves integration of anatomically distributed information across multiple frequency oscillations in rats.

255. The pain-sleep dialog: Interactive effects of pain and sleep state on behavior and cortical activity in the anterior cingulate and somatosensory cortices in mice

Raquel Adaia Sandoval Ortega1,2, M Renard1, P de Luna1, MX Cohen2, T Nevian1

1Department of Physiology, University of Bern, Bern, Switzerland, 2Donders Centre for Medical Neuroscience, Radboud University Medical Center, Nijmegen, the Netherlands

255. Objectives Chronic pain affects every fifth person and carries yearly costs of up to €300 billion in Europe alone, however effective treatments remain elusive. Remarkably, up to 88% of chronic pain patients present sleep disturbances, and yet pain processing is mostly studied in wake. Research questions To evaluate the bidirectional influence that pain and sleep have on each other, we performed two experiments in which we simultaneously recorded local field potential (LFP) in the anterior cingulate cortex (ACC; affective component of pain) and the somatosensory cortex (S1; sensory component of pain) in mice. We hypothesized that sleep modulates neural processing of painful stimuli. Materials and methods Animals received pinprick stimuli to the hind paws throughout their sleep cycle. Then, to investigate the effect of pain on sleep, we performed sleep recordings before and 2, 4 and 6 weeks after induction of chronic pain. Results The event-related potentials (ERPs) reveal a sustained response to pain in sleep even in the absence of a behavioral response. Furthermore, the phase and the power of slow frequencies (<10 Hz) at the time of the stimulation onset predicts the presence and type of evoked behavior. When assessing the effect of pain on sleep, chronic pain shifts the dominant frequency in sleep and wake. Sustained pain also potentiates inter-hemispheric synchronization strength, but not duration, in sleep only, and alters the scale-free dynamics in both sleep and wake. Interestingly, these effects were observed in the LFP but not in the EEG. Conclusions Here we show for the first time in naturally sleeping animals that painful somatosensation reaches both the ACC and S1 during sleep. Additionally, the sustained responses during sleep suggest the presence of sustained integration of the affective and sensory processing of pain. Furthermore, the pain-induced increase in autocorrelation and synchrony, together with the shift in dominant frequency, may reflect the faulty E/I balance observed in chronic pain. This in turn, may impair sleep homeostatic function, which may be reflected as sleep impairments. Therefore, given that sleep restores the E/I balance, sleep has untapped potential as a therapy to treat chronic pain.

1. Ebbs and flows away: Reducing mind wandering with intermittent theta burst stimulation over the dorsolateral prefrontal cortex

B.S. Steffen Rygg Aasen1, Ragnhild Drevland1, Dr Gabor Csifcsák1, Prof Matthias Mittner1

1UiT The Artic University of Norway

1. Background: Mind wandering (MW) is a rather omnipresent phenomenon. Research on the relationship between MW and the executive system (ES) have primarily focused on the role of the dorsolateral prefrontal cortex (DLPFC).Several non-invasive brain stimulation studies have investigated the relationship between the ES and MW by applying transcranial direct currently stimulation (tDCS) over the DLPFC to modulate MW propensity. However, results from this line of research is inconclusive and highly variable. The large variability may be, in part, due to the low intensity and spatial focality that tDCS has to offer. We report the first study attempting to use transcranial magnet stimulation (TMS) to modulate MW propensity. Methods: We will use a within-subject, accelerated design with three applications of intermittent theta burst stimulation (iTBS) over the DLPFC, interleaved with four blocks of the finger-tapping random sequence generation task (FT-RSGT) that allows to track the implementation of executive control (through measuring sequence entropy) and behavioural variability, an objective behavioural marker of MW. The experiment follows a triple-blind protocol that has been preregistered at https://osf.io/2g8nz. Data collection is currently ongoing. Hypotheses: We hypothesize that the excitatory iTBS protocol will decrease the subjective MW reports in the active, compared to the sham group. This hypothesis will be tested by considering the interaction effect of a 2 (stimulation: sham vs. real) x 4 (block) repeated measures analysis of variance using MW reports as dependent variable. With the pre-registered number of N=40 participants, we can detect a small effect size of ƞg2 = 0.044 with 80% power at α=0.05 (minimal ƞg2 = 0.055 at 90% power with α=0.05). We will follow up a significant interaction effect by calculating planned contrasts between baseline and post-stimulation blocks.

2. The effect of transcranial direct current stimulation on the interplay between executive control, behavioral variability and mind wandering.

Andreas Alexandersen1, Dr. Gábor Csifcsák1, Prof. Matthias Mittner1

1University of Tromsø (UiT)

2. Mind wandering is a mental phenomenon we humans experience on a daily basis. Yet, we still lack a complete understanding of the neural basis of this pervasive mental state. Over the past decade there has been an increase in publications using transcranial direct current stimulation (tDCS) to modulate the propensity to mind wander. Findings from these studies have been diverse and a satisfactory conclusion is lacking, a situation which calls for more accurate and focal stimulation techniques as well as high-powered, registered reports within the topic. Recently, a study reported successful reduction of mind wandering using high-definition tDCS (HD-tDCS) over the dorsolateral prefrontal cortex (Boayue et al., 2020). However, the final analysis pipeline was not pre-registered and hence only provides preliminary evidence on the efficacy of HD-tDCS in interfering with mind wandering. The current study is a direct replication attempt of the effect found by Boayue et al. (2020), with a high-powered, pre-registered study protocol. Furthermore, we extended the study by investigating whether the effects of HD-tDCS on mind wandering would be prolonged, as well as investigating the underlying processes of mind wandering by recording electroencephalogram and pupillary responses during a simple finger-tapping random sequence generation task, that is known to draw on executive resources. We failed to find any evidence of the original effect of reduced MW during and after stimulation. When combining data from Boayue et al., (2020) and the current study, the original effect of reduced MW after stimulation disappeared. We conclude that HD-tDCS over the DLPFC does not affect MW propensity. Furthermore, we recommend that previously reported effects of tDCS on mind wandering and other cognitive functions should only be accepted after a successful pre-registered replication. We also report neurophysiological findings related to executive functions and midfrontal theta power, as well as attention (occipital alpha power, mismatch negativity), and changes in tonic and phasic pupillary responses related to mind wandering collected in our study.

3. The Effect of Partial Sleep Deprivation on Mind Wandering and Cognitive Performance

Samy Babiker1, Steffen Rygg Aasen1, Aurora Marie Kleivik Vangen1, Sanna Aurora Sandell1, Silje Balsnes Haugan1, Dr. Hema Nawani1, Dr. Matthias Mittner1, Dr. Gabor Csifcsak1

1The Arctic University Of Norway, UiT

3. Mind wandering (MW) is sometimes defined as thoughts unrelated to the task at hand. Previous research has shown a variety of factors that influence MW such as mood, vigilance, or whether it arises spontaneously or deliberately. Moreover, recent research has distinguished MW from mind blanking (MB), which is characterized by off-task thoughts without reportable mental content. Even though MW has been associated with impaired cognitive performance, it is still unclear how this undesirable effect is related to the different manifestations of MW. Partial sleep deprivation (PSD) has also been linked to mood changes and decreased cognitive performance. However, research focusing on the association between PSD and MW in the context of executive functioning is still lacking. In a crossover pseudo-randomized within-subject study, we investigated whether PSD for three consecutive nights (3 hours less than habitual sleep) would induce more MW and worse performance, relative to normal sleep. We studied the finger tapping-random sequence generation task (FT-RSGT; Boayue et al., 2020) which, when combined with thought-probes that inquire participants about their task-focus, allows us to investigate the relationship the executive system and MW. Further, we aimed for characterizing the form of task-unrelated thoughts associated with PSD, both in terms of intentionality (spontaneous vs. deliberate) and content (with content vs. MB). Based on preliminary results (N = 20), PSD was associated with reduced positive affect scores, more overall MW reports and increased relative frequency of MB episodes, but not with the ratio of spontaneous vs. deliberate MW reports. With respect to the FT-RSGT, we found higher behavioral variability during PSD irrespective of task focus, whereas our measure of executive control (approximate entropy) distinguished between on-task and MW reports, but was not affected by PSD. These findings indicate that our PSD protocol induced distinct effects on MW and MB propensity and executive performance, which can have implications for both MW and sleep research. At ICON 2022, we will present findings from our full dataset (N = 30).

151. A predictive processing account of P300 during card sorting: Implications for a theory of prefrontal executive functions

Prof. Francisco Barcelo1

1University of the Balearic Islands

151. For decades, a common assumption in Cognitive Neuroscience has been that prefrontal executive control is mainly engaged during target detection (Posner & Petersen, 1990, 3: 25–42, Ann Rev Neurosci.). More recently, predictive processing theories of frontal function under the Bayesian brain hypothesis emphasize a key role of proactive control for anticipatory action selection (i.e., planning as active inference). Here, I review evidence of fast and widespread electroencephalographic (EEG) and magnetoencephalographic (MEG) fronto-temporo-parietal cortical activations elicited by feedback cues and target cards in the Wisconsin Card Sorting Test (WCST). This evidence is best interpreted when considering negative and positive feedback as predictive cues (i.e., sensory outcomes) for proactively updating beliefs about unknown perceptual categories. Such predictive cues inform posterior beliefs about high-level hidden categories governing subsequent response selection at target onset. Quite remarkably, these new views concur with early findings concerning two broad classes of P300-like cortical responses evoked by feedback cues and target cards in computerized WCST analogues. For instance, Stuss and Picton's (1978) interpretation of their P300 responses —in terms of the resolution of uncertainty about response (policy) selection, and the participant's expectancies for future perceptual or motor activities and their timing— were prescient of current predictive processing and active (Bayesian) inference theories. From these new premises, a domain-general frontoparietal cortical network is rapidly engaged during two temporarily distinct stages of inference and learning of perceptual categories that underwrite goal-directed card sorting behavior, and they each engage prefrontal executive functions in fundamentally distinct ways.

4. Decoding semantic and sensory predictions from EEG activity

Dr Louise Catheryne Barne1, Dr Elin Runnqvist, Dr F- Xavier Alario, Dr Andrea Desantis 1Onera

4. Prior expectations shape the way we perceive and interpret our environment. The preactivation account of prediction proposes that anticipating an upcoming sensory event leads to the preactivation of the neurons representing the expected stimulus. In line with this framework, this study aimed to decode from EEG activity the sensory modality (visual or auditory) and the semantic category (person or place) of a predicted word prior to its presentation, using multivariate pattern analysis. At the beginning of each trial, participants (N=29) chose the semantic category and the sensory modality of the to-be-presented word. 60% of the time their choice was entirely fulfilled. During the rest of the trials, the word could fully violate their expectations (e.g. they read a person’s name, while they expected a spoken place name), or it would violate either the modality or the semantic aspect only (e.g. they read a person’s name, while they expected a written place name). After the word presentation, participants reported as fast and as accurately as possible whether the person/place indicated by the word was French or not. Participants’ were faster in categorizing words whose modality was predicted compared to when this feature was unexpected. While semantic predictions did not boost response times, we observed a clear modulation of sensory and semantic expectations on the P300/N400 component and by increasing classification scores after the word presentation (sensory: p=0.028, testing time: 0.225 to 0.505; semantic: p=0.027, testing time: 0.505 to 0.765). These preliminary results clearly indicate that we successfully manipulated predictive processes. We did not find evidence for prestimulus category decoding, but further analyses are still in progress.

5. Open your eyes and listen – Complementary audiovisual information helps understanding speech in difficult hearing situations

Alexandra Begau1, Dr. Laura-Isabelle Klatt1, Dr. Edmund Wascher1, Dr. Daniel Schneider1, Dr. Stephan Getzmann1

1Leibniz Research Centre for Working Environment and Human Factors

5. Understanding someone talk amongst the babble of many others is challenging. Particularly with increasing age and thus declining sensory and cognitive functions, following speech and suppressing irrelevant information gets more difficult. Past research on “cocktail-party” situations has focused on unimodal presentation of speech, despite the evidence for the significance of perceiving visual speech in complex hearing environments. In the present EEG study, we explore the benefits of presenting audiovisual speech information in a dynamic “cocktail-party” paradigm in a younger and older age group (below 30 years and above 55 years old, respectively). We hypothesized congruent audiovisual information to be the most beneficial, especially for older participants. Furthermore, we investigate to which extent visual information is processed when perceiving speech. Videos of two talkers were displayed simultaneously in a horizontal array in three conditions, providing congruent audiovisual, valid visual and valid auditory information. In a forced-choice two-alternative discrimination task, participants responded to a target word that was displayed laterally within the participants’ instructed gaze direction. We analyzed behavioral performance and oscillatory power in the frontocentral theta and parietocentral alpha and beta bands. We found slower response times in the older group for unspecific visual compared to audiovisual information. An audiovisual benefit was found in accuracy measures with audiovisually congruent stimuli yielding the highest accuracy. In oscillatory activity, we observed a general frontal theta increase and parietocentral beta/alpha decrease after sound onset. Comparing visually unspecific and audiovisually congruent trials, we found higher theta power following visually unspecific information, irrespective of age group. Older adults generally show stronger suppression in alpha and beta power. Comparing auditory unspecific and audiovisually congruent information, we found stronger suppression in the alpha and beta band in auditory unspecific stimuli, with no interaction between both factors. Taken together, the results support theta power increase to reflect hightened need for control. We further discuss the role of alpha and beta in cognitive control and attentional allocation and age-related decline in these functions.

6. Auditory emotional distraction—between costs of orienting of attention and benefits of arousal

Carolina Bonmassar1, Florian Scharf2, Andreas Widmann1,3, Nicole Wetzel1,4,5

1Leibniz Institute for Neurobiology, 2University of Kassel, 3Leipzig University, 4Center for Behavioral Brain Sciences Magdeburg, 5University of Applied Sciences Magdeburg-Stendal

6. Distraction of attention by unexpected and task-irrelevant sounds has been discussed to comprise costs of orienting of attention toward a distracting event and benefits of arousal enhancement evoked by the processing of such events. Highly arousing distractor sounds may prioritize information processing and reduce distraction effects. In an audio-visual oddball paradigm, we examined the relationship between behavioral distraction effects—prolonged reaction times in a visual categorization task—and pupil dilation as an indicator of arousal in response to emotional and neutral unexpected and task-irrelevant novel sounds. Multilevel analyses revealed behavioral distraction and enhanced pupil dilation responses (PDR) following novel sounds in comparison to standard sounds at the group level. Importantly, we observed decreased behavioral distraction, i.e. behavioral facilitation, but enhanced PDR responses following emotional in comparison to neutral novel sounds. At the trial level the data provided evidence for a positive correlation between reaction times and PDR amplitudes in general but evidence against a negative correlation for reaction times and PDR for emotional sounds. Trials with larger PDRs (i.e., more arousal) were not related to a proportional speed up of reaction times at the trial level. Thus, we suggest that effects of the behavioral emotion-related facilitation and the increase in arousal reflected by pupil dilation are at least partly independent mechanisms. Moreover, an exploratory analysis revealed an impact of the tonic level of arousal as indicated by the baseline pupil diameter on performance and distraction effects. In addition, a positive correlation between performance and aspects of temperament were observed.

152. Conflict resolution and response inhibition: A combined Flanker and Stop Signal task

Carsten Bundt1,2, Liisa Raud2,3, René Huster1,2,4

1Multimodal Imaging and Cognitive Control Lab, Department of Psychology, University of Oslo, 2Cognitive and Translational Neuroscience Cluster, Department of Psychology, University of Oslo, 3Lifespan Changes in Brain and Cognition, Department of Psychology, University of Oslo, 4Sleep Unit, Department of Otorhinolaryngology/Head and Neck surgery, Lovisenberg Diaconal Hospital

152. Inhibition of goal-irrelevant stimuli and factors represents one of the main mechanisms by which flexible behavioral adaptation can be implemented. Inhibition as such, however, can take different forms. Response inhibition, for instance, is typically defined as the suppression or cancellation of pre-potent responses and can be referred to as “active inhibition” as it is supposedly realized via excitatory pyramidal cells. In contrast, the suppression of competing and simultaneously active response representations via diffuse local inhibitory interneuron assemblies such as in the flanker task can be referred to as “competitive inhibition”. Traditionally, the investigation of these two kinds of inhibition has been performed in isolation. To directly compare the effects of competitive and active inhibition on behavior, we implemented a paradigm in which the incongruent/congruent conditions of the flanker task were occasionally followed by a stop signal, signaling the cancellation of any response. This design resulted in two task conditions with two levels, respectively, consisting of congruency (congruent, incongruent) and action (Go, Stop). Here, the incongruent stop condition was of particular interest as it elicits both kinds of inhibition and it is currently unknown whether these facilitate or interfere with each other. Results revealed a standard competitive inhibition effect with Go reaction times being significantly faster after congruent compared to incongruent flankers and Go accuracy being significantly higher after congruent compared to incongruent flankers. In addition, stop signal task behavior was also as expected. Most interestingly, results indicated fewer unsuccessful stops and faster stop signal reaction times after incongruent compared to congruent flankers. Collectively, given that stopping performance was overall improved after incongruent compared to congruent flankers, our results remarkably suggest that the implementation of conflict resolution mechanisms (i.e., competitive inhibition) may facilitate response (i.e., active) inhibition.

7. Attention and expectation interacting modulations in the auditory cocktail party

Thaiz Sánchez-Costa1, Alejandra Carboni1, Dr. Francisco Cervantes Constantino1,2

1Facultad de Psicología, Universidad de la República, 2Instituto de Investigaciones Biológicas "Clemente Estable"

7. How attention and expectation interact at the neural level remains under debate, with mixed results from the visual literature so far. The interaction relates to whether the effects on neural coding of attention and expectation oppose, or else whether they contribute synergistically. The auditory cocktail party (CP) represents a significant problem where to test this interaction, since continuous speech objects evolve dynamically. To probe the interaction, we used temporally resolved measurements (EEG) of attention allocation during natural multispeaker listening. Participants (N=35) performed a speech comprehension task that was based on a simple priming design. Speakers’ stimulus signals and corresponding auditory EEG timeseries were analyzed by the temporal response function (TRF) method. This served to study the dynamics of speech encoding under attentional and expectation conditions. We found that expected auditory input about a primed target speaker abolished late (250-300 ms) but not mid-latency (130-160 ms) attentional modulations neurally, as shown by changes to the TRF. At the mid-latency range, moderate expectation suppressions limited listeners’ behavioral improvement in the attentional task. The findings lend support to the opposition hypothesis between attention and expectation. The effect of priming a masker speaker was further investigated, since according to the opposition hypothesis, attention and expectation may interact synergistically towards reducing the masker’s contribution to neural encoding (i.e. increasing attentional effects neurally). Results were again consistent with this hypothesis, as in this case, mid-latency attentional modulations were now boosted by expectation. In naturalistic scenarios, foreground or background stimuli detail may be differentially expected. The findings suggest that in a selective attention problem, background-related analyses exploit expectations in an automatic fashion at early cortical stages.

8. Concealed information detection with pupillometry in rapid serial visual presentation

Yining Chen1, Philipp Buchel1, Dr. Aytaç Karabay1, Dr. Sebastiaan Mathȏt1, Prof Howard Bowman2,3, Prof Elkan Akyürek1

1University of Groningen, 2University of Birmingham, 3University of Kent

8. The concealed information test (CIT) relies on bodily reactions to stimuli that are hidden in mind. However, people can use countermeasures, such as purposely focusing on irrelevant things, to confound the CIT. A method designed to prevent the use of countermeasures, based on rapid serial visual presentation (RSVP), presents each stimulus on the fringe of awareness. Previous studies showed that this RSVP in combination with electroencephalography (EEG) is valid at detecting information with various levels of salience, even when participants try to prevent such a reaction. Since EEG measures are not easily applicable outside the laboratory, we investigated here whether pupil size, which is easier to measure, is also a valid measure with this RSVP-based CIT. In our first study, 31 participants were asked to adopt a fake name, and search for this name in an RSVP task, while their pupil sizes were recorded. Apart from this fake name, their real name and a control name also appeared in the task. We found that the pupil dilated more in response to the task-irrelevant real name, as compared to control names. However, while most participants showed this effect qualitatively, it was only statistically significant for 6 participants when analysed individually. As a second study, we preregistered the proof-of-concept methodology and replicated the findings of the first one. In our third study, 31 participants were asked to search for a target face in an RSVP task while one of their parents’ faces and a control face also appeared in the task. We found that the pupil dilated more in response to their parents’ face, as compared to control faces. We also found that 7 participants showed this effect when analysed individually. Taken together, our results show that the current RSVP task with pupillometry can detect concealed information of identity and parents’ faces at a group level. Further development of the method may produce a valid and reliable concealed information detector at the individual level. Keywords: Concealed information detection; RSVP; pupillometry

10. Relationship between action games and cognitive control: mediating effect of working memory capacity and the moderating effect of problematic gaming.

Dr Andrzej Cudo1

1The John Paul II Catholic University of Lublin

10. Objectives. Action computer games are becoming increasingly popular. Previous studies indicated that this game genre could improve and train cognitive functions. On the other hand, the results of other studies demonstrated no relationship between gaming on action games and cognitive functioning or that gaming had negative consequences for gamers' cognitive functioning. In this context, problematic video gaming (PVG) is one of the factors that may explain the inconclusive results of previous studies. Considering the previous studies, PVG may negatively affect cognitive functioning, particularly in cognitive control. Research question. Consequently, the current study aimed to verify the relationship between problematic video gaming, action computer games and cognitive functions such as working memory capacity and cognitive control. Materials and methods. The study was carried out on a sample of 588 active video game players (304 female gamers) aged between 18 to 38 years (Mage = 22.12 years; SD = 2.94 years). The participants completed the IGDS9-SF and characteristic gaming questionnaire (CGQ). Additionally, they participated in the study's experimental phase, which consisted of Operation Span Task, Symmetry Span Task and AX-CPT Task. The Operation Span Task and Symmetry Span Task assessed working memory capacity. The AX-CPT task was used to assess cognitive control. Results. The results showed that the relationship between gaming frequency on action games and cognitive control was fully mediated by working memory capacity. Additionally, the PVG moderated the relationship between gaming frequency in action games and cognitive control. More precisely, for a low level of PVG, there was a positive relationship between the frequency of action game gaming and cognitive control. In contrast, there was no such relationship for a high level of problematic video gaming. Conclusions. The results may support the hypothesis of a positive relationship between gaming on action games and cognitive functioning, particularly working memory capacity. However, based on the results obtained, it may be speculated that PVG may suppress the positive effects of playing action games on cognitive functioning. This study was supported by a grant (UMO-2019/32/C/HS6/00340) from the National Science Center, Poland.

12. Mechanisms of far transfer from cognitive training: Should we train the ability to ignore distractions?

Annie Desmarais1, Alessandro Pozzi1, Lysandre Provost1, Hugo Fitzback-Fortin1, François Vachon1

1Université Laval

12. Cognitive training—the repeated practice of mental activities aiming to maintain or enhance one’s cognitive abilities—represents an interesting opportunity to improve quality of life for people of every age. The problem is that transfer from improvement of trained abilities to untrained abilities has not been demonstrated yet (i.e. far transfer effect). The mechanisms underlying effectiveness of far transfer are not well known. Greenwood and Parasuraman (2016) proposed that training the ability to ignore distractors is important in order to promote far transfer. The present study sought to test the effectiveness of a training program of attentional control based on the mechanisms of distractors suppression of the load theory (Lavie et al., 2014). Sixty healthy adults from 18 to 40 years old were randomly assigned to one of three adaptive training programs: i) competition response (CR) training, ii) N-back training, or iii) perceptual (control) training. Each training involved performing eight sessions of approximately 30 minutes over 4 to 8 weeks. An assessment of working-memory and attention-control tasks were performed on each group before and after training to assess learning and far transfer. Compared to control training, N-back and CR trainings demonstrated improvement at posttest in the trained task, but CR training was the only program to show improvement at posttest in far transfer (working-memory) tasks. The present findings provide support Greenwood and Parasuraman’s hypothesis and suggest that training mechanisms of distractors suppression is crucial in producing far transfer effects.

11. Semantic relatedness differentially mediates overt attention when searching for pictures versus words: An online webcam-based eye tracking study

Dr Giorgia D'Innocenzo1, Ms Elina Shoshina2, Dr Ana Raposo1, Dr Moreno I. Coco3

1Centro de Investigação em Ciência Psicológica (CICPSI), Faculdade de Psicologia, Universidade De Lisboa, 2Faculdade de Psicologia, Universidade de Lisboa, 3Department of Psychology, Sapienza University of Rome

11. Background: Research on the cognitive mechanisms supporting visual search shows that high-level processing of objects semantics contributes to the guidance of early overt attention: targets that are semantically unrelated to the distractors (e.g., a car in an array of animals) are fixated earlier than semantically related targets (e.g., an animal in an array of animals). Theoretical approaches such as Dual Coding Theory, however, posit that pictures hold a preferential cognitive status over words. Thus, it remains unclear whether early attention guided by extra-foveal processing of semantic information depends on stimulus modality (pictorial vs linguistic). Objectives and Research Question: The present study aimed to establish whether the modality of the stimuli used as the cue and the array context (i.e., object pictures vs printed words) influences access to semantic information, differentially mediating the early allocation of visual attention. Additionally, we intended to determine the robustness of our previous finding of early capture of visual attention by extrafoveal semantic processing by using low-resolution webcam-based eye tracking. Materials and Methods: In an online eye-tracking study, participants were asked to search for a target object, presented either as a picture or a word cue, in an array of distractor images or words. Results: When the cue was presented as a word and the array was made of object pictures, we replicated our previous work, i.e., the latency of the first fixation was faster when the target was unrelated to the distractors than when it was related. However, this effect was reversed when the cue and the array were both words. Across all conditions, semantically unrelated targets received more fixations than targets that were related to the distractors. Conclusion: Our results confirm that object semantics is accessed in extra-foveal vision and used to guide early overt attention, but this effect depends on the representational format of the target and its context (i.e., linguistic vs pictorial). Our findings also support the methodological use of webcam-based eye tracking for studying gaze behaviour, critically implying that wider segments of the population could be reached and costs associated with lab-based experimentation substantially reduced.

13. Efficient compression of sensory information during categorical decisions

Julie Drevet1,2, Dr Qiao Zheng3, Dr Jan Drugowitsch3, Dr. Valentin Wyart1,2

1Laboratoire de Neurosciences Cognitives et Computationnelles, Institut National de la Santé et de la Recherche Médicale (Inserm U960), 2Département d’Études Cognitives, École Normale Supérieure, Université PSL, 3Department of Neurobiology, Harvard Medical School

13. Perceptual decisions rely on a cognitive inference process that extracts the statistics of ambiguous sensory observations through imprecise computations. But theories diverge regarding whether this inference process integrates information in its native sensory space or in a compressed category space defined by current decision alternatives. Here we designed a visual categorization task in which we manipulated the ability of human observers to perform inference in sensory and category spaces. We found that human observers spontaneously integrate sensory information in category space by projecting it on the decision axis, upstream from inference. When observers are forced to integrate sensory information in its native space, they do so with lower precision and larger information loss. Magnetoencephalographic (MEG) brain activity showed compressed neural representations of stimulus and decision signals in conditions where observers perform inference in category space. Together, these findings indicate that humans mitigate the costs of imprecise inference by focusing limited resources on decision-relevant information.

14. Reducing mind wandering using cTBS over the left angular gyrus

Ragnhild Nicolaisen Drevland1, Steffen Aasen1, Dr Gabor Csifcsak1, Prof Matthias Mittner1

1Uit - The Arctic University of Norway

14. Mind wandering (MW) describes the shifting of attention from the external task to internal thoughts. Previous research identified the default-mode network (DMN) as an important system involved in self-generated thought. In the current study, we use inhibitory continuous theta burst stimulation (cTBS) to stimulate the left angular gyrus (AG) which is a region of the DMN that is accessible to transcranial magnetic stimulation. In a double-blind, within-subject cross-over design study participants will undergo repeated application of both active and sham cTBS over the left AG interleaved with a behavioral task (FTRSGT), while also capturing self-reported MW with thought-probes. The FTRSGT captures the person's behavioral variability (BV) and recruitment of executive control, which is an objective marker for MW. In an accelerated design, participants will complete four blocks of the task with interleaved cTBS. Data collection is currently ongoing, and the study is pre-registered at: https://osf.io/4axhs. Our main hypothesis concerns the effectiveness of cTBS to reduce MW and we expect that cTBS over the left AG will reduce self-reported MW compared to sham stimulation. We will perform a 2 (stimulation: sham vs. active) x 4 (block) repeated measures ANOVA with self-reported MW as dependent variable which we will follow-up with planned contrasts. We calculated the power for the interaction effect of the ANOVA and found that, given our pre-registered sample size of 40, the minimum effect-size we can detect with power of 80% and α=0.05 is ƞ2=.044. In addition, we hypothesize that active stimulation will have an accumulative effect across the four task blocks in reducing MW propensity, which will be captured using self-reported thought-probes and the behavioral responses on the FTRSGT. We also expect that when participants report mind wandering, their BV will be increased but their AE will be decreased.

15. Feature selection in Guided Search is associated with modulated neuronal excitability to target and distractor features in early visual regions

Katharina Duecker1, Prof Kimron Shapiro1, Prof Simon Hanslmayr2, Dr Yali Pan1, Prof Jeremy Wolfe3, Prof Ole Jensen1

1Centre For Human Brain Health, School of Psychology, University Of Birmingham, 2Centre for Cognitive Neuroimaging, School of Neuroscience and Psychology, University of Glasgow, 3Harvard Medical School

15. In visual search for a known target in a display (or a world) containing distractor items, attention is guided toward items having target features and away from items having distractor features. We used Rapid Invisible Frequency Tagging (RIFT) to understand the neuronal mechanisms underlying feature guidance in an MEG study. By applying frequency tagging at high frequencies (>50 Hz) we can probe neuronal excitability in early visual regions, as a measure of attentional selection, while minimizing the visibility of the flicker. We hypothesized the RFT responses to target features would be enhanced and responses to distractor features would be reduced when the roles of the respective features were known to participants. Participants (N=32) were instructed to indicate the presence or absence of a blue or yellow target “T” presented among blue and yellow “L” distractors. The colours were tagged at 60 and 67 Hz, respectively, making the flicker unperceivable. In the guided search condition, participants were informed about the target colour. In the unguided search condition, the colour of the T was randomized and not known to the participant. RFT responses were quantified by coherence between the MEG sensors-of-interest and the tagging signal. The RFT response to the Target-colour was significantly stronger than the response to the Distractor-colour, in the guided but not the unguided search condition (guided: T(29) = 3.4, p = 0.002; unguided: T(29)=-2.4, p = 0.024). Moreover, we find the response to the guided Target-colour to be significantly enhanced compared to the unguided Target-colour (T(29)=3.4, p = 0.002) while the response to the guided Distractor-colour was reduced compared to the unguided Distractor-colour (T(29)=-2.39, p = 0.024, n.s.). These results provide evidence that attentional selection is implemented by both a boosting of neuronal responses to target features in early visual regions as well as a decrease in the excitability associated with distractor features. While enhanced frequency tagging responses to attended compared to unattended features have been shown in the literature, the present results link this effect directly to feature guidance in visual search.

16. Modified EEG spectral content during attention task in non-demented healthy adults with genetic risk of Alzheimer's disease

Patrycja Dzianok1, Ewa Kublik1

1Nencki Institute of Experimental Biology PAS

16. Alzheimer’s disease (AD) slowly but inevitably impairs memory and other cognitive functions, although the exact etiology nor the course of the disease is not yet known. Understanding how genetic factors affect brain function in still healthy individuals could help to develop functional AD biomarkers and accelerate early diagnosis. Seventy-seven healthy middle-aged adults completed an EEG session during the Multi-Source Interference Task based on two main conditions: OO – low attentional-load, and FS – high attentional-load. AD risk genes, the APOE (rs429358/rs7412) and PICALM (rs3851179/rs541458) alleles were determined using a traditional Sanger sequencing protocol. Three groups, with different AD risk allocation were compared. Signal was filtered for delta (1-3 Hz), theta (4-7 Hz), alpha (8-12 Hz), and low beta (13-20 Hz) bands. Hilbert time-frequency analysis was performed for each band. The Hilbert envelopes were analyzed within three time windows (early, middle and late) of each single-trial. We found that beta band amplitude in parietal-central areas was higher for the single APOE-ε4 risk group as compared to the double risk group (APOE-ε4 and higher PICALM risk; p<.05). There was a visible (moderate to high) positive correlation between the reaction times and beta amplitude in control and double risk groups. However, it was not observed in the single APOE-ε4 risk group. Effect was more widespread for OO condition in all time windows; while for FS trials it was mostly visible in the early window for the double-risk group. The reaction time analysis showed no difference between groups in OO condition and a significantly longer reaction time for a single APOE-ε4 risk group in FS condition. EEG studies with AD patients reports a decrease of the beta band power during the resting-state protocol. Here, we show that middle-aged single-risk carriers are characterized by an overall stronger task-related beta band. Surprisingly, double-risk participants are more similar to the control group than to the single APOE-ε4 risk group. Future genotype-EEG phenotype studies for the early biomarkers of a possible cognitive decline are needed to fully discover the impact of a risk-gene interplay on cognitive abilities. [Supported by Polish National Science Centre grants no. 2018/31/N/HS6/03551 and 2016/20/W/NZ4/00354]

17. Neuronal oscillations in the preparative processes in Wisconsin card sorting test

Jasmin Elonen1, Hamed Haque1,2, Jaana Simola1,3, Matias Palva1,4,5, Satu Palva1,5

1Neuroscience center, Helsinki institute of life sciences, University of Helsinki, 2BioMag Laboratory, HUS Medical Imaging Centre, Helsinki University Central Hospital, 3Faculty of Educational Sciences, University of Helsinki, 4Department of Neuroscience and Biomedical Engineering, Aalto University, 5Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow

17. Shifting attention and rule selection allows humans to flexibly orient to rapidly changing situations. Set-shifting has previously been studied during the task execution but in this study the focus is on the preparative processes where planning and decisions for set-shifting take place. The local and network level neuronal oscillations related to preparative processes in set-shifting are not well known. The objectives of this study are to investigate the local oscillation amplitude dynamics and oscillation phase synchronization for preparative processes of set-shifting. We will also investigate if there is a difference in oscillations and behavioral measures between groups of faster and slower learners. Magnetoencephalography (MEG) was recorded from 26 healthy participants during the Wisconsin card sorting test (WCST). The analysis time window spanned from offset of response until the next stimulus onset. The participants were divided into two groups based on how well they adjusted to new rules i.e., how many late series errors they made in a five trial rule-series. The oscillation amplitude dynamics and phase-synchronization were then analyzed for the anticipating period for all participants and separately for fast and slow learner groups. Fast adaptation to new rule sets was seen as fewer number of late trial errors, a greater number of correct responses and faster reaction times than slow rule-adaptation. All participants were characterized by sustained increased theta amplitudes. The fast learner group also showed sustained increased theta phase synchronization throughout the analysis time window whereas the slow learner group only showed a transient theta phase synchronization. This study shows that theta-band phase synchronization dynamics are associated with preparative set-shifting in WCST.

18. Target facilitation in the absence of distractor suppression in visual search

Dr Norman Forschack1, Dr Christopher Gundlach1, Prof Dr Steven Hillyard2, Prof Dr Matthias Müller1

1Wilhelm-Wundt-Institut Für Psychologie, 2University of California

18. There is much debate about the neural mechanisms that achieve suppression of salient distracting stimuli during visual search. The proactive suppression hypothesis asserts that salient distractors are actively inhibited before attention can be shifted. A contrasting proposal holds that salient stimuli capture attention initially, and irrelevant stimuli are excluded later. By concurrently measuring stimulus-driven and intrinsic brain potentials in 36 healthy human participants, we provide converging evidence against early proactive suppression of highly salient distractors. Furthermore, these electrophysiological measures indicate that both stimulus-driven and goal-driven allocations of attention occur in conjunction with one another, with the goal-driven effect enhancing and prolonging the stimulus-driven effect. These results provide a new perspective on the traditional dichotomy between bottom-up and top-down attentional allocation.

19. A systematic review and meta-analysis of behavioural sex differences in executive control

Ms Alexandra Gaillard1, Mr Daniel Fehring2,3, Professor Susan Rossell1,4

1Centre for Mental Health, Faculty of Health, Arts and Design, Swinburne University Of Technology, 2Cognitive Neuroscience Laboratory, Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, 3ARC Centre of Excellence in Integrative Brain Function, Monash University, 4Psychiatry, St Vincent’s Hospital

19. As the current literature on sex differences is contradictory and inconclusive, this systematic review and meta-analysis sought to identify the magnitude of sex differences in a normative population in the three prominent executive control domains: performance monitoring, response inhibition, and cognitive set-shifting. In addition, we aimed to determine if behavioural sex differences are task-specific within each executive control domain. The databases PubMed, Scopus, and Web of Science were searched to obtain relevant empirical articles. Studies were included if participants were ≥18 years old, an executive control task measuring performance monitoring, response inhibition, or cognitive set-shifting was performed, and the sample included males and females within a 40% to 60% split. A random effects model was used to estimate the effect size for males and females in each executive control domain and in 16 individual executive control tasks. A total of 51 eligible studies, producing 68 independent effect sizes, with a total sample size of 2347 females and 2198 males were identified. Overall, males scored slightly higher in the domains of cognitive set-shifting (g = -0.27, p = 0.004) and performance monitoring (g = -0.17, p = 0.01) compared to females. Moderate task-specific sex differences were also observed in the domains of performance monitoring and cognitive set-shifting on the mental rotation test (g = -0.57, p < 0.001) and the CANTAB spatial working memory task (g = -0.60, p = 0.001). The remaining performance monitoring and cognitive set-shifting tasks yielded non-significant sex differences. There was no difference in performance between males and females in the domain of response inhibition, although moderate task-specific sex differences were observed on the delay discounting task showing a female advantage (g = 0.64, p = 0.002). The remaining response inhibition tasks yielded non-significant sex differences. This meta-analysis supports the notion of sex differences in executive control abilities. Our results suggest that sex differences are most evident in the domains of performance monitoring and cognitive set-shifting; however, these findings are task-specific and predominantly driven by a male advantage in spatial working memory tasks. Furthermore, within the domain of response inhibition, sex differences are also task-specific.

20. Time-Dependent Effects of Stress on Working Memory Related Prefrontal Processing

Dr Christoph Geißler1, Prof Dr Christian Frings1

1Trier University

20. It is generally assumed that acute stress influences working memory related processing. However, researchers so far have reported a diverse spectrum of stress effects or the lack thereof on both working memory performance and related prefrontal processing. On a hormonal level, the central stress response is mainly mediated by two systems. The locus coeruleus noradrenergic system, steering the central stress related noradrenaline release and the hypothalamic pituitary adrenal axis, steering the peripheral stress related release of cortisol, which crosses the blood brain barrier and thus as well can influence central processing. Both high levels of noradrenaline and cortisol have previously been associated with a reduction in firing of prefrontal pyramid cells and in turn a decline in working memory capacity. Central noradrenaline levels peak right after acute stress and decline rapidly to pre stress levels within 15 to 20 minutes after stressor offset. Central cortisol levels rise comparatively slower, reaching their peak about 35 minutes after acute stress and decline to normal about 95 minutes after acute stress. We set out to provide clearer insight into the mediating role of central noradrenaline and cortisol levels in the relationship between acute stress, working memory performance and processing. For this purpose, we employed a spatial working memory paradigm right before, 5 minutes after and 25 minutes after a physio-social stressor (socially evaluated cold pressor test) or a (warm water) control condition. During these instances, we measured working memory performance and working memory related prefrontal processing with functional near infrared spectroscopy. We expected a decline in working memory performance and related prefrontal processing in the stress group in comparison to the control group during both post stress measurement points. We further expected the first relative decline to be related to increased central noradrenaline levels and the second relative decline to be related to increased central cortisol levels.

21. Are age-related cognitive inhibition deficits domain-general?

Coline Grégoire1, Prof. Steve Majerus1,2

1Psychology and Neuroscience of Cognition RU, University of Liège, 2National Fund for Scientific Research

21. The unitary versus non-unitary nature of inhibition abilities and of age-related inhibitory deficits remains a strongly debated question? This study re-examined the nature of inhibition impairment in healthy aging by studying inhibition abilities across three domains (visual, semantic, phonological) by using tasks carefully matched regarding their structure and processing requirements. 130 young adults (20-40 years old) and 130 older adults (60-80 years old) performed two types of inhibition tasks. The first task was an immediate probe recognition (IR) task involving visually, phonologically or semantically related negative probe items that needed to be inhibited or neutral probe items, after the presentation of a four-item memory list (visual abstract shapes, nonwords or words). The second task involved a similarity judgment (SJ), participants needing to select one of two test items that matched best two target items; in half of trials, the wrong test item was cued via the presentation of a prime item and hence needed to be inhibited. The stimuli were abstract visual shapes, words or nonwords. For each task, we computed interference scores (inhibition vs. neutral conditions) separately for the visual, phonological and semantic versions Using Bayesian statistics, we observed that the inhibition effects were overall larger for older adults than for younger adults for SJ (BFincl = +∞ ) and an interaction between age group and domain (BFincl = 28,31), with particularly high interference scores in the elderly group for both semantic and visual conditions. Furthermore, a modality effect was found in SJ and IR where the phonological (nonwords) condition seemed less impacted by interference. These results suggest domain-general inhibitory difficulties in healthy aging, at least for the semantic and visual domains. Differences in task sensitivity were likely to explain the lesser inhibition impairment in the phonological domain and between SJ and IR.

22. Disentangling the roles of reward and object-status in visual attention

Mr Damiano Grignolio1, Dr David Acunzo1, Mrs Jaclyn Dell1, Dr Clayton Hickey1

1University of Birmingham

22. Human observers are able to use selective attention to prioritize visual features, like color or shape, as well as discrete spatial locations. Less well known is an additional effect of selective attention on object representations. Attention appears to ‘spread’ across visual objects, such that selection of one constituent part leads to prioritization of the whole object. While spatial and featural attention are known to be sensitive to prior reward experience, such that reward-associated features and locations become prioritized from early in the visual hierarchy, the relationship between reward and object-based attention has been the subject of less investigation. Here we show in 3 experiments that the effect of reward on object-based attention is mediated through its impact on visual features. In contrast to existing results, we find in Experiment 1 that the prioritization of reward-associated objects does not diminish the effect of object-based attention. In Experiment 2, we associate reward to specific colors to find that reward-associated colors are prioritized, but that this effect is additive with the influence of object status. Experiment 3 extends this finding by investigating the effect of prior reward during extinction, when reward is no longer available. The effect of reward on color sustains through extinction of the reward association and interacts with object-based attention. The emerging picture is that reward has an impact on object-based attentional prioritization when reward is bound to perceptual features that define objects.

153. Stimulus-induced changes in 1/f-like background activity in EEG

Dr Mate Gyurkovics1, Ms Grace Clements2, Dr Kathy Low2, Prof Monica Fabiani2, Prof Gabriele Gratton2

1University of Glasgow, 2University of Illinois at Urbana-Champaign

153. Research into the nature of 1/f-like, non-oscillatory electrophysiological activity has been growing exponentially in recent years in cognitive neuroscience. The shape of this activity has been linked to the balance between excitatory and inhibitory neural circuits, which is thought to be important for information processing. However, to date, it is not known whether the presentation of a stimulus induces changes in the parameters of 1/f activity that are separable from the emergence of event-related potentials (ERPs). Here, we present a novel method for analyzing event-related broadband changes and separating them from ERPs. Using data from a passive (n=46) and an active (n=23) auditory task, we found that the shape of the pre- and post-event spectra differed significantly after removing the frequency-content of ERPs, and that the post-event spectrum, outside of the alpha range, could be highly accurately modelled as the sum of the pre-event and ERP spectra plus a change in 1/f activity. This 1/f change manifests as an increase in low and a decrease in high frequencies. This rotational shift was largest at frontocentral regions, and its magnitude was related to the attentional demands of the task. The 1/f change is consistent with increased inhibition following the onset of a stimulus, and likely reflects a disruption of ongoing excitatory activity proportional to processing demands. Finally, these findings contradict the central assumption of baseline normalization strategies in time-frequency analyses, that background EEG activity is stationary across time. As such, they have far-reaching consequences that cut across several subfields of neuroscience.

23. Congruency triggers Response Facilitation: Dissociable EEG Correlates of Sequential Conflict Adaption

Céline Haciahmet1, Prof. Dr. Christian Frings1, PD Dr. Bernhard Pastötter1

1University of Trier

23. Cognitive control involves response conflict resolution as well as response facilitation processing, with the latter being rarely discussed in classic conflict monitoring accounts (e.g., Botvinick, Cohen, & Carter, 2004). While increased shielding after incongruent trials is a robust finding interpreted as up-regulation of cognitive control in the dorsal ACC and dorsolateral PFC, the neurophysiological correlate of increased cognitive relaxation after congruent trials is still unclear. In this poster, we will present a conceptual replication of Berger, Fischer, and Dreisbach´s (2019) Simon task setting in time-frequency EEG data, showing robust response facilitation as well as response conflict effects in the current trial dependent on the (in)congruency of the previous trial in reaction times, error rates and theta power increase (4-8 Hz). In addition to conflict-related theta power increase, we investigated whether the influence of (in)congruency on control adaptation is due to attentional (alpha power: 10-14 Hz) or motor adjustments (beta power: 15-25 Hz) in the intertrial phase (Pastötter, Dreisbach, & Bäuml, 2013). Taken together, our results pinpoint the need to merge classic top-down conflict resolution and bottom-up feature integration frameworks (Egner, 2014, 2017) to take conflict resolution and facilitation strategies into a more general account including contextual binding of stimulus features to fluent control states.

24. Attention to Speech: Mapping Distributed and Selective Attention Systems

Paz Har-shai Yahav1, Dr Galit Agmon1, Prof Michal Ben-Shachar1, Prof Elana Zion-Golumbic1

1Bar-Ilan University

24. When faced with situations where many people talk at once, individuals can employ different listening strategies to deal with the cacophony of speech sounds and to achieve different goals. In this fMRI study, we investigated how the pattern of neural activity is affected by the type of attention applied to speech in a simulated “cocktail party.” Specifically, we compared brain activation patterns when listeners “attended selectively” to only one speaker and ignored all others, versus when they “distributed their attention” and followed several concurrent speakers. Conjunction analysis revealed a highly overlapping network of regions activated for both types of attention, including auditory association cortex (bilateral STG/STS) and frontoparietal regions related to speech processing and attention (bilateral IFG/insula, right MFG, left IPS). Activity within nodes of this network, though, was modulated by the type of attention required as well as the number of competing speakers. Auditory and speech-processing regions exhibited higher activity during distributed attention, whereas frontoparietal regions were activated more strongly during selective attention. These results suggest a common “attention to speech” network, which provides the computational infrastructure to deal effectively with multi-speaker input, but with sufficient flexibility to implement different prioritization strategies and to adapt to different listener goals.

25. Sex hormones modulate sex differences and relate to hemispheric asymmetries in a divided visual field Navon task

Tobias Hausinger1,2, Prof. DDr. Belinda Pletzer1,2

1Department of Psychology, University of Salzburg, 2Centre for Cognitive Neuroscience, University of Salzburg

25. Sex differences in functional hemispheric asymmetries (FHA) have been hypothesized as a fundamental mechanism behind sex differences in global-local processing. So far, it has not been assessed how interactive effects of sex and hemifield presentation influence common indicators of global precedence. The current study is the first to investigate the involvement of FHAs by using a divided visual field Navon paradigm and controlling for sex hormone status. Moreover, various factors that have previously shown a reliable influence on global-local processing performance are verified within the context of unilateral presentation. 39 men and 39 naturally cycling women in their luteal cycle phase completed a divided visual field Navon task with the instruction to detect targets either at any level (divided attention) or only at the global or local level (selective attention) in three different spacing conditions. The obtained evidence reveals significant sex differences in the global advantage effect (faster reaction to global vs. local level targets) for densely spaced letter stimuli, as well as significant sex differences in global-local level interference, with findings on both measures being mediated by testosterone. Also, estradiol showed different relationships to the global advantage effect in men and women together with a positive relationship to global advantage for the selective attention condition. Behavioural reaction time results were mirrored by accuracy measures but presented significantly higher global- over local-level accuracy in women compared to men for the divided attention condition. Our results did not show significant sex differences in FHAs but indicate differential relationships between progesterone and FHAs in men and women. In conclusion, sex hormones emerged as central mediators of sex differences in global precedence and possible moderators of hemispheric asymmetries.

26. Strategic control over incentive salience in naturalistic human vision

Clayton Hickey1, Jaclyn Dell1, David Acunzo1

1University Of Birmingham

26. The association of reward to basic visual features like color or orientation causes objects with these features to become salient and attention-drawing. Much less is known about how reward impacts vision under more naturalistic circumstances, as when targets are defined by their membership in a category – like fruit, trees, birds – but individual category examples do not necessarily share low-level features. A small number of fMRI studies have shown that, under such circumstances, the representation of task-irrelevant examples of reward-associated categories are attentionally suppressed, suggesting that these objects would otherwise intrude on cognition at the expense of target processing. But the temporal imprecision of MRI leaves it unclear if this suppression emerges as a reaction to salience and attentional capture or if it instead reflects strategic control established over a longer time scale. Here, we use EEG to track the impact of financial reward on selective processing of examples of real-world visual categories – cars, trees, and people – that are presented in photographs of city- and landscapes. Event-related potentials, oscillatory analysis, and multivariate decoding of EEG reveal that strategic control over incentive salience emerges rapidly in this kind of naturalistic search. Reward-associated, task-irrelevant visual stimuli are poorly represented in the visual system, with neutral distractors intruding on visual cognition more than reward-associated distractors. In naturalistic tasks, we thus appear able to rapidly counteract the impact of incentive salience so that attention can be deployed strategically and adaptively.

27. Temporal EEG dynamics of foraging decisions in humans

Franziska Kirsch1, Hans Kirschner1, Adrian G. Fischer1,2,3, Tilmann A. Klein1,2,4, Markus Ullsperger1,2

1Otto-von-Guericke University Magdeburg, 2Center for Behavioral Brain Sciences, 3Freie Universität Berlin, 4Max Planck Institute for Human Cognitive and Brain Sciences

27. Objectives: In dynamic environments, humans need to sequentially choose between exploitation and exploration to maximize reward. According to the marginal value theorem (MVT), current reward rates need to be continuously compared to potential future rewards to forage optimally. Research question: The aim of the present study is to show that different environments modulate foraging behavior according to MVT and that this effect is reflected in electrophysiological neuronal activity. Materials and methods: We created a Gold-treasure-task in which participants are instructed to gain as much gold as possible within a given time while EEG was recorded. Participants first decide between two harvesting options varying in objective value. As the instantaneous reward rate (iRR) declines while harvesting, participants need to decide when to leave the chosen option to obtain greater rewards elsewhere. The foraging environment varied between blocks and could be more or less advantageous. We used robust regressions to examine factors influencing iRR at leave time. In a time-frequency regression approach, we investigated temporal EEG dynamics prior to the decision to leave. Results: Consistent with MVT, in advantageous harvest environments participants leave the chosen option at a higher iRR. The objective value of the option predicts the instantaneous reward rate at leave time in both environments. Additionally, in the disadvantageous block, the time left for foraging appears to be crucial for deciding to leave. A preliminary exploratory time-frequency analysis shows that differences between environments are reflected in frontocentral delta activity starting one second before the leave decision. Conclusion: By creating two different environments, we investigate adaptive foraging behavior of humans and its influencing factors. Analysis of behavioral data confirms the MVT and shows differences in behavior between environments. Analysis of concurrently recorded EEG revealed neuronal representations of variables underlying foraging decisions.

28. Allocating spatial attention in an audio-visual cocktail-party environment: evidence from ERPs and neural oscillations

Dr. Laura-Isabelle Klatt1, Alexandra Begau1, Dr. Daniel Schneider1, Dr. Stephan Getzmann1

1Leibniz Research Centre For Working Environment And Human Factors

28. Objectives and research question: A large body of evidence illustrates the multitude of interactions between our sensory modalities. Yet, little is known about how we select information from multisensory environments. In this pre-registered EEG study (https://osf.io/vh38g), we aimed to investigate the interplay and the temporal dynamics of unisensory attention mechanisms in an audio-visual search paradigm. Materials and methods: Subjects (N=36) were presented with two concurrent, lateralized acoustic speech stimuli and indicated the lateral position (left vs. right) of a pre-defined target word. In three separate task blocks, the acoustic speech stimuli were either presented without any concurrent visual information (Aonly), with congruent visual speech (AVcong) or with unspecific visual speech (AVunsp). The magnitude and onset latencies of the N2ac and N2pc component, established neuro-cognitive correlates of auditory and visual spatial attention, served as primary measures of interest. Further, modulations of fronto-central theta power and theta phase-based connectivity were explored. Results: While accuracy was close to ceiling in all conditions, response times showed a typical multisensory facilitation effect, with fastest responses for AVcong stimuli compared to AVunsp and Aonly stimuli. Contrary to our pre-registered hypotheses, N2ac/N2pc amplitudes and onset latencies did not vary between conditions. Bayes Factor analysis provided convincing evidence for the null hypothesis. Time-frequency analyses revealed relatively lower fronto-central theta power for AVcong (compared to Aonly and AVunsp) stimuli in an early cluster right after sound onset. Complementary to modulations of theta power, we observed a wide-spread increase in theta phase-based connectivity for Aonly and AVunsp (vs. AVcong) task blocks. Conclusion: The study sheds light on the interplay of audition and vision when allocating attention in multisensory environments. Notably, the behavioral audio-visual facilitation effect is not reflected in the magnitude or latency of ERP correlates of attentional selection. Yet, the presence of a pronounced N2pc component illustrates that visual attention is automatically deployed to the relevant target location, irrespective of whether the visual modality provides task-relevant information or not. Finally, the observed modulations of theta power and phase-based connectivity corroborate the relevance of neural oscillations and large-scale functional connectivity networks for multisensory processing.

29. Effects of meditation states and expertise on attentional and cognitive monitoring brain networks

Prof. Juliana Yordanova1, Porf. Vasil Kolev1, Porf. Peter Malinowski3, Prof. Antonino Raffone2

1Institute of Neurobiology, Bulgarian Academy of Sciences, 2Department of Psychology, Sapienza University of Rome, 3School of Psychology, Research Centre for Brain and Behaviour, Liverpool John Moores University (LJMU)

29. Objectives. Meditation practice is suggested to engage training of cognitive control systems in the brain. The objective of the present research was to evaluate the functional involvement of attentional and cognitive monitoring processes during meditation in long-term meditators. Methods. Electroencephalographic synchronization of fronto-parietal (FP) and medial-frontal (MF) brain networks was analyzed in highly experienced and novice meditators during different meditation states (focused attention, open monitoring and loving kindness meditation). The aim was to assess whether and how the connectivity patterns of frequency-specific FP and MF networks are modulated by meditation style and expertise. Results. Compared to novice meditators, (1) highly experienced meditators exhibited a strong theta synchronization of both FP and MF networks in left parietal regions in all mediation styles, and (2) only the connectivity of lateralized beta MF networks differentiated meditation styles. The connectivity of intra-hemispheric theta FP networks depended non-linearly on meditation expertise. In contrast, inter-hemispheric FP connectivity in faster frequency bands (fast alpha and beta) increased linearly as a function of expertise. Conclusions. The results confirm that executive control systems play a major role in maintaining states of meditation. The distinctive lateralized involvement of FP and MF networks appears to represent a major functional mechanism that supports both generic and style-specific meditation states. The observed expertise-dependent effects suggest that functional plasticity within executive control networks may underpin the emergence of unique meditation states in expert meditators. Supported by the BIAL Foundation (Portugal) for the project “Aware Mind-Brain: bridging insights on the mechanisms and neural substrates of human awareness and meditation”, and by the National Research Fund, Sofia, Bulgaria (Project KP-06-N33/11/2019).

30. Humans dynamically adjust sensory excitability to guide perceptual decisions

Julian Kosciessa1,2, Douglas D. Garrett1,2

1Max Planck Institute For Human Development, 2Max Planck UCL Centre for Computational Psychiatry and Ageing Research

30. Objectives: Perceptual decisions often require a systematic reduction of visual complexity. However, the extent to which relevant stimulus dimensions are known during sensation varies between different environments. To ideally guide upcoming decisions, observers should thus flexibly adjust the fidelity of sensory information processing according to the expected environmental uncertainty. Research question: We assessed whether healthy young adults increased visual excitability and arousal (as estimated via pupil diameter) when more features in a dynamic display were jointly relevant for an uncoming choice. Moreover, we assessed whether uncertainty during sensation influenced subsequent decision processes. Materials and methods: 47 healthy young adults (18-35 years) performed a dynamic visual attention task during 64-channel active scalp EEG acquisition. The task parametrically varied the number of to-be-attended visual target features (color, movement direction, size, and saturation of dot patterns) between which subjects had to switch during encoding, while holding the low-level input features constant across conditions. Neural dynamics were assessed in EEG via wavelet analysis and sample entropy. We further assessed pupil diameter as a proxy for neuromodulation (arousal). Behavioral modeling was performed using drift-diffusion modeling, while neural evidence accumulation was indexed via the centroparietal positivity (CPP). Multivariate analyses were performed via partial least squares (PLS), while univariate cluster-based permutation tests were used for the EEG and pupillometry data. Results: When more visual features were relevant, subsequent evidence accumulation for perceptual decisions decreased, as jointly indicated by behavioral and electrophysiological modeling. During sensation, target uncertainty increased pupil-based arousal and top-down attentional control as indicated by frontal theta power. Alongside, bottom-up visual excitability increased, as indicated by decreased posterior alpha power and increased posterior gamma power. Similarly, increases in sample entropy and shallowing of 1/f slopes jointly indicated an increase in the irregularity of neural dynamics during environmental uncertainty. Subjects with more pronounced increases in excitability under uncertainty exhibited higher rates of evidence accumulation, that were more strongly modulated under expected uncertainty. Conclusion: Jointly, this evidence suggests that humans dynamically adjust sensory excitability according to the processing fidelity required for an upcoming choice.

31. Alpha and theta activities reflect individual differences in Temporal Information Processing in Go/No Go task

PhD Klaudia Krystecka1, PhD Magdalena Stanczyk1, Dr Aneta Szymaszek1, Mrs Anna Bombinska1, Prof Elzbieta Szelag1

1Nencki Institute Of Experimental Biology, Polish Academy Of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland

31. Temporal Information Processing (TIP) constitutes an essential component of human cognition because many cognitive functions like language, attention, memory, motor control, planning, etc. are characterized by the specific temporal dynamics. As TIP is omnipresent in controlling human behaviour, one may expect that the temporal dynamics is rooted in neural oscillations reflecting rhythmic patterns of neural activity of the brain. In this study we concentrated on alpha rhythm that plays an active role in network coordination and communication, as well as on theta rhythm underlying various aspects of cognition and behaviour. The main goal of this study was to test the relationships between the efficiency of TIP measured in auditory perceptual behavioural task and activity of alpha and theta power in electrophysiological Go/No Go task. Forty six healthy participants (M_age = 25 years) completed: (1) auditory Temporal-Order Judgement task (TOJ) which measured the efficiency of TIP on the millisecond level, and (2) electrophysiological brain activity in Go/No Go task. We used the Fast Fourier Transformation for assessment of frontal and central theta (3.5-7.5 Hz) and alpha (7.5-12.5 Hz) spectral amplitudes from 2s epochs. To verify relationships between analysed oscillatory activities and subjects’ efficiency in behavioural TOJ task, Pearson correlations were performed. They showed positive moderate significant correlations between the indices of TOJ and (1) alpha power on both frontal (r = .369, p = .012) and central activity (r = .352, p = .016), moreover, (2) between TOJ indices and theta central activity (r = .295, p = .047). Furthermore, omissions of GO stimuli correlated positively with frontal (r = .442, p = .001) and central (r = .413, p = .003) alpha activity. These results showed that less efficient millisecond TIP was associated with higher both theta and alpha power. This suggests that higher alpha activity may reflect a state of reduced perception, whereas, higher theta activity reflects deficient inhibitory control. Such a new knowledge may provide more insights into the dynamic flow of information in our brains, as well as to the relationship ‘time-cognition’. Supported by National Science Centre, Poland, grant no. 2018/29/B/HS6/02038

32. The impact of age on executive function performance and the interactions of prefrontal cortex and autonomic functions

Pei-Hsin Ku1, Ray-Yau Wang1, Nai-Chen Yeh1, Yea-Ru Yang1, Chia-Fung Lu2, Szu-Fu Chen3, Yi-Fang Chuang4

1Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, 2Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, 3Department of Physical Medicine and Rehabilitation, Cheng Hsin General Hospital, 4Institute of Public Health, National Yang Ming Chiao Tung University

32. Cognitive aging is one of the major factors that endangers independence and quality of life in older populations. Executive function (EF), a family of high-order cognitive control essential for complex mental task, is likely to decline with age. Prefrontal cortex (PFC) is the key area for processing EF. Decreased EF performance is commonly related to altered PFC activation. In addition, PFC also plays a critical role in central autonomic network, referring to the modulation of autonomic nervous system. Several studies showed that impaired autonomic function, especially decrease in parasympathetic tone, could be linked to decreased EF performance. Therefore, it is important to understand the relationships among EF, ANS and PFC modulation, as well as the impact of aging. In this study, we monitored the ANS activity (through electrocardiography) and PFC changes (through cerebral blood flow) in both resting state and during performing EF tasks. In 31 healthy young adults (mean age 24.7 y/o) and 26 older adults (mean age 70.4 y/o), we found that general cognitive function did not differ between these two age groups, but EF performance significantly decreased in older adults, indicating that cognitively normal elderly may still have underlying EF impairments. While performing EF tasks, young adults showed larger changes of PFC but older adults did not seem to have significant activation compared to resting state. We also found that the change of heart rate from resting state to tasking was significantly greater in young than that in older adults, which was positively correlated to the task performance. Albeit the heart rate increased during tasks, it did not induce decrease in parasympathetic tone, nor was it correlated to task performance. The change of heart rate could reflect people’s alertness level and attentional flexibility. Overall, our preliminary findings showed that young adults could maintain the task performance by shifting attentional focus and with activation of PFC, while older adults had limited attentional and cerebral flexibility.

33. Pronounced distractibility of reasoning suggests a distorted structure of cognitive abilities in schizophrenia

Hanna Kucwaj1, PhD Adam Chuderski1

1Jagiellonian University

33. Objectives: Cognitive deficits are the core feature of schizophrenia. Impairments refer mainly to attention and executive functions, which are crucial abilities in analogical reasoning. We used four-term analogies with and without distractors to investigate the effect of distraction during analogical reasoning in schizophrenia. Raven’s Standard Progressive Matrices (RSPM) and Stroop task were applied to explore the relation between reasoning by analogy and other cognitive abilities. Research question: (i) are patients especially prone to distractibility during analogical reasoning (but perform normally when distraction is absent)? (ii) do individual differences in patients' distractibility result from general deficits in reasoning ability and/or executive control, or do these differences reflect an idiosyncratic deficit Materials and methods: Thirty healthy controls and thirty inpatient individuals who met the ICD-10 criteria for schizophrenia attempted the analogical reasoning task that consisted of 64 items. Distractibility was defined as the difference in error rates the distraction and no-distraction problems, indicating how strongly individual performance deteriorated in the presence of distractors. RSPM and the Stroop Test measured reasoning ability and executive control, respectively. Results: The patients' mean distractibility (M = 25.1% errors) was significantly higher than the mean distractibility of the controls (M = 9.4% errors), while in no-distraction condition both groups performed accurately. The controls' distractibility was significantly correlated with age, education (reversed), RSPM, and Stroop; furthermore, all these correlations were actually driven by RSPM, which explained 68.9% of the variance in distractibility. In contrast, none of these variables significantly predicted distractibility in the patients (RSPM explained as little as 4.8% variance). Conclusion: Although both patients and controls performed fairly accurately on the no-distraction analogies, patients’ performance in the presence of distractors was substantially distorted, suggesting deficits in attention and cognitive control affecting complex cognition. The difference in the pattern of correlations suggests different origins of the distractibility in the two groups. The results replicated a unitary structure of cognitive abilities in healthy controls (driven by fluid intelligence) but suggest a highly disintegrated such a structure in patients.

34. Unmasking instrumental associations by removing reinforcement

Hannah Kurtenbach1, Dr Eduard Ort1, Dr Monja Isabel Froböse1, Prof Dr Gerhard Jocham1

1Heinrich Heine University Düsseldorf

34. Acquisition of knowledge during instrumental learning is often measured by performance during reinforced behaviour. However, recent work in rodents found that animals’ instrumental performance was enhanced during periods when reinforcement was withheld. This indicates that reinforcement can mask acquired knowledge and lead to impaired performance. In the present study, we aimed to investigate whether such a beneficial effect of removing reinforcement translates to humans. Specifically, we tested whether performance during learning, as quantified by the sensitivity index d’, is improved during non-reinforced relative to reinforced task periods. Healthy volunteers performed a novel visual go/no-go learning task with deterministic reinforcement. To probe acquired knowledge in the absence of reinforcement, we interspersed five blocks without feedback. During reinforced periods, participants received feedback and reward or punishment for every response. In the non-reinforced blocks, participants were instructed to continue choosing as they would during the reinforced blocks, while performance feedback was temporarily omitted. In two independent samples (each n = 30), we found an increase in d’ in the non-reinforced task periods. We used computational modelling to understand the mechanisms driving this behavioural pattern. Our computational results suggest that the improved performance during non-reinforced blocks can fully be accounted for a more cautious mode of responding, as evidenced by a reduction of a general bias. Together with non-zero value initialization, this is sufficient to drive differential changes in hit and false alarm rate that jointly lead to an increased d'. To conclude, these results demonstrate that improved instrumental performance in our study does not unmask latent knowledge in humans. Instead, they suggest that the absence of reinforcement leads to a change of a general response bias.

154. When sound SPARCs cognitive control: An fMRI study of response conflict from spatial pitch associations

Robert Langner1,2, Rachel N. Pläschke1,2, Simon B. Eickhoff1,2, Lya K. Paas Oliveros1,2

1Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, 2Brain and Behaviour, Institute of Neuroscience and Medicine (INM-7), Forschungszentrum Jülich

154. The perception of auditory pitch has been found to be associated with spatial representations. In particular, the spatial-pitch association of response codes (SPARC) effect indicates that mappings of high-pitch auditory stimuli to right/high-positioned response locations lead to faster responses than do mappings of high-pitch stimuli to left/low-positioned response locations, and vice versa for low-pitch stimuli. When the spatial implications of pitch height are incompatible with instructed spatial response requirements, they are assumed to elicit a response conflict calling for top-down control to be resolved. Here, we investigated whether such SPARC incompatibilities recruit brain circuitry typically associated with conflict resolution in spatial stimulus–response compatibility tasks. Additionally, we examined whether and how the SPARC-related interference effect is modulated by response complexity and age. We used fMRI to measure brain activity in 43 young (25.6±3.4 yrs.) and 36 older (61.9±5.5 yrs.) healthy adults while performing speeded two-choice reactions to high- or low-pitched tones by pressing upper or lower response buttons with one or both hands concurrently. The compatibility between stimulus-pitch-implied and actually required response locations as well as the level of response complexity (unimanual vs. bimanual responding) was varied between blocks of trials. Responses in SPARC-incompatible trials were significantly slower than those in compatible ones, a difference that was further enhanced with higher response complexity (bimanual responding). Response slowing with higher age was found to be additive to these effects. Neurally, SPARC incompatibility was associated with higher activation of a wide-spread set of regions in bilateral prefrontal, parietal, midcingulate, and anterior insular cortices as well as bilateral thalamus and cerebellum. Cerebellar involvement appeared to be mainly driven by dual-response execution, indicating a potential neural substrate for coordinating responses under conditions of greater response selection difficulty. While age did not modulate the incompatibility-related network, increased activation levels in advanced age were observed in a few spots just anterior to premotor cortex, possibly reflecting neural dedifferentiation. In conclusion, SPARC incompatibility activates the well-known multiple-demand network, corroborating the idea that pitch-associated spatial representations automatically activate response tendencies which, if incongruent with instructed pitch-to-location mappings, require effortful top-down control to be overruled.

155. Causal role of the PFC on working memory protection from visual distractors using continuous measure of object memory recall

Mrs Olga Leticevscaia1, Dr Eva Feredoes1

1University Of Reading

155. Prefrontal cortex (PFC) is important in working memory (WM), particularly in mitigating external distractor impact, although causal evidence from healthy humans is limited. In the present study, we investigate in a normal sample if PFC is causally involved in protecting WM contents from external distractors by using transcranial magnetic stimulation (TMS). We hypothesize that right dorsolateral PFC (dlPFC) disruption decreases the ability to effectively protect WM contents from irrelevant visual stimuli. As part of work in progress, 14 healthy adults so far have attended two separate TMS sessions performing a continuous delayed WM task: an object had to be memorized and then chosen among similar versions shown around a circle, after a short delay. To distract participants during the delay, clips with moving shapes (‘high-distractor’) or a static noise (‘low-distractor’) was displayed. Prior to the task, continuous theta burst was given over right dlPFC or somatosensory cortex (S1; control site). Memory precision is measured as the angular offset between WM target and recalled image. Memory precision on high- vs low-distractor trials is compared, and the effect of TMS is assessed by comparing this distractor effect across the dlPFC and S1 sessions. Preliminary analysis (mixed repeated-measures ANOVA) of the data demonstrates trends both for distraction and dlPFC TMS effects. However, the analysis will be finalized after collecting the entire data sample (N=40). Modelling of errors will be performed; we predict that dlPFC TMS will increase random errors. Individual differences in distractor and TMS effects will also be explored. Demonstration of a significant dlPFC TMS effect will provide direct causal evidence for the necessity of this region for protecting visual WM information.

156. Planned, task-specific allocation of cognitive effort modulates EEG low frequency dynamics during task preparation

Nathalie Liegel1, Prof Daniel Schneider1, Prof Edmund Wascher1, Dr Stefan Arnau1

1Leibniz Research Centre for Working Environment and Human Factors

156. Cognitive effort positively affects task performance. Neuroscientific studies have explored the underlying mechanisms of this observation by manipulating the expected monetary incentive associated with successful task performance. Some studies implemented this manipulation by presenting task- and stimulus-unspecific incentive cues prior to the task so that anticipatory allocation of cognitive effort is possible. Other studies linked reward to specific aspects of the task itself, so that the deployment of effort cannot be planned. In the present study, we combine and extend both approaches to test how preparatory and task-specific effort affects performance and EEG activity. 28 participants performed a nested task design comprising a cued number classification task during the retention interval of a cued working memory task. Each trial started with a relevance cue indicating which of the two tasks would be more important in the upcoming trial. Subjects were told to engage in both tasks, but to concentrate on the important task. Feedback was given at the end of each trial. Feedback scores were calculated based on the actual task performance, with scores obtained from the relevant task being tripled. Participants performed significantly better in either task when it was important compared to when not. A cluster-based permutation test performed on time-frequency decomposed EEG data revealed that this behavioral effect was accompanied by modulations of theta, alpha and beta oscillatory power, predominantly during time intervals associated with preparatory processes. When the number classification task was important, theta power was increased prior to the number classification task cue, whereas alpha power was decreased during the cue-target interval. The results indicate that the human information processing system is capable to selectively prioritize relevant aspects of a task by deploying proactive cognitive control.

157. Executive functions are reflected in children’s P3a responses

PhD Tanja Linnavalli1,2,3, Outi Lahti4, PhD Minna Törmänen3,5, PhD Ben Cowley3,6, PhD Mari Tervaniemi1,2,3

1Cicero Learning, Faculty of Educational Sciences, University Of Helsinki, 2Cognitive Brain Research Unit, Faculty of Medicine,University of Helsinki, 3Department of Education, Faculty of Educational Sciences, University of Helsinki, 4Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, 5Institute for Professionalization and System Development, University of Teacher Education in Special Needs, 6Cognitive Science, Faculty of Arts, University of Helsinki

157..Objectives The aim of the current study was to explore the associations between executive functions (EF) (i.e., working memory, inhibition and cognitive flexibility) and auditory event-related potential (ERP) response P3a in 10–11-year-old children. P3a is known to have different developmental trajectories in childhood for small deviations and novel sounds: whereas the response amplitudes for small deviations seem to grow larger by age, the P3a for highly distracting sounds decreases with age. In both cases, the latency of the P3a response is expected to decrease with age and brain maturation. Research question We investigated if the amplitude and the latency of P3a response – considered to reflect involuntary orientation of attention – is associated with the performance in modified flanker task measuring different areas of EF. Materials and methods 10- to 11-year-old-children participated in an EEG measurement and a separate flanker task. A fast multifeature paradigm with both small deviations and novel sounds was presented in a passive condition. As the performance scores were high for all children in the flanker test, only the mean reaction times (RT) for the correct answers were used as a measure of EF. Results The P3a latencies for deviant sounds were associated with the reaction time reflecting inhibition. Additionally, the P3a latencies for novel sounds were marginally significantly linked to the reaction time reflecting set-shifting. The shorter the response latencies were, the faster the reaction time was. The magnitude of the P3a amplitudes had no association with RTs. Conclusion Our research revealed that unlike the P3a amplitudes, the P3a latencies are linked to the reaction times reflecting inhibitory skills, and marginally also to RTs reflecting set-shifting. These results are in line with the view that brain development contributing to the processing speed is linked to both early sensory level responses and reaction times reflecting EF skills.

160. Distinct EEG markers for intentional and unintentional mind-wandering

Dr. Adrien Martel1, Mr Nicolas Bruno1, Mrs Victoria Shevchenko1, Dr. Jacobo Sitt1, Dr. Antoni Valero-Cabré1

1Institut du Cerveau et de la Moelle Epiniere (ICM)

160. Recent years have witnessed a surge of interest in elucidating the underlying mechanisms of mind wandering (MW) with EEG. MW has been found to vary substantially along several cognitive dimensions, presumably as a function of the variable contributions and interplay of distinct neurocognitive processes. Amongst these dimensions, intentionality, i.e., the degree to which task-unrelated thoughts occur because of an intentional reallocation of attention, has recently emerged as a key explanatory variable. Although the involvement of executive control in the onset and maintenance of mind-wandering episodes has been established, it remains to be elucidated whether MW arises from a failure of executive control or whether both rely on, and thus compete for, the same cognitive resources. In the present study, we address this question by investigating the electrophysiological signatures of intentional and unintentional mind-wandering with a data-driven statistical approach and statistical-learning based methods on recorded EEG. Twenty-six participants performed a fixed SART with intermittent thought-probes prompting them to report on their attentional state. We employed a data-driven cluster-based permutation approach on the time frequency decomposition of the EEG for the statistical evaluation. Moreover, we performed univariate and multivariate analyses to estimate the discriminative ability of a large set of predetermined markers between reported attentional states and obtain novel univariate information about each individual marker. The cluster-based permutation revealed several significant clusters of growing endogenous synchronization in theta power (4-7 Hz) and increased phase synchrony for intentional MW when compared to unintentional MW. The results of the univariate and multivariate analyses identified theta band activity as a crucial predictor of MW in general and of intentional MW specifically. Our results reveal that divergent states of inattention are characterized by distinct constellations of EEG markers and that features of theta band activity are predictive of off-task states in general and of intentional MW specifically. Taken together, our findings shed new light on the key role executive control plays in the onset and maintenance of MW, and reaffirm the importance of distinguishing between types of task-unrelated thoughts in particular with regard to robust predictive modeling of attentional states based on EEG.

161. Orienting in an uncertain world: pupil-linked neuromodulation and temporal dynamics of expected and unexpected uncertainty

Dr. Anna Marzecová1, Dr. Eva Van den Bussche2, Dr. Tom Verguts1

1Ghent University, 2Faculty of Psychology and Educational Sciences, KU Leuven

161. The concept of attention can be formalized as Bayesian inference about which spatial locations are considered to be relevant in the near future. Theoretical computational work (Yu & Dayan, 2005) proposes that the attentional system estimates two forms of uncertainty, linked to distinct neuromodulatory systems. Expected uncertainty tracks the unreliability of predictive relationships within a familiar context. Unexpected uncertainty signals sudden changes of the environmental context. Their behavioral consequences and underlying neurophysiological mechanisms are not yet understood. First, to investigate how behavior is influenced by these two forms of uncertainty, we empirically dissociated expected and unexpected uncertainty in a spatial orienting paradigm. Second, we probed the link between uncertainty estimates and pupil-linked neuromodulatory responses. Third, we set out to characterize temporal dynamics of uncertainty estimates using electroencephalography (EEG). We simultaneously recorded eye-tracking and EEG while participants (N=29) performed a spatial cueing task with two cues (i.e., black and white arrow). Only one of the two cues reliably predicted the spatial location of a sinusoidal grating. Participants’ task was to infer which of the two cues predicted the grating's location and to make a speeded response to the grating. Unexpected uncertainty (UUn) was induced by cue switches - the validity of the previously relevant cue (e.g., black cue) dropped to chance level, while the other cue became predictive (e.g., white cue). Expected uncertainty (EUn) was related to reliability of the currently relevant cue (70% and 85% validity, respectively). We modeled EUn and UUn levels in the task using an approximate Bayesian learning algorithm (Yu & Dayan, 2005). We observed that response time (RT) varied as a function of model-derived uncertainty estimates. RT decreased with increasing levels of UUn and EUn. Phasic pupil responses decreased with increasing EUn, but increased with increasing UUn. We observed distinct temporal profiles of these effects. Uncertainty estimates were correlated with single-trial amplitude fluctuations of the P3 component and oscillatory signatures of attention. Our results show that attentional orienting relies on Bayesian estimates of expected and unexpected uncertainty. These estimates are distinctly tracked by pupil size fluctuations, supporting postulated links to neuromodulatory brainstem responses.

162. The spatio-temporal dynamics of the attentional spotlight and expectations

Phd Student María Melcón1, Sander van Bree, Yolanda Sánchez-Carro, Enrique Stern, Lydia Arana, Laura Barreiro-Fernández, Luca Kolibius, Elisabet Alzueta, Maria Wimber, Almudena Capilla, Simon Hanslmayr 1Department of Biological and Health Psychology,Universidad Autónoma De Madrid, 2Centre for Cognitive Neuroimaging, University of Glasgow, 3Centre for Human Brain Health, University of Birmingham, 4Department of Psychiatry, Universidad Autónoma de Madrid, 5Biosciences Division, Center for Health Sciences, SRI International

162. An informative cue draws attention to its location. However, neural behaviour during this orienting period is still under study. The underlying activity could either track the highlighted location constantly or, instead, it could fluctuate dynamically exploring the visual space. In the latter case, the sampling rate could remain constant or change over time. Overall, previous evidence in non-human primates point to prefrontal areas, parietal cortex and the thalamus as sources of attentional spotlight and a few works have focused on visual regions. To shed light on this issue, we applied time-sensitive decoding methods to posterior electroencephalographic (EEG) activity, recorded while twenty-seven human participants performed a visuospatial cueing task. We used informative cues (100% valid) to indicate whether attention should be covertly oriented to the left or right visual field. First, in order to decode the spatial locus of attention, we trained and tested a classifier on every time point combination of the orienting period, which resulted in a time generalization matrix (TGM) per participant. Then, to identify the rate at which attentional sampling occurs throughout time, a time-frequency analysis was applied independently to each row and column of these TGMs. Finally, the statistical analysis consisted of two-level permutation tests, first on the classifier performance and later on the frequencies. Our results show a dynamic evolution of the attentional spotlight. First, the cue triggers a rhythmic sampling response between left and right hemifields at 10 Hz for 250 ms (exploration state). Then, attention remains relatively stable at the cued hemifield until ~650 ms (exploitation state). In a second study, we used the same procedure to investigate whether these dynamics are affected by cue expectations (100% vs. 50 % validity). Our results show that while attention behaves similarly in the first exploration state, it exhibits a differential oscillatory pattern in the exploitation state. Together, our results reveal a novel insight into the temporal dynamics of the attentional spotlight in showing that information is sampled rhythmically from cued to uncued locations and only after an informative cue, attention settles onto the cued location. Funded by PGC2018-100682-B-I00 (MCIU/AEI/FEDER, UE)

163. Modulations of transfer effects on working memory by a single-session filter training under tDCS - individual response to network-oriented stimulation

Inga Menze1, Notger G. Müller1, Marlen Schmicker1

1Deutsches Zentrum für Neurodegenerative Erkrankungen

163. Objectives The frontoparietal network links processes of selective attention (prefrontal cortex) and working memory (WM) storage (posterior parietal cortex). Their interplay can explain interindividual variability in WM capacity. High capacity individuals show efficient filter and storage ability, whereas low capacity individuals lack filter ability and tend to strain their storage. However, filter training can lead to transfer effects on WM, manifesting as performance improvements. Our aim was to modulate this transfer by combining a filter training with transcranial direct current stimulation (tDCS). Research question We compared the transfer effects on WM after a single-session filter training that was either combined with sham-stimulation, conventional tDCS (anode F4, cathode contralateral cheek) or network-oriented frontoparietal tDCS (prefrontal anode, posterior parietal cathode). The latter aimed at simultaneously increasing filter ability and decreasing unnecessary storage activity. We assumed specific response to tDCS montages depending on individuals’ initial WM capacity, assessed using an independent WM task. Materials and Methods Three groups of young, healthy subjects were compared, either receiving sham (n=40), conventional (n=40) or frontoparietal tDCS (n=39). The transfer on a change detection task with and without distraction was analyzed depending on tDCS montage and initial WM capacity via linear mixed effect modeling. Results Transfer on WM differed systematically after frontoparietal tDCS compared to sham, especially in distractor conditions. The higher the WM capacity, the more beneficial the effects of the filter training under frontoparietal tDCS on transfer. Individuals with lower WM capacity benefitted especially from sole filter training (sham). Conventional tDCS led to performance improvements independent of WM capacity. However, it did not offer any additional advantages over sham or frontoparietal stimulation. Conclusion Our data give evidence for the modulation of transfer effects on WM performance by different tDCS montages, which vary with WM capacity. These findings are assumed to arise from differences in frontoparietal network activity. As such, the frontoparietal tDCS might have strengthened the frontostriatal pathway in high capacity individuals, which is associated with an efficient filter ability. In low capacity individuals, however, the cathodal stimulation of the posterior parietal cortex within the frontoparietal montage might have inhibited usual compensatory mechanisms.

35. The neuropsychological and neurophysiological signatures of age-related differences in mind-wandering

Dr Catherine Nora Moran1, Dr David McGovern1,2, Dr Mike Melnychuk1, Ms Greta Warren1, Mr Rónán Ó Grálaigh1, Dr Joanne Kenney1, Prof Alan Smeaton3,4, Dr Paul Dockree1

1Trinity College Institute of Neuroscience & School of Psychology, 2School of Psychology, 3School of Computing, 4Insight Centre for Data Analytics

35. Objectives In ‘mind-wandering’, attention disengages from the environment and shifts inward toward self-generated mental content. An age-related reduction in mind-wandering frequency has been consistently reported; however, it is unclear what mechanisms underlie this effect. Given the many adaptive and maladaptive mind-wandering corollaries, the extent to which mind-wandering is influenced by the natural ageing process warrants exploration. Research Question This study examined how the frequency and phenomenology of mind-wandering changes as a function of age, and investigated the shared and distinct neuropsychological and neurophysiological signatures of fluctuating attentional states in younger and older adults. Materials and Methods Thirty-four younger and 34 healthy older adults performed the Gradual Contrast Change Detection task in which they monitored a continuously-presented flickering annulus stimulus for intermittent gradual contrast reductions and responded to built-in experience sampling probes to discriminate the nature of their thoughts at discrete moments. Electroencephalography and pupillometry were concurrently recorded to ascertain neural indices of endogenous attention and perceptual decision-making during target- and probe-related intervals. Results Despite relative group parity in behavioural performance, older adults exhibited a lower propensity to mind-wander than younger adults, and less reaction time variability, an index of oscillatory attention cycles, consistent with steadier attentional engagement with age. Additionally, older adults tracked the downward stimulus trajectory with greater sensory integrity (reduced mean pre-target SSVEP amplitude), and demonstrated earlier initiation of evidence accumulation (earlier onset CPP), attenuated variability in the attentional signal (posterior alpha), and more robust phasic pupillary responses to target. Pre-probe signal analyses revealed that younger, but not older, adults exhibited intermittent sensory encoding, indexed by greater variability in the sensory and attentional signals prior to mind-wandering relative to focused states. Conclusion This research provides new insight into age-related mind-wandering, elucidating the distinct strategies employed by both groups during the task. Older adults suspended mind-wandering and implemented a more exploitative oscillation strategy and steadier engagement to circumvent their reduced cognitive resources and allay potential behavioural costs, when the context demanded. Conversely, younger adults exhibited greater exploration of the mind-wandering space and utilised their greater cognitive resources to flexibly alternate between competing goal-directed and mind-wandering strategies with limited costs.

164. Electrophysiological indices of selective attention predict the quality of object representation in the human brain

Mr Vinura Kisalkumara Munasinghe1, Mr David Acunzo1, Mr Damiano Grignolio1, Dr Clayton Hickey1

1University Of Birmingham

164. Our visual environment provides a rich source of information that threatens to overwhelm our cognitive capacity. To behave adaptively and intelligently, we use visual attention to select potentially important objects and mark them for prioritized downstream consideration. The neural basis of visual attention has been investigated extensively using event-related potentials (ERPs) and this has led to identification of the N2pc, an ERP component that emerges over visual areas contralateral to an attended stimulus. The N2pc appears to have two constituent parts: the target negativity (NT), which has been associated with prioritization, and the distractor positivity (PD), which appears to track visual suppression. Here we investigate how trial-wise variance in these components predicts the broader processing and representation of visual information in the brain. We had experimental participants complete a visual search task involving the categorization of a real-world target presented alongside a real-world distractor. Both targets and distractors were examples of natural categories of stimuli (foods, vehicles, animals, tools), and our design allowed us to i.) identify target-elicited NT and distractor-elicited PD in single trials, and ii.) use multivariate modelling to index the trial-wise quality of target and distractor representations across the brain. Results show that the amplitude of NT predicts an increase in target category information in the brain, whereas the amplitude of PD predicts a decrease in distractor information. These results confirm that NT and PD constitute close correlates of visual prioritization and suppression, and that these neural mechanisms play key roles in the gating of information processing in the visual brain.

165. Modulation of mind wandering using transcranial direct current stimulation – a meta-analysis

Dr Hema Nawani1, Prof Matthias Mittner1, Dr Gabor Csifcsak1

1Cognitive Neuroscience Research Group, Department of Psychology, UiT The Arctic University of Norway

165. Several studies have attempted the modulation of mind wandering (MW) by transcranial direct current stimulation (tDCS). The evidence, however, is inconclusive where some studies report increased, no effect or decreased MW relative to sham stimulation. These controversial findings are likely due to variability in tDCS protocols (e.g., target region, electrode placement, stimulation intensity), cognitive paradigms, blinding, risk of bias and (lack of) statistical power. In this work, we present the first meta-analysis of studies in this field where the target area was either the left dorsolateral or lateral prefrontal cortex (DLPFC/LPFC). Using relevant search engines and following PRISMA guidelines, 11 studies (selection criteria: sham-control, MW probes, cognitive task) were included in the meta-analysis out of 149 studies. Risk of bias (RoB) assessment was done using the Cochrane Collaboration’s tool, extended with evaluation of the presence/absence of preregistered study designs and analysis plans. A random effects meta-analysis revealed a significant effect indicating increased MW for active tDCS, b = 0.31, z = 3.82, p < .001, albeit with substantial heterogeneity, Q(24) = 61.68, p < .001; τ = 0.30, I² = 61.3%. Anodal vs. cathodal stimulation above left DLPFC/LPFC yielded statistically similar increase in MW irrespective of polarity. However, when adding risk of bias as a moderator variable, we observed a marked reduction in heterogeneity Q(23) = 33.94, p = .06; τ = 0.11, I²= 18.1%. In this analysis, the effect-size of studies with least risk of bias was zero, b = -0.06, z = -0.77, p = 0.44. With increased bias, the observed effect-sizes grow significantly, b = 0.05, z = 4.48, p < .001. We conclude that tDCS, when applied above the left DLPFC/LPFC, increases MW irrespective of polarity, an effect that is most likely driven by overestimated effect sizes and publication bias in low-powered studies. As a next step, we will include studies targeting other cortical areas (i.e., the medial prefrontal, parietal), and supplement our meta-analytic approach with estimates of the electric field strength, extracted via computational modeling. This approach will allow us to focus on the effective dosage elicited by the wide variety of stimulation protocols.

9. Rapid within-trial adjustments of cognitive control during conflict resolution

Dr. Adam Chuderski1, Mr. Michał Ociepka1, Dr. Patrycja Kałamała1

1Jagiellonian University

9. Objectives. The mechanisms of conflict resolution when multiple conflicts co-occur are not clear. Studies showed that control adjustment can occur in the time course of a single trial, when a preceding stimulus aspect enhances resolving the conflict related to a subsequent aspect. This study combined the word-word conflict with the Stroop conflict to examine cognitive control adjustments related to one and the same stimulus aspect. Research question. We asked whether and how control can be adjusted when the same aspect of stimulus elicits two co-occurring conflicts. Materials and methods. Sixty seven healthy young adults attempted the task while their EEG signal was recorded. The stimuli were two words, presented one above the other. The words were four Polish color names: red, green, blue, and brown, and four color-unrelated words: high, hidden, deep, and distant. There were four conditions, 50 trials each. (a) Both words indicated the ink color, yielding both word-word facilitation and Stroop facilitation. (b) A random word indicated the ink color, whereas the other word was color-unrelated, yielding Stroop facilitation and word-word conflict. (c) Both words indicated a different color than the ink color, yielding word-word facilitation and Stroop conflict. (d) One (random) word indicated a different color than the ink color, the other word was color-unrelated, so both types of conflict were elicited. Results. Error rate and reaction time data showed that the classic between-trial Gratton effect can also be observed in the time course of a single trial: the word-word conflict facilitated resolution of the Stroop conflict. ERP data showed two additive effects – the Stroop conflict and the word-word conflict – in the N450 time window – a ERP component commonly associated with resolution of these types of conflict. That suggests simultaneous and independent processing of each conflicts at the neural level. Conclusion. The control system seems to adapt flexibly and rapidly the different types of conflict by modulating information processing in ways that individually address each source of conflict. Processing conflicts in parallel does not reduce the effectiveness of the control system, but it may substantially improve its efficiency.

166. Neural Variability of Crosstalk Effects in Dual-Tasking and Its Modulation by Age

Lya Katarina Paas Oliveros1,2, Edna C. Cieslik1,2, Aleks Pieczykolan3,4, Rachel N. Pläschke2, Simon B. Eickhoff1,2, Robert Langner1,2

1Institute of Neuroscience and Medicine (INM-7: Brain and Behaviour), Forschungszentrum Julich, 2Institute of Systems Neuroscience, Heinrich Heine University Dusseldorf, 3Institute of Psychology, University of Wurzburg, 4Rheinische Fachhochschule Köln, University of Applied Sciences

166. Difficulties in dual-tasking arise from several sources and usually increase with age [1,2]. Here, we studied the neural correlates of between-task response-code crosstalk and their age differences, as well as how crosstalk-related brain activity is linked to other facets of dual-tasking. Using fMRI, we measured brain activity in 43 young (25.6±3.4 yrs.) and 36 older (61.9±5.5 yrs.) healthy adults while responding to high- or low-pitched tones by pressing upper or lower response buttons with one or both hands simultaneously [3–5]. We manipulated the compatibility between stimulus-pitch-implied and actual response locations (S-R compatibility) and the spatial congruency between simultaneous manual response codes for both hands (R-R congruency). Divided attention and task switching abilities were assessed outside the scanner. Dual-task costs (DTC) on performance increased with R-R incongruency, attesting to substantial crosstalk effects, and were further enhanced with age. Both groups showed asymmetric crosstalk: DTC were higher for S-R compatible than incompatible responses, while the opposite was true for R-R congruent trials, suggesting a strategic prioritization of limited processing capacity. R-R incongruent dual-tasking elicited activation in the multiple demand network [6–8], which is associated with flexibly allocating attention to response selection. This interacted with the increased response-code confusability in older adults, revealing hyperactivity in medial precentral gyrus and frontal pole. The task-specific network was modulated as follows: Across groups, lower divided attention abilities and global task-switching costs were linked to less activity in motor-parietal areas. For divided attention, this association was stronger for the older group in left intraparietal sulcus and right occipito-cerebellar areas. Our results suggest a dedifferentiation pattern in age or inter-individual variability in attentional strategies. References 1. Koch I, et al. (2018) Psychol Bull, 144:557–83. 2. Verhaeghen P, et al. (2003) Psychol Aging, 18:443–60. 3. Huestegge L, Koch I (2009) JEPHPP, 35:352–62. 4. Huestegge L, Koch I (2010) Mem Cognit, 38:493-501. 5. Pieczykolan A, Huestegge L (2018) Psychol Res, 82:109–20. 6. Camilleri JA, et al. (2018) Neuroimage, 165:138-147 7. Duncan J. (2010) Trends Cogn Sci, 14:172-179. 8. Worringer B, et al. (2019) Brain Struct Funct, 224:1845-1869.

167. Modulating visual working memory capacity with sensory entrainment

Indre Pileckyte1, Salvador Soto-Faraco1,2

1Center for Brain and Cognition, Pompeu Fabra University, 2Institució Catalana de la Recerca i Estudis Avançats (ICREA)

167. Visual Working Memory (vWM) is a set of cognitive processes for short-term maintenance and manipulation of visual information. One of the most notable features of working memory is its limited storage capacity, which is around 3 to 4 items, making it a significant information processing bottleneck for the rest of the cognitive system. One possible physiological mechanism for memory maintenance, that would explain such limited capacity is the nesting of brain oscillatory activity, namely fast gamma cycles coupled with much slower theta phase. Indeed, it has been shown that vWM capacity can be modulated in a predictable direction by transcranial electrical stimulation at theta frequency. Inspired by this evidence, we have explored whether vWM capacity could be similarly regulated via sensory entrainment, using visual and acoustic rhythmic stimulation at theta frequency. Our objective was to test the feasibility of sensory entrainment at specific theta frequencies, 4 Hz and 7 Hz, for vWM capacity upregulation and downregulation, respectively. In a series of within-subject behavioral experiments, we asked participants to perform a change-detection visual working memory task whilst being entrained with background visual or acoustic stimulation at 4 Hz and 7 Hz, in relation to a control condition. We estimated memory capacity with index K. In different experiments we manipulated entrainment modality, entrainment stimuli shape, rhythmicity effect and others. Contrary to prediction, vWM capacity increased with faster 7 Hz stimulation compared to slower 4 Hz stimulation in all but one experiment, with varying levels of significance due to sample size differences and weak effect size. Meta-analysis of 6 conducted studies revealed overall non-significant difference between the two conditions. The modality or shape of stimuli did not have a significant effect. Remarkably, we did not observe a significant effect of rhythmicity. The present pattern of results is at odds, but not necessarily incompatible, with what is obtained using electrical stimulation. Our results indicate that vWM capacity might be modulated by sensory stimulation via affecting arousal, in opposite direction to what would be expected from the rhythmic entrainment of ongoing oscillations. The lack of significant rhythmicity effect supports this interpretation.

168. Examining the Role of the Noradrenergic Locus Coeruleus for Predicting Attention and Brain Maintenance in Healthy Old Age and Disease

Emanuele Plini1, Dr Erik O' Hanlon, Dr Rory Boyle, Dr Francesca Sibilia, Gaia Rikhye, Dr Joanne Kenney, Prof Robert Whelan, Dr Michael Melnychuk, Prof Ian Robertson, Prof Paul Dockree 1Trinity College Institute of Neuroscience

168. The noradrenergic theory of Cognitive Reserve (Robertson, 2013-2014) postulates that the upregulation of the locus coeruleus-noradrenergic system (LC-NA) originating in the brainstem might facilitate cortical networks involved in attention, and protracted activation of this system throughout the lifespan may enhance cognitive stimulation contributing to reserve. To test the above-mentioned theory, a study was conducted on a sample of 686 participants (395 controls, 156 mild cognitive impairment, 135 Alzheimer's disease) investigating the relationship between LC volume, attentional performance and a biological index of brain maintenance (BrainPAD-an objective measure, which compares an individual's structural brain health, reflected by their voxel-wise grey matter density, to the state typically expected at that individual's age). Further analyses were carried out on reserve indices including education and occupational attainment. Volumetric variation across groups was also explored along with gender differences. Control analyses on the serotoninergic (5-HT), dopaminergic (DA) and cholinergic (Ach) systems were contrasted with the noradrenergic (NA) hypothesis. The antithetic relationships were also tested across the neuromodulatory subcortical systems. Results supported by Bayesian modelling showed that LC volume disproportionately predicted higher attentional performance as well as biological brain maintenance across the three groups. These findings lend support to the role of the noradrenergic system as a key mediator underpinning the neuropsychology of reserve, and they suggest that early prevention strategies focused on the noradrenergic system (e.g., cognitive-attentive training, physical exercise, pharmacological and dietary interventions) may yield important clinical benefits to mitigate cognitive impairment with age and disease.

171. The effect of sequences and stop signal delay adjustments in the stop signal task: An EEG study

András Puszta1,2, Carsten Bundt2, Oda van Jole2, Jørgen Kransberg2, Rene Huster1,2

1Helgeland Hospital, 2University of Oslo

171. Numerous studies investigated different aspects of the cognitive inhibition during stop signal task (SST). However whether we can implicitly predict the stop-signal delay (SSD) or our behavior is more adopted to trial history in this task is still a question that needs more exploration. Our aim was to determine how different go-sequences and the adaptation of the SSD affect different behavioral and EEG measures during the SST. We designed a SST with two blocks, during which the adjustment of the SSD varied across blocks (i.e., one block having a fixed pool of SSDs with random drawing, and the other containing the traditional tracking SSD-method). The number of go-sequences within the blocks was manipulated such that the number of go trials prior to a stop trial ranged from 1 to 5. Pre-stop speeding and post-stop slowing were measured as behavioral variables, and the N2 and P3 amplitude and latency of the stop ERPs as EEG correlates. Our results show a significant interaction between the sequence length and stop type on the pre-stop speeding and post-stop slowing. Specifically, participants tend to speed up more before unsuccessful stop trials, and this speeding was more pronounced with longer go-sequences. On the post-stop slowing participants slowed more after unsuccessful stop compared to successful stop and this slowing difference between successful-unsuccessful stop seemed less pronounced in longer sequences. In addition, we also found a tendency for interaction (p=0.052) between SSD-procedure and stop type indicating that the difference in post-stop slowing between successful-unsuccessful stop was diminished in the fixed blocks. Furthermore, we observed a significant difference between the two stop-type ERPs, and this difference was bigger at longer sequences. The results clearly show that the length of the go-sequence has a significant effect on the cognitive inhibition and the related electrophysiological correlates indicating that inhibition is highly dependent on the trial history. However, it seems that the SSD-adjustment procedure affected these measures less, indicating that the implicit effect of SSD-prediction is less important in the SST. Our suggestion is to control/equilibrate the number of sequences in the stop-signal task to avoid its above-mentioned effects.

169. Interactions between external and internal attention processes during working memory task

András Puszta1,2, Anne-Kristin Solbakk1,2,3,4, Rene Huster1,2, Tor Endestad1,2,3,4, Maria Forsmo1,2, Ingrid Holmen1,2,3, Ingrid Funderud1,2,3, Sara Nossen1,2,3, Szabolcs Sáringer5, Péter Kaposvári5, Venke Grane1,2

1Helgeland Hospital, 2University of Oslo, 3RITMO Centre for Interdisciplinary Studies in Rhythm, Time and Motion , 4Oslo University Hospital, 5University of Szeged

169. Literature converges on the prospect that attention to internal representations and external stimuli occurs via a shared resource during working memory, resulting in a competitive interaction between external and internal attention. However, how this shared attentional resource can be manipulated experimentally by external versus internal attention in the same task is still a question that remains unanswered. We designed a new associative working memory experiment, where the main task was to recall color-shape associations between shapes and colors of a segmented circle. EDA was manipulated by the number of segments in the segmented circle, while the IDA was manipulated by the number of associations that had to be remembered. As a pilot study, we registered the data through online distribution of the task using EprimeGo. To obtain other measures than behavioral data, we also began with on-site experiments, where we also registered eye-movement data and EEG data. Main effects and interactions between IDA and EDA on behavioral-, eye-movement data as well as on electrophysiological variables were analyzed. In total, 64 healthy volunteers participated in the study. Part of the participants had also eye-movement and EEG data (n=14). Our results showed significant interactions between all the investigated factors during the task, namely that the difference between low and high IDA condition was higher during high EDA condition. Furthermore, the effect sizes for eye-movement data were larger than for the behavioral measures. Our results suggest that this task is suitable for detecting the differences in the shared attentional pool that is driven by external and internal attention and that eye-movement and EEG data can dissociate more sensitively these attentional subprocesses. Our suggestion is its usage in a clinical cohort to test as a possible diagnostic tool for different neuropsychiatric disorders (such as ADHD).

170. Distinct roles of the N2 and P3 in action stopping

András Puszta1,2, Carsten Bundt2, Oda van Jole2, Jørgen Kransberg2, Margrethe Hansen2, Nina Auestad2, Rene Huster1,2

1Helgeland Hospital, 2University of Oslo

170. Recent studies found an association of indices of response inhibition and the P3. Other work suggests though that this association may not be functionally specific and that P300 parameters also correlate with other behavioral measures. It has been concluded that the lack of functional specificity suggested by these correlations may be driven by the timing of earlier processing stages (e.g., sensory processing), rather than inhibitory processes per se. To shed light on the possible roles the P3 and the also commonly elicited N2 play in response inhibition, we investigated modulations of these stop ERPs in consecutive stop trials. Our hypothesis was that the difference between a successful stop and a succeeding unsuccessful stop ERP reflects decreased inhibitory control, while the difference between successful stop ERP preceded by an unsuccessful stop reflects increased inhibitory control as well as error-related adaptations in cognitive control. We analyzed two different datasets that contained EEG-data of a standard two-choice stop signal task. We focused on N2 and P3 amplitude and latency differences in two consecutive stop-trials. As expected, there was no difference in the ERPs when the two consecutive stop trials resulted in the same behavior. However, we observed that the N2 amplitude was larger and peaked later in unsuccessful stop trials that were followed by a successful stop. Consequently, the N2 amplitude was attenuated and peaked earlier in successful stop ERPs after a preceding unsuccessful stop. The modulation of the P3 wave was interestingly restricted to the unsuccessful-successful sequences, namely that P3 amplitude was larger and peaked later in unsuccessful stop compared to the preceding successful stop, but there was no such difference in the P3 of the unsuccessful stop that followed the sequences. These results suggest that the N2 reflects the necessary inhibitory control that is required for successful inhibition while P3 seems to be responsible for the increased cognitive control possibly triggered by the error after unsuccessful stop trials.

172. Causal evidence for the role of the frontoparietal network in rhythmic attentional sampling

Isabel Raposo1,2, Dr Sara Szczepanski3, Dr Kathleen Haaland4, Dr Tor Endestad5, Dr Ann-Kristin Solbakk5, Dr Dr Prof Robert T. Knight3, Dr Dr Randolph F. Helfrich1

1Hertie Institute for Clinical Brain Research, University Medical Center Tübingen, 2International Max Planck Research School for the Mechanisms of Mental Function and Dysfunction, University of Tübingen, 3Helen Wills Neuroscience Institute, UC Berkeley, 4Dept. of Psychiatry and Behavioral Sciences, University of New Mexico Health Sciences, 5Department of Psychology, University of Oslo

172. Objectives: Contemporary models of attention suggest that the environment is sampled in a rhythmic manner at around 4 Hz, with alternating periods of heightened and diminished perceptual sensitivity. Numerous neuroimaging studies have implicated frontal and posterior parietal cortical areas, commonly referred to as frontoparietal network (FPN), in attentional control. Yet, it remains unclear if the FPN is causally involved in rhythmic attentional sampling. Research question: We investigated the causal contributions of the lateral prefrontal cortex (lPFC) and posterior parietal cortex (PPC) on rhythmic attentional sampling. Materials and methods: We recorded simultaneous scalp EEG and eye-tracking from chronic stroke patients with focal lesions in either PFC or PPC, while they performed a spatial attention task. Participants were cued to allocate their attention to either the left or right visual hemifield and after a variable cue-target interval (1000 – 2000 ms) a target was shown. The varied cue-target interval was used to assess behavior as a function of time. Results: Our results reveal increased rhythmic behavioral sampling in the theta (2-7 Hz) and alpha (12-16 Hz) bands in patients. At optimal sampling phases, patients performed on par with healthy controls, while performance was decreased during phases of already diminished sensitivity. A highly comparable pattern with increased power in theta and alpha frequency bands was observed in the EEG data. Correlation analyses revealed that enhanced low frequency activity predicted increased behavioral fluctuations; thus, revealing a causal relationship between oscillations and rhythmic attentional sampling. Voxel-based spectral lesion mapping revealed that PFC is causally involved in theta-band sampling, while PPC mediates alpha-band sampling. Conclusion: Our findings demonstrate that lesions in the attention network impair attentional sampling in a phase-dependent manner. Thus, rhythmic attentional sampling is not an inherent feature but an inherent limitation of oscillatory brain activity. Furthermore, this set of findings reveals that lesion-induced EEG slowing has immediate effects on the temporal dynamics of cognition.

173. Lateralized theta oscillations in prefrontal cortex during the prioritization of working memory representations

Justin Riddle1, Trevor McPherson2, Atif Sheikh1, Haewon Shin3, Eldad Hadar1, Flavio Frohlich1

1University Of North Carolina At Chapel Hill, 2University of California, San Diego, 3University of New Mexico

173. Objectives: Prefrontal cortex exhibits low-frequency oscillations in the theta range (4-8 Hz) during the delay period of working memory (WM) tasks. However, WM tasks often conflate multiple cognitive processes. When a lateralized retrospective cue is presented during the delay period, a subset of information is prioritized while another subset is suppressed. In our previous experiment, we demonstrated that theta-frequency transcranial magnetic stimulation to the left anterior middle frontal gyrus (aMFG) during processing of a retro-cue improved WM capacity. This effect was particularly strong when the information in the contralateral visual field to stimulation was prioritized. However, our previous study did not directly measure electrophysiology and there is limited evidence for lateralized theta oscillations in the prefrontal cortex. Research question: In the present study, we sought to investigate the presence of lateralized theta oscillations in response to a retro-cue during the delay period of a WM task using invasive recordings of electrophysiology. Materials and methods: Twelve patients undergoing surgery for intractable epilepsy completed a WM task with a retro-cue during the delay period. We quantified the amplitude of theta oscillations from 0.1 to 0.5 seconds following the retro-cue using Morlet wavelet convolution and averaged across electrodes that overlapped with an a priori region of interest encompassing aMFG from the Automated Anatomical Labeling Atlas. Results: Ten of the participants were able to complete the task above chance performance. In those participants, we found a significant decrease in response time when the participant could utilize the retro-cue relative to an uninformative neutral-cue (t=-3.48, p=0.007). There was no overall increase in theta amplitude in aMFG for retro-cues relative to neutral-cues (p>0.1). However, using an individual differences analysis, we found that the participants with the greatest lateralized theta activity in aMFG in response to the retro-cue (left versus right) showed the fastest response time (z=2.26, p=0.024). Of note, left aMFG showed a numerically stronger relationship to performance (r=-0.829, p=0.0824), than the right aMFG (r=0.392, p=0.607). Conclusion: Our findings suggest that the anterior prefrontal cortex does indeed exhibit a lateralized increase in theta amplitude during the prioritization of relevant information.

174. Does meaningful background speech consume attentional resources? A pupillometry study

Dr. Paula Ríos-López1,2, Mr. Andreas Widmann1,3, Dr. Aurélie Bidet-Caulet4, Pr. Dr. Nicole Wetzel1,2,5

1Leibniz-Institute for Neurobiology (LIN), 2Center for Behavioral Brain Sciences (CBBS), 3Wilhelm Wundt Institute for Psychology, Leipzig University, 4Lyon Neuroscience Research Center (CRNL), Université de Lyon, 5University of Applied Sciences Magdeburg-Stendal

174. Objectives Conversations in the background can impair our performance in a cognitive task, even when the task itself is not linguistic. With this study, we tested the assumption that this decrease in performance occurs because semantic processing, albeit unintended, consumes attentional resources. Research question Does meaningful compared to unintelligible irrelevant speech unintendedly consume attentional resources leading to a decrease in performance in a non-linguistic task? Moreover, can we measure this effect at the physiological level using pupillometry? Materials and methods Forty-one participants performed an auditory oddball task while listening to task-irrelevant speech in the background. For the auditory oddball task, participants had to discriminate the duration of a chain of sounds consisting of a standard animal sound that was repeated frequently (80%) and a deviant sound which occurred rarely and unexpectedly (20%). The participants, who were native speakers of German and had neither formal nor informal contact with the French language, performed the duration discrimination task while hearing in the background a story in (native meaningful) German or (foreign non-meaningful) French. We also quantified changes in pupil diameter to measure the effect of speech meaningfulness upon attentional allocation at the physiological level. Bayesian statistics were used to analyse the data. Results Participants' pupil dilation was larger in response to the sounds (both standard and deviant sounds) of the auditory task when the speech in the background was unintelligible (French) compared to meaningful (German). This suggested that semantic processing of the native irrelevant speech consumed attentional resources, which led to fewer resources available for the processing of the sounds of the attentional task. By contrast, at the behavioural level, we did not find a significant effect of language meaningfulness upon participants’ reaction times or accuracy. Conclusion We provide evidence that, at the brain level, semantic processing of task-irrelevant meaningful speech occurs and consumes attentional resources. Moreover, our results stress the potential of pupillometry for the examination of subtle cognitive processes that might not be detectable at the behavioural level.

175. Urgency influences decision making but not motor cortical representation of perceptual evidence

Julia Rogge1,2, Prof. Dr. Gerhard Jocham1,3, Prof. Dr. Markus Ullsperger1,2

1ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory Processes, 2Institute of Psychology, Otto-von-Guericke University, 3Institute of Experimental Psychology, Heinrich Heine-University

175. Adaptive decision making requires accurate but also timely decisions. While evidence for the available options is accumulated over time, environmental constraints can require fast and sometimes premature responses at the cost of performance accuracy. Decision strategies and neural correlates underlying this speed-accuracy trade-off are not yet fully understood. Here, we explore the effect of urgency on evidence accumulation and performance in a slow perceptual decision-making paradigm and whether this is reflected in motor cortical lateralization of beta band oscillations (13 - 30 Hz). Thirty-four healthy humans performed a task designed to measure slow accumulation of evidence (Cisek et al., 2009) during 64-channel electroencephalography recordings. The task stimuli were an initial set of 15 tokens, which moved individually to one of two target locations, one at a time. Participants were asked to select the target where the majority of tokens would end up. Thus, we sequentially provided bits of information about the required choice. The trials had different sequences which provided either informative, initially misleading, or random evidence. In some conditions we induced urgency by rewarding fast decisions with monetary gains or saving time spent on the task. Firstly, we found that participants’ behavior does not follow the predictions of normative evidence accumulation. Instead, a simpler estimation of evidence strength was adopted and other heuristics were additionally predictive of performance. Secondly, monetary and temporal incentives reduced decision time at the cost of accuracy. Thirdly, the amplitude of beta-power lateralization in motor cortex after each token is modulated by the previous token and the accumulated evidence. In contrast to our expectations, this representation of evidence is not directly influenced by urgency over and above reaction times. However, modulations of beta-power lateralization by reaction times are indicative of indirect urgency taking effect through hasty reactions. With this slow-paced decision paradigm, we identified parameters influencing evidence accumulation and the amount of information needed for committing to a decision. Specifically, conditions of urgency could be induced by monetary and time rewards. Further, our data suggest that simplified evidence estimation facilitates efficient human decision making. This estimation is reflected in the strength of beta-power lateralization.

176. Post-conflict attention adjustments: A test for proactive mechanisms reflected in frontal-parietal oscillations.

Dr Manuela Ruzzoli1,2,3, Dr Robin A., A. Ince1, Prof Antonino Vallesi4,5, Prof Gregor Thut1

1Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University Of Glasgow, 2BCBL, Basque Center on Cognition, Brain and Language, 3Ikerbasque, Basque Foundation for Science, 4Department of Neuroscience & Padova Neuroscience Center, University of Padova, 5Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital

176. The conflict-monitoring hypothesis suggests that conflict triggers cognitive control dynamics for adaptative behaviour, for instance, via attention enhancement; however, low-level confounds in stimulus and response features question this claim. We propose here a way to resolve this controversy, implementing a design that allows us to test for high-level conflict control over attention adjustment through the study of brain oscillations. Participants have to respond to a Flanker target, appearing at a validly cued, neutral or invalidly cued location, while EEG is recorded, therefore cognitive conflict and spatial attention are manipulated independently. Our hypothesis is that adaptive control relies on cross-trial and cross-frequency fronto-parietal interactions. More specifically, we expect cognitive conflict at trial N (signalled by the power of oscillation in the mid-frontal theta band, 5-7 Hz -reality check #1) to trigger spatial attention deployment more effectively (lateralized posterior alpha-band asymmetry, 8-14 Hz reality check #2) at trial N+1, in preparation for the next target, with associated behavioural benefits. We plan to test this hypothesis at the group and the single participant levels. We use mediation analysis to test a model in which pre-target alpha (at trial N+1) is a mediator between the theta power effect at trial N and the behavioural adaptation effects in RTs at trial N+1. We ran a behavioural version of the paradigm (448 trials in total, 17 participants). We reached a significant main effect of conflict (p = 0.000002, ηp2 = 0.83), a significant main effect of attention (p = 0.000010, ηp2 = 0.59), and the Gratton effect approached significance (p = 0.06, ηp2 = 0.25). The pilot data were used for sample size estimation, together with an analysis of the previous literature on EEG. We concluded that a sample size of 60 participants can be considered safe to replicate previous behavioural results and the results in terms of alpha (attention) and theta (conflict) power in the EEG (power > 95%, α = 0.05). Nonetheless, we decided to adopt a sequential analysis. So far, we have collected EEG and behavioural data (672 trials in total) from 27 participants. The pre-registration document can be found at https://osf.io/s9zn5/?view_only=4832300a128847a08dd729a2cc2fb70c.

177. The role of the anterior insula in mental word reversal tasks involving distinct levels of cognitive load

Teresa Sousa1,2, Miguel Castelo-Branco1,2,3

1Coimbra Institute For Biomedical Imaging and Translational Research, University of Coimbra, 2Institute for Nuclear Sciences Applied to Health, University of Coimbra, 3Faculty of Medicine, University of Coimbra

177. Objectives: In this study, we aimed to investigate the neural circuitry of cognitive load, which refers to the limited capacity of our working memory system. The anterior insular cortex (AIC) has been shown to play a crucial functional role in higher-level cognition, even being suggested as a hub for cognitive control and executive processing. This hypothesis has been mainly focused on perceptual-decision paradigms, and albeit it is believed that AIC is involved in more general cognitive processing rather than modality- and domain-specific processing, this remains to be tested in a broader range of domains. Research question: We wanted to test whether the AIC response and connectivity with other executive function high-level regions, essential to flexible, goal-directed behavior and decision under uncertainty, are modulated by task difficulty. We were, thus, particularly interested in the medial prefrontal cortex (mPFC), the dorsolateral prefrontal cortex, and the anterior cingulate cortex. Materials and methods: We used functional magnetic resonance imaging and an executive function paradigm with three levels of task difficulty to examine the role of the AIC in tasks of variable difficulty. A varying degree of response difficulty was created by asking participants to mentally revert a previously shown word, which could be a palindrome, anagram, or pseudoword (in order of difficulty). The paradigm was tested in 20 healthy volunteers. Data analysis was run based on general linear model and generalized psychophysiological interaction (gPPI) analyses. Results: We found increased AIC activation as a function of the cognitive load, reaching its maximum contrast when comparing the lowest and highest difficulty. Although both right and left AIC were modulated by task difficulty, the most evident difference was found at the former. gPPI analysis revealed decreased connectivity between AIC and mPFC when increasing the cognitive load. Conclusion: Our findings support previous suggestions of the involvement of AIC in general cognitive processing by adding evidence of its increasing activity with increasing difficulty of a mental reversal task. Moreover, they are in line with the hypothesized salience network role as a hub between distinct networks, such as the one involved in cognitive control and the frontoparietal executive network.

178. Evidence for a common ‘cerebral clock’ controlling both perceptual and motor timing: a cross-domain comparison

Ms Magdalena Stanczyk1, Ms Klaudia Krystecka1, Dr Aneta Szymaszek1, Ms Anna Bombinska1, Prof. Elzbieta Szelag1

1Laboratory of Neuropsychology, Nencki Institute of Experimental Biology, Polish Academy Of Sciences

178. A number of data has suggested that Temporal Information Processing (TIP) constitutes the neural frame for human cognition and it is an essential feature of perception or action. It is commonly accepted that TIP has not a monolithic entity and several time domains (or operational processing windows) can be observed in controling perceptual and motor acts on various levels. The question is whether TIP may be controlled by a common timing system, or different mechanisms may be active depending on the temporal or cognitive domain. In this study we verified relationships between some tense of millisecond TIP in the perceptual task and hundreds of millisecond TIP in the motor task. We aimed at verification whether participants classified as more (or less) efficient in performance on millisecond domain, are characterised, in parallel, by distinct patterns of performance in hundreds of milliseconds domain. 68 normal subjects participated in this study (Mage = 23). They underwent two tasks: (1) the perceptual auditory temporal-order judgement task indexed by the temporal order threshold reflecting the temporal resolution in some tense of milliseconds, and (2) the manual tapping task performed in the maximum (frequency of ca. 5 Hz / inter-response-intervals of ca. 200 ms) and self-paced tempo (frequency of ca. 2 Hz / inter-response-intervals of ca. 500 ms) to evaluate temporal control in motor activity. The results revealed that subjects classified as more efficient timers in millisecond domain indicated also the faster speed (M = 155 ms) in maximum tempo than those less efficient ones (M = 178 ms). In contrast, in self-paced tempo the difference between more and less efficient timers was nonsignificant. These findings suggest the contribution of a common internal time keeping system (termed as a hypothetical ‘cerebral clock’) which controls subjects’ performance, independently of the cognitive (perceptual or motor) and temporal (some tense or around hundreds of milliseconds) domains. The nonsignificant differences reported in the self-paced tempo may reflect the strong contribution of other cognitive resources (e.g., attentional ones) providing high variability in performance, as compared to the less-variable maximum tempo. Supported by National Science Centre, Poland, grant no. 2018/29/B/HS6/02038.

179. Investigating the nature of inhibitory control impairments in males with Klinefelter syndrome

René Huster1, Christina Thunberg1, Krister Fjermestad1,2

1University Of Oslo, 2Frambu Resource Centre for Rare Disorders

179. Objectives Klinefelter syndrome (KS; 47,XXY) has repeatedly been associated with attenuated inhibitory control [e.g. 1]. However, KS has also been associated with verbal difficulties, altered sensory processing and other impairments in higher cognition [2, 3], making it hard to assess whether these attenuations are truly inhibitory in nature. Thus, we aimed to further investigate the underlying nature of inhibitory impairments in KS males. Research question Do findings of attenuated inhibitory control in KS males actually reflect inhibitory impairments or rather impairments in supporting processes? Methods In a between-group design, 18 KS males and 15 healthy male controls performed an auditory stop-signal task while we collected behavioral, electroencephalographic (EEG) and electromyographic (EMG) data. We extracted common task performance measures and complemented these this with estimates derived from a Bayesian modeling approach. From the EMG, we extracted the peak latency of partial responses in successful stop trials. From the EEG, we extracted event-related potentials (ERPs) in both go and successful stop trials. Results Our initial results indicated attenuated inhibitory control, with longer stop signal reaction times in KS males found in both conventional and Bayesian estimates. However, this was not matched by a difference in the EMG-derived measure of stopping latency, nor accompanied by differences in stop-related ERP components. Furthermore, we found that KS males responded faster and made more omission and commission errors, and our Bayesian modeling estimates indicated they were more likely to fail triggering both go- and stop-processes. We also found evidence that KS males differed from healthy controls in both early sensory-related and later motor-related ERPs in go trials. Conclusion Our results cannot unequivocally support impaired inhibitory control in KS males. Instead, the overall pattern of findings suggests that these apparent impairments might stem from lower-level deviations in auditory and motor processing, coupled with alterations in how different aspects of the task is weighted. References [1] Fjermestad et al., American Journal of Medical Genetics Part C 184 (2), (2020) [2] Wallentin et al., NeuroImage: Clinical 11, 239 (2016) [3] Gravholt et al., Endocrine Reviews 39 (4), 389 (2018)

182. Reward-context effects on perceptual decision-making

Intan K. Wardhani1, Luc Vermeylen1, Nico Boehler1

1Ghent University

182. Reward effects on cognitive functions have received a lot of scientific attention over the years, usually finding that associating reward to a particular task (component) ubiquitously improves performance. Yet, this work largely focussed on transient reward effects using concurrent no-reward trials as the main comparison. Relatively little work has looked at the potential side effects of the reward context on these no-reward trials. The present study investigates the influence of a reward context on no-reward trials presented in temporal proximity to the reward trials. We compare these no-reward trials with ‘neutral’ trials from pure no-reward blocks, in which performance is never rewarded. In the task, we present Gabor patches that deviate to varying degrees from a reference orientation, with participants having to discriminate the direction of this orientation shift. Our behavioural results show that participants are more accurate in the no-reward trials than in the neutral trials from the pure no-reward blocks (i.e., a positive reward-context effect), with little effect on response time. We extend the analysis to drift diffusion modelling, in order to better characterise the underlying process dynamics.

183. From context to action: Complementary roles of population dynamics and network oscillations

Jan Weber1,2, Dr Anne-Kristin Solbakk3,4,5,6, Dr Alejandro Blenkmann3,4, Dr Anais Llorens3,4,7, Dr Ingrid Funderud3,4,6, Dr Sabine Leske3,4,8, Dr Pal Gunnar Larsson5, Dr Jugoslav Ivanovic5, Prof Robert Knight7,9, Dr Tor Endestad3,4, Dr Randolph Helfrich1

1Hertie-Institute for Clinical Brain Research, 2International Max Planck Research School for The Mechanisms Mental Function and Dysfunction, 3Department of Psychology, University of Oslo, 4RITMO Centre for Interdisciplinary Studies in Rhythm, Time and Motion, University of Oslo, 5Department of Neurosurgery, Oslo University Hospital, 6Department of Neuropsychology, Helgeland Hospital, 7Helen Wills Neuroscience Institute, UC Berkeley, 8Department of Musicology, University of Oslo, 9Department of Psychology, UC Berkeley

183. Contextual cues and prior evidence guide human goal-directed behavior. The neurophysiological mechanisms that implement contextual priors to guide subsequent actions remain undefined. Using human intracranial recordings, we demonstrate that a shift from high to low prior contextual evidence is mirrored in a neural switch from an oscillatory to a continuous processing regime in human prefrontal cortex. At the population level, oscillatory and continuous population dynamics reflect dissociable signatures supporting distinct facets of encoding, transmission and execution of context-dependent action plans. Prefrontal population activity encodes predictive context and action plans in serially unfolding and orthogonal subspaces using a continuous processing regime, while theta oscillations synchronize action-encoding population subspaces to mediate the prefrontal-to-motor information transfer. Collectively, our results reveal how two key features of large-scale population activity, namely continuous population dynamics and oscillatory synchrony, operate in concert to guide context-dependent human behavior.

180. Consistency or fluctuation? How humans manage limited search capacity over consecutive uncertain choices

Ms Alice Vidal1, Dr Salvador Soto-Faraco1, Dr Rubén Moreno-Bote 1Universitat Pompeu Fabra

180. Human choice fluctuates over time, especially in uncertain environments. Imposing variability on choice behaviours can have contradictory effects on performance [1], [2]. Many everyday life situations (investments, exams) involve making multiple, risky decisions using limited resources (money, time, cognitive load). It remains unknown whether, under such conditions, humans favour a stable homogenous allocation strategy, or fluctuate over time intentionally, and how these strategies impact optimality. Here, we used the Breadth-Depth Apricot Task [3] to test human behaviour (N=40) on multiple choice scenarios manipulating the number of consecutive choices (block length), the capacity available per block (capacity ratio), and the environment richness (success probability). We compared the empirical results to a model of optimal resource allocation. We found that when available resources are scarce (low capacity), allocation fluctuates more from trial to trial. This leads to more skipped trials (no resources spent) to allow a more extensive search on some others. These fluctuations are amplified in longer blocks resulting in a significantly higher proportion of skipped trials than optimal, and suggesting that participants take advantage of the larger resources available to heighten exploration. Our results also indicate that these behavioural fluctuations owe to an intentional strategy, since the majority of skipped trials occur while capacity is still available and are followed by trials with high resource allocation. Although cognitively costly and not beneficial here in terms of outcome, strategic resource allocation may reflect an advantageous behaviour in everyday-life. Finally, we found that, when sampling in poor environments, participants spread their resources across many options (breadth), while in richer environments, they focus on a few of them (depth). These trade-offs between breadth and depth reflect close-to-optimal strategies and are not perturbed by fluctuations in resource allocation across trials. To conclude, our results reveal that humans follow complex search strategies promoting fluctuations in resource allocation which strike a balance between the obtention of relevant information and the risk to leave some choices to chance. Although deviating from optimality, these fluctuations have little impact on performance and prioritise anticipation and gathering of information, both beneficial behaviours in a constantly changing world. [1]https://doi.org/10.1098/rstb.2007.2098 [2]https://doi.org/10.1016/j.cobeha.2016.07.003 [3]https://psyarxiv.com/hmf74/

181. Violation of rule-based auditory patterns is detected independently of attention at an early level of the auditory hierarchy

Mr. Vegard Volehaugen1, Dr. Sabine Leske1, Dr. Tor Endestad1,2, Dr. Anne-Kristin Solbakk1,2,3, Dr. Alejandro Blenkmann1

1University of Oslo, 2Helgeland Hospital, 3Oslo University Hospital

181. Objectives. We aimed to explore how attention modulates the detection of rule-based auditory deviance. Auditory perception depends on the formation of expectations at successive stages of a predictive hierarchy. Consequently, detecting deviance from auditory rules defined by non-adjacent dependencies is predicated on expectation formation at levels of processing with wider temporal tuning, relative to local deviance detection. Research question. Processing at levels with broad temporal tuning has been suggested to rely on attentional engagement. However, recent evidence indicates attention-independent extraction of global regularities even at early levels of the auditory hierarchy. Based on these findings, we hypothesized attention-independent electrophysiological responses to global deviance. Further, we hypothesized that these attention-independent processing dynamics would be expressed both in the time and time-frequency domain. Materials and methods. Tone sequences forming rule-based patterns were presented to healthy adults (N = 20) while EEG was recorded, in a modified version of the local-global paradigm. Predictability was manipulated by infrequently presenting deviations from the regular pattern. Attention manipulation was implemented by two task conditions: (i) an attend auditory condition in which participants kept mental count of unexpected pattern deviants, and (ii) a distraction condition in which participants performed a demanding visual task. The interplay of attention and predictability was assessed in analyses of ERPs and time-frequency representations. Results. Analyses of ERPs revealed significant pattern deviance responses in the timeframe of the mismatch negativity, which did not differ between attention conditions. A later attention-contingent response was observed in the P3b time-window. Time-frequency analysis showed a protracted increase in theta/delta-band power following unexpected pattern deviants concomitant with a later-onset broadband suppression of alpha/beta-band power. These low-frequency power modulations depended on attentional focus towards the auditory stream. Conclusion. The attention-independent responses to rule-based auditory pattern deviance suggests that global regularities are represented at early levels of the auditory hierarchy. Thus, the encoding of regularities expressed over longer time-intervals is achieved without attention directed towards the auditory stream. Attentional engagement does, however, impact the processing dynamics reflected in modulation of lower frequency-bands.

186. Segmental WM fascicle microstructural damage early predicts the corresponding cognitive domain impairment in CSVD patients by AFQ

Dr. Lili Huang1, Prof. Yun Xu1

1Nanjing Drum Tower Hospital

186. Background: The clinical manifestation of cerebral small vessel disease (CSVD) varies from cognitive impairment or mood disorder to abnormal gait. Using diffusion tensor imaging (DTI) technique, damages to microstructural integrity of white matter (WM) has been detected. However, current analytical techniques on DTI data have limitations, and previous findings did not explain the variations in clinical symptoms of CSVD. Herein, a new DTI analytical technique, Automated Fiber Quantifcation (AFQ), was employed to investigatethe damage patterns of WM microstructural integrity and the relationship between tract profiles and clinical symptoms in CSVD patients. Methods: A total of 144 CSVD patients and 100 healthy controls who underwent neuropsychological measurement and diffusion tensor imaging (DTI) examination were recruited. Cognitive function, emotion and gait were assessed in each participant. Automated Fiber Quantification (AFQ) was used to extract altered fiber properties between groups, and partial correlation and general linear regression analysis were performed to assess the relationship between position-specific WM microstructure and cognitive function.

Results: Specific segments in association fibers、commissural WM ROIs and projection fibers were injured

in the CSVD group (P < 0.05, FWE correction), and these injured segmentswere interhemispheric symmetry. Besides, damages to specifictract profiles (including the posteromedial component of the right cingulum cingulate, the occipital lobe portion of the callosum forceps major, the posterior portion of the left superior longitudinal fasciculus and the bilateral anterior thalamic radiation (ATR)) were related to the dysfunction of specific cognitive domains. Among which, we found ATR as key tracts whose profiles were associated with cognitive dysfunction most. The left ATR was a special fiber bundle associated with episode memory and language function, whereas the fractional anisotropy (FA) values of the intermediate component of the right ATR were negatively correlated with executive function and gait evaluation. Conclusions: Damages to WM fiber bundles were extensive interhemispheric symmetry and segmental limited in CSVD. The bilateral ATR were strategically located fibers related to clinical functional deficits. Besides, the plasticity of the fiber properties in the right ATR might reflect the compensatory of fiber structural adaptability and be related to the severity of symptoms.

184. Arithmetic problem solving during auditory distraction: An fMRI study

Artturi Ylinen1, Minna Hannula-Sormunen2, Jake McMullen2, Erno Lehtinen2,3, Patrik Wikman1,4, Kimmo Alho1,5

1Department of Psychology and Logopedics, University of Helsinki, 2Department of Teacher Education, University of Turku, 3Education Academy, Vytautas Magnus University, 4Department of Neuroscience, Georgetown University, 5Advanced Magnetic Imaging Centre, Aalto University

184. Arithmetic skills are critical in everyday life, and cognitive control is a crucial part of arithmetic thinking. During calculation, demands for cognitive control are likely to vary based on, for example, problem complexity and the specific type of arithmetic task performed. Furthermore, in real-life situations, external factors, such as distracting noise in a classroom, often require further focusing efforts when performing calculations. In the present study, we examined the brain mechanisms that enable focusing on arithmetic problems while being exposed to auditory distraction. Healthy young adults (n=20) took part in a functional magnetic resonance imaging (fMRI) experiment where they performed three types of numerical tasks: 1) Solve arithmetic problems of varying complexities (e.g.,

‘6-4=’? or ‘3⋅(3-1)=’?), 2) Create equations (e.g., ‘8=?’ given as a target solution, to which, e.g., ‘2+2+2+2’ or ‘16:2’ can be given as an answer), and 3) Match numbers (e.g., ‘68’ is shown and the participant clicks ‘6’ and ‘8’ as a solution). The tasks were factorially combined with four auditory distraction conditions: 1) Meaningful speech, 2) Nonsense speech, 3) Modulated white noise, and 4) No distraction. The data were analyzed for main effects of Task and Distractor, and their interaction. Arithmetic tasks were observed to modulate activity in regions previously associated with arithmetic processing, such as the dorsolateral prefrontal cortex (DLPFC), intraparietal sulcus (IPS), and posterior inferior temporal cortex. Additional task-related activations were observed in the superior temporal gyrus and sulcus (STG/STS), probably relating to differential auditory processing of the distractors depending on task. Distractor-related activity was also found in the STG and STS, but, interestingly, even in the DLPFC and IPS, possibly indicating interference effects on task-related processing. Interactions of Task and Distractor were observed in the left STG, also likely relating to varying distractor-related processing during the different tasks. To our knowledge, our results represent the first attempt to understand the neural basis of focusing on arithmetic problems during auditory distraction. These results have implications for the cognitive neuroscience of arithmetic processing and distration-related cognitive control. This study was supported by the Strategic Research Council, Finland (grant no. 312529) and the Emil Aaltonen Foundation.

185. The effects of anodal tDCS of the frontoparietal network on higher cognitive functions

Marko Živanović1, Jovana Bjekić2, Saša R. Filipović2

1Faculty of Philosophy, University of Belgrade, 2Institute for Medical Research, University of Belgrade

185. Previous studies have found that anodal tDCS of prefrontal and parietal regions has the potential to promote executive functions and other building blocks of higher cognition. However, little is known on whether these effects can be translated to more complex cognitive functions. The present study explored the effects of anodal tDCS over dorsolateral prefrontal cortex (dlPFC) and posterior parietal cortex (PPC) on higher cognitive functions, namely, fluid reasoning (Gf) and crystallized abilities (Gf), visual processing (Gv), and cognitive speed (Gs). Forty-eight right-handed volunteers (20-35 years, 50% females) participated in the sham-controlled cross-over experiment with two parallel groups (left and right hemisphere). Participants underwent four experimental sessions (at least two weeks apart) in which they received unilateral tDCS (1.8mA) over dlPFC, PPC, simultaneous stimulation of dlPFC and PPC (0.9mA per loci), or sham. In each session, the reference electrode was placed on the contralateral cheek. The tDCS was applied for 20min (30s ramp-up and ramp-down periods), while in the sham condition, the current was delivered only at the beginning and at the end in a 30s rump up/down fashion. For the assessment of cognitive performance, parallel forms of the tests were used. Each cognitive factor was assessed using two tests half of which were verbal and the other half nonverbal. In comparison to sham, stimulation of the left dlPFC resulted in facilitation of cognitive speed in the verbal domain, while both right dlPFC and PPC tDCS increased visual processing. Interestingly, a domain-specific disruption of nonverbal fluid reasoning was observed following right dlPFC stimulation and the same trend was observed for right PPC stimulation. Finally, simultaneous tDCS of dlPFC and PPC did not induce modulatory effects on any cognitive test. Results indicate that the performance on complex cognitive tasks can be modulated by tDCS but that the effects may vary depending on the stimulation site, laterality as well as cognitive tasks that are used as outcome measures. A possibility that the observed effects are mediated by modulation of lower-level executive processes will be discussed.

277. Sleep enhances online retrieval consolidation of strongly encoded memories

Daniel Baena Perez1,2, Jose L. Cantero1,2, Mercedes Atienza1,2

1Laboratory of Functional Neuroscience, Pablo de Olavide University, 2CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases

277. Reactivation of recently acquired memories during repeated retrieval and post-encoding sleep have been shown to enhance retention, likely facilitating qualitative transformation of memory. Whether online and offline consolidation processes are two independent factors promoting long-term memory or whether they can interact to enhance memory retention is unknown. To clarify this issue, we evaluated whether the interplay of neural oscillations supporting memory consolidation during sleep is associated with enhanced representational variability across repeated retrieval in the next morning (an index of memory transformation); and whether this relationship is moderated by the strength of memory encoding. To achieve these goals, memory was tested 4 times after a full night of sleep in two groups of participants, the control group that slept 8 h the night before and that showed stable EEG activity patterns across study repetitions in the training session (an index of strong memory encoding); and the sleep restricted group that only slept 4 h and showed decreased neural stability patterns across multiple encodings of the same event (an index of weakly encoded memories). The mixed model analysis revealed significantly lower item-specific pattern similarity across repetitions of successfully retrieved associations compared with forgotten associations in the group that slept 8 h the night before training, but not in the sleep restricted group. These results indicate that strongly encoded memory traces are more likely to suffer transformation after retrieval than weakly encoded memories. Importantly, the study further revealed for the first time the importance of sleep in this process. Representational variability across repeated retrieval was tightly associated with the slow oscillation-spindle coupling during slow-wave sleep the previous night, but only in the control group. Taken together, these findings strongly support the notion that offline consolidation processes during sleep interact synergistically with subsequent online retrieval to facilitate transformation of strongly encoded memories.

278. Sleep facilitates recovery of weakly encoded memories by affecting reinstatement of encoding processes at retrieval

Daniel Baena Perez1,2, Jose L. Cantero1,2, Lluís Fuentemilla3,4, Mercedes Atienza1,2

1Laboratory of Functional Neuroscience, Pablo de Olavide University, 2CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, 3Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), 4Department of Cognition, Development and Educational Psychology, University of Barcelona

278. Sleep is crucial for the acquisition and consolidation of new memories. However, it remains unknown whether normal sleep could have a restorative impact on weakly encoded memories resulting from insufficient sleep the night before training. Here, we showed that 4 h of sleep restriction the night before training is sufficient to disrupt the process of memory stabilization underlying a repeated exposure to the same event. Using pattern similarity analysis, we found that multiple encodings of the same event elicited less stable EEG patterns in sleep-restricted participants relative to participants who had a full night of sleep before training. Decreased encoding strength was linked to enhanced temporal grouping of fast spindles by the slow oscillations the night of recovery sleep; and increased slow oscillation-spindle coupling was, in turn, associated with the reinstatement of encoding processes during retrieval the next morning. Importantly, the degree of slow oscillation-spindle coupling emerged as an important determinant of successful recognition only for memories that were weakly encoded during the previous awake time. The current study provides novel insights into the dynamic interplay between awake and sleep memory processes.

279. Brain networks involved in place recognition based on personal and spatial semantics

Dr. Ewa Beldzik1, Dr. Aleksandra Domagalik1, Dr. Magdalena Fafrowicz1, Dr. Halszka Oginska1, Prof. Tadeusz Marek1

1Jagiellonian University

279. Have you ever been to Krakow? If so, then you may recognize the Wawel Royal Castle from a picture due to your personal semantic memory, which stores all autobiographical facts and repeated events of your past. If not, then you might still recognize the Wawel Royal Castle and be able to locate it on a map due to your spatial semantic memory. When recognizing a familiar landmark, how does neural activity depend on your memory related to that place? To address this question, we combined a novel task - the Krakow paradigm - with fMRI. In this task, participants are presented with a set of pictures showing various Krakow landmarks, each followed by two questions – one about its location, and the other about seeing the place in real-life, to trigger spatial and/or personal semantic memory, respectively. Group independent component analysis of fMRI data revealed several brain networks sensitive to the task conditions. Most sensitive was the medial temporal lobe network comprising bilateral hippocampus, parahippocampal, retrosplenial, and angular gyri, as well as distinct frontal areas. In agreement with the contextual continuum perspective, this network exhibited robust stimulus-related activity when the two memory types were combined, medium for spatial memory, and the weakest for baseline condition. The medial prefrontal network showed the same, pronounced deactivation for spatial memory and baseline conditions, yet far less deactivation for places seen in real-life. This effect was interpreted as self-referential processes counterbalancing the suppression of the brain’s ‘default mode.’ In contrast, the motor, frontoparietal, and cingulo-opercular networks exhibited the strongest response-related activity for the spatial condition. These findings indicate that recognizing places based solely on general semantic knowledge requires more evidence accumulation, additional verbal semantics, and greater top-down control. Thus, the study imparts a novel insight into the neural mechanisms of place recognition. The Krakow paradigm has the potential to become a useful tool in future longitudinal or clinical studies.

280. The influence of visual sampling on the encoding and interference of naturalistic episodes

Hannah Bernhard1,2, Anna Gaidosch1, Sophie Geiss1, Christine Paulus1, Rob Rouhl3, Vivianne van Kranen-Mastenbroek4, Bernadette Jansma1,5, Peter de Weerd1,5, Mark Roberts1,5, Joel Reithler1,5

1Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 2Centre for Integrative Neuroscience, Maastricht University, 3Department of Neurology, Maastricht University Medical Center, 4Department of Clinical Neurophysiology, Academic Center for Epileptology Kempenhaeghe & MUMC, 5Maastricht Brain Imaging Center (M-BIC), Maastricht University

280. During memory encoding, our continuous stream of experience is discretized at contextual boundaries. Such transitions are signaled by increased hippocampal activity, as observed at the offset of short movie clips. This offset response predicts subsequent memory and may reflect binding of the individual elements of an episode. Showing a second movie clip impairs memory of the first clip, but does this indicate impaired binding due to a perturbed offset response? Since binding is thought to occur within 1s post-stimulus, we set out to test whether introducing a short delay in the second clip’s onset leads to reduced memory interference. Furthermore, visual sampling behavior, implemented through eye movements, is important for information binding. More fixations while viewing images increase hippocampal activation and memory performance. But how does visual sampling affect encoding of naturalistic episodes? Extensive sampling could reflect binding of a higher number of elements within an episode, leading to better memory performance, but could also reflect stronger retroactive interference effects if the second movie is sampled in depth. Here, we will investigate the temporal specificity of retroactive memory interference, the role of visual sampling in encoding of naturalistic episodes and their interaction. We will measure visual sampling via eye tracking during a memory encoding task. 52 participants (effect size = 0.4; power = 0.8) will view movie clips (8s, no audio, 60 trials) in three conditions (post-stimulus interference by a second movie clip at 0s, at 2s, and no interference), followed by a simple distractor task to prevent active rehearsal of movie content and pro-active interference effects. Memory performance will be measured after varying delay intervals (free and cued recall). With this task, we aim to elucidate how episodic memory is affected by visual sampling and post-encoding interference. We hypothesize that participants’ memory will be worse for movies with interference than without interference, and worse for 0s compared to 2s delay. Deeper visual sampling (i.e., more fixations or pursuits) of movies will be positively correlated with memory performance. Lastly, deeper sampling behavior during the interfering movie will be negatively correlated with memory performance of the first movie.

281. Hippocampal theta tracks audio-visual integration in natural speech and predicts episodic memory formation

Dr Emmanuel Biau1, Dr Danying Wang2, Dr Hyojin Park3, Prof Ole Jensen3, Prof Simon Hanslmayr2

1University Of Liverpool, 2University of Glasgow, 3University of Birmingham

281. Recent studies showed that the brain takes advantage of the synchrony between rhythmic visual and auditory stimulations peaking at 4Hz theta rate to form new episodic memories. We extended this principle to the audio-visual speech domain where syllable boundaries temporally align lip movements with speech sounds on a common theta phase. We hypothesised that corresponding theta activity in the hippocampus tracks audio-visual synchrony during speech perception to bind information and form new memories. We designed a memory task presenting participants with short audio-visual clips of speakers’ face engaged in conversations, for which lip movements and auditory speech signals were either synchronous or asynchronous. In a subsequent retrieval test, participants were visually cued with a face picture taken from an audio-visual clip, and they had to recall which auditory speech was associated with the face cue during previous encoding. We recorded participants’ magneto-encephalogram signal (MEG) to address whether hippocampal oscillatory dynamics during encoding and retrieval predicted memory performances, depending on audio-visual speech synchrony. Results revealed that audio-visual asynchrony decreased theta power responses in the hippocampus during speech encoding, which predicted differences of memory accuracy between synchronous and asynchronous conditions. Further, by applying partial information decomposition analysis (PID), we showed that hippocampal theta oscillations tracked better redundant information conveyed both by lip movements and auditory envelope when they temporally aligned during synchronous audio-visual speech encoding as compared to the asynchronous condition. Altogether, these preliminary results show that theta oscillations from the hippocampus track audio-visual speech integration to form new episodic memories.

282. Neural mechanisms underlying the positive impact of stress on memory encoding and consolidation

Anne Bierbrauer1, Marie-Christin Fellner1, Oliver T. Wolf2, Nikolai Axmacher1

1Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 2Department of Cognitive Psychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum

282. It is well established that moderate stress improves memory encoding and consolidation. Specifically, objects that are manipulated during and thus central to a stressful episode – the Trier Social Stress Test (TSST) – are subsequently better remembered than non-manipulated control objects, and this effect is reduced in a non-stressful control episode (the “friendly-TSST”, f-TSST). Here, we attempted to investigate the neural basis underlying the improved memory for central objects in the stressful task. This is putatively related to changes in the neural representations of specific experiences, i.e. their memory traces. Participants were subjected either to the TSST (n = 33) or to the f-TSST (n = 31). On the next day, we assessed memory for objects from this episode and assessed the neural representations of these objects via functional magnetic resonance imaging (fMRI). Cortisol levels were elevated in participants that had undergone TSST and did not differ from baseline in f-TSST participants. We replicated the positive effect of stress on recognition memory for central objects. In addition, we showed that the memory improvement for objects that were encountered in a stressful episode related to differences in the neural representations of these objects in the left amygdala. Using fMRI, we found that stress specifically altered the representations of central objects: Compared to control objects, they became more similar to one another and more distinct from objects that were not part of this episode. Furthermore, higher similarity of central objects to the main stressor – the faces of the stress-inducing committee members – predicted better memory. This suggests that the central objects were closely integrated into a stressor-centered memory representation. Our findings provide mechanistic insights into how stress shapes the memory trace and have profound implications for neurocognitive models of stressful and emotional memory.

284. From brain waves to memory boost: Personalized frequency-modulated transcranial electric stimulation over posterior parietal cortex for associative memory enhancement

Dr Jovana Bjekić1, Dr Marko Živanović2, Dunja Paunović1, Katarina Vulić1, Uroš Konstantinovic1, Marija Stanković1, Dr Saša R. Filipović1

1University of Belgrade, Institute for Medical Research, 2University of Belgrade, Faculty of Philosophy

284. Non-invasive brain stimulation (NIBS) has gained increased interest in research of associative memory (AM) and its impairments. However, the one-size-fits-all approach yields inconsistent effects, thus putting forward the need for the development of personalized frequency-modulated NIBS protocols to increase the focality and the effectiveness of the interventions. Specifically, transcranial alternating current stimulation (tACS) and transcranial oscillatory current stimulation (otDCS) with theta-band frequencies (4-8Hz) are promising opportunities for memory neuromodulation. The aim of the current study was (1) to develop a method for extracting the individual theta-band frequency (ITF) to be used as an input parameter for personalized theta-modulated tACS and otDCS; (2) to assess the effects of tACS and otDCS in comparison to constant anodal tDCS and sham on different AM measures including short-term AM, delayed recognition, and cued recall. In a sample of 42 healthy volunteers, we extracted the ITF from the EEG signal recorded during successful encoding in an AM task, for each participant. In cross-over counterbalanced design, different stimulation protocols (tACS/otDCS/tDCS/sham) were delivered in separate sessions (7 days apart) for 20 minutes over posterior parietal cortex. The tACS and otDCS were applied using the ITF. Participants completed a series of AM tasks both during and following the stimulation. The study showed mixed results - depending on the outcome measure we observed either better AM performance in relation to tACS, otDCS, and tDCS or no effects of stimulation. We will discuss ITF-extraction challenges and possible methodological and conceptual explanations for the inconsistent effects.

283. Towards cross-linguistic assessment of associative memory

Dr Jovana Bjekić1, Dunja Paunović1, Eman Aldoughan2, Ali H. Al-Hoorie3, Fakieh Alrabai3, Luiz Biondi4,5, Milan Brázdil6,7, Po Ling Chen8, Luis Coelho9, Martin Dresler10, Mahmoud Elsherif11, Saša R Filipović1, Luise Graichen12, Joana Grave4,5, Inga Griskova-Bulanova13, Bartosz Gula14, Luka Juras15, Lenka Jurkovičová6,7, Boris Konrad10, Uroš Konstantinović1, Maida Koso-Drljević16, Audrey Mazancieux17, Katarina Mišetić16, Anja Podlesek18, Dikla Rapoport19, Lars Matthias Reich14, Alexandra Ružičková7, Kristian Sandberg20, Kathleen Schmidt21, André Silva4, Jordi Solé-Casals22, Marija Stanković1, Vojtěch Svoboda7, Diana Trujillo-Rodriguez23, Kostas Tsagkaridis24, Monika Undorf25, Isabella Wagner12, Grace Wang26, Michal Wierzchon27, Hoo Keat Wong8, Andrea Vranić15, Katarina Vulić1, Marko Živanović28, Daniel A Levy19

1University of Belgrade, Institute for Medical Research, 2King Faisal University, 3Independent researcher , 4University of Aveiro, 5William James Center for Research – Aveiro, 6Central European Institute of Technology, 7Masaryk University, 8University of Nottingham, 9Instituto Superior de Engenharia do Porto, 10Donders Institute, Nijmegen, 11University of Birmingham, 12University of Vienna, 13Vilnius University, 14University of Klagenfurt, 15Department of Psychology, University of Zagreb, 16University of Sarajevo, 17UNICOG, NeuroSpin center, CEA, INSERM, Université Paris-Sud, Université, Paris-Saclay, Gif-sur-Yvette, 18University of Ljubljana, 19Reichman University, 20Center of Functionally Integrative Neuroscience, Aarhus University, 21Soutern Illinois University, 22University of Vic - Central University of Catalonia, 23Boston University, Graduate Medical Sciences, 24Theological School of the Church of Cyprus, 25University of Mannheim, 26Auckland University of Technology, 27Jagiellonian University, 28Faculty of Philosophy, University of Belgrade

283. Associative memory (AM) is conceptualized as the ability to form links between two previously unrelated pieces of information so that the subsequent presentation of one activates the memory of the other. Unlike other types of memory for which standardized assessment tools exist, AM is assessed mostly by ad hoc tasks designed to tackle specific research questions that are not meant to capture AM as a universal cognitive ability. Typically, AM is assessed using paired-associate paradigms with unimodal (e.g., word pairs) or multimodal (e.g., face-word) stimuli sets. In culturally diverse and multilingual societies, the application of these paradigms can lead to an unreliable and biased assessment of memory abilities. To address this issue, we developed an AM paradigm that combines key aspects of AM assessment – associative encoding, associative recognition, and cued recall, as well as implicit AM effect. The stimuli for the task - pictures of common objects and natural scenes - have been selected to minimize language and culture effects. The task has been developed using free software (OpenSesame) and stimuli, in both online and offline mode of administration, thus enabling wide and free use for research purposes across different settings. The large-scale international collaboration is set to adapt the task into 25 languages so far, including Arabic, Bosnian, Czech, Catalan, Chinese, Croatian, Danish, Dutch, English, Estonian, French, German, Greek, Hebrew, Hungarian, Italian, Lithuanian, Malay, Polish, Portuguese, Romanian, Serbian, Slovak, Slovene, and Spanish. Data is collected across 26 countries with a total of 34 samples (150-300 participants each) to assess the psychometric properties of the task and crosslinguistic (in)variance of the memory performance. The collaboration is expected to result in a comprehensive multilingual AM assessment tool, that is freely available for research use.

285. Local vs global effects of schemas on facilitation of learning

Levan Bokeria1, Dr. Dingrong Guo1,2, Prof. Richard Henson1,3

1MRC Cognition and Brain Sciences Unit, University of Cambridge, 2School of Psychological and Cognitive Sciences, Peking University, 3Department of Psychiatry, University of Cambridge

285. Schemas are known to have a beneficial effect on learning of new congruent information. Human schema experiments typically last multiple days and schemas consist of knowledge of picture-location paired-associates (PAs) on virtual 2-dimensional boards. We propose a study to test (i) whether such schematic influences can emerge in minutes instead of days and (ii) whether schema-components have a local or global effects. The participants will learn locations of 6 hidden PAs on 5 different boards. 4 of these boards will also contain 6 visible PAs shown on each learning trial. On the first schema-consistent board, the visible PAs will remain stable across trials, while on the second schema-inconsistent board they will keep swapping locations with each other. On the third schema-landmark board, 2/6 visible PAs will remain stable and act as landmarks while others randomly relocate, whereas on the fourth random board all visible PAs will randomly relocate. The fifth no-schema control board will have no visible PAs. Crucially, on the schema-consistent, schema-inconsistent and schema-landmark boards, 2/6 hidden PAs (near-PAs) will be located adjacent to visible PAs while the rest (far-PAs) will be far away. On each board, each hidden PA will be learned across 8 trials. Learning speed will be measured by averaging accuracy for the last 4 repetitions. If schema effects are global and all visible PAs influence learning of hidden PAs, schema-consistent near-PAs will be learned faster than schema-landmark ones. However, if effects are local, near-PA learning will be equal across these boards, while on the schema-consistent board near-PAs will be learned faster than far-PAs. We plan a Bayesian sequential design with maximum N to examine support for the hypothesis that near-PA learning is (H1) or is not (H0) faster than far-PA learning. Setting BF10 criterion to 10, BF01 to 6 and max-N to 110, we achieve 82% chance of supporting H0 if there is no effect and 99.1% chance of supporting H1 assuming a medium effect size of 0.5. We hope that results from our study will add validity to shorter paradigms for studying schemas and elucidate the mechanisms by which schemas accelerate learning.

286. Lateralized EEG activity reflects retinotopic and screen-centered coordinates during visual short-term memory retention

Niko Busch1, Svea Schröder, Wanja Mössing 1University of Münster

286. Visual short-term memories (VSTM) are stored in the visual system in a lateralized manner, whereby each hemisphere primarily stores information from the contralateral hemifield. This lateralization is reflected in two electrophysiological markers of VSTM: the contralateral delay activity (CDA) and alpha-band lateralization. When the eyes move during memory maintenance, do these lateralized signals primarily reflect the memoranda’s retinotopic location before the saccade, or their saccade-independent spatiotopic location? To address this question, four objects, each consisting of two colored squares, were presented to the left, right, above, and below initial fixation, and participants memorized the colors of one of these objects. During the pre-saccade maintenance interval, both CDA and alpha power were lateralized according to the location of the memorized object. Participants then made a left or right saccade, or maintained central fixation. After another post-saccade delay interval, participants performed a color change detection task at the new fixation. During the post-saccade delay interval, the CDA continued to be lateralized relative to the memorized object’s original retinotopic location, even if the saccade had now moved that location into the opposite hemifield. By contrast, alpha power was lateralized depending on saccade direction and relative to the objects’ post-saccadic location (i.e. at the screen’s center). To determine whether post-saccadic alpha lateralization reflects a memory-specific spatiotopic representation or simply a bias towards to screen center, we conducted a second experiment that included a control condition without any memory task. Again, the CDA showed a retinotopic lateralization pattern before and after the saccade. Alpha lateralization after the saccade was again determined by saccade direction, even when the task did not require any memory maintenance. These results indicate that the CDA reflects memory representations coded in retinotopic coordinates, while alpha lateralization in this task reflects a lingering trace of attention towards salient, but not necessarily task-relevant screen locations.

287. How boundaries sculpt memories

Varnan Chandreswaran1, Dr David Stawarczyk1, Dr Anne Bierbrauer1, Dr David Clewett2, Dr Iva Brunec4, Dr Gillian Coughlan5, Prof Lila Davachi3, Prof Hugo Spiers6, Prof Michael Hornberger5, Ms Marta Silva7,8,9, Prof Lluis Fuentemilla7,8,9, Prof Morgan Barense4,10, Dr Jason Ozubko11, Dr Lukas Kunz12, Ms Dorothea Pink1, Prof Nikolai Axmacher1, Prof Hui Zhang1

1Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 2Department of Psychology, University of California, 3Department of Psychology, Columbia University, 4Department of Psychology, University of Toronto, 5Norwich Medical School, University of East Anglia, 6Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, Department of Experimental Psychology, University College London, 7Cognition and Brain Plasticity Group, Bellvitge Institute for Biomedical Research, 8Department of Cognition, Development and Educational Psychology, University of Barcelona, 9Institute of Neurosciences, University of Barcelona, 10Rotman Research Institute at Baycrest, 11Department of Psychology, State University of New York at Geneseo, 12Department of Biomedical Engineering, Columbia University

287. OBJECTIVE Boundaries are shifts between episodes that segment our continuous stream of experiences into discrete events and modulate diverse aspects of memory. Moving from the city streets to a park for example can be perceived as a shift from one episode to the next. Previous research found that neuronal patterns underlying different events are integrated within episodic boundaries and that the recall of items is enhanced when they are near a perceptual boundary (e.g., switch off a sound). In addition, the continuity of forming a mental map of a layout is interrupted by spatial boundaries (e.g., walls). However, it is unclear whether and how these boundary effects relate with each other. RESEARCH QUESTION In this project, we studied the link between behavioural patterns of participants across multiple spatial navigation and event segmentation paradigms. More precisely, we aimed to simultaneously investigate different types of boundary effects (i.e., spatial boundaries, episodic boundaries, and perceptual boundaries) and their relations to each other. MATERIALS AND METHODS N = 25 participants performed six established and two new paradigms across two successive days. Four of these paradigms investigated the effects of spatial boundaries, where we assessed spatial learning, wayfinding and path integration performance in a virtual environment that contained a boundary. Four event segmentation paradigms addressed episodic and perceptual boundaries where we investigated how boundaries modulate the memory for previously experienced pictures and movies. RESULTS Our preliminary results showed effects of boundaries. Subjects had an enhanced recall of contextual information at boundaries and needed more time to mentally replay segments of a movie that contained a boundary. When subjects could not remember a location well, they detoured towards spatial boundaries. We found that the performance of different spatial navigation paradigms was partially related with each other. However, we did not find correlations between the memory outcomes of different event segmentation paradigms and there were no strong intercorrelations of different types of boundary effects. CONCLUSION Other than expected we did not find obvious relationships between boundary effects in spatial navigation and episodic memory. The effects of boundaries in different paradigms might therefore reflect different underlying processes.

288. The role of STDP in human memory formation

Qiaoyu Chen1, Prof Kimron Shapiro1, Prof Simon Hanslmayr2

1University Of Birmingham, 2University of Glasgow

288. Although spike timing dependent plasticity (STDP) is believed to be important for neural communication and plasticity in human episodic memory, causal evidence is lacking due to technical challenges. In-vivo and in-vitro studies reveal a narrow STDP window (10-30 ms) corresponding to 30-100 Hz, i.e., the frequency band in gamma. Importantly, evidence from rodent and human intracranial EEG studies indicates that increased fast (60-80 Hz) gamma oscillations correlate with episodic memory encoding, while increased slow gamma oscillations (<50 Hz) correlate with episodic memory retrieval. To examine the causal role of STDP in human episodic memory encoding, healthy human participants were invited to complete a memory task where the STDP function was simulated during encoding by manipulating the temporal delay (phase lag) between the left and right visual cortices. The simulation was achieved by displaying one flickering (at 60 Hz) movie to each of the left and right visual fields, either in-phase (0 degrees) or anti-phase (180 degrees). EEG was recorded to verify the manipulation of phase lag. Participants were instructed to make associations between each pair of movies as the implicit and explicit memory were later tested. Behavioral results indicated no significant difference between in-phase and anti-phase conditions regarding recollection and familiarity of movie pairs. Nevertheless, consistent with previous findings, preliminary results confirm the ability to manipulate visual hemifields with a high temporal precision (8.33 ms). Further analysis is needed to understand the effects of the simulated STDP function on episodic memory and implicit memory.

290. Neural similarity between encoding and retrieval as a function of item typicality

Dr Emma Delhaye1, Dr Moreno Ignazio Coco2, Dr Mohamed Ali Bahri3, Dr Ana Raposo1

1Cicpsi, Faculdade de Psicologia, Universidade de Lisboa, 2Department of Psychology, Sapienza, University of Rome, 3GIGA-CRC IVI, University of Liege

290. Objective: Concept typicality is a key semantic dimension supporting the categorical organization of items based on their features, such that typical items (e.g., cat) share more features with other members of their category (mammal) than atypical items (e.g., whale), which are more distinctive. Typicality effects manifest in better accuracy and faster response times during categorization tasks, but higher performance for atypical items in episodic memory tasks, due to their distinctiveness. At a neural level, typicality has been linked to the anterior temporal lobe (ATL) and the inferior frontal gyrus (IFG) in semantic decision tasks, but patterns of brain activity during episodic memory tasks remain to be understood. Research question: We investigated the neural correlates of typicality in episodic memory to determine the brain regions associated with semantic typicality, and uncover effects arising when items are reinstated during retrieval. Materials and methods: In an fMRI study, 26 healthy young subjects first performed a category verification task on words representing typical and atypical concept (encoding), and then completed a recognition memory task (retrieval). Univariate analyses were used to separately analyse the encoding and retrieval phases, and we then compared the similarity of the representations from encoding to retrieval (ERS) using Representation Similarity Analyses. Results: In line with previous literature, we observed higher accuracy and faster response times for typical items in the category verification task, while atypical items were better recognized in the episodic memory task. During category verification, we observed a greater involvement of the angular gyrus for typical items and the IFG for atypical items. During the correct recognition of old items, regions belonging to the core recollection network were activated, and ERS analyses showed that typical items were reinstated more than atypical ones in several regions including the ATL. Conclusion: Our findings confirm the centrality of the ATL in the processing of typicality while extending it to memory retrieval. Moreover, we demonstrated that the correct retrieval of typical items requires finer-grained processing, evidenced by greater item-specific reinstatement in the ATL, which is needed to resolve their confusability with other members of the category due to their higher feature similarity.

289. Fast Mapping (FM) in adults using implicit memory measures? Methodological but not result replication of Coutanche and Thompson-Schill (2014)

Dr Elisa Cooper1, Dr Roni Tibon1,2, Dr Andrea Greve1, Prof Richard Henson1,3

1MRC Cognition and Brain Sciences Unit, University of Cambridge, 2School of Psychology, University of Nottingham, 3Department of Psychiatry, University of Cambridge

289. Fast cortical mapping is believed to be an incidental learning process that allows rapid, cortical-based memory formation, independent of episodic memory. Using an implicit reaction time measure and a fast mapping (FM) paradigm, Coutanche and Thompson-Schill (2014) reported evidence of non-word integration within 10-minutes of encoding (i.e., same-day lexicalisation). Here, Experiment 1 was a methodological replication, with power over 80% (N=56) using their published effect size, that found no evidence of same‐day lexical integration. Instead, a post-hoc analysis suggested evidence of semantic priming. Experiment 2 (pre-registered on OSF) tested whether semantic priming remained when making the stimulus set fully counterbalanced. Healthy adults were tested online in a between- participants design; N=180 providing power over 80% to detect the semantic priming effect and lexicalisation effect. Neither effect was detected, and Bayes Factors provided evidence for no effect. These results, together with our previous work, question whether fast cortical mapping exists in healthy adults, at least using this FM paradigm.

291. Maintenance of Bound or Independent Features in Visual Working Memory is Task-dependent

Ms Ruoyi Cao1, Prof. Yoni Pertzov1, Prof. Zaifeng Gao2, Pro. Leon Deouell1

1The Hebrew University Of Jerusalem, 2Zhejiang University

291. Over the last decade, seemingly conflicting results were obtained regarding the question of whether features of an object are stored separately, or bound together, in visual working memory. Many of these studies are based on an implicit assumption about a default, or fixed, mode of working memory storage. In contrast, here we asked whether the anticipated memory probes used in a given experiment might determine the format in which information is maintained in working memory, consistent with its task-oriented function. In order to test this flexible maintenance hypothesis, we recorded EEG while subjects performed a delayed-match-to-sample task with different requirements and load. In Experiment 1, by contrasting conditions with and without the requirement of maintaining bound features, we found significant differences in EEG signals recorded in central-parietal channels while controlling for differences in visual stimulation. Such difference was confirmed by multivariate pattern analysis (MVPA). Moreover, behavior results, topographical distributions and cross-contrast MVPA decoding jointly suggested that this effect is not the same as task load effect. These results were confirmed in Experiment 2 with an independent group of subjects with the same paradigm, providing reliable evidence that the format of object maintenance in visual working memory could be flexibly shaped by the current task.

292. Individual differences in mesolimbic and cortico-hippocampal functional connectivity predict how curiosity and information prediction errors enhance memory

Kathrin C. J. Eschmann1, Ashvanti Valji1, Vera Dehmelt1, Duarte F. M. M. Pereira1, Matthias J. Gruber1

1CUBRIC, School of Psychology, Cardiff University

292. Curiosity – broadly defined as the desire to acquire new information – enhances later memory. In addition, positive information prediction errors (IPEs) – that is, when information is perceived as more interesting than previously expected – can also facilitate later memory. Curiosity has been associated with dopaminergic activity within the mesolimbic circuit, particularly, in the ventral tegmental area (VTA) and the nucleus accumbens (NAcc). Prediction errors have also been linked to dopaminergic mesolimbic activity but furthermore suggest a critical role of the anterior cingulate cortex (ACC) and the hippocampus. Given that the memory-enhancing effects of curiosity and IPEs differ starkly between individuals, the question arises whether this inter-individual variability depends on individual differences in intrinsic functional connectivity between brain regions related to curiosity and IPEs. To answer this question, 80 participants took part in a trivia paradigm along with a separate 10-minute resting-state fMRI scan. During the trivia paradigm, participants were presented with trivia questions and their associated answers, to which they had previously rated their curiosity. Participants were asked to indicate how interesting they found the answer and IPEs were calculated as the difference between the interest and initial curiosity rating. Memory of the trivia answers was tested in a cued recall 24 hours later and memory enhancements were calculated as recall differences for the conditions of curiosity (high curiosity – low curiosity) and IPEs (positive IPEs – negative IPEs). Notably, both high curiosity and positive IPEs enhanced memory independently. For the relationship between memory enhancements and intrinsic functional connectivity, a double dissociation was found. Inter-individual differences in VTA-NAcc resting-state functional connectivity were associated with the magnitude of curiosity-based memory enhancements but not with IPE-related memory enhancements. In contrast, inter-individual differences in ACC-hippocampus resting-state functional connectivity were associated with the magnitude of IPE-driven memory enhancements but not with curiosity-related memory enhancements. These findings demonstrate that individual differences in task-independent intrinsic functional connections between dopaminergic mesolimbic and cortico-hippocampal regions account for the extent of curiosity-related and IPE-driven memory enhancements, stressing the importance to differentiate effects of curiosity and IPEs on learning and memory.

293. The effects of curiosity states on sleep-dependent memory consolidation for incidental spatial information

Mr Duarte Freyer Martins de Melo Pereira1, Ms Holly Kings1, Dr Matthias J. Gruber1

1Cardiff University

293. Curiosity is understood as an intrinsic motivational state driving individuals to seek information and close knowledge gaps. Recent studies have shown that curiosity enhances answer recall for trivia questions that are previously rated as inducing high curiosity. These curiosity states also enhance memory for information encountered incidentally (i.e., incidental faces). However, it is unclear if these incidental information spill-over effects occur for other types of information and whether these are enhanced via sleep-dependent memory consolidation. We investigated (i) whether curiosity enhances memory for incidental spatial information and (ii) if these memory enhancements interact with sleep consolidation. To study this, we presented participants with trivia questions and shortly after revealed the answers. During the answer anticipation phase, objects were presented at random locations. Participants’ free recall memory for trivia answers and cued recall for the object locations were tested twelve hours later. Critically, one group experienced a period of wake during this delay whereas the other experienced a night of sleep. For the sleep group, we used ambulatory EEG headbands to examine whether individual differences in polysomnography measures predict the magnitude of curiosity-enhanced memory for incidental information. Consistent with previous findings, we found an enhanced recall for trivia answers associated with high- compared to low-curiosity answers independent of group. Findings also suggest that during anticipation object locations observed leading up to the answers, are recalled more spatially accurately twelve hours later for high-curiosity associated objects versus low-curiosity associated objects. However, this only occurs for the sleep group and only for objects presented closer to question presentation. This suggests that curiosity’s effect on memory consolidation for incidental spatial information is temporally restricted to proximity of curiosity elicitation. Unexpectedly, polysomnography data revealed that individual differences in sleep stage duration showed no relationship with overall memory for spatial information and did not correlate with curiosity-related memory improvements. Our results are consistent with recent findings on how the temporal proximity to the elicitation of curiosity affects memory for incidental information. Furthermore, our findings suggest that the curiosity-related spill-over memory effect might be evident for different types of stimuli that are enhanced by sleep-dependent consolidation.

294. Prefrontal stimulation disrupts motor memory consolidation at the micro-time scale

Mareike Gann1, Nina Dolfen1, Edwin Robertson2, Genevieve Albouy1,3

1KU Leuven, 2University of Glasgow, 3University of Utah

294. Objectives and research question: Functional brain responses in hippocampo-cortical and striato-cortical networks play a critical role in motor sequence learning (MSL). We have recently shown that prefrontal brain stimulation applied prior to initial MSL can alter hippocampo-frontal as well as striatal responses during task practice. While brain responses in these regions are also known to be critical for motor memory consolidation, no studies have ever investigated whether such stimulation approaches can modulate this process. In the present study, we investigated whether prefrontal stimulation prior to initial MSL can alter the behavioral and neural correlates of motor memory consolidation that occurs at the micro-time scale. Materials and methods: 69 young healthy participants (age range 19-29 years, 46 females) were included in this study and received either control or active theta-burst stimulation prior to MSL. Task-related fMRI data was extracted from the short rest intervals - interleaved with task practice - that are known to support motor memory consolidation at the micro-time scale and preprocessed using SPM12. Results: Our behavioral results show that stimulation did not modulate overall performance on the MSL task. However, data analyses at the micro time-scale indicate that active stimulation as compared to control stimulation resulted in higher micro-online gains in performance speed (i.e., performance changes within practice blocks) and lower micro-offline gains in performance speed (i.e., performance changes across practice blocks reflecting processes taking place during the inter-practice rest periods). These results suggest that active prefrontal stimulation altered the balance between micro-online and micro-offline processes during initial MSL. Analyses of brain responses showed that active - as compared to control - stimulation disrupted hippocampal and caudate activity during the inter-practice rest intervals. Stimulation also altered the relationship between hippocampal activity during the inter-practice rest intervals and micro-offline gains in performance. Conclusion: In sum, our results indicate that active prefrontal stimulation prior to MSL altered the balance between micro-online and micro-offline processes at the behavioral level as well as hippocampal and striatal activity during the micro-offline episodes. Altogether, our findings suggest that prefrontal stimulation prior to MSL hindered fast motor memory consolidation processes, occurring at the micro-time scale.

295. How Expectancy and Prediction Error modulate Episodic Memory in Normal Aging

Dr Andrea Greve1, Dr Elisa Cooper, Dr Roni Tibon, Prof Richard Henson 1MRC CBU, University of Cambridge, UK

295. While many aspects in our environment differ continuously, some encounters are highly repetitive and follow a schema which confers the ability to generate predictions. Recent research has focused on the fate of our memories that conflict with our predictions or schemas and found that they are better remembered than unrelated events. Yet events that conform to our schemas can also be better remembered, producing a “U-shaped” function of congruency: superior performance for both schema incongruent and congruent events relative to unrelated events. This behavioural prediction of the ‘Schema-Linked Interactions between Medial prefrontal and Medial temporal region’ (SLIMM) framework (1) has recently been confirmed in studies testing healthy young adults (2). However, direct evidence for the neural prediction that the incongruency advantage is mediated by the Hippocampus, while the congruency advantage is driven by the Medial Prefrontal Cortex (mPFC), is still lacking. Here we examined this potential neural dissociation in healthy ageing with one in-person study and one online study, each comparing 24 Older and 24 Young participants, who completed a procedure very similar to Greve et al. (2). If the Hippocampus shows greater decrease in volume during normal ageing than the mPFC, we expect aging to attenuate the incongruency advantage to a greater extent than the congruency advantage. Hippocampal and mPFC volumes are measured using structural MRI to test for correlations between these volumes and the size of the behavioural congruency/incongruency effect in the first study. The second online study established the generalisability of our behavioural findings using a wider demographic sample of the aging population. By probing the underlying mechanism proposed by SLIMM, our data provide deeper insights into the effects ageing exhibits on the interaction between episodic and semantic memory. References: (1) Van Kesteren, M.T.R., Ruiter, D.J., Fernández, G. & Henson, R.N. (2012). How schema and novelty augment memory formation. Trends in Neurosciences, 35, 211-219 https://doi.org/10.1016/j.tins.2012.02.001 (2) Greve, A., Cooper, E., Tibon, R. & Henson, R.N. (2019). Knowledge is power: prior knowledge aids memory for both congruent and incongruent events, but in different ways. Journal of Experimental Psychology: General. http://dx.doi.org/10.1037/xge0000498

296. Investigation of how an allocentric spatial schema enhances memory in humans

Dingrong Guo1,3, Levan Bokeria1, Richard Henson1,2

1MRC Cognition and Brain Sciences Unit, University of Cambridge, 2Department of Psychiatry, University of Cambridge, 3School of Psychological and Cognitive Sciences, Peking University

296. New memories are not stored on a tabula rasa: most of our new experiences are incorporated into our prior knowledge networks or schemas. Classic rodent studies have found that systems consolidation of new spatial memory can occur quickly if they are learned in a trained associative schema of pair associations (PAs). Human studies have also examined the effects of schema on memory with various paradigms. However, most human studies implement non-spatial paradigms or test spatial memory in egocentric settings. A spatial navigation task that is analogue to rodent studies has not been employed in human studies. In addition, in such a spatial schema, whether new learning depends on local PAs or the global associative network is unclear. Here, we developed an analogue spatial navigation task that is adapted to humans. During training, participants were trained to learn 6 object-location PAs either in a consistent schema or in an inconsistent schema environment. During new learning, 4 old PAs were replaced by 4 new PAs with new locations and new objects. To test whether new learning depends on local PAs or global networks, we further manipulated the distance between new PAs and old ones - 2 of the 4 new PAs were next to the replaced old PAs, the other 2 new PAs were far from the replaced old PAs. To ensure the participants encode the PAs in an allocentric way, the start points were varied at each trial. The memory of new PAs will be calculated as the navigation time and routes to the new targets. In sum, there are two aims: First, to replicate the results in rodents, we expected the memory of new PAs would be better in the consistent condition than in the inconsistent condition. Second, we expected that the memory of near and far PAs would be at the same level if new learning depends on the associative networks. Otherwise, if the new learning depends on local PAs, the memory of near PAs would be better than the memory of far PAs in the consistent schema condition, but remain the same level in the inconsistent condition.

297. Perceptual and conceptual representations in memory encoding, consolidation and retrieval

M.sc. Rebekka Heinen1, M.Sc. Elias M.B. Rau1, Dr. Nora A. Herweg1, Prof. Dr. Nikolai Axmacher1,2,3

1Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 2State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, 3IDG/McGovern Institute for Brain Research, Beijing Normal University

297. OBJECTIVE Existing theories make different predictions about how processing format shapes memory representations. The levels of processing framework suggests that conceptual rather than perceptual processing boosts memory. Consolidation may transform memories to become more conceptual. And the account of transfer appropriate processing suggests superior memory when encoding and retrieval format match. Here, we provide novel evidence showing that these existing theories can not fully account for the effects of processing depth on memory. RESEARCH QUESTION In a series of three experiments, we investigate how processing of perceptual or conceptual features during encoding, consolidation and retrieval affects subsequent memory. MATERIALS AND METHODS In study I, participants rated conceptual or perceptual similarities of a series of image pairs drawn from different categories. Subsequently, we presented the same images again, mixed with new images drawn from either the same (“new exemplars”) or new (“new concepts”) categories. Participants indicated their confidence that each image was old or new. In study II, we used the same design but paired perceptual and conceptual ratings during encoding with condition-specific sounds. One sound was played again during post-encoding sleep to reactivate associated memories. In study III, participants made perceptual or conceptual forced-choice similarity judgements before we tested their memory on separate perceptual and conceptual retrieval tasks. RESULTS In contrast to the levels of processing framework, processing format during encoding did not affect subsequent memory. This can not be explained by an ineffective encoding manipulation, as we observed a link between participants’ ratings and subsequent memory. Cueing of conceptual processing during sleep led to higher confidence for old images whereas perceptual cueing led to higher confidence for new exemplars. Conceptual encoding improved conceptual retrieval, whereas perceptual encoding did not improve perceptual retrieval. CONCLUSION Our results suggest that encoding formats shape differences in memory performance through consolidation and retrieval processes. Specifically, consolidation of conceptually encoded material promotes more generalized representations, whereas consolidation of perceptual processing promotes distinct representations. Our results further suggest that effects of transfer appropriate processing are asymmetric. Whereas instructions promoting conceptual processing at encoding facilitate later conceptual retrieval, perceptual encoding does not benefit from task instructions.

298. Theta oscillations support map-based navigation

Dr. Nora Alicia Herweg1, Dr. David Stawarczyk1, Prof. Andreas Schulze-Bonhage2, Dr. Lukas Kunz3, Prof. Nikolai Axmacher1

1Ruhr University Bochum, 2University Medical Center Freiburg, 3Columbia University

298. Objectives: Theta oscillations have been implicated in memory encoding and retrieval processes, in particular in the realm of spatial navigation. However, the precise mechanisms by which theta supports way-finding are not fully understood. Here, we aim to close this gap by studying the link between hippocampal theta oscillations and the navigation behavior of human subjects. Research question: In our study, subjects had to navigate to remembered target locations in a virtual open arena. This task can be solved using different strategies: subjects may be memorizing associations between specific landmarks, actions and target locations (“landmark-based strategy”) or they may be learning the environment’s spatial layout more generally, allowing them to flexibly plan novel routes without relying on one particular landmark (“map-based strategy”). In a first step, we asked whether we can use subjects’ trial-specific trajectories to infer the type of information that informed their movements. In a second step, we asked whether theta oscillations are associated with the recruitment of one particular strategy. Materials and methods: We recruited 33 patients who were undergoing clinical seizure monitoring with intracranial EEG. Subjects navigated a virtual arena to learn the locations of eight unique objects. On each trial, they retrieved the location of a cued object by navigating to the remembered location. Subsequently, they received feedback and collected the object from its correct location. Results: We reasoned that if subjects were exclusively using a map-based navigation strategy, they should take a straight-line path from each start location to each (presumed) target location. We observed, however, that subjects’ retrieval trajectories were variable: some trajectories were straight, while others deviated from a straight-line path. These deviations were often associated with a narrow distribution of final heading directions over trials, suggesting that subjects relied on specific landmarks on these trials. We found that theta power increased whenever a subject’s trajectory resembled a straight-line path and decreased on trajectories that deviated from this path. This effect held up when controlling for other variables such as speed and accuracy in final drop location. Conclusion: Our results indicate that hippocampal theta oscillations support map-based navigation.

299. Anticholinergic agent diminishes feedback learning in healthy participants

Jonathan Hils1, Alexander Weuthen1, Steve Schulz1, Prof Markus Ullsperger1,2

1Department of Neuropsychology, Institute of Psychology, Otto-von-Guericke Universität Magdeburg, 2Center for Behavioral Brain Sciences, Magdeburg

299. Cholinergic dysfunction has been related to deficits in memory function, although it is still debated which cognitive processes required for memory formation are affected. Based on previous results on diminished post-error adaptations, we suspect that intact cholinergic function for memory is mediated by post-error upregulation of attention to stimulus features. To test this assumption, a placebo-controlled double-blind electroencephalography (EEG) study with young male participants (age range 18 to 30 years) was initiated. During two separate sessions, participants received 4mg of the selective muscarinic acetylcholine receptor 1 (M1) antagonist biperiden or placebo. At expected peak time of biperiden blood levels, participants performed a feedback associative learning task (FALT) and a 1-back localizer task during simultaneous EEG recording. Participants were instructed to memorize associations between faces or houses with a set of twelve gabor patch orientations. After indicating their level of confidence, they received feedback on respective retrieval correctness. Preliminary results of the first 20 participants showed that biperiden diminished memory performance by 15.3 % during biperiden session (mean accuracy = 48.6 %) compared to placebo (mean accuracy = 63.9 %). Analyses of event-related potentials showed modulation of the feedback-related negativity (FRN) and subsequent P300 amplitude by biperiden administration. In time-frequency power analyses, alpha power modulation during encoding and late processing of feedback explained performance differences between biperiden and placebo sessions. Further analyses will investigate how biperiden influences attentional allocation during encoding by using stimulus-specific decoding models derived from the localizer task.

300. Parietal alpha suppression is related to working memory capacity for numbers

Yi-Fang Hsu1, Jarmo Hämäläinen2

1National Taiwan Normal University, 2University of Jyväskylä

300. Alpha suppression is proposed to reflect a surge in cortical excitability to enhance stimulus processing in working memory. The attenuated state of alpha might reflect the prioritisation of behaviourally relevant information, making it a proxy for working memory functioning. Despite the growing interest in utilising the advancement of brain-based measures to evaluate individuals’ cognitive processes, there was a lack of consistent evidence on the relationship between alpha suppression and working memory performance. To investigate whether interindividual differences in alpha suppression might be related to variability in working memory capacity, we recorded electroencephalography (EEG) from 38 healthy participants while they performed an arithmetic task of either low or high working memory load. Participants were required to calculate either the product of digits (i.e., low-load condition) or the difference between the product of digits (i.e., high-load condition). To model the event-related spectral perturbation (ERSP), we applied a 3-cycle Morlet wavelet where the cycles linearly increased with frequency by a factor of 0.8 from 4 to 30 Hz. To estimate the effect of working memory load, we used permutation statistics with false discovery rate (FDR) correction for the alpha band. We found alpha suppression at parietal regions, which became more prominent as working memory load increased. The pattern of alpha suppression was present in approximately 76% of the participants. Importantly, the more the alpha suppressed as working memory load increased, the lower the Digit Span score in WAIS-IV, where participants were to repeat the numbers in the same order (i.e., digit span forward), repeat the numbers in reverse order (i.e., digit span backward), or repeat the numbers in numerical order (i.e., digit span sequencing). That is, alpha suppression was more prominent in participants of worse working memory capacity. Our findings suggest that alpha activity, subject to interindividual differences in sensitivity, could serve as a brain-based measure of an individual’s working memory functioning.

301. Effects of repeated encoding on visual recognition accuracy

Almut Hupbach1, Mengting Zhang1

1Lehigh University

301. Objectives. Memories change over time and with reactivation. Systems consolidation theories assume that memories undergo a time-dependent change from episodic and context-specific to semantic and context-free. In particular, the Competitive Trace Theory (CTT; Yassa & Reagh, 2013) posits that repeated encoding of the same item leads to semanticization and loss of episodic detail, due to competition among non-overlapping contextual traces. However, our previous studies show that repeated encoding improves memory for item details (Zhang & Hupbach, 2020). Research question. The present study assessed how repeated encoding affects item and source memory, when repetitions occur in the same or in varied contexts. Based on CTT, we assumed that experiencing the same item in different contexts induces competition among contextual traces thereby impairing both item and source memory. Materials and methods. Participants encoded images of common objects either once, three times in the same or three times in different contexts. Contexts were implemented as colored backgrounds or different encoding tasks. During test, participants performed a mnemonic discrimination and a source recognition task. Results. I support of CTT, we found that repetition across varied color backgrounds and varied encoding tasks impaired source memory in comparison to single encounters with the items. However, in contrast to CTT, we found that repeated encoding strengthened memory for perceptual item details, regardless of whether repetition was experienced in the same or different contexts. Conclusion. We propose that the specific method of memory reactivation determines which item features are preserved in memory during the consolidation process. Implications of our findings for systems consolidation theories and applied settings are discussed.

302. Body ownership and the neural processes of memory encoding and reinstatement

Dr Heather Iriye1, Prof H. Henrik Ehrsson1

1Karolinska Institutet

302. Memories are inextricably tied to having a body. Yet, we are just beginning to understand how the fundamental perception of one’s body as one’s own (i.e. body ownership) influences neural processes during encoding and retrieval. Here, we investigated how body ownership influences patterns of neural activity associated with memory formation and reactivation during retrieval. We immersed participants within pre-recorded videos viewed through virtual reality glasses, which depicted realistic, everyday events that included a natural first-person view of a mannequin’s reclining body which was aligned with the location of the participants’ real bodies during fMRI scanning. We manipulated feelings of body ownership over the mannequin using a perceptual full-body illusion. Participants saw an object touch the mannequin and simultaneously felt touches on the corresponding location of their real body, which created an illusory sense of ownership over the mannequin. As a control condition, we disrupted the illusion by delivering seen and felt touches in an alternating pattern in half of the videos. The experimenter was blind to the condition assigned to each video. 1 week later, participants retrieved memories for the videos during fMRI scanning. Participants answered cued recall questions concerning specific event details at the end of each session to assess memory accuracy. Preliminary results suggest that patterns of activity during encoding in lateral frontal, medial and lateral temporal, posterior parietal, and visual cortices were able to differentiate between memories encoded with differing levels of body ownership. Further, by correlating patterns of activity at encoding and retrieval, we found that forming memories with intact compared to disrupted body ownership increased reinstatement of that event during retrieval in the hippocampus according to how vividly the event could be recalled. Our findings have the potential to provide new insights into how to optimize memory for past events and preserve the ability to vividly relive the past in the context of both healthy ageing and clinical disorders (e.g., Alzheimers Disease).

303. Long-term Memory Associations Provide Cross-modal Access to Sensory Working Memory

Güven Kandemir1, Prof. Elkan Akyürek1

1University Of Groningen

303. Recent evidence showed that cross-modal access to sensory working memory (WM) is limited. Wolff and colleagues (2020) investigated cross-modal sensory access by presenting a task-irrelevant visual impulse (a white disk) to perturb the WM network, and were able decode not only visual but also auditory memories. Conversely, an auditory impulse (brief noise) revealed auditory WM contents exclusively. In this study, we investigated if long-term memory can enable cross-modal access to WM. We first paired 6 auditory pure tones with 6 visual orientation gratings in a learning session. Next, a discrimination task for the orientation memories was completed with simultaneous EEG recording. Orientations had to be recalled either from long-term memory via their auditory counterparts, or were visually presented. Orientation information was then decoded from EEG responses to auditory and visual impulses. The results suggested that an auditory impulse could now indeed reveal visual WM, when visual memories were recalled via their auditory counterparts. Neural patterns for visual memories formed by visual presentation and auditory-cued recall i cross-generalized, supporting that the auditory impulse effect was in fact reflecting visual memories. These results demonstrate that long- term memories are rapidly ported to WM, and that they enable cross-modal, association-driven readout of WM contents.

304. Phase separation of competing memories along the human hippocampal theta rhythm.

Casper Kerrén1,3, Sander van Bree2,3, Benjamin Griffiths J.3,4, Maria Wimber2,3

1Max Planck Institute for Human Development, Berlin, 2Centre for Cognitive Neuroimaging, Institute for Neuroscience and Psychology, University of Glasgow, 3Centre for Human Brain Health, School for Psychology, Birmingham, 4Ludwig Maximilian University of Munich, München

304. Competition between overlapping memories is considered one of the major causes of forgetting and it is still unknown how the human brain resolves such mnemonic conflict. In the present pre-registered MEG study, we empirically tested a computational model that leverages an oscillating inhibition algorithm to minimise competition between memories. We used a proactive interference task, where a reminder word could be associated with either a single image (non-competitive condition) or two competing images, and participants were asked to always recall the most recently learned word-image association. Time-resolved pattern classifiers were trained to detect the neural reactivation of target and competitor memories from MEG sensor patterns, and the timing of these reactivations was analysed relative to the phase of the hippocampal 3Hz theta oscillation. In line with our central hypothesis and the oscillating inhibition model, optimal classification of target and competitor memories locked to increasingly different phases of the hippocampal theta rhythm. Participants who behaviourally experienced lower levels of interference also showed larger phase separation between peak reactivations of the two overlapping memories. The findings provide evidence that the temporal segregation of memories, orchestrated by slow oscillations, plays a functional role in resolving mnemonic competition by separating and prioritising relevant memories under conditions of high interference.

305. Brain oscillations during real-world episodic autobiographical memory retrieval

Nareg Khachatoorian1, Dr Danai Dima1, Dr Marie Poirier1, Dr Corinna Haenschel1

1City, University of London

305. Electroencephalograph (EEG) has been used widely in understanding the mechanisms of recognition memory. Studies using the event-related potential to interpret the EEG signal have outlined the role of parietal old-new effect as a signature for the recollection processes and frontal old-new effect as a signature for the familiarity processes (Mecklinger, 2006; Rugg & Curran, 2007). In addition, studies using time-frequency decomposition methods have shown the role of synchronisation in gamma (25-100 Hz) and theta (4-7.5 Hz) bands (Gruber, Tsivilis, Giabbiconi, & Müller, 2008) in the reinstatement of episodic details (Nyhus & Curran, 2010). Furthermore, desynchronization in alpha (10-13 Hz) and beta (13-18 Hz) bands (Hanslmayr, Staudigl, & Fellner, 2012), argued to allow information transfer for the recollection of memories (Hanslmayr, Staresina, & Bowman, 2016). While these studies shed light on the neurophysiological mechanisms of recognition of episodic memory, they have used laboratory-based stimuli such as words and pictures, leaving such mechanisms for the real-world autobiographical memories unexplored. Therefore, the aim of this study is to examine these EEG effects in the context of real-world autobiographical episodic memories. Using wearable cameras cues from participants’ (N=29) real-world autobiographical memories were captured and used in a recognition task one week later while their EEG was being recorded. Participants were assigned to one of two enhancement exercises. Retrieval practice – recalling the content of the tour, which is thought to stabilise the semantic content of the memories. And, photo review – reviewing the wearable camera photos, which is thought to stabilise the visual content of the memories. This allowed examination of the EEG effect, and their relationship with different content of the memories (sensory vs semantic). A parietal old-new effect in the photo review condition was observed, suggesting that it is influenced by the sensory information. Furthermore, there were desynchronizations in the gamma frequency band in the photo review condition over the frontal electrodes and parietal electrode which may indicate the role of gamma in sensory information transfer. The lack of old-new EEG effects in the retrieval practice condition suggests that semantic information may not be associated with the EEG signatures for recognition memory.

306. Tracking neural representations of trauma-analogue memory intrusions

Mr Malte Kobelt1, Dr Gerd Waldhauser1, Mrs Aleksandra Rupietta2, Mrs Rebekka Heinen1, Prof Henrik Kessler3, Prof Nikolai Axmacher1,4

1Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, 2Department of Clinical Psychology and Psychotherapy, Faculty of Psychology, Ruhr-University Bochum, 3Department of Psychosomatic Medicine and Psychotherapy, LWL-University Hospital, Ruhr University Bochum, 4State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University

306. Unwanted memory intrusions of traumatic experiences are a hallmark symptom of posttraumatic stress disorder. However, it is poorly understood how traumatic experiences are represented in the brain and how their neural representations are reactivated during memory intrusions. Here, we combined the trauma film paradigm with pattern similarity analysis of functional magnetic resonance imaging (fMRI) data to investigate how neural representations of trauma-analogue experiences differ from the representations of neutral events and how they are reactivated during memory intrusions. Participants watched film clips of traumatic material and of thematically matched control episodes in the MR scanner. Subsequently, they reported involuntary memory intrusions during a resting phase. Compared to neutral events, trauma-analogue experiences were associated with higher activity in the amygdala and wide-spread visual areas. Enhanced neural processing in both areas was related to a higher number of memory intrusions across participants. Using pattern similarity analyses, we found that neural representations of trauma-analogue experiences were more generalized in visual areas compared to neural representations of neutral events. Interestingly, we also found that representations of trauma-analogue experiences were more similar to representations of neutral experiences than neutral experiences were to other neutral experiences, providing potential evidence of cue-generalization as a basis of memory intrusions. Prior to memory intrusions, neural activity increased in the hippocampus and occipitoparietal areas. Moreover, the neural activity pattern of a specific trauma-analogue experience was reactivated during memory intrusion of that same episode in anterior cingulate cortex. By contrast, activity patterns in visual areas were not specific for individual trauma-analogue experiences but instead were highly similar between different memory intrusions. Our results show that memory intrusions rely on a complex neural interplay between enhanced visual processing, generalized visual representations and the reactivation of trauma-specific representations in anterior cingulate cortex. Disentangling the precise roles of these representational characteristics may help unravel the neural pathway of unwanted memory intrusions and provide a mechanistic basis for novel treatment options.

307. Hippocampal neurons sparsely code individual episodic memories in humans

Luca Kolibius6,1,2, F Roux1,2, G Parish1,2, M Ter Wal1,2, M van der Plas6,1,2, R Chelvarajah3, V Sawlani3, D. T. Rollings3, J. D. Lang4, S Gollwitzer4, K Walther4, R Hopfengärtner4, G Kreiselmeyer4, H. M. Hamer4, B. P. Staresina7,1,2, M Wimber6,1,2, H Bowman1,2,5, S Hanslmayr6,1,2

1School of Psychology, University Of Birmingham, 2Centre for Human Brain Health, University of Birmingham, 3Complex Epilepsy and Surgery Service, Neuroscience Department, Queen Elizabeth Hospital Birmingham, 4Epilepsy Center, Department of Neurology, University Hospital Erlangen, 5Centre for Cognitive Neuroscience and Cogntivie Systems and the School of Computing, University of Kent, 6Institute of Neuroscience and Psychology, University of Glasgow, 7Department of Experimental Psychology, University of Oxford

307. Introduction When you remember the last time you had a coffee with a loved one you rely on your hippocampus to reinstate that episode. This episode will contain a multitude of features (weather, smell of the coffee, music playing), but how the hippocampus binds all these elements into one episode remains unsolved. The indexing theory (Teyler and DiScenna, 1986) proposes that neurons in the hippocampus achieve this through a conjunctive code that binds all features within the episode. In contrast, others have suggested that hippocampal neurons code for specific categories (Quiroga, 2012). Methods In search of an answer to this issue, we have recorded the activity of 625 single neurons in the hippocampus of human epileptic patients (N = 16). During a self-paced memory association task patients formed unique episodic memories comprising an animal cue and two associate images (places or faces). Each episode was learned and retrieved only once. Results We contrasted the empirical firing reinstatement (firing rate at encoding multiplied with retrieval) of every single unit during every episode with a shuffled distribution. Next, we excluded potential concept neurons that showed increased firing to the animal cue at encoding. In a second level shuffling procedure we show that a significant number (N = 147/625; p < 0.001) of single units showed a memory specific reinstatement of neural firing during individual episodes. We termed these single units Episode Specific Neurons (ESNs). We still find a significant number of ESNs when limiting our analysis to single units that reinstate one episode with face associates and one with place associates (p < 0.01). Such neurons unlikely code for a specific concept because the stimulus material in these episodes does not overlap. Conclusions In conclusion, we provide evidence that individual neurons code discrete episodes via an increased firing rate during encoding and retrieval. We demonstrate that these Episode Specific Neurons do not reflect the coding of a particular feature in the episode (i.e., concept). Instead, they code for the conjunction of the different elements that make up the episode. Teyler & DiScenna (1986). Behav Neurosc. Quiroga (2012). Nat Rev Neurosc.

308. Plasticity in control and memory circuits forecasts PTSD symptoms evolution

Dr Giovanni Leone1, Dr Charlotte Postel1, Mrs Fraisse Fraisse1, Mr Thomas Vallée1, Dr Fausto Viader1, Dr Vincent de La Sayette1, Dr Denis Peschanski2, Dr Jacques Dayan1,3, Dr Francis Eustache1, Dr Pierre Gagnepain1

1Normandie Univ, UNICAEN, PSL Research University, EPHE, INSERM, U1077, CHU de Caen, GIP Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine, 2Université Paris I Panthéon Sorbonne, HESAM Université, EHESS, CNRS, UMR8209, 3Pôle Hospitalo-Universitaire de Psychiatrie de l’Enfant et de l’Adolescent, Centre Hospitalier Guillaume Régnier, Université Rennes 1

308. Introduction Post-traumatic stress disorder (PTSD) has long been characterized as a memory disorder rooted in the alteration of hippocampal structural integrity. Recently, we suggested that the disruption of memory control processes is also central to understand PTSD (Mary et al., Science, 2020). In a follow-up computational study, we further showed that PTSD overprioritizes prior belief when regulating intrusive memories, and lacks reactive control (Leone et al., in revision). Here, we used a longitudinal design to investigate the evolution of these two disorders in individuals exposed to the 2015 Paris terrorist attacks and whether plastic changes in memory control and hippocampal disorders forecasted the future evolution of symptoms severity. Methods High-resolution hippocampal subfield volumes and fMRI activations during a memory suppression task were collected one year (T1) and three years (T2) after the attacks, in 100 trauma-exposed and 75 non-exposed participants. Participants further underwent a clinical phone-call evaluation five years after the trauma (T3). We used computational and dynamic causal modelling to capture the predictive and reactive suppression of the hippocampus orchestrated by the prefrontal cortex. Results Eighteen participants remitted from PTSD three years after the trauma, while 34 did not. Remitted participants showed plastic volumetric changes in right-CA1 (T=2.99, p= .009) and left-CA2-3/DG (T=2.31, p=.035) subfields and a recovered balance between predictive and reactive memory control (T=2.415, p=.029) between T1 and T2, mostly driven by the improvement of reactive mechanisms. On the contrary, participants with persistent PTSD showed a volumetric reduction between T1 and T2 of the right-CA2-3/DG (T=-3.33, p=.0025) and a persistent imbalance in memory control towards predictive mechanisms. Moreover, we found that the individual improvements in reactive control and CA2-3/DG volume between T1 and T2 forecasted the reduction of intrusive symptoms severity five years after the trauma (Spearman-rho=0.40, p=.046 and Spearman-rho=-.72, p=.002, respectively). Discussion These findings revealed that neurocognitive plasticity occurring in control and memory circuits is central to understand the persistence of the trauma and remission process. Our results shed light on a dual mechanism involving both memory control and hippocampal functioning restoration to inaugurate future clinical improvements, potentially representing a target for therapeutic interventions.

309. Representational geometry of visual working memory information in human gaze patterns

Dr. Juan Linde-Domingo1, Dr. Bernhard Spitzer1

1Max Planck Institute For Human Development

309. Miniature eye-movements have been recognized as a potential confound in decoding visual working memory (VWM) contents with neuroimaging techniques like M/EEG and fMRI. However, the very information in content-dependent gaze patterns has rarely been assessed directly. Here, we combined eye-tracking with representational geometry analyses during cued maintenance of visual object orientation to track its dynamics in VWM. Although participants (n=29) were actively discouraged from eye-movements through closed-loop penalties for breaking fixation, we found robust representations of the retro-cued stimulus orientations in miniature gaze patterns (<1 degree visual angle) that were sustained and continuously ramping-up throughout the retention periods. Complementary EEG recordings (in n=26 participants) showed analogous patterns in multivariate ERP- and alpha signals to be short-lived, and overall less robust than those in gaze. Geometry analysis of the gaze patterns revealed that they carried categorical orientation biases early on, in terms of a repulsion from cardinal axes, which remained stable throughout retention, and which also registered in subsequent behavioral responses. Moreover, when just-seen stimuli were cued for maintenance, gaze patterns sustained orientation information specific to each object. However, intervening stimuli and/or temporary inattention rendered the gaze pattern object-independent, consistent with a more abstract, generalized orientation representation in WM. We further found evidence in single-trial analysis that during sequential encoding into VWM, eye gaze carried simultaneous information about previous and current stimulus orientations, adding to the wealth of information that was latent in 2-dimensional gaze space. Together, our findings highlight the utility of gaze geometries in tracking VWM information and its representational dynamics.

310. Remembering the past during new learning: the temporal dynamics of integrative encoding

Zhenghao Liu1, Inês Bramão1, Mikael Johansson1

1Department of Psychology, Lund University

310. Memories may integrate elements experienced in different events. For instance, meeting a woman leaving her house, and later meeting another woman entering the same house, may allow us to infer that the two women live together. Such memory representations are thought to rely on integrative encoding mechanisms, allowing us to make inferences about the world and generalize knowledge to entirely new situations. This study uses multivariate pattern analysis (MVPA) of electrophysiological data to elucidate the temporal dynamics of integrative encoding. We adapted the associative inference task to investigate cross-episode memory integration. Participants first learned overlapping paired associates, AB and CB pairs, that comprised a word and a picture (a face or a bird). Memory was later tested for the AC inferred associations, and for the direct AB and CB associations. MVPA was used to measure the online reactivation of previously learnt AB memories during encoding of the CB events. Reliable reactivation of AB was observed between 1.5 and 3 s. Participants (n=29) were divided into subgroups according to their AC performance: good and poor generalizers. Interestingly, while both groups showed comparable levels of AB reactivation during CB learning, the reactivation effects were associated with different consequences. For good generalizers, reactivation was predictive of later AC inference performance, suggesting that an integrated ABC representation was formed during BC learning. This interpretation is corroborated by behavioral data showing that direct and indirect inferred associations were retrieved equally fast. Altogether, this suggests that AC inference in this group of participants was based on integrative encoding mechanisms. Conversely, for poor generalizers, the reactivation of AB was instead negatively correlated with BC retrieval performance, indicating that AB reactivation impaired BC learning. Additionally, this group of participants took longer to retrieve inferred associations than direct associations, suggesting that successful AC inference was accomplished by flexibly recombining the direct AB and CB associations during retrieval. The present study extends previous literature by revealing the temporal dynamics of memory integration and providing an account of inter-individual differences in the capacity to make inferences across distinct episodes. Key words: Memory integration, EEG, MVPA, integrative encoding, flexible retrieval

311. Behavioral and computational evidence for state space factorization supporting compositional reuse of experience in humans

Lennart Luettgau1,2, Rani Moran1,2, Kimberly L. Stachenfeld3, Zeb Kurth-Nelson1, Raymond J. Dolan1,2

1Max Planck UCL Centre For Computational Psychiatry And Ageing Research, University College London, 2Wellcome Centre for Human Neuroimaging, University College London, 3DeepMind

311. Objectives Our everyday experiences are produced by several interacting processes. For example, meeting friends in the park in summer is the product of a community structure and the cycle of the seasons. Representing the factors underlying experience enables efficient reuse of knowledge and rapid adaptation to similarly structured environments. Research question Here, we test the idea that humans decompose state spaces into underlying factors and compositionally reuse these to support efficient behavior. Materials and methods Our paradigm featured two cyclic graph factors (4 and 6 states, respectively), each state represented by a distinct image. Participants observed trajectories in the 24-state product graph, wherein each state was composed from two graph factor states. Crucially, participants experienced only 12 product states. However, agents deducing the two graph factors could infer the 12 unexperienced compositions by recombining knowledge. We repeatedly assessed knowledge of both graph factors separately by asking participants to make predictions about upcoming states in the trajectory (Sequence Probes) and to infer transitions between unexperienced states (Inference Probes). Using computational simulations, we compared candidate learning mechanisms to observed behavior. Results Across four studies, we found above-chance performance that increased over time – with Sequence Probe accuracy greater than Inference Probe accuracy. Consistent with a state space factorization account, inference accuracy was higher for the 4-state than the 6-state graph factor. Computational simulations indicated that a successor feature model, learning predictions about the unique product states performed at chance during Inference Probes. Another successor feature model, learning expectations about features constituting the product states, showed above-chance accuracy in Inference Probes, but no performance increase over time. In this model, Inference and Sequence Probe accuracy were indistinguishable. A hybrid of both successor feature models, with time-varying weighting between models based on the usefulness of both models’ inferential predictions, captured some features of the observed behavior, but predicted no difference between both graph factors’ Inference Probe accuracies. Conclusion We show that humans factorize representations of structure underlying their experience. Such compositional representation of knowledge allows for efficient reuse of prior knowledge to facilitate inferences about never experienced, but possible, novel states of the world.

312. Prefrontal transcranial direct current stimulation enhances inhibition during semantic memory retrieval

Dr Martin Marko1, Dr Igor Riečanský1

1Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences

312. Semantic control involves neural and cognitive mechanisms that regulate semantic processing and memory retrieval. Neuroimaging studies have indicated that controlled semantic processing engages the left prefrontal cortex (PFC), yet the functional role of the prefrontal activity remains poorly understood. In a double-blind randomized controlled experiment, participants from three distinct groups received anodal transcranial direct current stimulation (tDCS) over left lateral PFC (n = 40), a control tDCS over temporoparietal cortex (n = 40), or sham stimulation (n = 41), while executing automatic and controlled semantic retrieval tasks as well as additional control tasks assessing working memory and semantic judgement. We found that excitatory tDCS of the left lateral PFC improved inhibition of prepotent associative responses but had no significant effect on free-associative retrieval or switching between retrieval rules. The prefrontal tDCS also enhanced working memory capacity, which was independent from the effect on inhibition. The control temporoparietal tDCS had no significant effect on any cognitive measure. Our findings show that semantic inhibition and switching may represent partially distinct components of the semantic control and indicate that the left lateral PFC may primarily exert a filtering process that either constrains the access to semantic representations (i.e., a proactive pre-retrieval inhibition) or suppresses already retrieved responses (i.e., a retroactive post-retrieval inhibition). The recognition of such an inhibitory process could inspire novel treatments targeting altered semantic processing. Grant support: APVV-19-0570

313. Curiosity-motivated learning and reward: Investigation with dynamic stimuli

Stef Meliss1, Cristina Pascua-Martin1, Kou Murayama1

1University of Reading

313. Memory encoding is facilitated by dopaminergic modulation of hippocampal activity which can be triggered by monetary rewards as well as curiosity. However, little is known about how monetary rewards and curiosity jointly influence incidental encoding and its underlying neural processing. In two online (n1 = 78 and n2 =79) and one fMRI study (N = 50), we presented 36 magic tricks to participants and asked them to estimate how many people can find the solution to each magic trick and to rate their curiosity. In the reward group, participants were promised performance-dependent monetary reward for each correct estimate, whereas the control group worked on the task without such incentives. After one week, participants took a surprise memory test. Across all studies, we observed a consistent effect of curiosity: participants were more likely to remember a trick if they were more curious about it. While the online studies further showed reward-related memory enhancement, statistically significant effects were not observed in our fMRI sample. To account for the dynamic nature of the stimuli, we analysed the data using intersubject representational similarity analysis (Finn et al., 2020) to identify areas in which similarity in (a) curiosity, (b) memory encoding and (c) curiosity-motivated learning enhancements predicts similarity in brain response. These analyses revealed clusters distributed across the cortex: curiosity and memory both independently and positively predicted activations in the supramarginal gyrus, middle frontal gyrus and lateral occipital cortex. In addition, whereas curiosity was associated with inferior frontal gyrus, memory was associated with precuneus and lingual gyrus. Curiosity-motivated learning enhancements negatively predicted activations in inferior temporal gyrus, angular gyrus, superior/inferior frontal gyrus, nucleus caudate and anterior and posterior cingulate cortex. Additionally, the predictive effect of curiosity-motivated learning enhancements was more pronounced in e.g. medial occipital cortex in the reward compared to control group whereas the opposite effect was observed in lateral parts of the occipital cortex. These findings show that, using dynamic stimuli, the effects of curiosity and reward on memory are broadly distributed in cortical areas. In fact, our results highlight brain areas associated with reward motivated learning outside the commonly-observed hippocampus-VTA loop.

349. Electrophysiological Correlates of Motor Memory Reactivation at Different Phases of the Slow Oscillation

Dr Judith Nicolas1,2, Prof Brad King3, Mr David Levesque4, Dr Latifa Lazzouni5, David Wang6, Prof Nir Grossman7, Prof Stephan Swinnen1,2, Dr Julien Doyon5, Dr Julie Carrier4,8, Prof Geneviève Albouy1,2,3

1Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, 2LBI - KU Leuven Brain Institute, KU Leuven, 3Department of Health and Kinesiology, College of Health, University of Utah, 4Center for Advanced Research in Sleep Medicine, 5McConnell Brain Imaging Centre, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 6Elemind Technologies Inc Massachusetts Institute of Technology, 7Faculty of Medicine, Department of Brain Sciences, Imperial College London, 8Department of Psychology, Université de Montréal

349. Motor memory consolidation can be enhanced by targeted memory reactivation (TMR) during post-learning sleep. Based on evidence that brain excitability fluctuates with the phase of sleep oscillations such as Slow Waves (SW) and spindles (12-16 Hz – sigma – bursts), we hypothesized that the effect of TMR on memory consolidation depends on the phase of the stimulated SW. Here we employed a sophisticated, closed-loop procedure to apply TMR at two different SW phases (up vs. down) and tested the effect of these phase-specific stimulations on the behavioral and electrophysiological correlates of motor memory consolidation. Twenty-seven young healthy adults (age range 18-30, 15 females) participated in this study. Each participant performed a motor sequence learning task including three different movement sequences (associated to three different sounds) before and after a night of sleep monitored with EEG. Two sequences were reactivated during post-learning sleep (the third sequence served as a no reactivation condition) at different phases of the SW (up vs. down) using real-time SW detection and closed-loop auditory stimulation procedures. Up-, down- and non-stimulated SWs averaged at the trough of the SW were compared. Time-frequency analyses were also performed on the extracted signal. Behavioral data revealed that TMR time-locked to the SW-down phase resulted in deterioration of performance as compared to up and no stimulation. EEG data indicated that stimulation increased SW amplitude around the SW trough irrespective of the phase stimulated. Phase-specific modulations of SW amplitude were observed at the peak of the SW, whereby up-stimulated SWs showed higher amplitude. However, this effect reversed later (1 to 1.4s post trough)with greater amplitude for the down-stimulated SWs. Time-frequency analyses revealed that the sigma band power locked to the trough of the up-stimulated SW significantly correlated with performance improvement on the reactivated-up sequence. Last, sigma band power around the SW peak was significantly higher for the up- than the down-stimulated SWs. Taken together, these results show that TMR effects on motor memory consolidation depends on the phase of the stimulated SW. Our electrophysiological results provide strong evidence for a phase-dependent modulation of SW amplitude and sigma power known to support memory consolidation.

350. Switching between neural modes at sequential fixations in free viewing predicts successful episodic memory

Dr Andrey Nikolaev1,2, Dr Inês Bramão1, Dr Roger Johansson1, Prof Mikael Johansson1

1Department of Psychology, Lund University, 2Brain & Cognition Research Unit, KU Leuven

350. Objectives The formation of episodic memories is critically determined by how we visually sample the world over time via sequences of eye movements. Nonetheless, in the neuroscience of human memory, memory encoding has almost exclusively been studied in experimental paradigms where the study material is presented in a single fixed location on the screen, and where eye movements are treated as artifacts. Thus, the neural mechanisms subserving memory construction across eye movements are virtually unknown. Research question What are the neural correlates of episodic memory formation during eye movements in natural visual behavior? Materials and methods We developed an associative memory task in which participants encoded multiple events, each comprising distinct elements from three categories (faces, places, objects) in different locations of the screen. The spatial configuration of the element locations allowed us to separate relevant and irrelevant saccades for integrating them into a coherent event. Participants memorized the event, while their EEG and eye movements were simultaneously recorded. Episodic memory was thereafter assessed by testing retrieval of the element associations specifying each event. In the EEG analysis, we overcame the problem of overlapping EEG responses to sequential saccades in free viewing using a deconvolution approach. We segmented EEG relative to the fixation onset and examined the power of EEG signals in the theta and alpha frequency bands. Results High subsequent memory performance was predicted by theta synchronization over the centro-parietal areas during fixation intervals after saccades relevant to event integration. This may reflect the binding of elements into coherent event representation. High memory performance was also predicted by alpha desynchronization during fixations after task-irrelevant saccades. This may reflect discrimination of elements from the same category, which is necessary for successful memory encoding. Finally, high frontal theta power during fixations after scrutinizing, within-element saccades predicted high memory. This may reflect increased visual sampling of elements leading to better memory. Conclusion Thus, memory formation across eye movements is characterized by three neural mechanisms that rapidly turned on and off in a saccadic sequence during event encoding. These mechanisms provide essential building blocks for the construction of episodic memory during naturalistic viewing.

351. Top-down control of multi-item working memory representations

Daniel Pacheco Estefan1, Marie Christin Fellner1, Lukas Kunz2, Hui Zhang1, Peter Reinacher3, Charlotte Roy3, Andreas Schulze-Bonhage3, Linglin Yang4, Shuang Wang4, Jing Liu5, Gui Xue6, Nikolai Axmacher1

1Ruhr University Bochum, 2Columbia University, 3University of Freiburg, 4Zhejiang University, 5University of Hong Kong, 6Beijing Normal University

351. Visual working memory depends on both material-specific posterior brain areas that support the representation of the to-be-maintained stimulus features and executive control areas in the prefrontal cortex (PFC). These two areas putatively support bottom-up (storage) vs. top-down (control) functions that rely on oscillations in the gamma and beta frequency bands, respectively. A previous intracranial EEG (iEEG) study combined representational similarity analysis (RSA) and deep neural networks (DNNs) as a model of the processing hierarchy along the ventral visual stream (VVS) and showed that maintenance of natural images relied on both high-level visual and semantic information (Liu et al., PNAS 2020). How selective attention prioritizes the representational formats of relevant working memory contents and suppresses irrelevant contents remains an open question, however. Here, we addressed this issue using a multi-item working memory task involving a retro-cue. We recorded iEEG activity from patients with electrodes in VVS, PFC, and/or hippocampus. We report a dissociation of the representational signatures across working memory stages: During encoding, item-specific information was selectively observed in VVS and hippocampus, but not in the PFC. During maintenance, the geometry of activity patterns in the PFC was captured by the deepest layers of a recurrent DNN model. This effect was transient, locked to the presentation of the cue, and was specific to the beta (16-28Hz) frequency band. Our results suggest that PFC represents task-relevant information in an abstract representational format, dynamically affecting distributed representations in the VVS and hippocampus through top-down inhibitory mechanisms.

352. Actions attenuate sensory responses, increase pupil diameter, and disrupt memory encoding for concurrent, but unpredictable sounds.

Nadia Paraskevoudi1,2, Dr. Iria SanMiguel1,2,3

1Institute of Neurosciences, University of Barcelona, 2Brainlab - Cognitive Neuroscience Research Group, Department of Clinical Psychology and Psychobiology, University of Barcelona, 3Institut de Recerca Sant Joan de Déu

352. Actions modulate sensory processing by attenuating responses to self- compared to externally-generated inputs, which is traditionally attributed to specific motor predictions. Yet, suppression has been also found for stimuli merely coinciding with actions, pointing to unspecific processes that may be driven by neuromodulatory systems, and specifically the locus coeruleus whose activity can be tracked by pupillometry. Meanwhile, the effects of self-generation on memory remain largely unknown. While some studies report better memory recall for self-generated stimuli (i.e., production effect), further evidence suggests that memory is driven by prediction errors (i.e., worse memory for self-generated inputs). Yet, to-date, no attempts have been made to assess the role of self-generation and motor-related prediction on the subsequent memory retrieval for these stimuli. Here, we assessed the specific and unspecific effects of actions on sensory processing and memory encoding of concomitant, but unpredictable sounds, using a combination of self-generation and memory recognition task, while recording EEG and pupil data. At encoding, subjects performed button presses that half of the time generated a sound (motor-auditory; MA) and listened to passively presented sounds (auditory-only; A). At retrieval, two sounds were presented and participants had to respond which one was present before. We measured memory bias and memory performance by having sequences where either both or only one of the test sounds were presented at encoding, respectively. Results showed worse memory performance – but no differences in memory bias – and attenuated responses for MA compared to A sounds, that were accompanied by larger pupil diameter for the former. Critically, the larger the attenuation and pupil diameter, the worse the memory performance for MA sounds. Nevertheless, sensory attenuation did not correlate with pupil dilation. Collectively, our findings suggest that actions disrupt memory encoding and show that sensory attenuation and pupil dilation during actions reflect simultaneous, albeit independent processes.

353. Using functional connectivity to understand age differences in neural category specificity

Claire Pauley, Dr Verena R. Sommer, Dr Markus Werkle-Bergner, Dr Myriam C. Sander 1Max Planck Institute For Human Development

353. Neural dedifferentiation, the finding that neural representations become less distinctive with advancing age, is commonly implicated in senescent cognitive decline. Studies investigating neural dedifferentiation often find an age-related decline in the specificity of categorical representations in visual regions. It has been proposed that age differences in functional connectivity (FC) to category-specific regions may account for the age-related reduction in neural distinctiveness. We sought to investigate this hypothesis in an fMRI study with a group of younger and older adults. Participants performed an incidental encoding task consisting of face and house images and subsequently completed a surprise old/new recognition memory task. First, we used a representational similarity analysis (RSA) searchlight approach in order to identify brain regions that show category-specific activity during recognition: greater pattern similarity of stimuli from the same category (i.e., house-house) compared to stimuli between categories (i.e., house-face). This analysis revealed a bilateral area of occipital and ventral visual regions demonstrating high category specificity for houses. Within this region, mean across-voxel category specificity was lower in older adults than in younger adults, in line with the neural dedifferentiation hypothesis. Then, we assessed whole-brain, voxel-based FC to this region of high category specificity. We found strong connectivity in occipital, ventral temporal, and posterior parietal cortices, revealing a network of category specificity in regions involved in visual and attention processes. Age differences in FC were found in these same regions, with younger adults demonstrating stronger connectivity than older adults. Finally, using partial least squares correlation analysis, we identified a latent variable that optimally represented a multivariate relationship between voxel-wise connectivity and interindividual differences in category specificity. Bootstrap sampling revealed connectivity to occipital regions driving this association, such that connectivity was positively associated with category specificity. These findings suggest that participants demonstrating higher neural distinctiveness in category-specific regions also have increased coactivation between these regions and early visual cortices during memory recognition. Thus, we provide novel evidence for a link between category specificity and distributed FC patterns, revealing FC as a possible contributor to age-related neural dedifferentiation.

354. Theta:gamma phase coupling and evoked gamma activity reflect the fidelity of mental templates during memory matching in visual perception

Charline Peylo1,2, Elisabeth V.C. Friedrich1, Tamas Minarik1,3, Anna Lena Biel1,2, Paul Sauseng1

1Department of Psychology, Ludwig-Maximilians-Universität München, 2Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, 3Center of Functionally Integrative Neuroscience, Aarhus University

354. Objectives: Top-down predictions of future events shaped by prior experience are an important control mechanism to allocate limited attentional resources more efficiently and are thought to be implemented as mental templates stored in memory. Increased evoked gamma activity and theta:gamma phase-phase coupling over parieto-occipital areas have previously been observed when mental templates meet matching visual stimuli. Research question: Here, we investigated how these signatures evolve during the formation of new mental templates and how they relate to the fidelity of such. Materials and methods: Based on single-trial feedback, participants learned to classify target shapes as matching or mismatching with preceding cue sequences while EEG was recorded. In the end of the experiment, they were asked to freely reproduce targets as means of template fidelity. Results: We observed fidelity-dependent increments of matching-related gamma phase locking and theta:gamma phase coupling in early visual areas around 100–200-ms poststimulus over time. Conclusion: Theta:gamma phase synchronization and evoked gamma activity might serve as complementary signatures of memory matching in visual perception; theta:gamma phase synchronization seemingly most important in early phases of learning and evoked gamma activity being essential for transition of mental templates into long-term memory.

355. Evidence for the neural information flow during memory reconstruction from feature-specific reaction times

Mr Christopher Postzich1, Dr Juan Linde-Domingo2, Dr Marije ter Wal3, Prof Maria Wimber1,3

1Institute of Neuroscience & Psychology and Centre for Cognitive Neuroimaging (CCNi), University of Glasgow, Glasgow, UK, 2Center for Adaptive Rationality, Max Planck Institute for Human Development, Berlin, Germany, 3School of Psychology & Centre for Human Brain Health, University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK

355. During visual perception, stimulus information initially flows in a feed-forward manner along the visual processing hierarchy. This process is assumed to involve a gradual transformation from low-level perceptual details in sensory areas to high-level conceptual representations. Recent behavioural and electrophysiological evidence suggests that when visual objects are reconstructed from memory, this processing hierarchy is reversed such that high-level conceptual features are reliably activated before low-level perceptual details (Lifanov et al., 2021, Nat. Commun.; Linde-Domingo et al., 2019, Nat. Commun.). Here, in five experiments, we asked if this reverse reconstruction hierarchy generalises to different stimulus features (Exp. 1 and 2), depends on the type of memory cue used (Exp. 3), and is significantly modulated by the features attended during learning (Exp. 4 and 5). All experiments used an associative cued recall paradigm, combined with feature-specific reaction times that are thought to tap into feature-specific neural processing speed. The results show that the reverse reconstruction effect generalises to different features probed, with the constraint that perceptual features need to be independent from object semantics. Evidence for a reversed information processing hierarchy very reliably replicates for different cue types (scenes vs words) and is unaffected by attentional manipulations that prioritise perceptual or conceptual features during learning. A cross-experiment GLMM shows a significant average advantage of semantic over perceptual feature access during retrieval in reaction times and accuracies. To gain a deeper understanding of this reverse retrieval effect, we included the above mentioned as well as previously published datasets in a Hierarchical Drift Diffusion Model (HDDM) to estimate parameters underlying our reaction time distributions. Consistently across experiments, we find that reconstructing conceptual versus perceptual object features creates a difference in the drift rates, suggesting that reaction time differences between these conditions mainly stem from differences in the speed of evidence accumulation.

356. The role of semantic codes in verbal working memory maintenance

Ms Pauline Querella1, Dr Lucie Attout1, Dr Wim Fias2, Dr Steve Majerus1,3

1Psychology and Neuroscience of Cognition RU, University of Liège, 2Experimental Psychology UR, University of Ghent, 3National Fund for Scientific Research

356. Although the impact of long-term memory (LTM) knowledge on working memory (WM) performance has been well demonstrated, the nature of the interactions between WM and semantic LTM remains poorly understood. While some theoretical models consider that this intervention indicates a temporary and direct activation of LTM during WM maintenance, others consider that LTM only intervenes during recall, in order to reconstruct degraded memory traces. The aim of this study was to examine the extent to which semantic knowledge in LTM is temporarily activated during the maintenance phase in WM, by determining, via fMRI, whether brain markers of semantic knowledge are observable during the maintenance phase in verbal WM. Twenty-five healthy participants (18-35 years old) participated in this study. The multivariate brain signals of four semantic categories were pre-determined via an implicit semantic activation task (reading aloud of words from four semantic categories). Next, the participants were asked to maintain words in a verbal WM task, these words being the names of the four semantic categories implicitly activated in the preceding task. Via multi-voxel pattern analyses, we were able to distinguish the neural patterns associated with the four semantic categories both in the semantic activation task and during the maintenance stage of the WM task (Bayesian factors BF10>1.98210 and BF10>10.436, respectively, for category decoding against chance level decoding). However, when attempting to predict the neural patterns associated with the semantic categories between the two tasks, prediction rates did not exceed chance level, indicating that the multivariate brain signals associated with the maintenance of semantic category names in the WM task and those associated with semantic categories in the implicit semantic activation task differ. These results indicate that deep semantic representations in LTM are not necessarily activated during maintenance in WM and suggest a more limited intervention of semantic LTM in WM.

357. Memory reinstatement and transformation in children and adolescents

Elias M.B. Rau1, Dr. Marie-Christin Fellner1, Rebekka Heinen1, Dr. Hui Zhang1, Dr. Elisabeth L. Johnson2, Qin Yin3,4, Dr. Eishi Asano5, Prof. Dr. Noa Ofen3,4, Prof. Dr. Nikolai Axmacher1

1Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 2Departments of Medical Social Sciences and Pediatrics, Northwestern University, 3Life-Span Cognitive Neuroscience Program, Institute of Gerontology, Wayne State University, 4Department of Psychology, Wayne State University, 5Departments of Pediatrics and Neurology, Children Hospital of Michigan, Wayne State University

357. OBJECTIVE It has been argued that episodic memory retrieval relies not only on the truthful and veridical reinstatement of neural activity encountered during encoding, but also on representational transformations that reflect the extraction of relevant features and statistical regularities. Here we aimed to investigate the neural representations of visual stimuli and describe how they unfold in space and time. RESEARCH QUESTION We characterized the similarity of item-specific neural representations between encoding and subsequent recognition in visual and associative brain regions and assessed its functional relevance for successful memory across a wide age range from childhood into young adulthood. MATERIALS AND METHODS We analysed intracranial EEG data of individuals aged 6-32 years with electrodes implanted for the clinical evaluation of refractory epilepsy. By using representational similarity analysis, we characterized the similarity of electrophysiological features between scene representations during encoding and subsequent recognition across a hierarchy of brain areas from primary visual cortex to those upstream the ventral visual processing pathway, including medial temporal and fronto-parietal structures. RESULTS We found greater reinstatement of neural patterns formed during encoding for remembered versus forgotten scenes in inferior and medial temporal areas. Interestingly, we also identified fronto-parietal areas in which transformed neural patterns (i.e., changes of stimulus-specific patterns from encoding to recognition) supported successful memory. CONCLUSION Whereas the truthful and veridical reinstatement of representational traces benefits memory in higher order visual association cortices, transformed representations may be more beneficial in fronto-parietal cortices. These transformed neural patterns are possibly the result of feedback-related mechanisms that undergo prolonged maturation during adolescence. Further analyses will investigate whether age-related variability in reinstatement can explain observed gains in episodic memory performance during development.

358. The how and when of sleep-dependent gist abstraction

Dr Karsten Rauss1, Dr Nicolas Lutz2, Johanna Himbert1, Jessica Palmieri3, Eva-Maria Kurz1, Prof. Dr. Jan Born1

1Eberhard-Karls-Universität, 2Ludwig-Maximilians-Universität, 3Albert-Ludwigs-Universität

358. Current theories of memory processing postulate a slow transformation from episodic to gist-like memories which is thought to benefit from sleep. We previously used a non-verbal version of the Deese-Roediger-McDermott (DRM) paradigm to investigate sleep-dependent gist abstraction in the visual domain (Lutz et al. 2017, Sci Rep). Healthy volunteers learned sets of abstract shapes derived from a common prototype, and their memory performance was measured for learned shapes, new shapes, and previously unseen prototypes. Results indicated a beneficial effect of sleep on gist abstraction only after a one-year retention interval. In the present follow-up experiment, we aimed to investigate sleep-dependent visual gist abstraction in more detail by testing memory immediately after learning; after an interval of one week; and after a delay of one year. In addition, we separated stimuli into those that closely resembled their prototype, and those more removed from the prototype, as indicated by similarity judgements obtained from a separate sample of participants. We then recorded data from N = 16 healthy volunteers in a within-subjects design, where different sets of shapes were learned either in the morning or in the evening, followed by initial consolidation during wake or sleep, respectively. Our results indicate high levels of (false) prototype recognition across all measurement points. In particular, we found higher recognition rates for the non-learned prototypes than for the actually learned shapes after one year. However, in contrast to our previous findings, this effect was not sleep-dependent after either one week or one year. We propose that this divergence is due to our manipulation of stimulus similarity, which resulted in a reduction of the number of shapes per set that participants were required to learn. Thus, our results may indicate that sleep-dependent gist abstraction occurs only under conditions of high information load at encoding.

359. Cortical and sub-cortical contributions to schema-facilitated motor memory consolidation

Serena Reverberi1, Nina Dolfen1, Bradley King2, Genevieve Albouy1,2

1Department of Movement Sciences, KU Leuven, 2Department of Health and Kinesiology, University of Utah

359. Objectives and research question New information is rapidly learned when compatible with previous knowledge. This “schema effect” has been widely studied in declarative memory and recently extended to motor (sequence) memory, where the schema consists of the ordinal structure of a learned sequence. The goal of this study was to use multivariate pattern analyses (MVPA) of fMRI data to investigate the neural substrates underlying this process. Based on previous literature, we focused on the contribution of the hippocampus, medial prefrontal cortex (mPFC) and striatum to the integration of new motor information into pre-existing schema. Materials and methods A preliminary sample of young healthy participants performed 2 experimental sessions, approximately 24h apart. During Session1 (S1), all participants learned a bimanual eight-element motor sequence. During Session2 (S2) participants learned a novel sequence with an ordinal structure that was either highly compatible (COMP) or incompatible (INCOMP) with that learned in S1. Eight runs of fMRI data were collected during S2 task practice and analyzed with multivariate approaches, using 8 regressors of interest per task run (i.e., one per sequence element). We tested whether the across-runs correlations of multi-voxel parameter estimates corresponding to new and old sequence elements were modulated by ordinal compatibility. Results Both groups successfully learned the S1 sequence (main effect of practice block on reaction time (RT), p<0.001) with no baseline difference across groups (p=0.36). During S2 the COMP group displayed enhanced performance (lower RT) during a pre-scan test (near significant group effect p=0.057). MVPA revealed that the caudate nucleus shows higher coding for new, compared with old, elements in the INCOMP versus the COMP group (group x new/old interaction p=0.04). Our results indicate that hippocampus and mPFC preferentially code for sequence elements (irrespective of old/new status) under COMP versus INCOMP conditions although this difference was non-significant in this preliminary sample. Conclusion This study provides new insights into the neural substrates supporting schema-mediated motor memory consolidation. Preliminary results indicate that the striatum supports integration of novel material presented in a schema-incompatible context while hippocampo-frontal areas support retention of old - and integration of novel - material in a schema-compatible context.

360. Independent component analysis reveals two functionally distinct posterior alpha rhythms during a working memory task

Dr Julio Rodriguez Larios1,2, Dr Hesham ElShafei3, Mrs Melanie Wiehe3, Prof Saskia Haegens1,2,3

1Department of Psychiatry, Columbia University, College of Physicians and Surgeons, 2New York State Psychiatric Institute, 3Donders Centre for Cognitive Neuroimaging

360. Oscillatory activity in the human brain is dominated by posterior alpha oscillations (8-14 Hz), which have been shown to be functionally relevant in a wide variety of cognitive tasks. One prevailing theory posits that alpha power is positively associated with the level of cortical inhibition, which is expected to increase in task-relevant areas and decrease in task-irrelevant areas. Although posterior alpha oscillations are commonly considered a single oscillator anchored at individual alpha frequency (IAF; ~10 Hz), previous work suggests that IAF reflects a spatial mixture of different brain rhythms. In this study, we assess whether independent component analysis can disentangle functionally distinct posterior alpha rhythms in the context of short-term memory retention. Magnetoencephalography (MEG) was recorded in 34 subjects performing a spatial working memory task in which task difficulty was modulated by introducing visual distractors during the memory retention period. Group analysis at sensor level revealed an increase in alpha power (assessed at the individual peak frequency) and a decrease of individual peak frequency during memory retention in posterior brain regions. However, single-subject analysis of independent components showed the existence of two types of alpha rhythms: one that increases in power during memory retention (Alpha1) and another one that decreases in power (Alpha2). Crucially, these two types of alpha rhythms were differentially modulated by task difficulty and differed in their spatiotemporal characteristics. Alpha1 components showed a power increase in the presence of distractors, had a lower peak frequency (~8-10Hz) and mostly originated in early visual areas. Alpha2 components decreased in power in the presence of distractors, had a higher peak frequency (~10-14 Hz) and had a more variable source extending to occipital and parietal areas. Together, our results suggest that modulations in posterior alpha oscillations reflect the dynamics of at least two distinct brain rhythms with different spatiotemporal characteristics and functional implications. Based on our results and previous literature, we propose that during short-term memory retention, Alpha1 power increases reflect inhibition of early visual areas whilst Alpha2 power decreases reflect the involvement of higher-order areas that support the transient storage of visual information.

361. Pattern reinstatement and attentional control: overlapping processes during episodic long-term memory retrieval

Melinda Sabo1, Prof. Edmund Wascher1, Dr. Daniel Schneider1

1Leibniz Research Centre for Working Environment and Human Factors

361. Episodic long-term memory retrieval involves the reinstatement of neural patterns from the encoding phase, a process recently argued to be reflected in alpha/beta (8-20 Hz) oscillatory activity. However, comparable cortical patterns were also observed during switches in the focus of attention within working memory representations. The current study assesses independently these two processes based on alpha/beta-band activity in the electroencephalogram. In the encoding phase, subjects were presented with an object on a certain position on the screen (left, tight, top or bottom) and their task was to imagine it on a new position for later report. In each trial, either the task-irrelevant presentation position or the task-relevant imagination position was lateralized. In the retrieval phase, objects were centrally presented and subjects were required to make an old/new judgement, followed by the report of the imagination position associated with each old object. Two competing hypotheses were formulated. According to the pattern reinstatement account, changes of lateralized alpha/beta activity reflecting pattern reinstatement would predict similar topographical effects during encoding and retrieval. Conversely, the influence of attentional control processes during retrieval would be associated with the suppression of alpha/beta power contralateral to the to-be-reported imagination position and with the increase of activity relative to the irrelevant presentation position. Our results support this latter pattern. This shows that an experimental differentiation between selective attention and pattern reinstatement processes is necessary when studying the neural basis of episodic long-term memory retrieval.

362. Metformin prevents methotrexate-induced cognitive and hippocampal neurogenesis impairments in a rat model

Nataya Sritawan1, Ram Prajit1, Kornrawee Suwannakot1, Salinee Naewla1, Anusara Aranarochana1, Apiwat Sirichoat1, Wanassanan Pannangrong1, Jariya Umka Welbat1,2

1Department of Anatomy, Faculty of Medicine, Khon Kaen University, Thailand, 2Neuroscience Research and Development Group, Khon Kaen University

362. Methotrexate (MTX) is commonly used in combination with other drugs as an adjuvant chemotherapy. MTX inhibits dihydrofolate reductase (DHFR) leading to folic acid deficiency and thereby disrupts DNA synthesis and cell proliferation, which has been associated with cognitive impairment in many patients. Metformin is currently used as the first-line drug to treat type 2 diabetes. Previous studies have demonstrated that metformin can reduce neuroinflammation and hippocampal neuronal cell loss, which subsequently improve memory. Therefore, the aim of the present study was to investigate the effects of metformin on a reduction of memory and hippocampal neurogenesis induced by MTX chemotherapy in a rat model. Male Sprague-Dawley rats were divided into control, MTX, metformin, and preventive groups. MTX (75 mg/kg BW) was administered by intravenous injection on days 7 and 14. Rats were administered with metformin (200 mg/kg BW) by intraperitoneal injection for 14 days. Some of the MTX-treated rats received co-treatment with metformin once a day for 14 days in preventive group. Memory was determined using novel object location (NOL) and novel object recognition (NOR) tests. Hippocampal cell survival, immature neuron and cell cycle arrest in the subgranular zone (SGZ) were quantified by immunostaining for 5-bromo-2’-deoxyuridine (BrdU), doublecortin (DCX) and p21, respectively. Levels of protein expression including brain-derived neurotrophic factor (BDNF), nuclear factor erythroid 2-related factor (Nrf2), and DCX were determined by Western blotting. Furthermore, scavenging enzymes activities and malondialdehyde (MDA) level changes in hippocampus were investigated. Rats receiving MTX alone showed memory impairment, cell survival, and immature neuron reduction. Decreasing in scavenging enzymes activities and the levels of BDNF, Nrf2, and DCX protein expressions in the hippocampus were found. In addition, MTX showed a significant increase in numbers of p21-positive cells and MDA levels. However, results in the preventive group showed amelioration of memory impairment, and reductions cell survival and immature neurons in the SGZ. There were also increases in scavenging enzymes activities and the levels of BDNF, Nrf2, and DCX. Moreover, it showed a significant decrease numbers of p21-positive cells and MDA levels. These results represent that metformin can prevent memory and hippocampal neurogenesis impairments caused by MTX chemotherapy.

363. DWI reveals rapid microstructural reorganization following motor sequence learning

Whitney Stee1,2, Dr Michele Guerreri3, Dr Antoine Legouhy3, Prof Hui Zhang3, Prof Philippe Peigneux1,2

1UR2NF-Neuropsychology and Functional Neuroimaging Research Unit affiliated at CRCN – Centre for Research in Cognition and Neurosciences and UNI - ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), 2GIGA - Cyclotron Research Centre - In Vivo Imaging, University of Liège (ULiège), 3Department of Computer Science & Centre for Medical Image Computing, University College London

363. Introduction: Diffusion-weighted imaging (DWI) allows observing rapid (micro)structural brain remodeling in cortical and subcortical regions after restricted motor learning time. Even if very sensitive, diffusion tensor imaging (DTI) is inherently non-specific, limiting information about the underlying cellular processes. Multicompartment diffusion imaging (Neurite Orientation Dispersion and Density Imaging – NODDI) that estimates the microstructural complexity of dendrites and axons would allow tracking neural density changes that dynamically develop in the short-term in white and grey matter with improved specificity. Therefore, we combined both measures to get a better understanding of microstructural brain mechanisms underlying time-dependent motor memory consolidation processes. Methods: Sixty young (18-30y), healthy adults underwent two DWI MRI sessions before and after 1h-Serial Reaction Time Task learning (30 blocks – 96 trials/block) followed by 30min break. DTI and NODDI analyses were conducted on 6 bilateral subcortical regions of interest (ROIs). Results: A multivariate analysis on DTI and NODDI parameters revealed microstructural modulation in the left thalamus (p = 0.006) and putamen (p = 0.005), the right caudate (p = 0.006), and bilateral hippocampus (ps < 0.007) and cerebellum (ps < 0.001). Univariate post-hoc tests disclosed (a) decreased mean diffusivity (MD) in the left putamen, right caudate, bilateral hippocampus, and cerebellum; (b) decreased free water fraction (FWF) in bilateral cerebellum and the right caudate; and (c) increased neurite dispersion index (NDI) in the left putamen. Fractional anisotropy (FA) and orientation dispersion index (ODI) remained unaltered. Conclusions: MD reductions in subcortical ROIs confirm previously reported motor learning-related microstructural changes developing in the short term. Also, reduced FWF in similar regions indicates increased tissue proportion following learning, whereas enhanced NDI in the left putamen suggests a motor learning-related reorganization in brain tissue microstructure and neurite density, probably reflecting structural brain plasticity changes.

365. The FN400/N400 memory effects for perceptually fluent and disfluent words

Dr. Paweł Stróżak1, Dr. Andrew Leynes2, M.Sc. Marcin Wojtasiński1

1The John Paul II Catholic University Of Lublin, 2The College of New Jersey

365. Objectives: Processing fluency is a metacognitive cue in human decisions that can also influence memory judgments. Recognition memory studies have shown that increased familiarity for stimuli that are perceptually more fluent results in more “old” responses. However, the event-related potential (ERP) studies indicate that perceptual fluency manipulations influence the centro-parietal N400 reflecting semantic processing, but not the frontal FN400 that reflects familiarity. Thus, the exact neural mechanisms of the fluency effects on recognition remain unresolved. Research question: The aim of the study was to analyze the FN400/N400 memory effects separately for perceptually fluent and disfluent words. We asked whether enhanced perceptual fluency is interpreted as familiarity, increases recognition accuracy and elicits larger FN400 potentials. Materials and methods: We conducted two ERP experiments in which participants (N=24 in each experiment) encoded words and then performed a recognition test in which half of the words was clear or blurry. The experiments differed in the difficulty of the memory task, with four long study-test blocks in Experiment 1 (120 words at encoding in each block) and eight short study-test blocks in Experiment 2 (60 words at encoding in each block). Results: In more demanding Experiment 1, participants made more hits for less fluent (blurry) words, which was accompanied by the larger N400. For high confidence responses, the topography of this effect shifted towards frontal electrodes (the FN400 for blurry words). In less demanding Experiment 2, no behavioral differences between clear and blurry words were observed. However, there was an apparent discrepancy in the pattern of ERP results, with the frontal FN400 for blurry words and the parietal N400 for clear words. Conclusion: The results indicate that perceptual fluency is capable of influencing recognition memory judgments under more demanding conditions, but the direction of this influence is reversed (more “old” responses for less fluent stimuli) than usually reported. This pattern of results is resembled at the neural level, with the familiarity-related FN400 for less fluent items recognized with high confidence. In less demanding conditions, the neural processes responsible for recognizing less fluent and more fluent items are topographically separated, albeit without influencing recognition accuracy.

366. MiR-204-3p/Nox4 mediates memory deficits in a mouse model of Alzheimer’s disease

Ms Wenyuan Tao1, Mr Jianwei Ge1, Mr Linjie Yu1, Dr Xiaolei Zhu1, Dr Yun Xu1

1Nanjing Drum Tower Hospital

366. Background: Oxidative stress plays a critical role in the pathogenesis of Alzheimer's disease (AD), and microRNAs (miRNAs) contributes to the oxidative stress and memory deficits in AD. Methods: MiRNA microarray was performed using the hippocampus of 6-month-old APPswe/PS1dE9 (APP/PS1) mice. The miR-204-3p overexpression lentivirus (Lv-miR-204) was injected into bilateral hippocampus of APP/PS1 mice. The memory function was examined by Open filed, New-object reorganization, Fear condition and Morris water maze tests. The beta-amyloid (A-beta) levels were determined by immuofluorescence and ELISA. The protein levels of synaptic proteins were determined by western blotting. The potential targets of miR-204-3p were predicted by Targetscan, and confirmed by luciferease assay and western blotting. Long-term potentiation (LTP) was recorded to evaluate the synaptic functions. The levels of 4-hydroxynonenal, 3-nitrotyrosine, and 8-hydroxy-2'-deoxyguanosine were detected by ELISA and the level of H2O2 was examined by spectrophotometry. Reactive oxygen species (ROS) was determined by fluorescence assay. Results: MiR-204-3p was significantly downregulated in the hippocampus and plasma of 6-month-old APPswe/PS1dE9 (APP/PS1) mice and in the plasma of AD patients. MiR-204-3p overexpression attenuated memory and synaptic deficits in APP/PS1 mice. Lv-miR-204 treatment decreased amyloid levels and oxidative stress in the hippocampus. NADPH oxidase 4 (Nox4) was a target of miR-204, and Nox4 inhibition protected neuronal cells against Aβ induced neurotoxicity. Furthermore, GLX351322 treatment rescued synaptic and memory deficits, and inhibit oxidative stress and amyloid levels in the hippocampus of APP/PS1 mice. Conclusion: MiR-204-3p attenuated synaptic and memory deficits and inhibit oxidative stress in APP/PS1 mice by targeting Nox4, and miR-204-3p overexpression and/or Nox4 inhibition might be a potential therapeutic strategy for AD treatment.

367. Brief odor exposure induce lingering mnemonic biases for upcoming visual events

Mr Joan Tarrida1, Mr Manuel Moreno1, Mr Jordi Vidal4, Dr David Panyella4, Prof Josep Marco-Pallarés1,2,3, Prof Lluís Fuentemilla1,2,3

1Department of Cognition, Development and Educational Psychology, University of Barcelona, 2Cognition and Brain Plasticity Group, Bellvitge Institute for Biomedical Research, 3Institute of Neurosciences, University of Barcelona, 4Dept. Research & Development, Antonio Puig SA

367. Odor representation in the brain can extend beyond its sensory input for few seconds. It is unknown, however, whether such odor persistent trace representation can shape mnemonic processing for upcoming events in humans and if so, whether this effect is odor hedonic valence dependent. Here, we recorded scalp electroencephalographic (EEG) activity in 23 healthy participants while they were encoding pictures that were preceded, 6 seconds before, by two diferent odors, L-Carvone or N-Butanol. The hedonic valence of each odor was rated by the participant at the end of each trial. After 48 hours, participants completed a surprised recognition test of the encoded pictures. We found that the odor hedonic rating predicted memory confidence of the associated picture. In turn, confidence predicted whether the picture was remembered or not and this effect was greater for pictures preceded by unpleasant odors. Event-related potential and representational similarity analyses of the EEG signal showed that patterns of brain responses elicited by odor exposure persisted for 3-4 seconds, and that odor-induced pattern of brain responses were reinstated at the encoding of the upcoming picture when odor was rated unpleasant. These results provide evidence that odor-induced persistent trace representations can influence subsequent mnemonic processing for visual events.

368. Expectations about sounds but not omissions are mediated by predictability-specific neural templates

Dr Ruxandra I. Tivadar1, Mrs Pinar Kavis Göktepe1, Mr Sigurd A. Lerkerød1, Ms Mena Lerf1, Ms Anna S. Morf1, Prof Athina Tzovara1,2,3

1Institute for Computer Science, University Of Bern, 2Helen Wills Neuroscience Institute, University of California, 3Sleep Wake Epilepsy Center / NeuroTec, Department of Neurology, Inselspital, Bern University Hospital, University of Bern

368. Objectives Predictive processing theories posit that our brains rely on stimulus-specific models of predicted events to prepare for their occurrence and fill in missing information. Here, we constructed an electroencephalographic (EEG) paradigm consisting of auditory cue-target or cue-omission pairs at three predictability levels (100%, 70%, 30%) to investigate how predictability of sounds and omissions are cortically implemented. Research Question It remains unclear whether probabilistic predictions about the presence or absence of future events are encoded in a similar way. We hypothesized that predictions about occurring auditory stimuli would result in pre-activation of sound- and prediction-specific neural templates, reflecting patterns of activity similar to those in response to the upcoming stimulus. Materials and Methods We recorded HD-EEG in 21 volunteers while they were listening to abstract sounds occasionally followed by a pure tone. We manipulated the predictability of the tone following each of the sounds (0%, 30%, 60%, 100%). Participants’ task was to indicate a fraction (0-1) by which they thought that the individual sounds would predict the target. We analysed brain activity for sounds and omissions separately in terms of the strength and topography of the EEG response, of active sources supporting encoding of predictability, and of decoding and temporal generalization, which indicated how neural stimulus templates were activated during the whole stimulus period. Results Predictions about sounds but not omissions were mediated both by pre- and by back-activation of neural templates, which encoded not only stimulus identity, but also predictability. These predictions originated from distributed brain regions, and mainly from the anterior prefrontal cortex. We further found that strength of EEG responses to both sounds and omissions was inversely related to predictability, and that a time period in the EEG response fulfilled the necessary conditions for a global sensory prediction error signal, encompassing both sounds and omissions. Conclusion Our results lay a strong basis for predictive processing research, by showing that in preparation for predicted sounds, the brain builds stimulus- and predictability- specific templates, which are pre-activated as early as one second before actual sound occurrence.

371. Altering stimulus timing via sensory entrainment at gamma frequency induces STDP-like recall performance in human episodic memory

Danying Wang1,2, Prof Kimron Shapiro2, Prof Simon Hanslmayr1,2

1University of Glasgow, 2University of Birmingham

371. Previous studies using rhythmic sensory stimulation (RSS) show that binding multisensory information into human episodic memory depends on precise timing between sensory inputs. At the cellular level, one such finely tuned timing mechanism is spike timing dependent plasticity (STDP). If a pre-synaptic neuron fires within a short delay before a post-synaptic neuron, the connection from the pre-synaptic to the post-synaptic neurons will be strengthened. If the temporal order of the two spikes is reversed, then the synaptic connection will be weakened. The time window for synaptic modification falls within the gamma frequency range. However, evidence on the causal role of gamma synchronisation and STDP in human episodic memory is lacking. We investigated this using RSS to entrain visual and auditory cortices at gamma frequency (37.5 Hz). Luminance of video clips and volume of sound clips were modulated by a 37.5 Hz sine wave with four phase offsets: 0°, 90°, 180° and 270°, which corresponds to the delay of 0 ms, 6.67 ms, 13.33 ms and 20 ms, respectively, between visual and auditory inputs. One group of participants (N=48) was cued with videos and asked to recall paired sounds. Another group of 48 participants were cued with sounds and recalled paired videos. EEG was recorded in 24 participants for each group. The normalised visual cued recall accuracy was better when visual stimulus led by 6.67 ms relative to the normalised auditory cued recall accuracy in large sample sizes (N = 48 for each group). Single trial analysis on participants who had EEG recorded (N = 24 for each group) showed that trial-by-trial phase differences between entrained visual and auditory source activity predicted recall performance in a way that is consistent with the STDP learning rule. Visually cued recall was better than auditory cued recall when the visual stimulus led the auditory stimulus by 6.67 ms, while this pattern was reversed when the auditory stimulus led the visual stimulus by 6.67 ms. Our findings provide novel evidence for STDP in human learning and memory, which builds a bridge from in-vitro studies in animals to human behaviour.

369. Power dynamics of the EEG spectrum when encoding words in variable size lists

Viktors Veliks1, Dmitrijs Igonins, Juris Porozovs, Aija Klavina 1University Of Latvia

369. Changes in the spectral power of EEG waves are significant for identifying the ongoing cognitive processes. Lists of different length ranging from 2 to 180 high-frequency Latvian colloquial nouns were visually presented randomly to 25 participants in 5 separate sessions. The words were divided into lists of different length, their presentation was followed by a two-choices recognition test. The inter-stimulus interval was 4 seconds. The power of the EEG wave spectrum was calculated for -100÷2000 ms at the presentation of each stimulus using a standard EEG preprocessing procedure. The mean values and standard deviations of the signal power in each of the EEG wavebands were calculated for each presented word in serial order for all participants and sessions. The averages were calculated from the sum of signal pairs of the following ROIs: F7, F3 and P3, T5 that reflected cortical activity in areas involved in the processing and storage of lexical information. The overall recognition accuracy was from 8o% to 67.5%, depending on the list length. Specific memory load size ranges were identified in which there were significant changes in spectral EEG power. In the area of the first seven units presented, alpha power increased from the first unit. Beta, theta, and gamma power fell. Delta power in this range fell from a local maximum at the first unit of the list to a local minimum at the second unit, and then increased without reaching a local maximum by the end of the range. This pattern of power change was observed in both the Broca and Wernicke regions. As subsequent units were coded, alpha power increased up to 49 units and decreased to 68, theta power increased up to the 43rd unit and maintained its level until the 55th unit. Beta power continued to drop from the 8th to 18th units and rose again to the 49th unit, remaining at this level until the 68th. Gamma power dynamics showed a similar pattern. The data obtained may help in understanding the role of different EEG waves in encoding specific amounts of information in long-term memory. The research in the framework lzp-2019/1-0152.

372. Investigating Neural Substrates of Successful Memory Encoding using fMRI

Alexander Weuthen1, Markus Ullsperger1,2

1Otto-von-Guericke-Universität Magdeburg, Department of Neuropsychology, 2Center for Behavioral Brain Sciences

372. In stable environments good memory is a useful ressource to guide adaptive behavior. However, recognizing the need for behavioral adaptations after errors can also improve the updating process of memory contents. Here, our goal was to assess the neurophysiological interplay between performance monitoring and memory in a newly developed visual learning paradigm. In this task, participants had to learn associations between different faces and a set of eight possible orientations of gabor patches. On each trial, participants were presented a face and had to adjust the associated gabor patch orientation. After indicating the confidence in their decision, participants received feedback on their choices followed by the correct face and orientation combination, to enable learning of the associated gabor patch for recall in future trials on the same face. In a separate 1-back localizer task, we trained a support vector machine to distinguish between faces and houses based on voxels in fusiform gyrus. For each trial in the memory task, the model was then used to predict whether a face was presented and the decision function was extracted to display respective model certainty. Increased face representativity was related to regions among basal forebrain, posterior medial frontal cortex and frontoparietal network, and overlapped with regions associated with low confidence and negative feedback. The interplay between these regions could underly the mechanism how performance monitoring enhances stimulus representativity when memory encoding needs to be improved.

373. Impulse-based decoding of working memory for colour

Guven Kandemir1, Sophia Wilhelm1, Prof. Dr Elkan Akyurek1

1Experimental Psychology, University Of Groningen

373. Working memory (WM) theories propose that information is maintained by persistent firing. Recently the idea of activity-silent WM states has been proposed, stating that WM content is stored in activity-silent states. These states are difficult to measure using current neuroimaging techniques. However, Wolff and colleagues (2017) showed that although memory for orientation gratings fade from ongoing activity as time progresses, this memory can still be decoded from the EEG response to a visual impulse. This so-called impulse perturbation approach mimics the idea of using sonar to infer the surface of the sea floor, but applies this to making inferences about brain states. In this technique, an uninformative, but high-contrast stimulus is presented during the delay period, which functions to reactivate memory traces that can then be measured by EEG. However, the technique has so far only been tested on orientation gratings. This has invited concerns about the broader validity of the technique and the degree to which the impulse response might be driven by eye movements elicited by the gratings. To address these, we applied the visual impulse technique to centrally presented colour stimuli. The results showed that the approach can be used to study colour WM. More specifically, we saw that the cued colour item could be reactivated by the impulse. Furthermore, time-course decoding showed that in initial stimulus presentation decodability had dropped shortly after stimulus presentation, providing evidence for the idea that activity-silent states take over WM storage after encoding. The results provide further evidence that the current methodology provides a powerful tool to study the neural correlates of WM in new detail.

370. Is manual sensorimotor system involved in explicit memory for manipulable objects? A test with action priming and hand immobilization

Jeremy Villatte1, Prof Laurence Taconnat2, Dr Solène Kalénine3, Dr Yannick Wamain3, Prof Lucette Toussaint1

1Université de Poitiers, 2Université de Tours , 3Université de Lille

370. Embodied theories of cognition (Barsalou, 1999, 2008) propose that sensorimotor experience is critical to high-level cognitive processes. Various studies have investigated the role of the sensorimotor system in declarative memory tasks and reported mixed results (e.g. De Vega et al., 2021; Zeelenberg et al., 2020). Our goal was to investigate new experimental paradigms that could reveal a direct relationship between sensorimotor arousal and declarative memory. On one side, we aimed to assess whether decreased stimulation of the manual sensorimotor system could impair memory encoding for manipulable targets. To do so, we used short-term (24 hours) hand immobilization, which is known to elicit plasticity in hand cortical representations (Hubert et al., 2006) and to impair various type of cognitive tasks (Furlan et al., 2016). On the other side, we aimed to strengthen the activation of manual sensorimotor system during learning in an explicit memory task. We then used the action priming paradigm (Borghi et al., 2006), i.e., manipulable objects were displayed after hand grip pictures that may or may not prime the manual gesture corresponding to the target. Classically, this type of paradigm results in faster response times for objects primed by a congruent grasping hand, which is interpreted as activation of the sensorimotor system. Therefore, in this experiment, participants in a control and an immobilized group learned lists of manipulable objects. Half of the objects were primed with congruent grasping hands pictures, the other half with non-grasping hands. In a subsequent recognition test, the targets were presented without primes, among distractors. Mixed-model analysis were performed on correct recognition times and revealed no main effect of immobilization or action priming. However, a significant group x prime interaction revealed longer correct recognition latencies for immobilized participants only when objects were not primed by a congruent grasping hand during learning. This result, shows that recognition time was impaired when arousal in the sensorimotor system during learning was minimum, which suggests that declarative memory encoding has a direct relationship with the sensorimotor system.

374. Post-encoding reactivation binds episodic sequences in long-term memory

Xiongbo Wu1,2,3, Bernhard P. Staresina4, Lluís Fuentemilla1,2,3

1Cognition and Brain Plasticity Group, Bellvitge Institute for Biomedical Research, 2Department of Cognition, Development and Educational Psychology, University of Barcelona, 3Institute of Neurosciences, University of Barcelona, 4Department of Experimental Psychology, University of Oxford

374. In episodic encoding, the unfolding experience is rapidly transformed into a memory representation that binds separate episodic elements into an integrated episodic form, so that it can be later recollected completely. Here, we examined whether this memory transformation takes place rapidly once the encoded episode is completed by means of neural reactivation. We asked participants to encode trial-unique combinations of face-object-scene picture triplets that were subsequently recalled in a test. We used representational similarity analysis of scalp electroencephalography (EEG) recordings during encoding and found evidence for memory reactivation of the just encoded episodic elements after encoding, i.e., at the offset following each triplet images presentation (i.e., at 500 ms at offset period onset). Neural patterns associated to item’s categories were obtained from a different set of images and applied on EEG signals to index the magnitude of discriminability across image categories during sequence encoding and at the offset period. We found that the degree of category discriminability decreased as a function of item order in the sequence, indicating the gradual integration of items’ category from the sequence during online encoding. However, we found much smaller degree of category discriminability at offset period presentation (i.e., at 500 ms at offset period onset) for sequences that would be later recollected compared to those that would be forgotten. Given the temporal overlap of the neural reactivation and the discriminability index analysis and the specificity of the effects in relation to memory performance, we conclude that episodic offset memory reactivation is a mechanism engaged to support integration of episodic elements in long term memory.

375. Neural correlates of metamemory in a face-name associative learning task

Dr Weiyong Xu1,2, Dr Tiina Parviainen1,2, Dr Miriam Nokia1,2

1Department of Psychology, University of Jyväskylä, 2Jyväskylä Centre for Interdisciplinary Brain Research, University of Jyväskylä

375. OBJECTIVES: The ability to accurately assess one’s own memory performance (metamemory) is essential for adaptive behavior, but the brain mechanisms underlying subjective confidence of memory are not fully understood yet. RESEARCH QUESTION: In this study, we investigate the neural correlates of subjective judgments of memory performance in a face-name association learning task using magnetoencephalography (MEG). MATERIALS AND METHODS: Healthy young adults (N= 32, 9 males, aged 25.1±4.3 years) took part in the study. The task consisted of 6 rounds of encoding and recall, separated by brief resting periods. During encoding, 40 face-name pairs were presented. During recall, each face was presented twice alone and once followed by a list of 4 names from which the participant selected the correct name. Then the participant was asked to rate how confident they were in their choice. After each round, the participant was informed of the percentage of face-name pairs that they had correctly remembered, but no information was given about which pairs were remembered correctly. MEG data were analyzed using representational similarity analysis (RSA) with a spatiotemporal searchlight approach to isolate the brain response that correlated with the confidence rating. In addition, time-frequency analysis was performed to investigate oscillatory responses. RESULTS: According to RSA, brain responses especially in the right occipital regions at 300–700 ms after the onset of the face presentation during recall correlated with the confidence rating of memory. Further, brain oscillatory responses at alpha (8–12 Hz) and beta (12–30 Hz) bands evoked by the presentation of faces alone during recall showed decreased power as a function of confidence. That is, alpha- and beta-band suppression was stronger in response to confidently remembered faces, as evaluated by the participant themself. CONCLUSION: Our preliminary results reveal neural response patterns related to metamemory. It would be interesting to examine these response features during encoding and recall in individuals with impaired memory or to modulate the response features to see how it affects performance.

85. Temporal integration and segregation of visual information are associated with different speeds of neural oscillations: evidence from sEEG

Dr David Acunzo1, Dr Benchi Wang2, Dr Clayton Hickey1

1University Of Birmingham, 2South China Normal University

85. Our visual environment is dynamic and visual input accordingly varies over time. To make sense of continuously changing information, our visual system balances two complementary processes: temporal segregation in order to identify visual changes; and temporal integration to identify consistencies in time. Previous research using magnetoencephalography (MEG) has found that when experimental participants complete a task requiring temporal integration and temporal segregation of visual stimuli, pre-stimulus brain activity in the alpha range (8-12 Hz) oscillates at a slower rate when participants are preparing for integration rather than segregation. To further investigate this relationship, we had volunteer patients with surgically implanted intracranial electrodes complete a visual task involving segregation and integration. The intracranial EEG data confirms the link between alpha and the temporal window of integration and provides novel insight on a.) the spatial loci of these changes in rhythmic activity, and b.) the relationship between low-frequency oscillatory changes and effects at higher frequencies (>30 Hz).

86. Distinguishing modulation of early visual cortex by reward cues from the same or different sensory modalities

Jessica Emily Antono1, Roman Vakhrushev1, Dr. Arezoo Pooresmaeili1

1European Neuroscience Institute - Göttingen

86. Reward signals shape behavior and guide decision making. Reward effects do not exclusively occur at higher levels of cortical hierarchy, but also impact on the activity of early sensory cortices. We have previously demonstrated that cross-modal auditory reward cues enhance the representation of visual targets in early visual areas. In this study, we focused on distinguishing between reward-driven modulations associated with cross-modal and within-modal cues. Participants performed a visual discrimination task in the presence of visual or auditory task-irrelevant reward (within- and cross-modal, respectively) cues. Both cue types were previously associated with different levels of monetary reward. Concurrently with the visual task and the preceding associative learning block, fMRI data was recorded. We expected that high reward cues modulate visual sensitivity for both within- and cross-modal cues. Specifically, we hypothesized that the modulations ensuing from different reward cues targets different areas in the visual cortex, indicating that reward processing follows a different pathway depending on the sensory modality of the reward-associated cues. Our preliminary results with eight participants showed different signs of modulation for visual and auditory reward cues pointing to the possibility that different pathways may underlie our effects. Whereas visual high reward cues decreased V1 responses compared to low reward cues, a reversed pattern was observed for auditory rewards. We considered two possible mechanisms for these effects. In the first scenario, the value of cross- and within-modal reward cues are identically represented in reward-coding areas, whereas higher tier visual areas mediate the difference in the sign of modulation. Alternatively, this distinction already occurs at the stage where reward values are encoded. Our results thus far point to the second possibility as reward-coding areas such as ventral striatum already showed negative modulations for visual and positive modulations for auditory reward values during the visual discrimination task. These results indicate that ventral striatum encodes reward values dependent on the task’s attentional demands, suppressing the representation of potentially interfering reward cues and enhancing those that are not distracting. Our subsequent connectivity analyses will further investigate how reward information is broadcasted between valuation areas and visual cortex.

87. Cardiac effects on visual and auditory duration perception

Dr Irena Arslanova1, Prof Manos Tsakiris1

1Royal Holloway University of London

87. All perception is shaped by the passing of time – every experience occurs in time. Yet, how we experience the passing of time is highly subjective. When we stare at the hands of a clock, a minute can feel much longer than when we are swept in a fun activity. How this subjective experience of time arises is a hotly debated issue. Salient changes in external milieu (e.g., fluctuations in the visual scene) as well as in motor and internal states (e.g., speed of body movement and level of arousal) have all been postulated to influence duration perception. Here, we focus on the role of interoceptive signals, like the beating of the heart, which provide a continuous background to all information processing. One hypothesis could be that the heart rate itself influences the experience of time. However, investigating durations that encompass multiple heartbeats (> 1s) can be confounded by participants counting. To avoid this limitation, we present to-be-estimated visual and auditory stimuli of shorter durations (< 400ms) to distinct phases of the heart cycle (systole or diastole). If the heart plays a role in time perception, cardiac signalling should influence perceived durations. Indeed, data from 30 participants suggests that visual and auditory stimuli were perceptually shorter when presented at the systole relative to the diastole. This effect was more pronounced in the visual domain, where temporal perception was generally more imprecise than in the auditory domain. One explanation could be that the noise from baroreceptor firing at the systole contaminates perceptual processing resulting in shorter temporal durations – an effect that is more detrimental in visual compared to auditory modality. Overall, these results extend the role of cardiac signalling to temporal exteroceptive processing and propose a mechanism by which the heart affects how we experience time.

88. Somatosensory deviance detection ERPs and their relationship to analogous auditory ERPs and interoceptive accuracy

Dr. Piia Astikainen1, Ms Elina Kangas1, Dr. Elisa Vuoriainen2, Ms. Xueqiao Li1, Dr. Pessi Lyyra1

1University of Jyväskylä, 2Tampere University

88. Objectives: We investigated whether different somatosensory changes elicit automatic deviance detection ERPs (mismatch response and P3a) with same sensitivity, and whether these responses in the somatosensory and auditory sensory modalities correlate, reflecting a general prediction error mechanism of the central nervous system. Furthermore, the objective was to explore whether interoceptive functions, which have been associated with predictive coding theory, correlate with deviance detection brain responses. Research questions: The present study aimed to examine i) whether sMMR and sP3a are elicited in the intensity and location deviance conditions within the somatosensory modality and whether the amplitudes of the brain responses are correlated between these somatosensory conditions; ii) whether ERP amplitudes of the auditory and somatosensory deviance detection components are related; and iii) whether somatosensory and auditory information processing measured by deviance detection ERPs and interoceptive accuracy measured by the heartbeat discrimination task are related. Materials and methods: We measured amplitudes of ERPs to changes in somatosensory stimuli’s location and intensity and in sound intensity in healthy adults (n = 34). Interoceptive accuracy was measured with a heartbeat discrimination task, where participants indicated whether their heartbeats were simultaneous or non-simultaneous with sound stimuli. Results: We found a mismatch response and a P3a response to somatosensory location and auditory intensity changes, but for somatosensory intensity changes, only a P3a response was found. Unexpectedly, there were neither correlations between the somatosensory location deviance and intensity deviance brain responses nor between auditory and somatosensory brain responses. In addition, the brain responses did not correlate with interoceptive accuracy. Conclusions: The results suggest that although deviance detection in the auditory and somatosensory modalities are likely based on similar neural mechanisms at a cellular level, their ERP indexes do not indicate a linear association in sensitivity for deviance detection between the modalities. Furthermore, although sensory deviance detection and interoceptive detection are both associated with predictive coding functions, under these experimental settings, functional relationships were not observed. These results should be considered in the future development of theories related to human sensory functions.

89. Decoding object categories from single fixations in natural viewing conditions

Carmel Ruth Auerbach-Asch1, Gal Vishne1, Prof Leon Y. Deouell1

1Hebrew University Of Jerusalem

89. Background: Object category information can be decoded from M\EEG data in passive viewing conditions during which eye-movements are restrained. However, understanding natural perception requires free-viewing conditions in which subjects are actively viewing the world. Fixation-related potentials, analyzed using GLM to disentangle overlapping responses, provide information about object processing in such natural conditions. Multivariate analysis (MVPA) may enable greater sensitivity and utilize the potential of high-dimensional recordings, yet it requires single-trial data, inaccessible from standard GLM. Here, we ask whether object related activity can be decoded from single fixations in free-viewing conditions and if the patterns of activity elicited by stimulus onset (VEPs) are similar to those elicited by eye fixations (FRPs). We decode object categories in natural viewing condition and provide a methodological pipeline for estimation of single trial data after deconvolution of overlapping sequential activity. Results: Using simulations we examine the effect of the overlap correction, compared to simple averaging on decoding, considering inter-fixation interval distribution, and SNR. We show that category information can be decoded from single fixations in natural viewing conditions. Furthermore, cross-decoding analysis shows that category-related activity can be decoded from FRP using weights obtained from training on VEPs.

90. Influences of temporal order and volatility in temporal reproduction

Cemre Baykan1, Xiuna Zhu1, Fredrik Allenmark1, Hermann J. Müller1, Zhuanghua Shi1

1General and Experimental Psychology, Department of Psychology, LMU Munich

90. Despite the standing role of temporal pattern processing in speech and music, the way we acquire or reproduce those patterns is still susceptible to perceptual biases. Although temporal rhythms have been well studied, how the temporal structure is precisely reproduced in terms of its basic element - time interval - has yet been largely neglected in the literature. The current study aimed to investigate the effect of temporal order and volatility on the reproduced duration. We used a temporal reproduction task in which participants (n = 15) reproduced either decelerating (DS), accelerating (AS) or random auditory sequences (RS) with finger taps. The DS consisted of two sequences with the same mean (700 ms) and the standard deviation (294 ms): [400, 500, 900, 1000] ms and [400, 600, 700, 1100] ms, whereas the AS had the same intervals but in an inverted order, and in the RS, the orders of the sample intervals were randomized. Despite the sample sequences having the same mean and variance, our results showed that the pattern mean reproduction and its precision depended on the sequence structure. The mean reproduction significantly decreased from the AS to the RS and to the DS (p < .001, η² = .56). Moreover, the central tendency bias (i.e., assimilation of the reproductions to the group mean) in the AS was smaller compared to the RS and the DS (p < .001, η² = .55). Based on those findings, we modeled the pattern reproduction with the assumptions that (i) the reproduction pattern is an outcome of the Bayesian integration between the ensemble mean and individual duration and (ii) the reproduced variability depends on its temporal position in the sequence. The model predicted the behavioral results, which showed that the differential mean reproduction comes from the weighted average of the durations according to their Weber fractions, and the central tendency is modulated by an updating mechanism from sequence intervals, with a higher weight on the first interval, during pattern processing.

91. Cortical Response to Changes of Auditory Statistics: Local and Global representations

Ms Martina Berto1, Emiliano Ricciardi1, Pietro Pietrini1, Davide Bottari1

1IMT School For Advanced Studies

91. The human auditory system relies on local and global representations, depending on the amount of entering temporal details. When local information exceeds system constraints, acoustic details are summarized into a set of average statistics and global structure emerges. Two major questions concerning local and global representations of sound remain unsolved. First, whether these two computations can occur automatically. Second, whether they can be distinguished at the neural level. A computational auditory model was employed to extract auditory statistics from natural sounds and generate synthetic exemplars in which we can control local and global properties. We recorded EEG activity while participants (N= 24; F= 12; mean age= 27.13 years, std= 2.83) were exposed to auditory streams containing triplets of sounds including two standards and an oddball. Two experimental contexts were designed: in Local Discrimination (experiment 1) the oddball sound varied from standards only for its local features (i.e., standard and oddball sounds represented different instances of the same sound object, varying only for small acoustic details); in Global Discrimination (experiment 2), oddball varied for its global structure (standard and oddball were different sound objects containing different auditory statistics). Different sound durations were employed in separate blocks to manipulate the amount of acoustic information and statistical variability between standards and oddballs. We expected short and long sounds to engage local (experiment 1) or global (experiment 2) representations, respectively. As predicted, neural responses associated with local discriminations exceeded global ones for short sounds, whereas the opposite pattern emerged at longer durations. Electrical source estimates revealed that local discriminations mainly engaged auditory regions of the right hemisphere, while global discriminations of the left hemisphere. This study represents the first instance in which it was possible to directly measure distinct neural correlates of acoustic discriminations guided by the local or global structure of sensory inputs. While previous evidence on mismatch negativity showed that the auditory system is capable of pre-attentively capturing disparities in an upcoming stimulation, here we demonstrated that it also develops a functional architecture to automatically categorize sound changes according to the temporal scale (local or global) at which it had occurred.

92. Investigating the impact of agency on visual perception: a behavioral and EEG study.

Emmanuelle Bonnet1,2, Louise Barne1,2, Guillaume Masson2, Andrea Desantis1,2

1DTIS-ICNA, ONERA, 2Institut de Neurosciences de la Timone, Aix Marseille University

92. Being an agent structures the way we experience our environment. For example, it has been shown that voluntary actions produce outcomes that are attenuated in terms of their perception and cortical response compared to externally generated outcomes. However, which processes lead to these perceptual changes remains unclear. This study combines visual psychophysics and EEG to investigate the influence of intentionality and prediction on the processing of sensory outcomes. Three types of outcomes are compared: those predicted by a voluntary action, those predicted by a forced action and those predicted by a stimulus. The outcome is a grating whose orientation is (to some extent) predicted by the action/stimulus preceding it. Participants’ task is to indicate whether the grating is brighter than another visual grating presented at trial onset. They must also reproduce the orientation of the grating following the action/stimulus. We expect to replicate previous findings on sensory attenuation showing that gratings generated by actions are experienced as less bright than those predicted by a stimulus. Secondly, the comparison between voluntary and forced actions will evaluate the effect of intentionality on sensory processing and the neural underpinnings of this effect will be investigated with EEG. Finally, this study will evaluate the neural sharpening hypothesis of sensory attenuation by investigating whether this perceptual phenomenon is accompanied by improved behavioural performance (i.e., better reproduction of the grating orientation). These results will contribute to the ongoing research investigating the effect of being an agent on perception.

93. The origin of the effect of articulatory interference on speech perception.

Sarah Carneiro Pereira1, Charlie Guérit1, Charlotte Dutrieux1, Prof Gilles Vannuscorps1,2

1Psychological Sciences Research Institute, Université catholique de Louvain, 2Institute of Neuroscience, Université catholique de Louvain

93. The execution of silent articulatory lip or tongue movements is known to affect the perception of corresponding (lip or tongue related) speech sounds. This finding is often considered as a piece of evidence that speech perception is supported by motor articulatory resources (the motor interpretation). However, the execution of silent articulatory movements involves not only the motor system, but also the auditory/phonological system, to which articulatory representations are connected in the service of speech motor control. Hence, the reported effect could be a by-product of the activation of auditory rather than motor representations (the auditory interpretation). Objective. The aim of the two experiments reported here was to discriminate these two hypotheses. Research question. To do so, we tested the effect of the execution of both speech-related and non-speech-related lip movements on the perception of lip-related and non-lip-related speech sounds. Both lip movements mobilize lip motor representations, but only the speech-related movement activates auditory/phonological representations. Thus, the central question was whether only speech-related lip movements (in line with the auditory interpretation) or both types of lip movements (in line with the motor interpretation) would affect the perception of lip-related speech sounds beyond the effect of control conditions. Materials and methods. We determined the minimal signal/white noise ratio at which participants could discriminate two pairs of syllables (bilabial/lingual and lingual/lingual) while performing a repetitive movement of the finger or one of two lip movements: a speech-related lip movement (experiment 1) or a non-speech-related lip movement (experiment 2). Results. The results of frequentists and Bayesian statistical analyses indicated that in comparison to the execution of finger movements, the execution of speech-related lip movements interfered significantly more with the perception of lip-related than non-lip-related speech sounds. There was no such disproportionate effect when participants executed non-speech-related lip movements. Conclusion. This finding is in line with the auditory interpretation.

94. Alterations in event related potential (ERP) associated with tinnitus severity

Kyungmi Chung1,2, MD, Ph.D (Associate Professor) Jin Young Park1,2

1Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei University Health System, 2Department of Psychiatry, Yonsei University College of Medicine, Yongin Severance Hospital, Yonsei University Health System

94. Objectives: The aim of this study was to investigate whether the amplitude and latency features in ERP components, such as N1 and auditory mismatch negativity (aMMN) in the frontocentral region of interest, could serve as a neurophysiological marker for subjective tinnitus severity. Materials and methods: A total of 21 tinnitus patients (14 women), aged 45–72 years (M = 58.33, SD = 7.07), were classified into two groups by self-reported Tinnitus Handicap Inventory (THI) scores: (1) no or slight handicap (THI 0–16; N = 10, 48%) and (2) mild to moderate handicap (THI 18–76; N = 11, 52%). While employing a two-tone passive auditory oddball paradigm where the 750 Hz standard (75 dB; 180 trials, 75%) and 1,000 Hz deviant (75 dB; 60 trials, 25%) tones were randomly presented for 100 ms and the inter-stimulus interval varied randomly between 1000 ms and 1300 ms (a maximum presentation time of 5 min 30 s), all patients were asked to not only read given text slides created by Microsoft PowerPoint and presented on a 13.3ʺ LCD display (1440 × 900 resolution, 60 Hz refresh rate) either at the same speed as usual or at a speed slightly faster than they can normally read, but also ignore any incoming auditory stimuli from a headset and recording room. Results: The result revealed that only aMMN amplitude at FCz was significantly different across the two tinnitus severity conditions, t (19) = 2.298, p = .03, Cohen’s d = 1.00, not aMMN latency and both N1 amplitude and latency at the same electrode site. Particularly, the ‘no or slight handicap’ group (M = –0.55, SD = .32) showed more attenuated aMMN amplitude than the ‘mild to moderate handicap’ group (M = –.92, SD = .41). Conclusion: This study provided the evidence that increased frontocental aMMN amplitude has the potential to reflect the tinnitus patients’ symptom severity associated with psychological distress as the 3 out of 21 patients with mild to moderate tinnitus handicap were diagnosed with sleep disorder, generalized anxiety disorder, or major depressive disorder.

95. The Computer, A Choreographer? Aesthetic Responses to Computer-Generated Dance Choreography.

Dr. Kohinoor Darda1,2,3, Dr Emily Cross2,3

1University of Pennsylvania, 2University of Glasgow, 3Macquarie University

95. Is artificial intelligence (AI) changing our culture or creating its own? With advancements in AI and machine learning, artistic creativity is moving to a brave new world of possibility and complexity, while at the same time posing challenging questions, such as what defines something as art, what is the role of human creativity in an automated world, and do we evaluate artificial art in the same way as art made by humans? Across two pre-registered and statistically powered experiments we shed light on the nature of aesthetic responses toward computer-generated art by investigating observer prejudices against computer-generated dance choreography, and the impact of expertise and pre-conceived beliefs about the origin of artistic creation. Our results provide substantive evidence that an explicit bias exists among dance experts against computer-generated choreography, and the mere belief about a dance work’s origin biases aesthetic responses toward artworks among both dance experts and dance naïve participants. Follow-up experiments now seek to explore the relationship between stimulus and knowledge cues to human animacy and their link to aesthetic appreciation of human- and computer-generated dance choreography. The implications of the current study serve to inform several disciplines across the arts and sciences including but not limited to empirical aesthetics, artificial intelligence, engineering, robotics, and social cognition and neuroscience. Along with physical form and content of artificial agents and art productions, the viewers’ knowledge and attitudes toward artistic AI and artificial agents will need to be optimised for effective human-computer/human-AI interactions. Moreover, exploring the link between bottom-up and top-down cues to human animacy and the aesthetic appreciation of dance movement can shed light on the cognitive and neural mechanisms underlying action perception and evaluation.

96. Symmetry perception ERP (the SPN) is not modulated by visual short-term memory.

Yiovanna Derpsch1, Dr Giulia Rampone1, Dr Marco Bertamini1, Dr Alexis Makin1

1University Of Liverpool

96. Objective The aim of the study was to investigate whether representations of visual symmetry are altered when maintaining colour or shape information in visual short-term memory (VSTM). Research question The visual system can detect symmetry effortlessly and within 100 ms. EEG studies have measured a symmetry related ERP component called the Sustained Posterior Negativity (SPN). Previous work has found that the SPN is automatic, and not altered by the participant’s task or spatial attention. However, no studies have tested whether the symmetry response interacts with information in visual short term memory. If symmetry perception is not affected by having to memorise shapes or colours, it would mean that the SPN is not modulated by memory load. Conversely, if symmetry perception is affected by processing a concurrent memory task, it would mean that VSTM does modulate the SPN. Moreover, it could be that holding shape information in memory interferes with symmetry perception more than holding colour information in memory. We preregistered our study in aspredicted.com (https://aspredicted.org/eh57m.pdf.). Method In the memory condition, 24 participants judged whether stimuli had changed from the sample to the test presentation. The sample and test were either four coloured squares or four black shapes. The difficulty of the colour and shape memory tasks were matched at ~75% correct. In the passive judgement condition the trials were identical, but participants merely made a trivial judgement about the border colour of the test presentation. In the interval between sample and test, we presented a symmetrical or random dot pattern, which required no response. The DV was SPN amplitude for the symmetrical pattern (symmetrical – random waves at posterior electrodes). Results SPN amplitude was the same in all four conditions, that is, whether participants were holding colour or shape information in memory, and whether they were in the memory or passive condition. Conclusion The SPN is not modulated by visual short-term memory load. We argue that the extrastriate symmetry response is robust to concurrent memory demands, as well as changes to task and spatial attention.

97. Impairments in path integration, rotational memory and balancing in patients with temporal epilepsy

Dr. Milos Dordevic1,2, Julia Gruber2, Prof. Friedhelm Schmitt2, Prof. Notger Müller1,2

1DZNE, 2Neurology Clinic, Otto-von-Guericke University

97. This study aimed at assessing behavioral deficits related to a suspected disturbance of the vestibulo-medial temporal lobe (MTL) axis in patients with temporal lobe epilepsy (TLE). The axis model proposes that the vestibular system and the MTL are tightly linked both structurally and functionally so that alterations of one structure should entail disturbances in the other. Accordingly, TLE patients with their functional and possible structural temporal lobe pathology should show deficits in vestibular-related behavior. Twenty TLE patients and their age- and gender-matched controls underwent three test batteries that challenged vestibular and MTL functions: balancing, path integration and rotational memory. Compared to controls, TLE patients showed inferior performance in all three tests. These results confirm the hypothesis of a disturbed vestibulo-MTL axis in TLE. In the current study these behavioral deficits emerged without evidence of any brain volume differences between the patients and their controls as depicted by high-resolution MRI. This speaks for a dissociation between functional and structural alterations in TLE.

98. Conflict monitoring and attentional adjustment during binocular rivalry

Alice Drew1, Mireia Torralba1, Manuela Ruzzoli1,2,3, Luis Morís Fernandez1,4, Alba Sabaté1, Marta Szabina Papai1, Salvador Soto-Faraco1,5

1Multisensory Research Group, Centre for Brain and Cognition, Universitat Pompeu Fabra, 2BCBL, Basque Center on Cognition, Brain and Language, 3Ikerbasque, Basque Foundation for Science, 4Departamento de Psicología Basica, Universidad Autonoma de Madrid, 5Institucio Catalana de Recerca i Estudis Avançats (ICREA)

98. To make sense of ambiguous and, at times, fragmentary sensory input, the brain must rely on a process of active interpretation. At any given moment, only one of several possible perceptual representations prevails in our conscious experience. Our hypothesis is that the competition between alternative representations induces a pattern of neural activation resembling cognitive conflict, eventually leading to fluctuations between different perceptual outcomes in the case of steep competition. To test this hypothesis, we probed changes in perceptual awareness between competing images using binocular rivalry. We drew our predictions from the conflict monitoring theory, which holds that cognitive control is invoked by the detection of conflict during information processing. Our results show that fronto-medial theta oscillations (5–7Hz), an established electroencephalography (EEG) marker of conflict, increases right before perceptual alternations and decreases thereafter, suggesting that conflict monitoring occurs during perceptual competition. Furthermore, to investigate conflict resolution via attentional engagement, we looked for a neural marker of perceptual switches as by parieto-occipital alpha oscillations (8–12Hz). The power of parieto-occipital alpha displayed an inverse pattern to that of fronto-medial theta, reflecting periods of high interocular inhibition during stable perception, and low inhibition around moments of perceptual change. Our findings aim to elucidate the relationship between conflict monitoring mechanisms and perceptual awareness. This abstract is the one associated to the published study (DOI: 10.1111/ejn.15554). We would hope to present the findings of this study in a poster session.

99. Representational similarity analysis of neural processing of global and local biological motion

João Valente Duarte1,2, Rodolfo Abreu1, Miguel Castelo-Branco1,2

1Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), ICNAS, University of Coimbra, 2Faculty of Medicine, University of Coimbra

99. Discrimination of biological motion, the movements of animate entities, is vital for survival in nature, and particularly in humans is crucial for accurately perceiving dynamic bodily signals underlying nonverbal social cognition. Although neuroimaging and neurophysiology studies have identified a network of brain areas that process biological motion, the distinct computation and integration of local “life motion” animacy and global dynamic body perception remains to be understood. In this study we addressed this functional separation of the correlates of the perception of life motion, defined as characteristic for the local motion of parts of living beings, from perception of global motion of a body. We hypothesized that life motion is hierarchically processed in a first stage, relying on a subset of early-level areas, which that send information to higher-level regions underlying the second stage of biological motion processing. We produced local motion by using a single dot motion perceptual decision paradigm featuring the biomechanical details of local realistic motion of a single human joint, besides classical whole-body point-light displays. We used event-related deconvolution GLM and representational similarity analysis (RSA) of fMRI to investigate the two-stage framework for neural processing of biological motion. We discovered that two key early dorsal and two ventral stream regions (visual motion selective hMT+ and V3A, extrastriate body area EBA and a region within fusiform gyrus FFG) showed robust and separable signals related to encoding of life motion and global motion. These signals reflected two independent processing stages, as revealed by representation dissimilarity analysis and deconvolution of fMRI responses to each motion pattern. This study showed that higher level pSTS encodes both classes of biological motion in a similar way, revealing a higher-level integrative stage, and reflecting scale independent biological motion perception. Our results reveal a two-stage framework for neural computation of biological motion, with an independent contribution of dorsal and ventral regions for the initial stage. The two-stage framework for neural processing of biological motion supports the idea of an evolutionarily ancient neural mechanism that is activated by the perception of local and global biological motion in humans.

102. Decoding acoustic and visual features of continuous speech from EEG in children and adults.

Phd Student Marta Fantoni1, Ms Alessandra Enrica Chiara Federici1, Dr Ivan Campogonara2, Dr Emiliano Ricciardi1, Ms Alice Martinelli1, Dr Elena Nava3, Ms Evgenia Bednaya1, Dr Davide Bottari1

1IMT Scuola Alti Studi Lucca, 2New York University Abu Dhabi, 3Università di Milano Bicocca

102. Neural entrainment refers to the temporal alignment of the neural activity with the regularities of an occurring stimulus. While few studies investigated audio-visual speech processing in adults, how neural entrainment unfolds in children is still unclear. Here, we aimed to quantify how well acoustic and visual features of speech can be decoded from children and adult neural activity. We recorded EEG activity while participants (17 children, mean age: 8y, range: 5-12; 16 young adults, mean age: 26y, range: 24-31) were exposed to continuous audio-video speech. Neural entrainment was measured through backward temporal response function (TRF) modeling that enables reconstructing stimulus features from the neural response. The sound envelope and the area subtending lip-movements were used as acoustic and visual regressors, respectively. First, we quantified the entrainment to sound envelope and lip-movements by comparing each regressor against a null distribution. We then contrasted the two reconstruction performances to check for any differences in time domain between the sound envelope and lip-movements reconstructed signals. All analyses were performed within the time-lags 0-600 ms, to measure the delay in the neural activity following a change in the sound envelope and lips movements. In children, successful reconstruction performance was obtained for both the auditory and visual regressors. The sound envelope consistently differed from the null-distribution at time-lags between 5-375 and 405-420 ms, whereas the lips movements between 30-120 and 180-450 ms. When comparing outcomes of acoustic and visual regressors, the sound envelope exceeded the reconstruction of lips movements at time-lags between 5-210 ms. In adults, the sound envelope differed from the null-distribution between 5-495 ms, whereas for lips-movements between 135-495 ms. The comparison between the acoustic and visual regressors showed a greater reconstruction performance of the sound envelope compared to the lip-movements between 5-150 ms. Our results revealed that backward modeling can be successfully applied on both sound envelope and lip-movements to measure the neural entrainment of speech signals in both children and adults. Regardless of the age, reconstruction performance was greater for sound envelope than lip-movements at early time-lags, that is, in first phases of stimulus processing.

101. Impaired evoked and induced neural oscillations during visual search in cerebral visual impairment

Alessandra Federici1, Dr Christopher R. Bennett2, Dr Corinna M. Bauer2, Prof Emiliano Ricciardi1, Prof Peter J. Bex3, Prof Lotfi B. Merabet2, Dr Davide Bottari1

1MoMiLab, IMT School for Advanced Studies Lucca, 2The Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, 3Translational Vision Lab. Department of Psychology, Northeastern University

101. Individuals with cerebral visual impairment (CVI) often present with deficits related to visuospatial processing which are associated with alterations in oscillatory activity in the alpha range. To further characterize the neurophysiological basis of higher-order perceptual dysfunctions in this population, we measured neural oscillations while participants performed a virtual reality-based visual search task. By assessing evoked and induced components of neural oscillations, we aimed to shed light on dysfunctional visual search processing in CVI. Ten CVI participants (mean age:17.4±2.7) and 16 age-matched individuals with a neurotypical development (mean age:19.2±2.1) were recruited to perform a visual search task paired with eye-tracking to simulate the exploration of a naturalistic scene (finding a toy in a toy box). EEG activity was recorded while participants were instructed to search, locate, and fixate a specific target toy placed randomly among surrounding toys. The complexity of the visual scene was manipulated and comprised of a low and high level with respect to the number of unique surrounding distractors and background. A series of non-parametric cluster-based permutation analyses (p<0.025, two-tailed tests) were performed without a priori assumptions across all electrodes, timepoints, and frequencies separately for low [4-30Hz] and high [30-60Hz] ranges on induced and evoked components of oscillatory activity. Regardless of the level of visual task complexity, a general absence of evoked theta [4-6Hz] activity (<0.5s) was found in the CVI group (p<0.003). While the control group displayed an enhancement of induced alpha activity [8-14Hz] between 0.36-0.44s in the high with respect to the low task condition, in the CVI group this modulation was absent (p<0.008). Moreover, CVI participants showed an overall delayed induced gamma response [40-55Hz] between 0.46-0.50s (p<0.01) compared to controls. These results reveal that visual search activity in CVI is associated with substantial alterations in neural activity, independent of the level of visual task complexity, at both low and high-frequency ranges of neural oscillations (theta, alpha, gamma rhythms), and implicate both feedforward (evoked activity) and feedback (induced activity) processing. Such alterations suggest that CVI is associated with widespread deficits within the visual system, implicated both local and distributed levels of neural processing.

320. Altered induced oscillatory activity by temporary monocular deprivation: distinct neural signatures for visual and audio-visual processing

Alessandra Federici1, Dr. Giulio Bernardi1, Dr. Irene Senna2, Marta Fantoni1, Prof Marc Ernst2, Prof Emiliano Ricciardi1, Dr Davide Bottari1

1MoMiLab, IMT School for Advanced Studies Lucca, 2Applied Cognitive Psychology, Ulm University

320. A series of behavioral and neuroimaging studies demonstrated that a brief period of monocular deprivation (MD) induces short-term plasticity in the adult visual system. Moreover, behavioral studies have recently shown that MD affects also multisensory perception. By using MD to induce short-term plasticity we investigated short-term changes of evoked and induced neural oscillations associated to visual and audio-visual processing. Twenty young adults (mean age 28.45±2.67 SD, 8 males) performed a visual discrimination task monocularly before (t0) and after (t1) a phase of MD (150min) while EEG was recorded. Participants were asked to report the number of perceived flashes while irrelevant beeps could be presented. For our aim, data analysis focused on single flash visual condition and on audio-visual condition inducing “fission illusion”, which comprised the same number of visual events. We performed a series of cluster-based permutation analyses between power change (t1 minus t0) in the Deprived eye and in the Undeprived eye, across all electrodes, timepoints [0-0.5 s], and frequencies, separately on induced and evoked activity occurring at low [4-30 Hz] and high [30-80 Hz] frequency ranges. Source estimation was performed to identify involved brain areas. At the behavioral level, we computed the d’ change (t1 minus t0) in each eye, both in visual and audio-visual condition. In visual condition, we found a decrease of induced alpha power [10-16Hz] within 150 ms selectively for the Deprived eye (p<0.009). This effect was localized in the right parieto-occipital area and was associated with a decrease in visual sensitivity (d’; p<0.039). In audio-visual condition, we found an increased induced gamma power [65-75Hz] in the Undeprived eye between 100 and 300 ms (p<0.015). This effect emerged at the right intraparietal sulcus and left posterior thalamus. Results clearly showed selective MD effects on both visual and audio-visual processing with distinct neural signatures. While alpha decreased after MD selectively for the Deprived eye during early visual processing, in the Undeprived eye gamma increased at later latency of audio-visual processing. Notably, both visual and audio-visual processing alterations were found selectively for induced neural oscillations, revealing a prominent role of feedback processing in short-term plasticity.

103. Is there an association between cognitive and visual decline?

Simona Garobbio1, Dr Karin Pilz2, Dr Marina Kunchulia3, Prof Michael H. Herzog1

1Epfl, 2Cito Institute for Educational Measurement, 3Free University of Tbilisi and Ivane Beritashvili Center of Experimental Biomedicine

103. Cognitive and visual abilities decline with age. Recently, it has been suggested that the risk to suffer from dementia is associated with decreased visual acuity. Two theories, the sensory deprivation theory (stating that visual impairments cause cognitive decline) and the common cause theory (stating that cognitive and visual decline are caused by a general age-related decline of the system) have been proposed to explain the relationship between cognitive and visual changes. There is currently no consensus on which theory is valid. However, both agree that visual factors could act as biomarkers for cognitive decline. Given the limited research studying the link between vision and cognition using multiple measures of vision, we tested a battery of 19 visual tasks on 39 older adults with mild cognitive impairment (i.e., MCI group, age = 67 ± 5, 26 females) and 91 without evidence of cognitive decline (i.e., healthy group, age = 66 ± 5, 60 females), as measured by the Montreal Cognitive Assessment. Our results revealed a strong association between visual and cognitive decline. The tasks showing the largest effect sizes were orientation discrimination, biological motion, motion detection and visual search. However, mirroring previous results in young adults, there were only weak correlations between the performance levels of the visual functions in both the healthy and the MCI groups, arguing against a common factor. Our results suggest that visual and cognitive abilities decline simultaneously, but they do so independently across visual and cognitive functions and participants.

104. Experience-related attenuation of distractive deviants in the mouse somatosensory system

Newsha Ghasemi Nejad1,2, Gwendolyn English1,2, Prof. Dr. Mehmet Fatih Yanik1,2, Dr. Wolfger von der Behrens1,2

1Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology, 2Neuroscience Center Zurich,University of Zurich and Swiss Federal Institute of Technology

104. Successful adaptation to our ever-changing world depends on our ability to move attention quickly in space and to learn about our immediate environment. A strong driver for automatic, involuntary attentional shifts is a sudden change in the sensory input, which typically results in an enhanced neuronal response compared to expected stimuli. In event-related potentials, such deviating stimuli elicit an additional negative wave called Mismatch Negativity (MMN). Due to its sensitivity to neuropsychiatric conditions, MMN has gained importance in clinical research. For example, the reduced size of MMN signal is considered as a potential biomarker for disorders such as Schizophrenia. Stimulus-specific adaptation (SSA) has been proposed as a single neuron correlate of MMN. SSA describes the property of neurons to adapt to frequent stimuli while remaining highly responsive to deviating stimuli. However, little is known about the relationship between SSA and perception, specifically how it relates to exogenous attentional processes. The goal of this study is to assess whether deviant stimuli trigger attentional reallocation and influence signal processing at the single neuron level in the primary sensory cortex. We therefore designed a new behavioral paradigm for mice and combined it with extracellular recordings. In this paradigm, animals performed a simple visual detection task. The visual target stimulus was preceded by a spatial somatosensory deviant stimulus embedded in a sequence of repetitive stimuli (‘standard’) without carrying any information about the upcoming location of the visual target. We hypothesized that the uninformative deviant will trigger an attentional shift and affect behavioral performance (e.g. signal detection and reaction time). Statistical analysis revealed a significant deviant effect on the animals’ performance: faster reaction times but worsened detection were achieved in the presence of a deviant stimulus compared to standard-only control trials (no deviant stimulus) which coincided with enhanced neural responses to deviant stimuli compared to standard stimuli. However, this behavioral and neural effect diminished over time (days) potentially as a result of active suppression of a distractive deviant. Further analysis is needed to clarify the link between this diminishing distractor (deviant) effect and its relevance on attention.

106. Rhythmic interactions between the mediodorsal thalamus and prefrontal cortex precede human visual perception

Benjamin James Griffiths1, Tino Zaehle2, Stefan Repplinger2, Friedhelm Schmitt2, Juergen Voges2, Simon Hanslmayr3, Tobias Staudigl1

1Ludwig-Maximilians-University, Munich, 2Otto-von Guericke-University, Magdeburg, 3University of Glasgow

106. Background: The thalamus is much more than a simple sensory relay. High-order thalamic nuclei, such as the mediodorsal thalamus, exert a profound influence over animal cognition. However, given the difficulty of directly recording from the thalamus in humans, next-to-nothing is known about thalamic and thalamocortical contributions to human cognition. Research Question: To what extent do thalamocortical connections underpin visual detection? Materials and Methods: Six patients undergoing simultaneously thalamic iEEG and whole-head MEG recordings, and twelve healthy participants undergoing whole-head MEG recordings, completed a near-threshold visual detection task. We tested whether patterns of thalamic and prefrontal cortical ongoing low-frequency activity could predict upcoming visual detection performance, and examined how these thalamic and cortical may interact to support visual detection. Results: We observed that the phase of both ongoing mediodorsal thalamic and prefrontal low-frequency activity was predictive of perceptual performance. Critically however, mediodorsal thalamic activity mediated prefrontal contributions to perceptual performance. Conclusions: These results suggest that it is thalamocortical interactions, rather than cortical activity alone, that is predictive of upcoming perceptual performance and, more generally, highlights the importance of accounting for the thalamus when theorising about cortical contributions to human cognition.

105. Electrophysiological representations of veridical head direction in humans

Benjamin James Griffiths1, Thomas Schreiner1, Julia Schaefer1, Christian Vollmar1, Elisabeth Kaufmann1, Soheyl Noachtar1, Tobias Staudigl1

1Ludwig-Maximilians-University, Munich

105. Background: Information about heading direction is critical for navigation as it provides us with the means to orient ourselves in space. However, given that “true” head direction signals require physical rotation of the head, and most human neuroimaging experiments depend upon fixing the head in position, little is known about how veridical head direction is represented in the human brain. Research Question: To what extent does the population-level electrophysiological activity represent veridical head direction in humans? Materials and Methods: Thirty-two healthy participants undergoing scalp EEG recordings, and eight patients with intracranial depth electrodes, completed a series of orientation tasks in which they made physical head rotations while physical head position was recorded. Forward encoding models were used to predict EEG activity based on current head position. Results: We identify a posterior network centred upon the retrosplenial cortex that is both sensitive and specific to changes in head direction that are as small as 10°. Notably, activity in this network precedes the execution of head movement, suggesting that this signal is anticipatory (matching what has been reported for head direction signals in rodents). We go on to replicate these effects in the patient sample as well as identify similar effects in the intracranial data recorded from the parahippocampus. Conclusions: Together, these results reveal a network of regions that track veridical changes in head direction that is reminiscent of what has been reported in rodents. Intriguingly however, when comparing our findings to those previously reported, the comparatively high accuracy with which the observed network predicts head direction indicates that population activity (relative to single units) may be key to representing fine-grained head direction information in the human brain.

107. Pre- and Post-choice Build-up of the Centro-parietal Positivity Predicts Confidence

Dr John Grogan1, Dr Wouter Rys1, Dr Simon Kelly2, Prof Redmond O'Connell1

1Trinity College Dublin, 2University College Dublin

107. Various models of perceptual decision making suggest that evidence accumulation may continue after an initial choice in order to inform confidence judgments. However, it has yet to be established whether such post-decisional processes continue to accumulate evidence in favour of the choice alternatives or operate within a new reference frame (e.g. whether or not the preceding choice should be revised). We traced the dynamics of an electrophysiological signature of motor-independent evidence accumulation known as the centro-parietal positivity (CPP) in order to determine its sensitivity to confidence judgments. In a first experiment participants made speeded two-alternative motion discrimiantion judgments and simultaneously reported their confidence. As expected, the CPP exhibited a significantly larger amplitude prior to choice reports when participants were more confident. In a separate experiment, confidence reports were delayed by 1000ms relative to initial contrast discrimination judgments. Across trials we randomly varied whether or not the physical evidence remained visible during the post-choice delay period. In this context, the pre-choice amplitude of the CPP only scaled with final confidence on trials in which evidence was extinguished during the delay period. Upon execution of the initial choice report, the CPP was observed to return toward baseline before undergoing a second build-up in advance of the final confidence judgment. This second stage CPP scaled with final confidence but in the opposite direction to the pre-choice CPP, with a larger build-up prior to low confidence judgements and changes-of-mind. Encoding of the evidence in early visual regions was stronger on high-confidence trials, suggesting that participants had not simply stopped attending to the evidence when they had high confidence in their initial choice. These results suggest that rather than evidence accumulation for the choice alternatives continuing after the point of commitment, it is instead reframed to selectively represent new evidence against the chosen option.

108. Spatial dimension of steady-state visual evoked potentials in mouse primary visual cortex

Rasa Gulbinaite1, Mojtaba Nazari-Ahangarkolaee2, Dr. Edgar Bermudez-Contreras2, Prof. Michael X. Cohen3, Prof. Majid H. Mohajerani2

1Netherlands Institute For Neuroscience, 2University of Lethbridge, 3Donders Institute for Brain, Cognition, and Behavior

108. Sensory cortices stimulated by rhythmic sounds, lights, or touch will respond in a rhythmic manner with frequencies identical or harmonically related to the stimulus (steady-state evoked potentials). Although such responses are preserved across species, reported temporal frequency tuning curves in human and mouse primary visual cortex (V1) do differ. In human EEG recordings (macroscale), V1 shows temporal frequency tuning with characteristic resonance peaks at ~10, ~20, and ~40 Hz, whereas only a single peak below 8 Hz is present in temporal tuning curves derived from multiunit and spiking activity (microscale) in mouse V1. By imaging transgenic animals expressing high temporal resolution glutamate fluorescent reporter iGluSnFR, we sought to characterize temporal frequency tuning in mouse V1 and its spatial distribution at a mesoscale neuronal activity. For this, we used a wide range of sine-wave modulated temporal frequencies (2-72 Hz). We found that mouse V1 responded to flickering light as high as 56 Hz – a limit dictated by the kinetics of iGluSnFR fluorescent reporter. Most importantly, temporal tuning curves showed resonance peaks at 8 Hz, 15 Hz, and 33 Hz, indicating that resonance phenomena in mouse V1 highly resemble that of humans. We also observed a spatial organization in temporal frequency preference across V1: (1) lower flicker frequencies activated larger portions of V1 as compared to higher flicker frequencies; (2) all temporal frequencies elicited response at stimulus corresponding retinotopic location of V1, with additional spatial peaks present at certain temporal frequencies. In conclusion, contrary to previous reports some spatial clustering of temporal frequency preference in mouse V1 exists, and temporal frequency tuning with prominent resonance peaks is preserved across species and across spatial scales of neural activity.

109. Neural signature of evidence accumulation and motor preparation in a prolonged contrast comparison task including no physical noise

Hadiseh Hajimohammadi1, Dr Simon P. Kelly1

1School of Electrical and Electronic Engineering and UCD Centre for Biomedical Engineering, University College Dublin, Belfield

109. Although protracted evidence integration lies at the heart of most decision models, the extent of its role remains unclear in certain situations such as in tasks with long stimulus durations, or when stimuli contain no physical noise. Here we designed a contrast comparison task which encouraged prolonged integration by presenting very weak evidence on most trials and making the subjects unaware of short evidence durations to investigate the neural process underpinningn such decisions. We recorded EEG during a task where subjects indicated which of two oppositely-oriented, flickering gratings had higher contrast, with responses deferred until stimulus offset. After a baseline period of equal, 50% contrast, the gratings underwent a small change in opposite directions for 0.2, 0.4, 0.8 or 1.6 sec before stepping back to equal contrast so that subjects believed that all trials contained evidence for the full 1.6 sec. On 20% of trials a trivially-easy contrast difference was presented for 1.6 sec. Nine subjects participated in the experiment so far and the data collection is ongoing. Accuracy steadily increased over all durations. Preliminary analysis showed that the centro-parietal positivity (CPP), previously shown to reflect evidence accumulation, exhibited a prolonged increase over time for lower contrast conditions, but peaked at around 600ms for the high contrast trials at more than twice the amplitude. We found an interesting dissociation between two signatures of motor preparation; whereas the lateralised readiness potential (LRP) monotonically increased and was very delayed for the lower contrast conditions, Beta amplitude lateralised early on, with this lateralisation reducing at the end of the stimulus as the ipsilateral signal caught up with the contralateral signal. This difficult perceptual task seems to encourage the prolonged accumulation of evidence before decision commitment even for stimuli with no physical noise. Although a bound is set, it is set high above the average cumulative evidence attained on the predominant difficult trials. LRP and Beta amplitude appear to play distinct roles in motor preparation.

110. Neural Mechanisms of Low-Frequency Electrical Stimulation on Pain Processing: A Sham-Controlled, Laser-Evoked Potential Study

Ms Danielle Hewitt1, Dr Adam Byrne1, Ms Jessica Henderson1, Ms Alice Newton-Fenner1, Dr John Tyson-Carr1, Dr Christopher Brown1, Dr Nicholas Fallon1, Dr Andrej Stancak1

1University of Liverpool

110. Objectives External low-frequency peripheral nerve stimulation (LFS) has been proposed as a novel method for achieving pain relief in neuropathic pain patients. Previous studies have reported that LFS elicits long-term depression-like effects on human pain perception. However, the neural mechanisms underlying LFS are poorly understood. To probe the analgesic effects of LFS, we investigated the effect of active LFS versus sham stimulation on behavioural and neural processing of laser stimuli using electroencephalography (EEG). Research Question Does active LFS reduce the amplitude of laser-evoked EEG potentials? Materials and Methods LFS was applied to the radial nerve of 25 healthy volunteers over two sessions using active (1 Hz) or sham (0.02 Hz) frequencies. Mildly noxious laser stimuli were applied to the left hand before and after LFS. Subjective pain ratings were collected for each stimulus. Laser-evoked potentials, consisting of N1, N2 and P2 components, were recorded using a 129-channel Geodesic EGI system. Repeated measures ANOVAs were calculated to investigate differences in mean subjective ratings and laser-evoked potential amplitudes over time (pre or post LFS) and stimulation type (active or sham). Results Subjective laser pain ratings were reduced by 4 points ± 1 (mean ± standard deviation) after stimulation. No significant difference in subjective pain ratings was found between active and sham stimulation. Active LFS was associated with selective attenuation of P2 amplitude in ipsilateral frontocentral electrodes. Amplitude of N1 and N2 components reduced equally after active and sham stimulation. Conclusion Results suggest a selective attenuation of somatosensory processing after LFS. Reduction of long-latency laser-evoked potential components is consistent with attentional modulation of nociceptive processing, which may be due to reduced stimulus saliency with repeated presentation. Reduced behavioural ratings and LEP amplitude after both active and sham LFS highlights the importance of appropriate control conditions in future investigations of LFS.

111. Magnocellular-parvocellular imbalance correlates with mirror image discrimination

Marie Houbben1, Gilles Vannuscorps1,2

1Psychological Sciences Research Institute, Université catholique de Louvain, 2Institute of Neuroscience, Université catholique de Louvain

111. Objectives. From the retina, information is conveyed to the brain through two main complementary channels: a parvocellular (P) channel highly sensitive to stimuli of high spatial frequency, high-contrast and low-temporal frequency, and a magnocellular (M) channel mostly sensitive to stimuli with complementary characteristics. In the brain, information from the P channel mostly flows to occipito-temporal « ventral stream » areas aimed at object recognition, and information from the M channel mostly flows to occipito-parietal « dorsal stream » areas involved in spatial vision. The objective of this study is to contribute to a better understanding of how these complementary streams interact to support visual experience. Research question. Recent neuropsychological studies have reported three individuals who couldn’t discriminate mirror images of high-contrast and high-spatial frequency shapes (biased toward the P-channel), but had far less or no difficulty at all for low-contrast, low-spatial frequency shapes. Here, we tested the intriguing hypothesis that efficiency at discriminating mirror images may depend on the balance between the involvement of M- and P- channels in processing a visual stimulus. Materials and methods. To test this hypothesis, we first determined participants’ P- and M- efficiency (N=40). We used a two-alternative forced-choice orientation discrimination task and a staircase design to measure their contrast sensitivity threshold for P-biased (8 c/°, square-wave, ramped) and M-biased (0.5c/°, sine-wave, gaussian mask, intermittent flashing) gratings tilted 45° left or right from the vertical. Then, we tested participants’ ability to discriminate tilted asymmetrical shapes differing in terms of either a plane-rotation (40°), a mirror reflection across a vertical axis, or a mirror reflection across a shape-based axis in a speeded same/different judgment task. Results. We found significant positive correlations between an index of P-M imbalance (P-efficiency – M-efficiency) and individuals’ ability to discriminate both types of mirror images. Conclusion. These results suggest that an adequate balance between M- and P- channels could be determinant in our ability to discriminate mirror images.

112. Alpha power is coupled to the infra-slow gastric rhythm in different visual tasks

Janina Hüer1,2, Nicolai Wolpert1, Catherine Tallon-Baudry1

1Laboratoire de Neurosciences Cognitives et Computationelles, Ecole Normale Supérieure, Inserm, PSL University, 2Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society

112. Rhythmic bodily signals influence cortical activity as well as perception in animals and humans. In addition to influences from cardiac and respiration cycles, the infra-slow gastric rhythm (0.05 Hz) has recently been shown to be coupled to brain activity in humans. Alpha power in occipitoparietal areas and the insula, as well as BOLD activity in a large network cutting across classical resting-state networks, are coupled to the phase of the gastric rhythm. So far, the coupling has only been investigated during resting-state. Does gastric-brain coupling also occur when participants are engaged in a task? Here, we address this issue in two experiments where participants were either passively presented with different natural images or were performing a visual perceptual task at threshold. We measured the gastric basal rhythm using electrogastrography and brain activity with magnetoencephalography and analysed gastric-alpha coupling during fixation. We find that alpha rhythm power was significantly coupled to the phase of the gastric rhythm in both experiments. Source analysis and parcellation into resting state networks revealed that coupling consistently occurred within the default and visual network, while differences between the experiments appeared for the somatomotor network. Our results show that alpha power is coupled to the gastric rhythm while participants are engaged in a more active behaviour, which opens the possibility that gastric-alpha coupling plays a functional role.

114. Pre-stimulus oscillation phase predicts visual perception

Joonas Juvonen1,2, Jonni Hirvonen1,3, Matias Palva1,2, Satu Palva1

1Neuroscience Center, University of Helsinki, 2Department of Neuroscience and Biomedical Engineering, Aalto University, 3Biomag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital

114. Perception of and attention to visual stimuli has been proposed to fluctuate rhythmically. In line, correlation between pre-stimulus alpha and theta phase with stimulus detection and attention, respectively, has been reported in frontal and posterior brain areas in scalp electroencephalography (EEG) potentials. However, the results are inconclusive as no prior studies have tested this far whether fluctuations in perception and attention are present concurrently. Moreover, the cortical sources underlying these putative phase-behavior relationships have remained scarcely addressed. We used three visual threshold stimulus detection tasks (N = 20 for each task) together with magnetoencephalography (MEG) and individual-cortical-anatomy based source modeling to (1) test the hypothesis of pre-stimulus oscillations biasing stimulus detection and attention in separate frequencies and, importantly, (2) to identify the underlying cortical sources. We used Phase Opposition Sum (POS), a phase-based metric robust to variations in signal-to-noise ratio, to quantify phase-behavior coupling and estimated significance with permutation statistics and cluster correction. We found that the pre-stimulus phase in alpha and theta frequency bands was indeed significantly predictive of visual detection performance in all three tasks. The phase-behavior correlation of theta oscillations was stronger in the task condition with a pre-stimulus attention cue, implying a functional role for theta in top-down attentional processes. Source modeling showed that the phase-behavior correlations arose predominantly in the fronto-parietal and cingulo-opercular control systems and in the hierarchy of task-relevant processing systems, i.e., the dorsal attention system and visual system. These findings thus extend prior art by revealing that the pre-stimulus phase effects arise in the co-operation of brain systems achieving control and processing functions. Moreover, these findings corroborate the predictive nature of pre-stimulus phase in visual threshold stimulus detection in a comparable set of experimental paradigms with foveal stimulus.

115. Isolating signatures of motor-independent evidence accumulation signals in human and monkey EEG

Dr. Katerina Kalou1, Prof. Redmond O'Connell1, Prof. Simon Kelly2, Prof. Tobias Teichert3

1Trinity College Institute of Neuroscience , Trinity CollegeDublin, 2School of Electrical and Electronic Engineering, University College Dublin, 3Department of Psychiatry, University of Pittsburgh

115. Neural signals that accumulate evidence for perceptual decisions have been identified in a variety of species and brain regions. An extensive set of monkey neurophysiology studies have established that neurons in brain areas that plan the decision-reporting actions reflect the accumulation of sensory evidence towards an action-triggering threshold. In parallel, investigations of human electroencephalogram (EEG) data have identified a new class of decision signal over centro-parietal scalp sites (Centro-Parietal Positivity, CPP) that has the unique characteristic of tracing evidence accumulation irrespective of the sensory or motor demands of the task. To examine whether such a motor-independent evidence accumulation signal is a uniquely human process or simply one that has been overlooked by intracranial investigations, we analyzed EEG data collected from both human and macaque subjects while they performed the same auditory oddball task. Our 6 human participants were asked to discriminate a frequency deviant tone among a number of identical standard tones. The frequency difference between each standard and target tone (dF) was varied to define 5 different levels of sensory difficulty. Our human EEG data highlight a slowly building positive CPP component following target tones, peaking between 400ms and 700ms, that is absent following standard tones. Furthermore, there was a significant effect of dF on the amplitude reached by the CPP by the time of response. To test for the existence of a similar signal in monkey EEG, we conducted a re-analysis of 32-channel cranial EEG data collected from 3 macaques performing the same auditory oddball task. As with our human participants, the behavioral results indicate a rise in accuracy with dF. Using a data driven approach (ICA) we isolated a cluster of centrally located electrodes that exhibited the characteristic pattern of slowly building positivity rising 300ms after target tone presentation and peaking close to response execution. This signal slope is modulated by evidence strength and RT and reaches higher amplitudes for targets compared to standard tones, presenting a potential monkey homolog of the CPP. Data analysis is ongoing and will provide a more detailed examination of the commonalities and differences between the observed human and monkey EEG signals.

116. Biases in duration judgements caused by visual changes unveil the interaction between sensory and temporal perception

Dr. Wouter Kruijne1, Prof. Dr Christian N L Olivers2, Prof. Dr. Hedderik Van Rijn1

1University of Groningen, 2VU Amsterdam

116. Models of time perception have contrasting views on whether duration percepts are computed by dedicated neural clock circuits or whether they emerge from computations that are intrinsically linked to sensory perception. Support for intrinsic computations is found in many ‘temporal illusions’, the compressions or dilations of perceived time that arise when stimuli with different sensory manipulations are timed. For example, stimuli that are brighter and louder or unexpected oddball stimuli are perceived as lasting longer. However, many of these illusions can also be explained by dedicated models, as these manipulations might modulate ‘arousal’ or ‘surprise’, and thereby indirectly speed up or slow down the dynamics of dedicated clock computations. Here, we present support for the intrinsic view through ‘change bias’ effects. Across a series of psychophysical and electrophysiological experiments, we found that a change in location between two stimuli that mark the start and the end of an interval causes a consistent lengthening of its perceived duration. Crucially, this change was always fully predictable and identical to stimuli in trials without a change, and should therefore not elicit more surprise or arousal. In the EEG-data, we found neural repetition suppression effects that were predictive of the amount of temporal dilation. In follow-up studies we explored the effects of changes in six different feature dimensions (location, luminance, orientation, size, numerosity and face identity), and found that although most feature changes will yield neural repetition suppression effects, they do not always affect temporal perception. Finally, decoding analyses provided evidence for overlapping representations of sensory changes and interval durations, for those feature dimensions where changes affected temporal percepts. Taken together, these results support intrinsic models as they suggest that sensory responses have a causal influence on temporal perception. However, they additionally suggest that not all sensory areas are involved in the computation of a temporal percept to an equal extent. As such, the change bias effects could be an instrumental tool in uncovering how temporal information is extracted from sensory responses.

118. Quantifying ownership signal processing and perceptual bias in the rubber hand illusion: A signal detection study

Dr Renzo Lanfranco1, Dr Marie Chancel2,1, Prof Henrik Ehrsson1

1Karolinska Institutet, 2Université Grenoble-Alpes

118. The sense of owning one’s body arises from the integration of multiple sensory signals. Researchers typically employ bodily illusions like the rubber hand illusion (RHI) to study body ownership. The RHI involves stroking a person’s hand (hidden) alongside a visible fake rubber hand placed in front of them; this induces the feeling that the rubber hand is their own. However, most RHI studies have relied on subjective reports and indirect measures to assess the perceptual, cognitive, and physiological qualities of body ownership. Unfortunately, these measures are vulnerable to several potential confounding factors such as response bias, poor introspective skills, and task compliance effects. To objectively quantify body ownership, we have recently developed a two-alternative forced-choice (2AFC) paradigm whereby participants experience the RHI simultaneously with two rubber hands. Stimulation asynchronies in the order of 50, 100, and 200 ms between the two rubber hands are introduced using robot arms, and participants must report which rubber hand feels most like their own solely based on the feeling of hand ownership that the illusion induces. Here, we present four 2AFC experiments that have been analysed under a signal detection theoretic (SDT) framework to determine how different visuo-tactile manipulations modulate sensitivity to body ownership information and the perceptual biases induced by the illusion. We found that body ownership is extremely sensitive to temporal incongruencies in tactile stimulation. Indeed, even stimulation asynchronies of 50 ms caused noticeable changes in body ownership, leading to above-chance discrimination performance. Furthermore, varying the distance between the two rubber hands modulated both ownership sensitivity and perceptual bias. Conversely, varying the congruence between the materials stimulating the rubber hands and the real hand exclusively modulated perceptual bias. Additionally, manipulating participants’ visibility of the rubber hand stimulation procedure (to prevent them from making tactile predictions) exclusively modulated their perceptual bias – they became more prone to RHI-induced perceptual biases, like favouring the rubber hand closer to their body midline. Using this novel paradigm and SDT analysis, we show how the temporal, spatial, and tactile congruence principles of body ownership modulate body ownership information processing and perceptual bias during the RHI.

119. Differences in audiovisual speech processing in CI users with unilateral and bilateral hearing loss: an ERP study

Mrs Natalie Layer1, Ms Anna Weglage1, Dr Verena Müller1, Prof. Dr Hartmut Meister2, Dr Ruth Lang-Roth1, Prof. Dr. Martin Walger1,2, Dr. Micah M. Murray3,4,5,6, Dr. Pascale Sandmann1

1University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Otorhinolaryngology, Head and Neck Surgery, Audiology and Pediatric Audiology, Cochlear Implant Center, 2Jean-Uhrmacher-Institute for Clinical ENT Research, University of Cologne, 3The Sense Innovation and Research Center, Lausanne and Sion, 4The LINE (The Laboratory for Investigative Neurophysiology), Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, 5CIBM Center for Biomedical Imaging of Lausanne and Geneva, Lausanne, 6Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, TN

119. The cochlear implant (CI) is an auditory prosthesis that can help understanding speech in patients with severe to profound sensorineural hearing loss. Yet, hearing via a CI is not the same as natural hearing, which is why the patients may develop compensatory strategies to overcome the limited information provided by the CI. Presently, it remains unclear if CI-related compensatory strategies subsequent to CI implantation are limited to hearing-related functions or also extend to visual functions, and also whether these strategies vary between different CI user groups. To better understand the electrophysiological correlates of audiovisual speech perception in CI users with unilateral (single-sided deafness) or bilateral hearing loss (CI on one ear, CI or hearing aid on contralateral ear), the current event-related potential (ERP) study presented syllables in auditory, visual, and audiovisual conditions. A group of normal-hearing (NH) controls was also tested. The behavioural results revealed multisensory integration for both the CI user groups and the NH controls, as shown by audiovisual reaction time facilitation beyond race model predictions. Likewise, the ERP data exhibited multisensory effects for all three groups as revealed by topographic and source analyses over the period of the N1-P2 components. Specifically, we observed a modulation of the auditory-cortex response in conditions with additional visual information. Nevertheless, CI users with bilateral hearing loss showed a different pattern of N1 topography, indicating a stronger visual influence on auditory speech processing compared to CI users with unilateral hearing loss and NH listeners. Apart from the multisensory condition effects, both CI user groups revealed a delayed auditory-cortex activation and an additional activation in the visual cortex at the N1 latency, as well as better speech-reading abilities compared to NH listeners. Overall, these results extend previous findings by demonstrating distinct multisensory processes between NH listeners and different groups of CI users. This suggests that compensatory strategies are developed after implantation, which are manifested in improved visual abilities and altered cortical activation patterns, and which are observable independent of the hearing status of the second ear.

120. The effects of stimulus inversion on the neural representations of face and Chinese character recognition

Mr. Chun-Hui Li1, Dr. Bo-Cheng Kuo1

1Department of Psychology, National Taiwan University

120. Objectives and Research Question The ability of humans to recognise faces and words is important for social interaction and communication. The recognition of faces or words is particularly challenging when they are presented upside down. However, it remains unclear whether the influence of stimulus inversion on the recognition of words is similar to how it influences the recognition of faces. Here we investigate the neural correlates of the influences of inversion on faces and Chinese characters with functional magnetic resonance imaging (fMRI) and magnetoencephalography(MEG). Materials and Methods Participants (fMRI: N = 14; MEG: N = 16) performed a one-back identity-matching task for faces, simple Chinese characters and compound Chinese characters, respectively. We manipulated stimulus orientation to be upright and inverted. fMRI data were acquired on a Siemens 3T MAGNETOM Prisma MRI scanner and MEG data were acquired on a 306-channel Triux (Elekta Neuromag) system at the Imaging Center for Integrated Body, Mind, and Culture Research, National Taiwan University, Taipei, Taiwan. We performed two types of analysis: an univariate analysis and a multivariate pattern classification analysis (MVPA), on both fMRI and MEG data. Results Across two experiments, we observed the influences of inversion on recognition for all stimulus types. Inverted stimuli showed slower response times than upright stimuli, with stronger activity in the fusiform gyrus (FG). While common activation was identified in the FG for inversion among all stimulus types, fMRI univariate results showed functional specificity for face and character recognition regardless of the stimulus orientation. Our fMRI MVPA results demonstrated that classifiers trained on face inversion can decode the representations of character inversion in the character-selective area. Moreover, our MEG data showed the M170 inversion effect for all stimulus types. The MEG MVPA results confirmed the decoding results from the fMRI data suggesting that the classifiers trained on face inversion can decode the activity patterns of character inversion, which began at approximately 120 ms and extended to 400 ms. Conclusion In conclusion, our results suggest that the influence of stimulus inversion on face and Chinese character recognition shares similar configural representations in activity patterns in the functional specialized brain area.

121. The short-term passive exposure to non-native speech contrasts induces learning at neural and behavioural level in adults

Dr. Kaisa Lohvansuu1, Dr. Xueqiao Li1, Ass. Prof. Piia Astikainen1

1University of Jyväskylä

121. Objectives: During the first years of life auditory discrimination ability is enhanced by passive speech sound exposure by environment. However, in adulthood passive exposure has often showed to be insufficient to promote discrimination ability. Here we investigated whether short-term passive exposure to speech sounds can induce changes in long-term representations indexed by the mismatch response but also in behavioural discrimination ability. Research question: We studied whether a short-term passive exposure in human adult participants can affect plastic changes at brain level and/or whether improved discrimination ability can be seen at behavioural level. We supposed the exposure on four consecutive days could cause modulations in brain responses in consequence of the exposure, i.e., perceptual learning, and even learning on behavioural level. Materials and methods: Healthy, right-handed Finnish speaking monolingual young adults (N = 15) were passively exposed to non-native Chinese tonal sounds altogether 7h during four consecutive days, 1.5 − 2h per day. Same-different discrimination tasks and EEG recordings using passive oddball paradigm were performed on day 1 (pre-measurement) and on day 4 (post-measurement). Results: Increased MMN amplitudes at day 4 for the exposed speech sound contrasts were found as compared with brain responses measured at day 1, which acted as a control. At behavioural level shortened reaction times for day 4 compared to day 1 for discrimination of speech sounds were found. Conclusion: We found that very short-term passive exposure sufficed to modulate brain responses, i.e., induce changes in long-term memory representations, and improve behavioural level discrimination ability. The results indicate learning-related plastic changes and suggest that novel speech sound contrasts are possible to learn without active effort by short-term passive exposure also in adulthood.

122. Explaining flexible continuous speech comprehension from individual motor rhythms

Christina Lubinus1, Dr Anne Keitel2, Prof Jonas Obleser3,4, Prof David Poeppel1,5,6,7, Dr Johanna Rimmele1,6

1Max Planck Institute for Empirical Aesthetics, 2Psychology, University of Dundee, 3Department of Psychology, University of Lübeck, 4Center for Brain, Behavior, and Metabolism, University of Lübeck, 5Department of Psychology, New York University, 6Max Planck NYU Center for Language, Music, and Emotion, 7Ernst Strüngmann Institute for Neuroscience

122. When speech is too fast, the tracking of the acoustic signal along the auditory pathway deteriorates, leading to suboptimal speech segmentation and decoding of speech information. Thus, speech comprehension is limited by the temporal constraints of the auditory system. Previous research using simpler auditory stimuli suggests that individual differences in auditory-motor coupling strength might shape such temporal constraints. In two behavioral experiments, we here test this hypothesis. We characterize individual differences in the comprehension of naturalistic speech stimuli as a function of the individual coupling strength between the auditory and motor systems, as well as the preferred frequencies of the two systems (spontaneous speech motor production rate and preferred auditory rate). As expected, our data show that speech comprehension performance declined at higher rates. Importantly, auditory-motor coupling strength and the spontaneous speech motor production rate affect speech comprehension: both, higher auditory-motor coupling and a higher spontaneous speech mo-tor production rate were related to better speech-comprehension performance. Furthermore, performance increased with higher linguistic sentence predictability (using a recurrent neural network) -particularly at higher speech rates and for individuals with high auditory-motor coupling strength- and with participants’ higher working memory capacity (Digit Span). These findings support the notion of an individual preferred auditory regime that allows for optimal auditory (speech) processing. Our findings provide further evidence for a model that assigns a central role to motor-system-dependent individual flexibility in continuous speech comprehension.

123. Independence and overlap of symmetry representations in the extrastriate cortex

Dr Alexis Makin1, Ms Yiovanna Derpsch1, Dr John Tyson-Carr1, Dr Giulia Rampone1, Dr Marco Bertamini1

1University of Liverpool

123. Objectives To determine the nature of symmetry coding in the visual cortex Research Question Psychophysical work has examined many questions about symmetry perception and its role in perceptual organization. We also know that all types of symmetry activate a network of extrastriate brain regions, and generate an event related potential called Sustained Posterior Negativity (SPN). However, it is unclear whether different symmetry types are coded by independent or overlapping neural mechanisms. Materials and Methods We addressed this question with a novel sequential presentation paradigm. In 5 experiments, we recorded EEG while participants viewed trials where three patterns were presented in succession (500 ms per pattern, separated by 200 ms gaps). There were 48 participants in each experiment. We examined whether history effects on SPN amplitude would transfer across changes in various visual dimensions. Transfer indicates that overlapping mechanisms are involved. Results Experiment 1 found that sequential presentation of three reflectional symmetries causes an increase in SPN amplitude. We termed this increase SPN priming. Experiment 2 again replicated SPN priming, but found that it did not survive changes in retinal location. Experiment 3 replicated SPN priming again, but found that it did not transfer across unpredictable changes in axis orientation. However, Experiment 4 found SPN priming did survive orthogonal changes in axis orientation (i.e. horizontal to vertical or vice versa). Finally, Experiment 5 also found that SPN priming transferred between reflection and rotation, and between reflection and Glass patterns. Conclusions We conclude that the symmetry representations in the extrastriate cortex are constrained by retinotopy, but there is considerable overlap between regularities presented at the same retinal location.

124. Does temporal predictability enhance auditory temporal resolution ? Behavioral results from a gap detection paradigm

Valentine Mandin1, Dr Virginie van Wassenhove1, Dr Sophie K. Herbst1

1Cognitive Neuroimaging Unit, INSERM, CEA, CNRS, Université Paris-Saclay, Neurospin Center, 91191 Gif-sur-Yvette

124. Perception takes advantage of the dynamic structure of our sensory environment. Predictions of “when” an event will occur, derived from temporal regularities in the sensory inputs, can be used to orient attention in time. Temporal predictions improve the motor responses to, and the perceptual processing of, predicted sensory inputs. Here, we asked whether the perceptual benefits of temporal predictions can be explained by an enhanced temporal resolution of the sensory system. A higher sampling rate of information at predicted moments in time would improve the sensory analysis. Studies in the visual modality (Correa et al., 2006) indeed showed that temporal resolution was improved by non-rhythmic temporal predictions, constructed from a predictive time interval separating two discrete events. Thus, we tested whether temporal predictions improve the temporal resolution of auditory processing, operationalized as the detection of short gaps in noise. The onset of the gap was either temporally predictable (fixed foreperiod), or not (variable foreperiod). Human participants (N=26) were tested on a 2-alternative-forced-choice version of the gap detection task, in which two sounds were played, with only one of them including a short silent gap. The sounds contained two different fundamental frequencies, making comparison across frequency channels in the auditory system mandatory to complete the task. We measured performance for varying gap durations by means of psychometric curves. Our analyses showed that temporal predictions did not improve participants’ gap detection threshold or sensitivity. However, response times were significantly faster for gaps occurring at predictable moments in time. These response times improvements indicate the use of temporal predictions, and suggest a possible decrease of decision times by temporal predictability. Participants could respond only after the stimulus sequence ended, hence a simple enhancement of motor processes could not explain this improvement. In conclusion, non-rhythmic temporal predictions did not benefit auditory temporal resolution in our paradigm. However, response time improvements suggest a speeding up of the underlying information processing cascade. Together, these results provide us with more information about effects of temporal predictions in audition.

125. Investigating the reverse motion illusion in random dot kinematograms

Pat Mc Keown1, Dr Elaine Corbett1,2, Prof Redmond O'Connell1

1Trinity College Institute Of Neuroscience, 2School of Electronic and Electrical Engineering, University College Dublin

125. Background Random dot kinematograms (RDKs) have been at the heart of many key advances in our understanding of perceptual decision making. Recent research using continuous judgement tasks in which motion directions vary around 0-360 degrees has highlighted a strange phenomenon, whereby participants occasionally report motion in the direction opposite to that which was presented - dubbed “the reverse motion illusion” (Manning, Meier, & Giaschi, 2022). Bae and Luck (2021) highlight temporal smearing, whereby the order of successive dot presentations is misperceived, as a likely explanation for this reverse motion perception. Systematic research to determine the stimulus parameters and individual differences that impact the reverse motion illusion has yet to be conducted. Hypotheses Temporal smearing and local versus global perception biases are implicated in the reverse motion illusion. Reverse responding will be associated with higher confidence than other inaccurate responses if it reflects a distinct process. Experimental Procedures To establish the role of temporal smearing, we will vary the frame rate of our RDKs (60Hz, 90Hz, 120Hz) and measure any changes to the rate of reverse motion perception. We will also administer a critical flicker fusion task to investigate the influence of inter-individual differences in visual sampling rates. Additionally, to test whether reverse motion perception arises from undersampling of the dots, we will measure individual differences in local/global bias using Navon figures. Finally, we will collect choice confidence data for each trial using a continuous scale. Analysis Pipeline We will test the effect of RDK frame rate on the incidence rate of reverse motion perception, controlling for overall differences in choice precision, using a within-subjects design. We will separately test for a correlation between individual CFF threshold and local/global bias. Statistical Power Analysis When testing the impact of RDK frame rate, a sample size of 20 participants is sufficient to achieve statistical power of 0.8 to detect a medium effect (f=0.3). A sample of 67 participants will be collected to examine correlations between reverse motion perception rates, CFF and local/global bias.

126. Discerning feedforward decision formation in human V1 using EEG: A response-time dependent choice probability in the C1 component

Dr Kieran Mohr1, Prof Simon Kelly1

1University College Dublin

126. Objectives: The goal of this study was to demonstrate feedforward choice probability in human V1 using the C1 component of the VEP. Choice probabilities are plagued by interpretational difficulty: do they reflect decision-triggering feedforward activity or decision-related feedback activity? One way to address this issue is to use rapid decision paradigms where choices are based on a “snapshot” of sensory evidence as this constrains the range of response times that are compatible with decision-triggering neural responses. Research question: Does the C1 exhibit choice probability in a rapid contrast judgement task and is the strength of the choice probability dependent on response time? Furthermore, is C1 choice probability independent of choice-predictive signals that follow the C1 and that precede the stimulus? Materials and methods: 128-channel EEG was collected while participants performed a difficult contrast discrimination between two arrays of contrast gratings that appeared in the upper left and lower right quadrants of the visual field for 39 ms. The C1, P1 and N1 components of the VEP were measured and a nonparametric, cluster-based statistical procedure (Maris and Oostenveld 2007) was used to identify choice predictive activity at later latencies and preceding stimulus onset. C1 choice probability was assessed across response time sextiles while controlling for these additional signals. Results: Significant choice probability emerged even while controlling for choice-predictive signals both preceding stimulus onset and following C1 latency. This choice probability emerged only in trials where responses were committed between approximately 300 ms and 400 ms. Conclusion: By using EEG, choice probability in human V1 could be measured while controlling for a broad selection of other choice-predictive signals. What’s more, C1 choice probability emerged only in some trials where the latency of the response was consistent with a causal relationship between the C1 and the decision. It did not emerge when choices were too fast to be generated by the C1 or were slow enough that other signals could drive the decision. It is therefore likely that the C1 played a decision-driving role.

128. Reading point-light walkers and amorphous – a TMS study.

Olivia Morgan Lapenta1,2, PhD Claudia Valasek2, BSc Sofia Macarini2, PhD Paulo Sérgio Boggio2

1Psychological Neurophysiology Lab, CIPsi - University of Minho, 2Social and Cognitive Neuroscience Lab - Mackenzie Presbyterian University

128. Objectives: (i) Evaluate if human actions with and without pictorial information result in comparable motor facilitation clarifying the adequacy of point-light (PL) human actions in motor observation and motor resonance research; (ii) Verify if the isolated aspects of human shape, i.e., without movement; and the isolated aspect of movement, i.e., PL in amorphous shape, are not enough for eliciting motor network response and thus that motor facilitation is specific to human action perception involving human motor and spatial configurations. Research question: Are PL human actions suitable stimuli for action observation experiments evaluating motor resonance response and what are the adequate parameters for preparing their control stimuli? Methods: Motor evoked potentials (MEPs) of M1 were recorded from 18 healthy subjects using transcranial magnetic stimulation (TMS) during presentation of full-body video clips of: everyday human actions either with (real movement - RM) or without (biological point-light - PLbio) pictorial information, scrambled moving point-lights (PLscr) and static point-lights forming a human shape (PLs). All videos were approximately 1000ms long. Peak-to-peak MEP amplitude (maximal distance) was individually averaged for each condition (RM, PLbio, PLscr, PLs). Results: rmANOVA considering MEP as dependent variable and condition as within-subject factor revealed a main effect for Stimuli (F1,17= 6.91; p=.029; np2 =.16). Specifically, Fisher LSD post hoc revealed that such effect was due to inferior MEP amplitude in PLs condition when compared to RM (p=.016), PLbio (p= .006) and PLscr (p=.047). Conclusion: Our findings account for future studies elaboration by providing information on similar CE increase during PLbio and RM observation, thus corroborating the use of human PL in motor resonate/action observation studies. Noteworthy, PLscr also engaged the motor network, which could be due to kinematic aspects of human velocity profile or anthropomorphism of non-biological agents. Observation of PLs resulted in significantly smaller MEPs. Therefore, M1 activation seems restrict to movement perception but not to human form. Thus, planning the control stimuli and task context is crucial when using PL displays in the study of human action perception and the action observation network activation.

127. Spatial and temporal (non)binding of audio-visual stimuli: effects on motor tracking and underlying neural sensory processing

Olivia Morgan Lapenta1,2, BSc Ashleigh Clibborn2, BSc Ayah Hammoud2, PhD Peter Keller2, PhD Sylvie Nozaradan4, PhD Manuel Varlet2,3

1Psychological Neuroscience Lab, CIPsi - University of Minho, 2The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, 3 School of Psychology, Western Sydney University, 4Institute of Neuroscience, Universite catholique de Louvain

127. Objectives: Compare the steady-state evoked potentials (SSEPs) of spatially or temporally congruent and incongruent audio-visual stimuli and evaluate how congruency affects the motion tracking of visual stimuli. Research question: Does spatial or temporal congruency of audio-visual stimuli affect motion tracking and evoke differential SSEPs? Methods: We use EEG frequency-tagging techniques to investigate the selective neural processing and integration of visual and auditory information in the tracking of a moving stimulus and how spatial and temporal (in)congruency between the two modalities modulate these sensory neural processes and synchronization performance.Participants were instructed to track a red dot flickering at 15 Hz that oscillated horizontally with a complex trajectory on a computer screen by moving their index finger. An auditory pure tone with continuous pitch modulation at 32 Hz was presented with lateralised amplitude modulations in left and right audio channels (panning) that were, in Experiment 1, either spatially congruent or incongruent (same direction vs. opposite direction vs. no panning), and in Experiment 2, either temporally congruent or incongruent (no delay vs. medium or large delay), with the oscillating visual stimulus. Results: Both experiments yielded significant EEG responses at the visual (15 Hz) and auditory (32 Hz) tagging frequencies. Further, in Experiment 1 participants had lower performance and larger amplitudes at the auditory frequency during no panning condition. No significant correlation between the two measures was found. In Experiment 2 no changes in the amplitude of the EEG responses or in performance were found. Conclusion: The movement synchronization performance and the neural processing of visual and auditory information were not influenced by phase congruency manipulation. For spatial congruency, the moving auditory stimuli led to better performance, irrespective of congruency, when compared to the non moving sound. Importantly, there were no significant responses at 17 and 47 Hz corresponding to the intermodulation frequencies of 15 and 32 Hz, suggesting an absence of global integration of visual and auditory information. These results encourage further exploration of the conditions that may result in the selective processing of visual and auditory information and their integration in the motor tracking of moving environmental objects.

129. Do you automatically track time?

Mr. Yvan Nedelec1, Prof Virginie van Wassenhove1

1Cognitive Neuroimaging Unit, INSERM, CEA, CNRS, Université Paris-Saclay, NeuroSpin center

129. Time perception can be assessed with behavior and electroencephalography (EEG). To demonstrate that the brain automatically detects changes in duration, EEG studies have used the Mismatch Negativity (MMN) paradigm in which infrequent duration changes (deviants) in a sequence of frequent durations (standards) elicit a negative wave (the MMN), whether participants paid attention or not to the sequence. However, two shortcomings in the literature were identified: whether the observed MMN results from a violation of the sequence temporal regularity or a change in duration, and whether the temporal scale of durations matter are unsettled questions. Consequently, we conducted an EEG study testing duration changes in rhythmic or non-rhythmic sequences and at two different temporal scales (2x2 conditions). We hypothesized that because durations below 200 ms are building blocks of perception, they may elicit an MMN, whether embedded in a rhythmic sequence or not. On the contrary, durations above 200 ms may elicit an MMN only in rhythmic sequences, as temporal regularities will facilitate the tracking of duration changes. The sequences consisted of empty intervals, delimited by auditory clicks, and separated by fixed or variable (rhythmic or not, respectively) inter-stimulus intervals. Within each sequence, stimuli could be standard or deviant (+/- 30%) durations. We tested two temporal scales, a standard duration of 100ms or 600ms (below and above the temporal window of integration at 200 ms). We used control sequences where all durations were equally presented in a randomized order. The evoked responses (ERPs) for each deviant duration of each condition were computed. MMNs were revealed by subtracting control ERPs from the deviant ERPs. Permutation spatiotemporal t-tests were used to identify the MMN responses, and F-tests to assess differences across conditions. To compare rhythmic and non-rhythmic ERPs, and identify shared processes and latency differences, a temporal generalization analysis was performed between the two conditions (rhythmic and non-rhythmic). A sample size of 13 participants was estimated using reported values in the literature (t-test at peak amplitude on a single electrode). To avoid type II errors, 30 participants were recruited.

130. Are we there yet? Neural signatures of evidence accumulation in temporal decisions

Nir Ofir1, Prof Ayelet Landau1

1HUJI

130. Cognitive models of timing postulate an abstract pacemaker whose ticks are counted and accumulated to form an internal representation of time. However, physiological manifestations of the pacemaker or the accumulation process have not yet been identified. We measured electroencephalography (EEG) of participants while they performed a temporal-bisection task in which they were requested to categorize the duration of visual stimuli as short or long. We found that the stimulus-offset and response locked activity (EEG) depends monotonically on the stimulus duration. To relate this activity to the underlying cognitive processes, we used a drift-diffusion model. The model includes a noisy accumulator starting with the stimulus onset, and a decision threshold. According to the model, a stimulus duration will be categorized as “long” if the accumulator reaches the threshold during stimulus presentation. Otherwise, it will be categorized as “short”. Although the model was proposed to account for a binary decision, it postulates a continuous process of evidence accumulation. We found that at the offset of stimulus presentation an EEG response marks the distance of the accumulator from the threshold. Therefore, this model offers an accurate description of our behavioral data as well as the EEG response using the same two model parameters. We then replicated this finding in an identical experiment conducted in the tactile domain. We also extended this finding to two different temporal ranges (sub- and supra-second). Taken together, the work provides a new way to study the cognitive processes underlying temporal decisions, using a combination of behavior, EEG and modelling.

131. Brain and spinal cord interactions underlying conditioned pain modulation

Dr. Karita Ojala1, Prof. Christian Büchel1

1Institute Of Systems Neuroscience, University Medical Center Hamburg-Eppendorf

131. Background Conditioned pain modulation reflects the individual’s internal pain inhibition capacity and has been shown to be impaired in certain chronic pain conditions. We will investigate the involvement and interactions of the descending pain modulatory pathway in the spinal cord and the brain during conditioned pain modulation with pressure in healthy humans. Hypotheses To establish successful conditioned pain modulation, subjective painfulness ratings for test pain stimuli should be lower during moderately-to-highly painful (experimental) than non-painful (control) conditioning pressure. We hypothesize reduced activity to test pain stimuli in traditional pain-responsive regions (rostral anterior cingulate cortex, anterior + posterior insula, periaqueductal grey, rostroventral medulla) as well as the cervical spinal cord, in experimental vs. control conditioning trials. BOLD responses are also expected to be negatively correlated with individual conditioned pain modulation magnitude. Experimental procedures We use a within-subjects design of 2 experimental and 2 control blocks in randomized order, of 2 trials each. On each trial, participants receive conditioning pressure for 200 s on the left arm and 9 test pain stimuli of 5 s on the right arm, and rate subjective painfulness after each test stimulus. Pressure is applied with an automated cuff algometer (Nocitech, Denmark) and calibrated individually. Brain and cervical spinal cord (C5-C7) BOLD fMRI responses are measured near-simultaneously, total volume TR 1.991 s. We also measure skin conductance, pulse, and respiration. Analysis pipeline Pain ratings will be analyzed in R with one-sided paired t-tests and mixed models accounting for temporal effects over blocks/trials and individual slopes. Spinal cord data will be preprocessed with the Spinal Cord Toolbox and brain data in SPM12. Brain and spinal cord fMRI analysis is conducted in SPM12 with categorical mixed effects models with above-mentioned regions of interest. Statistical power analysis and pilot data The minimum required sample size for 95% power is 13 based on G*Power calculations for behavioral pilot data with Cohen’s d = 0.99, pain ratings for experimental < control trials, t(12) = 3.58, p = 0.002 (one-tailed paired t-test). However, to adequately power the study for detecting smaller neural effects, we plan to measure 40 participants in the fMRI study.

132. Population receptive fields isolate or combine target and flankers in (un)crowding

Mr. Ayberk Ozkirli1,2, Dr. Maya A. Jastrzębowska1,2, Prof. Bogdan Draganski2,3, Prof. Michael H. Herzog1

1Laboratory of Psychophysics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 2Laboratory for Research in Neuroimaging, Department of Clinical Neuroscience, Lausanne University Hospital and University of Lausanne, 3Neurology Department, Max Planck Institute for Human Cognitive and Brain Sciences

132. Crowding by neighboring elements leads to the deterioration of target discrimination. This phenomenon is traditionally explained with feedforward, hierarchical models. In these models, a “bottleneck” at the earliest stages of visual processing causes an irreversible loss of information, which is perhaps due to the pooling of target and flanker features when they fall within the same receptive field. He et al. (2019) used fMRI and showed that population receptive field (pRF) size in V2 is smaller in a weaker crowding condition as compared to a strong crowding condition. Their results are in line with the traditional explanation, with pRF size acting as a proxy for the strength of the “bottleneck”. Here, we estimated pRF sizes in three stimulus configurations, corresponding to no crowding, crowding and uncrowding, i.e., the alleviation of crowding due to the presence of additional flankers. Local, feedforward models suggest that pRF sizes in uncrowding should be the same as or larger than those in crowding. However, we found that, in fact, pRF sizes in the uncrowding condition are significantly smaller than in the other two conditions. This was true across early visual areas V1 to V4, with the exception of V3 in the no crowding vs. uncrowding comparison. We did not find any difference between the crowding and no crowding condition in any of the tested visual areas. Our results suggest that while in crowding, target and flanker features are combined because they fall within the same receptive field, in uncrowding, the target is isolated from the flankers to a greater extent through a decrease in pRF size. These findings contradict purely feedforward models of vision, rather suggesting that pRF size can be modulated through feedback modulation dependent on global context. We posit that recurrent processing plays a critical role in (un)crowding and vision in general. Acknowledgements: We would like to thank our funding sources: Swiss National Science Foundation (NCCR Synapsy, project grant numbers 32003B_135679, 32003B_159780, 324730_192755, CRSK-3_190185, 176153), the Leenaards Foundation, Fondation ROGER DE SPOELBERCH, and the Partridge Foundation.

133. Sensory processing sensitivity modulates attention engagement with emotional pictures

Beata Pacula-Leśniak1, Dr Joanna Pilarczyk1, Dr Michał Kuniecki1

1Jagiellonian University

133. Objectives: The current study aimed to disentangle the relation between the perceptual and emotional intensity of the visual stimulus and their impact on visual attention in the context of Sensory Processing Sensitivity (SPS): biologically-determined increased susceptibility to environmental inputs. SPS includes both perceptual sensitivity - being able to notice subtle stimuli and being more easily overwhelmed by intensive stimuli - and affective sensitivity, i.e. sensitivity to emotional clues. However, the relation between perceptual and emotional sensitivity is still far from clear. Research question: The current study examined the impact of images’ emotional load, perceptual intensity, and their interaction on visual attention patterns among people varying in Sensory Processing Sensitivity level. Materials and methods: We selected 315 stimuli from the emotional pictures databases and manipulated the perceptual saliency of the key objects to obtain three conditions: saliency increased, decreased, and unchanged (natural). Participants (N=60) saw all emotional pictures in a free-viewing procedure for 4 sec. Then participants’ Sensory Processing Sensitivity was measured using the Highly Sensitive Person Scale for research purposes (Aron & Aron, 1997). Results: During the exploration of emotional pictures people scoring higher on SPS fixate less on the negative regions of interest, while there are no differences for neutral and positive regions of interest. There is no impact of SPS on the early attention capture by emotional stimuli. Saliency manipulation was effective for attention capture, but not for attention hold, and its effect diminished with each fixation. Moreover, the saliency effect on attention is not modulated by sensory processing sensitivity. Conclusion: Sensory Processing Sensitivity influenced visual attention hold: highly sensitive persons fixated less on the key objects in negative images, while there were no differences for neutral and positive ones. On the other hand, SPS did not modulate the effect of perceptual saliency on attention. There was also no interaction between saliency, emotional load, and SPS. Overall, the results suggest the prevalence of the emotional component of SPS over the perceptual one in shaping the attention engagement with visual stimuli.

134. Cardio-audio and auditory regularity processing in human wakefulness and sleep

Andria Pelentritou1, Christian Pfeiffer2, Sophie Schwartz3, Marzia De Lucia1

1Laboratoire de Recherche en Neuroimagerie (LREN), Department Of Clinical Neurosciences (DNC), University Hospital (CHUV) and University of Lausanne (UNIL), 2Robotics and Perception Group, University of Zurich, 3Department of Neuroscience, Faculty of Medicine & Swiss Center for Affective Sciences & Geneva Neuroscience Center, University of Geneva

134. Objectives. The human brain can detect statistical regularities across interoceptive and exteroceptive stimuli. We hypothesised that auditory regularity processing is preserved in states of altered vigilance, such as during deep sleep. Research Question. We focused on cardiac and auditory inputs and attempted to outline the cardiac and neural correlates of cardio-audio regularity inference in wakefulness and sleep. Materials and methods. We recorded continuous electrocardiography (ECG) and electroencephalography (EEG) during wakefulness and sleep in healthy volunteers (N=26). We presented auditory sequences at a fixed pace (isochronous) or in synchrony to the ongoing heartbeat that were rarely interrupted by unexpected sound omissions. A third sequence with random sound-to-sound intervals (asynchronous) was used as a control condition. We investigated whether interbeat intervals were affected by sound omissions across auditory regularity types and across awake/sleep conditions using repeated measures ANOVAs with factors ‘auditory condition’ (three levels) and ‘order’ (four levels, before, during, and two after the omission). Cluster permutation statistical analysis assessed the EEG omission response across experimental conditions. Repeated measures ANOVAs with factor ‘auditory condition’ tested the influence of auditory regularities on the time-interval between sounds and the slow oscillation (SO) peak in N2 sleep. Results. Omissions produced a long-lasting heartbeat deceleration in the synchronous condition as revealed by significant interaction of the repeated measures ANOVAs on interbeat intervals (F(AWAKE)=14.1, F(N1)=10.7, F(N2)=11.7, F(N3)=6.2, F(REM)=8.5, p<0.0005) and post-hoc comparisons (p<0.05). EEG omission responses in the synchronous and asynchronous conditions differed (p<0.05) after heartbeat onset at 226-274ms in wakefulness and at -99-117ms and 322-500ms in N2 sleep. Furthermore, significant differences between the isochronous and asynchronous were observed at 226-288ms in wakefulness and 83-226ms in N2 sleep after omission onset. The median sound to SO latencies were different across auditory conditions (F=4.04, p<0.05) with higher latencies in the asynchronous condition (p<0.05) compared to the synchronous and isochronous conditions. Conclusion. Neural monitoring of cardiac signals induces an expectation of auditory signals upon cardio-audio regularities during wakefulness and NREM sleep (N2), as expressed by a modulation of the heartbeat and neural omission response, and a reorganization of the ongoing SO activity in N2 sleep.

135. Cardio-audio regularity processing occurs in the absence of consciousness

Andria Pelentritou1, Nathalie Ata Nguepnjo Nguissi1, Matthias Haenggi2, Frédéric Zubler3, Marzia De Lucia1

1Laboratoire de Recherche en Neuroimagerie (LREN), Department Of Clinical Neurosciences (DNC), University Hospital (CHUV) and University of Lausanne (UNIL), 2Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, 3Department of Neurology, Inselspital, Bern University Hospital, University of Bern

135. Objectives. The human brain can implicitly infer on the temporal relationship between cardiac and auditory inputs in predicting future auditory events. Here, we hypothesised that this ability is preserved during coma, a deep unconscious state. Research Question. We investigated whether the brain can form predictions of sounds based on cardio-audio regularity in the absence of consciousness, demonstrated as omission mismatch negativity responses. Materials and methods. We recorded continuous electrocardiography (ECG) and electroencephalography (EEG) in 57 comatose patients during the first 24h after coma onset, of whom 35 survived beyond unresponsive wakefulness (favourable outcome) at three months. We presented auditory sequences at a fixed pace (isochronous) or in synchrony to the ongoing heartbeat that were rarely interrupted by unexpected sound omissions. An auditory sequence with random sound-to-sound and heartbeat-to-sound intervals (asynchronous) and a baseline without auditory stimulation served as control conditions. Cluster permutation statistical analysis assessed the EEG omission response across experimental conditions. This analysis was complemented by time-running t-tests (p<0.05) on the Global Field Power (GFP) between conditions with False Discovery Rate correction for multiple comparisons. Results. In patients with favourable outcome, contrasting the synchronous to the asynchronous condition revealed a significant negative difference (p<0.05, two-tailed) in the EEG omission responses; this difference was observed between 253ms to 338ms following heartbeat onset, located at posterior-central electrodes. Similarly, comparing the synchronous and baseline conditions revealed a posterior-central negative cluster between 251-430ms in the same patients. No differences (p>0.05) were observed in the omission responses between the isochronous and asynchronous or baseline conditions. GFP analysis revealed differences in the synchronous against baseline omission responses when time-locking to heartbeat onset between 12ms to 23ms, 48ms to 63ms and 421ms to 498ms but not in the synchronous against asynchronous or in the asynchronous against baseline comparison. All statistical tests performed in patients with unfavourable outcome provided no significant results. Conclusion. The human brain can monitor temporal regularities across cardiac and auditory inputs in deep unconscious states. In unconscious states, predictive processing of auditory regularities may preferentially occur when sound stimuli are synchronous to bodily inputs, such as heartbeats, a potentially important mechanism for survival.

136. "Stubbornness" but not confirmation bias predicts poorer performance in repeated perceptual decision-making tasks

Dr Alexis Pérez-bellido1, Mr Angel Bujalance1, Prof Lluis Fuentemilla1

1University of Barcelona

136. Humans are “suboptimal” decision makers. When presented multiple times with similar information, we have a natural tendency to repeat our previous choices despite of being mistaken. This repetition bias does not exclusively depend on response-level biases. In fact, it has been shown that in perceptual decision-making tasks, we integrate information asymmetrically by giving stronger weight to information samples that are consistent with our previous beliefs, in line with confirmation bias. In this study, we used reverse correlation to describe how decisions are determined by information and decision dependent consistency biases. We presented participants with repeated sequences of six differently oriented gratings. After each sequence, participants categorized whether the mean orientation of the sequence was closer to the cardinal or the diagonal axis. Repeated sequences contained the same average category information as in the first presentation, but in half of the repetitions the participants experienced exactly the same sequence of oriented gratings presented before and in the other half gratings were oriented different. As expected, our results showed that participants were biased to repeat previous choices and weighted more the information that was consistent with their previous decisions. However, participants exposed twice with same orientation information experienced stronger confirmatory biases. Individual differences in metacognitive skills were not related to stronger confirmation biases. Indeed, stronger tendency to experience a confirmation bias did not lead to poorer performance. Instead, individual differences in “stubbornness” (an information independent bias to repeat previous choices) paired with lower metacognitive sensitivity predicted poorer performance. This study demonstrates that differences in consistency between previous decisions and sensory information induce biases in evidence accumulation. Moreover, the confirmation bias increases when participants perceive exactly the same sensory information. However, confirmation bias does not seem to have a negative impact on participants performance, at least in those tasks in which information is highly correlated across repetitions. Instead, a lack of flexibility (“stubbornness”) of participants to change their mind critically harmed their ability to improve their perceptual decisions.

137. Modulation of visual contrast sensitivity with individualized transcranial random noise stimulation is time-dependent and specific for the primary visual cortex.

Weronika Potok1,2, Alain Post1, Dr. Marc Bächinger1,2, Prof. Dr. Nicole Wenderoth1,2,3

1Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zurich, 2Neuroscience Center Zurich (ZNZ), University of Zurich, Federal Institute of Technology Zurich, University and Balgrist Hospital Zurich, 3Future Health Technologies, Singapore-ETH Centre, Campus for Research Excellence And Technological Enterprise (CREATE)

137. Transcranial random noise stimulation (tRNS) has been shown to significantly improve visual perception. Previous studies demonstrated that tRNS delivered over cortical areas acutely enhances visual contrast detection of stimuli when tRNS intensity is optimized for the individual. However, it is currently unknown whether tRNS-induced signal enhancement could be achieved within different neural substrates along the retino-cortical pathway and whether the beneficial effect of optimal tRNS intensities can be reproduced across sessions. In 3 experimental sessions, we tested whether tRNS applied to the primary visual cortex (V1) and to the retina improves visual contrast detection (preregistration: https://osf.io/gacjw). We first measured visual contrast detection threshold (VCT; N=24, 16 females) during tRNS delivery separately over V1 (no-tRNS, 0.75, 1, 1.5mA) and over the retina (no-tRNS, 0.1, 0.2, 0.3mA), determined the optimal tRNS intensities for each individual (ind-tRNS) and retested the effects of ind-tRNS within the sessions. We further investigated whether we could reproduce the ind-tRNS-induced modulation on a different session (N=18, 13 females). Finally, we tested whether the simultaneous application of ind-tRNS to the retina and V1 causes additive effects. We found that at the group level tRNS of 0.75mA decreases VCT compared to baseline when delivered to the V1 [F(3, 69)=4.54, p=0.006]. Beneficial effects of ind-tRNS could be replicated when retested within the same experimental session [t(23)=1.72, p=0.049] but not when retested in a separate session [t(17)=-0.17, p=0.43]. Applying tRNS to retina did not cause a systematic reduction of VCT irrespective of whether the individually optimized intensity was considered [within t(23)=1.05, p=0.15 and between sessions t(17)=0.2, p=0.42] or not [F(3, 69)=1.69, p=0.18]. We also did not observe consistent additive effects of V1 and retina stimulation [t(17)=0.8, p=0.22]. Our findings demonstrate that V1 seems to be more sensitive than retina to tRNS-induced modulation of visual contrast processing. Moreover, the individual optimal tRNS intensity appears to vary across sessions.

138. The visual fixation shift between experimental trials exceeds the stereoacuity threshold, which reveals a stereoacuity strategy under fixational eye movements

Anna Ptukha1

1University of Helsinki

138. Binocular vision creates representation of space from differences between images projected to the retinae of two eyes. Stereo information can be lost when differences between the 2D projections change with fixational eye movements (FEMs), which occur a few times per second within fixation. In vision experiments, a short presentation time of about 200 ms helps to minimize the effect of FEMs on stimuli. Yet, there is an elephant in each stereo experimentation room since many repeated trials are required (e.g., in the method of constant stimuli). The gaze fixation shift at the start of each trial, which is determined by FEM aptitude in the specific conditions, is a serious concern in case stimuli are not corrected in gaze-contingent manner. Two psychophysics studies [1,2] were self-replicated with the addition of simultaneous eye tracking at 1000 Hz in binocular mode. Observers demonstrated stereoacuity up to 0.01 arcmin (all had stereoacuity of at least 2 arcmin). The stereoacuity threshold was always less than half of typical gaze position shift between trials in a common block (>10 arcmin in the specific conditions). Also, change in gaze position within a trial depended on stimuli parameters, such as the left or right position from the centre of fixation. We concluded that only distinct patterns of FEMs can appear to allow for high stereoacuity only along distinct directions. The problem of deriving 3D scene from several pairs of 2D projections is ambiguous considering humans do not have precise readout of their eye positions. An assumption about stability of spatial position of objects potentially helps to reduce the ambiguity. Indeed, a perceived scene does not change with FEMs during fixation, thus a common solution should be assigned to pairs of 2D projections formed from a given 3D scene during possible FEMs. Moreover, the discovered dependance of FEMs on stimuli parameters supports the hypothesis about spatio-temporal encoding of visual information, and the active vision paradigm. 1. Ptukha A, Mamassian P. (2017) Interactions between horizontal and orientation disparities in stereopsis. Journal of Vision. 17(10):1056. Meeting abstract. 2. Mamassian P, Ptukha A. (2017) Stereopsis from oriented lines. Perception. 46(12):263. Meeting abstract.

139. Rhythmic sampling between eye channels

Daniele Re1, Prof Ayelet N. Landau1

1Hebrew University of Jerusalem

139. Whenever we view a cluttered scene, our attention allocates resources dynamically in order to compute efficiently the visual information. When two locations compete for resources, ongoing performance fluctuates at 4 Hz per location in alternation. In a recent study we have shown that when

participants monitor a single location visual-target detection unfolds at an ∼8 Hz rhythm, leading us to the conclusion that the 4 Hz sampling emerges from the division of the 8 Hz rhythm. This division – 8 to 4 Hz - can occur not only when attention distributes among locations but also among overlapping objects defined merely by their features (color and motion direction; Re et al., 2019). This indicates that rhythmic sampling orchestrates attention beyond spatial selection processes. However, little is known about whether unaware selection processes, might also unfold rhythmically. In order to shed light on this question, we investigated the temporal dynamics of inter-ocular selection processes. We presented a single central grating to which participants had to orient their attention. At an unpredictable moment, a four-dot cue appeared around the grating. Participants were instructed to detect a faint target which appeared briefly on the grating. Target timing was densely sampled as a function of the four-dot cue. Gratings were presented to both eyes (binocularly). The cue and the target could appear either binocularly or monocularly. In monocular presentation, a target and a cue could either appear in the same- or in the opposite-eye. Participants were unaware of the eye-of-origin manipulation. When participants were processing a single location using both eyes (binocular condition) we found an ~8 Hz fluctuation in target detection performance. However, a cue that was presented to the right eye generated a 4 Hz fluctuation in target detection at the same as well as the opposite eye. Together, these findings replicate previous rhythmic sampling at 8 Hz which divides to 4 Hz in competitive interaction. Moreover, it extends previous findings of this pattern to inter-ocular competition, where the competitive interaction is unaware to the observer.

140. Direct Cochlear Recordings in Humans Show a Theta Rhythmic Modulation of Auditory Nerve Activity by Selective Attention

Patrick Reisinger1,2, Quirin Gehmacher1,2, Thomas Hartmann1,2, Thomas Keintzel3, Sebastian Rösch4, Konrad Schwarz5, Nathan Weisz1,2,6

1Centre for Cognitive Neuroscience, University of Salzburg, 2Department of Psychology, University of Salzburg, 3Department of Otorhinolaryngology, Klinikum Wels-Grieskirchen GmbH, 4Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University Salzburg, 5MED-EL GmbH, 6Neuroscience Institute, Christian Doppler University Hospital, Paracelsus Medical University Salzburg

140. The architecture of the efferent auditory system enables prioritization of strongly overlapping spatiotemporal cochlear activation patterns elicited by relevant and irrelevant inputs. So far, attempts at finding such attentional modulations of cochlear activity delivered indirect insights in humans or required direct recordings in animals. The extent to which spiral ganglion cells forming the human auditory nerve are sensitive to selective attention remains largely unknown. We investigated this question by testing the effects of attending to either the auditory or visual modality in human cochlear implant (CI) users (3 female, 13 male). Auditory nerve activity was directly recorded with standard CIs during a silent (anticipatory) cue-target interval. When attending the upcoming auditory input, ongoing auditory nerve activity within the theta range (5-8 Hz) was enhanced. Crucially, using the broadband signal (4-25 Hz), a classifier was even able to decode the attended modality from single-trial data. Follow-up analysis showed that the effect was not driven by a narrow frequency in particular. Using direct cochlear recordings from deaf individuals, our findings suggest that cochlear spiral ganglion cells are sensitive to top-down attentional modulations. Given the putatively broad hair-cell degeneration of these individuals, the effects are likely mediated by alternative efferent pathways compared with previous studies using otoacoustic emissions. Successful classification of single-trial data could additionally have a significant impact on future closed-loop CI developments that incorporate real-time optimization of CI parameters based on the current mental state of the user.

141. Action planning modulates perceptual confidence

Remi Sanchez1,2,3, Dr Karen Davranche2, Dr Thibault Gajdos2, Dr Andrea Desantis1,3,4

1Département Traitement de l’Information et Systèmes, ONERA, 2Laboratoire de Psychologie Cognitive, UMR 7290, CNRS, Aix-Marseille Université, 3Institut de Neurosciences de la Timone, UMR 7289, CNRS, Aix-Marseille Université, F13005, 4Université de Paris, CNRS, Integrative Neuroscience and Cognition Center, F75006

141. Dominant models of metacognition argue that the quality of sensory information determines perceptual confidence. However, recent accounts suggest that also motor signals contribute to confidence judgments. In line with this assumption, we investigated whether facilitating or impeding the planning of an action that implements a perceptual decision, influences perceptual confidence. Participants reported the orientation of a Gabor and indicated the level of confidence on their response. A visual cue, displayed before the Gabor, induced the planning of an action that could be compatible/incompatible with the response side and/or effector subsequently used to report the Gabor. Perceptual confidence increased when participants prepared contralateral actions (irrespectively of the primed effector), while accuracy remained unchanged. Consistent with models arguing that metacognition results from the integration of information across the perception-action cycle, these findings suggest that general lateralized and not effector-specific action preparatory signals impact perceptual confidence.

142. A bias generating temporal distortions in serial perception

Franklenin Sierra1, Prof David Poeppel2,3, Dr. Alessandro Tavano1

1Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, 2Department of Psychology, New York University, 3Ernst Strüngmann Institute for Neuroscience

142. Objectives Precisely estimating event timing is essential for a range of perceptual and cognitive tasks, yet temporal distortions are ubiquitous in our daily sensory experience. One specific type of temporal distortion is the time order error (TOE), which occurs when estimating the duration of events organized in a series. Research question In two behavioral experiments, we tested whether the relative duration of two stimuli in a sequence, regardless of their predictability (fixed Standard S or ever-changing Comparison C), is a causal factor in generating distortions. Materials and methods In a two-interval forced choice (2IFC) task, participants were presented with two visual durations, Standard (120 ms) and Comparison, separated by an inter-stimulus-interval (ISI) varying between 400 and 2000 ms. We flipped the positions of S and C in two separate experiments. Accuracy was analyzed by using generalized linear mixed models (GLMMs) and Bayesian observer models to replicate behavior for both experiments. Results In alignment with previous research, an ISI longer than a second reduces TOEs, and when C is in first position TOEs increase for all ISIs. Importantly, we show that TOEs tend to emerge when the first event in a series is shorter than the second event, independently of event type (S or C). Finally, by taking in consideration all these factors we were able to simulate our results by using a Bayesian observer model. Conclusion We show that participants disproportionately expand first-position shorter events and thus, TOEs arise under sensory uncertainty because of serial perceptual encoding inefficiency. These results suggest the existence of a strong bias in perceiving ordered event durations, whose neurophysiological basis can be investigated in future research.

143. Rhythmic facilitation of visual discrimination is dependent on individuals spontaneous motor tempo

Leah Snapiri1, Ms Yael Kaplan1, Dr Nir Shalev2, Prof Ayelet N. Landau1

1The Hebrew University of Jerusalem, 2University of Oxford

143. Rhythmic structure in our daily experience originates from various sources. It is generated endogenously and observed in spontaneous fluctuations in behaviour and performance. It can also arise exogenously from everyday stimuli, such as speech, motion and music. Here we examine how individual differences in spontaneous rhythms of motion affect the tendency to use external rhythmic structure to guide perception. We first test the consistency of individual spontaneous rhythms in three motor tasks: tapping walking and bouncing. We find that individuals exhibit stable rhythmic preferences for action; namely, they spontaneously move at preferred tempi, which are consistent across time, tasks, and interactive settings. We then examine the impact of individuals spontaneous rhythms on rhythmic facilitation of perception. We utilise a visual discrimination task in which targets can appear either in-phase or out-of-phase with a preceding rhythmic stream of visual stimuli. We manipulate the tempo of the visual stream over different experimental blocks [2Hz /1.4Hz /0.7Hz]. We find that individuals discriminate better targets that apear in synchrony with the preceding stream. The magnitude of modulation increases monotonically with the stimulation tempo, with maximal benefits for the slowest tempo presented. Furthermore, the magnitude of modulation is also dependent on individuals’ spontaneous tempo. Specifically, Individuals with slower spontaneous tempi show greater rhythmic modulation compared to faster individuals. This discovery suggests that different tempi affect the cognitive system with varying levels of efficiency, and that self-generated rhythms impact our ability to utilize rhythmic structure in the environment for guiding perception and performance.

144. Joint effect of pre-stimulus alpha-band amplitude and phase on visual awareness

Enrique Stern1, María Melcón1, Lydia Arana1, Dr Claudia Poch2, Dr Pablo Campo1, Dr Almudena Capilla1

1Universidad Autónoma De Madrid, 2Universidad Nebrija

144. Whether or not we perceive a visual stimulus depends not only on the intrinsic properties of the stimulus, but also on the brain state at the time of its appearance. Previous studies have attempted to identify the neural correlates of visual awareness by studying spontaneous brain fluctuations prior to stimulus onset. Alpha-band oscillations (8-14 Hz) have been established as the most critical correlate of visual perception, although it is not yet clear whether it is the amplitude or the phase of the oscillations at the time of stimulus onset that has the greatest impact on subsequent detection. According to the pulsed inhibition theory, visual perception would depend on the interaction between both alpha-band power and phase. Thus, alpha phase would have a pulsatile influence on neural excitability levels – and therefore on performance – only when alpha amplitude is high; if alpha amplitude is low, visual perception would be favored regardless of phase. In this study, we aimed to test this hypothesis, by recording high-density electroencephalography (EEG) activity (128 channels) while participants (N = 31) performed a near-threshold target detection task. EEG data were analyzed following a data-driven approach, with no a priori assumptions about the specific frequency range or time window in which effects were expected. We first reduced the data using independent component analysis (ICA) and selected the major occipital component. We then performed a time-frequency decomposition of the signal by means of the fast Fourier transform (FFT). For each time-frequency point, trials were separated into quartile bins according to alpha power. Then, for the trials with the lowest and highest alpha power, we computed the degree of phase opposition when the stimulus was seen versus unseen. Our results show a significant effect of pre-stimulus alpha-band amplitude on stimulus detection. We also found an interaction of alpha power and phase, although this effect was not as consistent. Overall, our results support the pulsed inhibition framework and suggest that when pre-stimulus alpha power is high and excitability levels are therefore lower, the phase of alpha oscillations provides periodic windows of opportunity for perception. Funded by PGC2018-100682-B-I00 (MCIU/AEI/FEDER, UE).

145. Active learning improves memory and differentially affects neural responses

Stefanie Sturm1,2,3, Dr Jordi Costa-Faidella1,2,3,4, Dr Iria SanMiguel1,2,3,4

1Brainlab – Cognitive Science Research Group, 2Institute of Neuroscience, 3University of Barcelona, 4Fundació de Recerca Sant Joan de Déu

145. Active learning – being able to control information while learning – has been shown to enhance memory in different domains. Further, stimuli generated by oneself as opposed to an external source trigger attenuated neural responses and are remembered better (“production effect”). Studies using event-related potentials have shown that the neural attenuation of responses to self-generated visual or auditory stimuli is frequently linked to the Sense of Agency (SoA) – the subjective experience of causing our own actions and their sensory consequences. However, the coincidental presence of movement during sound processing has also been shown to attenuate neural responses, regardless of whether there was causality between action and sound, and whether the sound was intentionally generated. The current study asks whether agency over an auditory stimulus alone, controlling for the movement factor, can enhance memory formation and affect ERPs. Participants learned associations between the movements of a cursor and 8 different sounds. Critically, the cursor was controlled either by their own eye movements (active learning) or by an external agent (passive learning). During fixed time intervals, participants memorised movement-sound associations by actively exploring them or passively watching a guided exploration. Later, their memory was tested presenting movement-sound pairs that either matched or mismatched the learnt associations. Since eye movements in both conditions were equivalent, we were able to study the effect of agency while controlling for the effect of movement. We found that participants were able to learn movement-sound associations faster in the active learning condition. On a neural level, ERPs time-locked to the onset of sound stimuli showed that learning progress was linked to an attenuation of the P2 and P3 components at fronto-central sites. Active control over sound stimuli was reflected in ERPs in a large positive deflection starting around 200ms post-stimulus at parietal sites. During memory tests, the amplitude of the N1 was larger the further learning progressed, while the P2 was attenuated. Movement-sound pairs matching the learnt associations had an enhancing effect on the P3 relative to mismatching pairs. Our results show that the SoA alone, independent of movement, helps learning and memory and modulates sensory responses.

146. Rhythmic modulation of perceptual reports depends on participants’ internal state

Mr Tommaso Tosato1, Dr Gustavo Rohenkohl1,2, Prof Pascal Fries1,3

1Ernst Strüngmann Institute, 2Department of Physiology, Institute of Biosciences, University of São Paulo, 3Donders Institute for Brain, Cognition and Behaviour, Radboud University

146. Objectives. In the last decade, several studies showed rhythmic modulations of perceptual performance, in some cases tracing a direct relationship between these modulations and brain rhythms. In psychophysics, these rhythms can be investigate by probing perception at different times relative to a reset event (i.e. flash, button press, etc). Research question. Existing studies using self-paced motor actions as reset events show a substantial discrepancy with regard to the frequency, and strength of the rhythmic modulation. To resolve these discrepancies, we recorded a larger number of participants (n=50) who performed a visual detection task and applied analysis techniques which grant high sensitivity and specificity. Materials and methods. Participants detected a faint visual probe (2 dimensional Gaussian of Sigma 0.6° and 7.3° eccentricity) presented at a variable time intervals (between 100 ms and 1100 ms) after a self-paced button press. Task performance was staircased to 50% detection accuracy. We applied the Least Square Spectrum on the single trial’s response values to transform the accuracy time course to the frequency domain. We then performed a fixed-effect, and a random-effect non-parametric statistical test. Multiple comparison correction was done using a max-based approach. Results. The analysis of the aggregate data surprisingly did not show any significant rhythmic modulation of detection accuracy. However, based on previous publications, we explored the possibility that the perceptual rhythmic modulation depends on the person’s internal state. When we split participants based on their decision criterion, we found a significant rhythmic modulation with a peak at 17 Hz in the group of participants with lower criterion (i.e. more liberal). When we split trials based on the response history, or based on task epoch’s average performance, we found a significant 17 Hz rhythm in trials preceded by an “absent” response, and in trials performed during epochs of low average performance. Conclusion. Perceptual rhythms after a self-paced motor action are not always present. However, a rhythmic modulation of detection accuracy in the beta frequency range may emerge during specific internal states of the participant, such as lower arousal, lower decision criterion, or weaker priors.

147. An investigation into the necessary conditions for perceptual organisation using the SPN

Dr John Tyson-Carr1, Dr Giulia Rampone1, Dr Amie Morris1, Dr Marco Bertamini1, Dr Alexis Makin1

1University Of Liverpool

147. Objectives To determine the necessary conditions for perceptual organisation. Research Question Humans must generate coherent visual representations to guide behaviour. This often involves grouping visual elements into larger gestalts. The rules governing such perceptual organisation have been well described, and we know a lot about the spatial and temporal dynamics of perceptual organisation in the brain. The current experiments utilised the sustained posterior negativity (SPN) to investigate the necessary conditions for perceptual organization. The SPN is an ERP generated at posterior electrodes by visual regularity. Do we find an SPN in tasks where participants attend to other stimulus dimensions? Materials & Methods A total of 130 participants each completed one of five tasks. In all task’s participants viewed patterns with varying levels of regularity (0%, 20%, 40%, 60%, 80%, 100%) whilst EEG was recorded. The five tasks required participants to either discriminate regularity, colour, sound/colour congruence, direction/colour congruence or distribution of dots and make a binary decision. The tasks each had different perceptual requirements, directing attention towards various aspects of the stimuli. Results The SPN scaled with the level of regularity in all tasks. Source dipole modelling revealed that the parametric SPN was generated by bilateral sources in the extrastriate cortex. However, the SPN was selectively enhanced in the Regularity discrimination task, and an additional equivalent current dipole, located around the posterior cingulate, was evident in this task at high levels of regularity. Conclusion Results indicate a parametric response to symmetry within the extrastriate cortex, which is enhanced when attention is directed toward regularity. This may be due to employment of decision-related processes mediated by the cingulate. However, the presence of a SPN across all tasks highlights the automaticity of perceptual organisation.

150. The Role of Evidence Accumulation in Perceptual Decisions About Noiseless Stimuli

Mr Kevin Walsh1, Dr. David McGovern2, Dr. Redmond O'Connell1

1Trinity College Dublin, 2Dublin City University

150. According to sequential sampling models, perceptual decisions are the product of the integration of samples of sensory information over time until a threshold is reached. Extended evidence accumulation is an effective strategy when choices are based on physical evidence that is noisy or rapidly varying, but it is less obvious that this approach is beneficial when the evidence is noiseless and invariant. In this study, electroencephalographic (EEG) activity was measured as 12 human participants completed a two-alternative forced choice contrast discrimination task in which stimuli were presented at a fixed contrast for the duration of each decision. Brief (150ms) evidence pulses were presented at unpredictable times to perturb the decision process mid-flight. Tracing the impact of these pulses of evidence on both behaviour and electrophysiological indices of evidence accumulation (the centroparietal positivity) and motor preparation (the lateralised readiness potential) provided estimates of the longevity of sensory samples in the decision process. These estimates far outlasted the proposals of decision models that require little or no evidence integration, suggesting that participants also accumulate evidence in perceptual decisions about noiseless stimuli.

148. Perceptual extrapolation of body movements is driven by internal models of others’ body

Mr Antoine Vandenberghe1, Prof Gilles Vannuscorps1,2

1Psychological Sciences Research Institute, 2Institute of Neuroscience

148. Objectives. After a moving object has disappeared, people typically mislocate its final position to where it would have been if it had continued to move for a few milliseconds, a phenomenon known as Representational Momentum (RM). RM is reduced for body movements that would have been biomechanically difficult to continue along the same trajectory. That perception of body movements is shaped by biomechanical constraints originally thought to affect only movement execution is widely considered compelling evidence that the perception of others’ body movements is supported by motor simulation and tuned by the body abilities of the observer. An alternative, however, is that body movement perception is constrained by knowledge learned through visuo-perceptual experience and tuned to the body abilities of others. The two studies reported here aimed at discriminating these two hypotheses. Research Question. To do so, we tested whether participants perceive differently two actors with different body abilities. Materials and methods. In Experiment 1, we first used two pictures to familiarize participants with the maximal amplitude of arm movement of a “flexible” and a “rigid” actor. Then, we asked participants to watch a series of video-clips depicting the actors performing either a movement of maximal amplitude (80% of trials) or of an “intermediate” amplitude (20%), that is, a movement that would have been easy to continue for the “flexible” actor, but impossible for the “rigid” actor. After each video, participants had to decide whether the position of the actors’ arm at the end of the video corresponded to that depicted on a probe picture, on which the arm was slightly moved forward or backward. We measured the size of participants’ RM for the intermediate movements (% of errors for forward minus backward probes). At the beginning of the experiment, participants were told to pay attention to the identity of the actor, which could help them solve the task. In Experiment 2, there was no such instruction and no familiarization phase. Results. In both experiments, RM was significantly larger for the flexible than for the rigid actor. Conclusion. Findings indicate that visual experience modulates the perception of others’ body movements.

149. Perception of body movements and postures is shaped by models of others’ body

Gilles Vannuscorps1

1UCLouvain

149. Objectives. Findings from the Hand Laterality Judgment (HLJ), Apparent Motion (AM) and Representational Momentum (RM) paradigms indicate that our visual system refers to an internal model of the human body biomechanics to constrain body movement perception, fill-in missing information, and predict the future location of moving body parts: (1) it is quicker to identify the laterality of a hand depicted in a comfortable than in an awkward posture and orientation; (2) when the shortest path of motion between two rapidly alternating pictures of body postures is not biologically plausible, we typically perceive a longer but biologically plausible path of apparent motion; and (3) although we typically perceive the location of a moving body part slightly shifted forward along its trajectory, this is not (or less) the case if the movement would have been biologically hard to continue along the same trajectory. An outstanding issue concerns the nature of that internal model. According to a popular view, the perception of others’ body movements and postures is supported by the same internal model that underlies the planning and control of our own movements, acquired through motor experience and proprioceptive feedback. Alternatively, perception is entirely supported by models tuned to the body abilities of others, learned through visuo-perceptual experience. My aim was to discriminate these two possibilities. Research question. I tested whether two individuals born completely without upper and lower limbs (IDs), and who therefore may only have acquired knowledge of the body biomechanics through visual experience, would show the typical biomechanical bias on perception. Materials and methods. The IDs and control participants performed traditional versions of the HLJ, AM and RM tasks. Results. In the three task, the performance of both the controls and the two IDs was significantly influenced by implicit knowledge of the body biomechanics. Conclusion. Perception of body movements and postures is shaped by internal models of others’ body. This also implies that the presence or absence of biomechanical biases in perceptual tasks should not be used anymore to probe the integrity of the covert stages of action production in patients with motor execution disabilities.

208. Competing cognitive pressures on human exploration in the absence of trade-off with exploitation

Ms Clemence Almeras1, Dr. Valérian Chambon, Dr Valentin Wyart 1Laboratoire De Neurosciences Cognitives et Computationnelles, Département D'Etudes Cognitives, ENS-PSL-INSERM u960

208. Exploring novel environments through sequential sampling is essential for efficient decision-making under uncertainty. In the laboratory, human exploration has been studied in situations where exploration is traded against reward maximisation. By design, these ‘explore-exploit’ dilemmas confound the behavioural characteristics of exploration with those of the trade-off itself. Moreover, outside the laboratory, most choices do not yield immediate rewards. Aims: Here we wanted to document the novel patterns of human exploration arising when exploration is released from its trade-off with reward maximisation. Methods: We designed a novel sequential sampling task where exploration can be studied and compared in the presence and absence of a trade-off. Detailed model-based analyses of choice behaviour reveal specific patterns arising only in situations where information seeking is not weighed against reward seeking. Results: As expected, human choices are directed toward the most uncertain option available, but only after an initial sampling phase consisting of choice streaks from each novel option. These findings outline competing cognitive pressures on information seeking: the repeated sampling of the current option (for hypothesis testing), and the directed sampling of the most uncertain option available (for structure mapping). Interestingly, these two forms of information seeking are co-expressed in the same participants. Conclusions: This task overcomes the long-standing confound between the behavioural signatures of exploration and those of explore-exploit dilemmas. In addition, our findings provide compelling insights into an undocumented competition between local and global forms of information seeking, that is only expressed when exploration is not traded-off against reward maximisation.

210. Discovering basic cognitive stages in a visual discrimination task with HsMM-MVPA analysis

Hermine Berberyan1, Hedderik van Rijn2, Jelmer Pieter Borst1

1Bernoulli Institute, University of Groningen, 2Department of Experimental Psychology, University of Groningen

210. Introduction: Dating back to the 19th century, the discovery of cognitive processing stages has been of great interest to researchers in cognitive science. As RT-based methods (Donders, 1868; Sternberg, 1969) did not provide direct measures of the ongoing process, we turned to neural data. To detect cognitive processing stages in EEG data, a combination of hidden semi-Markov model analysis (HSMM) and multivariate pattern analysis (MVPA) was developed (Anderson, Zhang, Borst, & Walsh, 2016). Although several studies have used this method to discover stages in different tasks, a functional interpretation of the observed stages in more complex tasks remained a challenge. Objectives: The goal of the current project was to validate HsMM analysis as a method for discovering and interpreting stages in cognitive tasks. Materials and methods: To that end, two experiments were designed where participants had to perform simple visual discrimination tasks while their EEG was recorded. While keeping the set of stimuli the same in both experiments, we varied the decision complexity to observe the resulting changes in decision-making stages in HsMM-MVPA models. Additionally, drift-diffusion model were fitted to the data (Ratcliff, 1978), to complement and evaluate the results of the HsMM-MVPA analysis. Results: The HsMM-MVPA analysis showed that the duration of the fourth stage signifying the decision was clearly longer in Experiment 2 than in Experiment 1. This was confirmed by the results of the diffusion models – the differences between two experiments were observed in the parameters that contribute to decision making (mean drift rate and threshold). Conclusion: We have shown that processing stages can be reliably detected with HsMM-MVPA analysis. With the help of experimental manipulations and additional mathematical modeling, cognitive processes can be attributed to the stages.

211. Examining the shift between internal and external cognition; a behavioural study.

Miss Sara Calzolari1,2, Dr Andrew Bagshaw1,2, Dr Davinia Fernández-Espejo1,2

1Centre for Human Brain Health, University of Birmingham, 2School of Psychology, University of Birmingham

211. Objectives Despite the brain’s constant need to flexibly balance internal and external information, research on cognitive flexibility has focused solely on shifts between externally oriented tasks. These studies found slower response times (RT) when participants switched task compared to task repetitions. However, the costs of switching across internally oriented processes (and specifically self-referential cognition) or between internal and external domains have never been investigated. Here, we used a novel cued task-switching paradigm to induce shifts between external and internal monitoring, with the aim of exploring the behavioural signatures of cognitive flexibility for self-related processes and when comparing within-domain and between-domain shifting. Research questions Do self-referential tasks display switch costs, similarly to externally oriented tasks? Is there an additional cost to switching between internal and external domains? Materials and methods We tested (online) 200 healthy volunteers and measured RT and accuracy. Stimuli were written trait and bodily adjectives. In each trial, we instructed participants via cue presentation to perform one out of four possible tasks: assessing if the third letter was a consonant, if the penultimate letter was a vowel (both externally oriented), if the adjective applied to their personality, or if it described a bodily sensation they were currently experiencing (both internally oriented). 40% of trials were switches to another task (1/4 within-internal, 1/4 within-internal, 1/4 internal to external, 1/4 external to internal). Results We found evidence of switch costs (faster RT for task repetitions than switches) both in the internal and external domains (main effect of switching: p<.001; post-hoc internal and external domain: p<.001). Moreover, within-domain switches were faster than between-domain switches (p<.001). Conclusion We demonstrated the presence of switch costs in self-referential tasks for the first time and observed increased effort in shifting across domains compared to staying within domain, possibly suggesting competition between different underlying networks. We introduce a new method to explore the interplay of these ubiquitous processes.

212. A complex pattern of neural effort during fluid reasoning

Dr. Adam Chuderski1, Ms. Patrycja Kałamała1, Mr. Bartłomiej Kroczek1, Mr. Michał Ociepka1, Ms. Hanna Kucwaj1, Dr. Emiliano Santarnecchi2, Dr. Adam Gagol1

1Jagiellonian University, 2Harvard Medical School

212. Objectives. Discrepant findings suggest that high intelligence (Gf) – the individual ability to solve novel problems with abstract reasoning – is related with either larger neural efficiency (decreased brain activity) or larger effort (increased activity), as compared to low Gf. EEG data were collected during two Gf tests, in order to disentangle the relationship between Gf and neural effort. Research question. An interaction between the individual fluid intelligence level, the difficulty of intelligence test items, and the time course of a trial was searched for. Materials and methods. A total of 164 young healthy adults solved two popular reasoning tests while their EEG signal was recorded. Raven Advanced Progressive Matrices (RAPM) consists of a 3 by 3 matrix figure with the lower right-hand entry missing and to be completed with one out of eight alternatives. In A:B::C:D Analogies, a simple pattern of shapes B is generated from A using several geometric transformations, and D that matches the same transformations must be selected out of four alternatives. Each test’s 36 items vary in difficulty from easily solved to virtually unsolvable. Response alternatives were hidden for the first 30 seconds of each trial, and only this signal was analyzed. Brain activity was indexed by event related desynchronization (ERD) – the amount of drop in alpha power due to cognitive effort, with the resting state session serving as the baseline. Another four reasoning tests measured individual Gf. Results. In each test, pronounced ERD lasted until the middle of easy trials, while it lasted until the very end of difficult trials. In easy trials, ERD correlated negatively with Gf, while in difficult trials this correlation was positive. The correlations were stronger in late parts of trials. Overall, the ERD pattern explained 18.9% variance in Gf in RAPM, and 4.6% variance in Analogies (cross-validated). Conclusion. The interaction between Gf and neural effort is complex. People high on intelligence engage less cognitive resources (are more efficient) only when the task does not draw on their total capacity, but engage more resources than people low in intelligence when the task demands require full investment of available ability.

213. Intrinsic decision biases are under cognitive control

Clémence Compain1,2,3, Prof Anil K. Seth1,2, Dr Maxine Sherman1,2

1SACKLER CENTRE FOR CONSCIOUSNESS SCIENCE, UNIVERSITY OF SUSSEX, 2SCHOOL OF INFORMATICS AND ENGINEERING, UNIVERSITY OF SUSSEX, 3LEVERHULME DOCTORAL SCHOLARSHIP PROGRAMME, FROM SENSATION AND PERCEPTION TO AWARENESS, LEVERHULME TRUST

213. Objectives and research question: People generally exhibit intrinsic decisions biases when they are asked to make a forced choice. We investigated whether these biases can be reduced on instruction, and whether such a reduction improves metacognitive efficiency. Materials and Methods: 69 participants performed a numerosity discrimination task online. The stimulus was 120 vertically or horizontally oriented lines distributed on an imaginary grid. Participants had to report whether there were more horizontal or vertical lines and their confidence in that report. Baseline measures of decision bias were calculated after the first block. We then informed participants of their bias and asked them to reduce it in block 2 (experimental group). Data from an active control group (feedback about error rate) and a baseline group (no feedback) were also collected. Results: Participants instructed to reduce their bias did so successfully without changing their task performance. Participants instructed to reduce their error rate both improved and exhibited reduced bias, suggesting effort/concentration increased. Participants who did not receive any feedback did not improve and their bias did not change, suggesting that the results observed for the experimental and control groups are accountable to the instructions they received. We did not find an influence of bias on metacognition, nor did participants’ metacognition change after feedback. Conclusion: Altogether these results suggest that participants are able to control their intrinsic decision biases once they are informed of them, regardless of how well they can infer their decision accuracy.

214. EEG correlates of feedback processing during reinforcement learning do not necessarily distinguish between action-contingent versus random outcomes

Gabor Csifcsak1, Dr. Hema Nawani1, Dr. Matthias Mittner1

1Uit The Arctic University Of Norway

214. A key assumption of reinforcement learning (RL) theory is that instrumental choices are informed by prediction error signals (PEs) that code the mismatch between expected and observed action outcomes. The feedback-related negativity/reward positivity (FRN/RewP) event-related potential is a prominent candidate for the neural manifestation of PEs, and has been associated with subsequent behavioral adjustments that optimize task performance. In this work, we present novel data from our previously published study (Csifcsak, Melsæter, Mittner, 2020), in which we investigated behavioral and EEG correlates of intermittent absence of outcome controllability (“yoking”) during RL in healthy adults. While our previous publication focused on EEG signals during decision-making, here we analyzed whether neural activity during feedback processing is influenced by the absence of contingency between action choices and outcomes in a computer-based card game (orthogonalized Go/NoGo task). Forty-six participants were randomized to “control” and “yoked” groups, forming control-yoked pairs. In 6 blocks of the task, all participants received action-contingent outcomes (70/30% probability), whereby in 3 “induction” blocks, yoked participants were presented with random outcomes matched to their control pair. Despite this manipulation, the yoked group reported similar levels of perceived outcome controllability as controls, indicating that they might have developed “illusion of control”. Feedback-locked EEG was analyzed in various ways to test if it was influenced by the absence of outcome controllability (yoking). Neither the sensitivity of the FRN/RewP to favorable vs. unfavorable outcomes, nor event-related potentials outside the FRN/RewP time window or outside the frontocentral scalp region distinguished between the two groups. Moreover, using hierarchical linear modeling (LIMO EEG), we found that tracking of signed and unsigned PEs by the EEG was not sensitive to yoking. Finally, various measures representing dynamics of EEG microstates were comparable across the two groups. We conclude that under conditions resembling illusion of control, the EEG signal during outcome evaluation reflects aspects of the feedback stimulus (i.e., valence, expectancy) that are not contingent on preceding actions, and therefore, cannot drive instrumental learning. These results have implications for interpreting the feedback-locked EEG signal during RL, and the FRN/RewP in particular.

215. Direct brain recordings reveal continuous encoding of structure in random stimuli

Julian Fuhrer1

1University Of Oslo

215. How does the brain process randomness? Mounting evidence suggests it tries to make sense of any given sequence, generating sophisticated internal models that continuously draw on statistical structures in the unfolding sensory input to maintain a detailed representation of its environment. However, it is unknown how specifically this modelling applies to random sensory signals. Here, we investigate conditional statistics, through transitional probabilities, as an implicit structure encoding a random auditory stream. We evaluate this through a trial-by-trial analysis by applying information-theoretical principles to intracranial electroencephalography recordings. Based on high-frequency activity (75–145 Hz), we demonstrate how the brain continuously encodes conditional relations between random stimuli in a network outside of the auditory system following a hierarchical organization including temporal, frontal, and hippocampal regions. We further hypothesize that in lower frequency bands (alpha/beta), there might be a hierarchically inverse cascade of involved regions which originates in higher cortical areas and possibly encodes an event already prior to its onset. Linking the frameworks of statistical learning and predictive coding, our results illuminate an implicit process that might be crucial for the swift detection of patterns and unexpected events in the environment.

216. The association of self-reported intake of fat and sugar with peripheral expression of dopaminergic genes

Franziska Rausch2,3,4, Hendrik Hartmann1,2,3, PhD Lieneke K Janssen3, Dorit Schleinitz4, Prof Dr Peter Kovacs2,4, Prof Dr Annette Horstmann1,2,3,4

1Department Of Psychology And Logopedics, Medical Faculty, University Of Helsinki, 2Collaborative Research Centre 1052, University of Leipzig, 3Department of Neurology, Max Planck Institute for Human Cognitive & Brain Sciences, 4IFB AdiposityDiseases, University of Leipzig

216. Objectives: The western food environment is dominated by foods high in saturated fat and added sugar. Animal studies provide evidence that diets high in fat and sugar (HFS) change dopamine signal transmission by up- or down-regulation of dopaminergic genes. These modifications of dopamine signaling can influence choice behavior and cognition. Research Question: The possible impact of HFS on the dopaminergic system has not been studied in humans. We aimed to find first evidence that increased self-reported intake of HFS is associated with peripheral expression of dopaminergic genes and furthermore linked expression to behavioral phenotypes. Material and methods: We grouped 75 healthy male participants according to their self-reported HFS intake into low- (LFS) and high-consumers (HFS). In an exploratory design, we used expression of peripheral dopaminergic genes as surrogate for central gene expression. Using qPCR, we quantified mRNA expression levels of genes that are directly part of the dopaminergic system or have been suggested to impact dopamine signal transmission. Additionally, participants performed experimental tasks of dopamine-related cognitive processes and completed questionnaires assessing impulsivity, motivation, and personality. Results: Expression levels of dopamine receptor D3 and uncoupling protein 3 were higher in the HFS compared to the LFS group, p = .013 and p = .009 respectively; expression levels of uncoupling protein 2 were significantly lower in the HFS group, p < 0.001. Cognitive performance did neither differ between diet groups nor correlate with expression of dopaminergic genes. Furthermore, the two diet groups did not differ in measures of impulsivity, motivation, or personality. Conclusion: The evidence for an association of HFS intake with central expression of dopaminergic genes provided by this study is sparse and effects on behavioral phenotypes can not be seen. This study was one of the first investigating the possible association of HFS with central dopamine and explorative in nature. Based on our findings and the vast body of animal literature, we propose using short-term dietary interventions in combination with dopamine imaging and pharmacological challenges to further investigate this possible link.

217. Influence of linguistic labels on concept formation and perception in a deep unsupervised neural network model

Malte R Henningsen-Schomers1,5, Max Garagnani2,1, Friedemann Pulvermüller1,3,4,5

1Brain Language Laboratory, Freie Universität Berlin, 2Dept. of Computing, Goldsmiths, University of London, 3Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, 4Einstein Center for Neurosciences, 5Cluster of Excellence ‘Matters of Activity. Image Space Material’, Humboldt-Universität zu Berlin

217. OBJECTIVES/RESEARCH QUESTION Whether language influences perception and thought remains a subject of intense debate. We address this question in a brain-constrained neurocomputational model of fronto-occipital (extrasylvian) and fronto-temporal (perisylvian) cortex including spiking neurons. The unsupervised neural network was simultaneously presented with word forms (phonological patterns, “labels”) in perisylvian areas and semantic grounding information (sensory-motor patterns, “percepts”) in extrasylvian areas representing either concrete or abstract concepts. Following the approach used in a previous simulation, each to-be-learned concept was modeled as a triplet of partly overlapping percepts; the models were trained under two conditions: each instance of a perceptual triplet (patterns in extrasylvian areas) was repeatedly paired with patterns in perisylvian areas consisting of either (a) a corresponding word form (label condition), or (b) noise (no-label condition). We quantified the emergence of neuronal representations for the conceptually-related percepts using dissimilarity (Euclidean distance) of neuronal activation vectors during perceptual stimulation. Category learning was measured as the difference between within- and between-concept dissimilarity values (DissimDiff) of perceptual activation patterns. RESULTS A repeated-measures ANOVA with factors SemanticType (concrete/abstract) and Labelling showed main effects of both SemanticType and Labelling, and a significant interaction. We also quantified the “label effect” in percentage change from NoLabel to Label conditions, separately for between- and within-category dissimilarities. This showed that the label effect was mainly driven by changes in between-category dissimilarity, was significantly larger for abstract than concrete concepts, and became even larger in the “deeper” layers of the model. CONCLUSION A brain-constrained neurocomputational simulation was performed to explore putative brain mechanisms of associating conceptual categories with linguistic labels. We found a clear Whorfian effect of category labels on the processing of conceptual instances: the model’s activity in response to perceptuo-motor grounding patterns was modulated depending on whether or not labels had been provided during the training phase. Labels were highly beneficial for semantic category learning performance, and this benefit was more strongly pronounced for abstract compared to concrete concepts and even more so in the deeper-lying semantic ‘hub’ areas of the model than in the primary areas, where stimulation was given.

218. Reliability of visual and auditory MMN

Kairi Kreegipuu1, Nele Põldver, Maria Krajuškina, Jüri Allik 1University of Tartu

218. Mismatch negativity (MMN, Näätänen et al., 1978) is a window to the pre-attentive information processing in the brain. MMN refers to charactersitic processing of a rare deviant stimulus relative to frequent and predictable standard stimulus. It has been shown that MMN and its visual counterpart (vMMN) typically decrease related to the decline in cognitive and health status of people (e.g., see Kremláček et al., 2016, Näätänen et al., 2012). The main research question of the study is whether (v)MMN has an acceptable reliability. Two types of reliability of biomarkers have recently been analyzed (Hedge et al., 2018): one indicated by low standard error of measurement and the other by high test-retest reliability. For MMN, a reasonably high test-retest reliability has been shown [e.g., Frodl-Bauch et al., 1997; Tervaniemi et al.,1999] but almost nothing is known about vMMN (a recent exception comes from our laboratory, Kask et al., 2021), or the comparison of MMN and vMMN. We will test on the same sample of 60 participants both MMNs (auditory and visual) and their both reliabilities here. We expect that (1) MMN and vMMN correlate positively, and (2) vMMN test-retest and between-participants reliability is at least moderate (.5<). We asked participants to run (v)MMN experiments twice (with at least a week between the sessions). The (v)MMN stimuli were tones with differences in frequencies (1000 Hz and 1200 Hz), or letters (either “B” and “T”). The role of stimuli (either standard or deviant) was switched in the middle of the experiment, and the proportion of deviants was 20 percent. Our data show the existence of much stronger auditory MMN than vMMN for selected stiimuli in the same sample. The role of stimuli has also a significant effect on (v)MMN, (i.e., there is asymmetry in the deviance detection process in the brain). The test-retest reliability was moderate for MMN and weak, but significant for vMMN. Auditory MMN and vMMN were positively correlated but the effect was weak and only seldom statistically significant. Our research is the first relatively big sample reliability study for the auditory and visual MMN.

219. The minimal exposure duration required for neural processing of faces and emotional expressions

Dr Renzo Lanfranco1, Dr Andrés Canales-Johnson2, Professor Axel Cleeremans3, Dr Hugh Rabagliati1, Dr David Carmel4

1Department of Psychology, University of Edinburgh, 2Department of Psychology, University of Cambridge, 3Center for Research in Cognition & Neurosciences, Université Libre de Bruxelles, 4School of Psychology, Victoria University

219. Faces and their emotional expressions are widely believed to be processed quickly, efficiently, and perhaps even unconsciously. What is the minimal exposure duration required for a face image to be visually discriminated? Is there a processing advantage for upright over inverted faces and for emotional over non-emotional faces? Due to hardware limitations, studies examining fast visual processing typically present stimuli for suprathreshold durations and disrupt processing with a mask. Here we report four experiments using a newly developed LCD tachistoscope that enables sub-millisecond presentations. In two experiments, participants had to discriminate the location and the presentation order of a face from that of a scrambled face, in extremely brief presentations (without a mask) ranging in duration from 600 to 6,200 microseconds (µs). We found that above-chance face discrimination requires about 2,500µs of stimulation, with an advantage for upright over inverted faces seen for durations greater than 3,500µs. Both perceptual discrimination and metacognitive sensitivity increased with exposure duration, with higher scores for upright faces on both measures. We found no evidence of differential discrimination of emotional faces. In another set of two experiments, we measured EEG event-related potentials to search for neural evidence of differential unconscious processing of faces and emotional expressions. Whilst we found evidence of face processing at 4,288µs of exposure, we only found evidence for differential processing of emotional versus neutral faces at longest exposure duration (6,200µs), once participants could reliably report perceiving the stimuli. Additionally, we found neural evidence of conscious access of faces at 4,288µs of exposure. Finally, large-scale information integration significantly increased with this brief range of exposure durations. These findings clarify the minimal exposure duration required for face perception, emotion processing, and conscious access and suggest that while holistic processing (i.e. of upright vs inverted faces) provides an advantage in perception and awareness, emotional expressions would not enjoy an advantage reaching perceptual awareness.

220. Hypnotic visual hallucination induces greater lateralised top-down modulation over brain activity than visual mental imagery

Dr Renzo Lanfranco1, Mr Alvaro Rivera-Rei2, Prof David Huepe2, Prof Agustin Ibanez2, Dr Andres Canales-Johnson3

1Karolinska Institutet, 2Universidad Adolfo Ibanez, 3University of Cambridge

220. Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. We have used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.

221. The microstructural and connectomic fingerprints of cardiac interoception

Dr Nicolas Legrand1, Dr Niia Nikolova1, Dr Leah Banellis1, Dr Micah Allen1

1Aarhus University

221. Objectives Physiological signal dynamics such as cardiac activity can bias perception and metacognition. A dysfunctional adaptation to this influence could be associated with the development and precipitation of psychiatric disorders. However, the neural fingerprinting of cardiac interoception, and its relation with psychometrics outcome is still poorly understood. Here, we used a novel psychophysics approach to quantifying individual profiles in cardioceptive perceptual and metacognitive sensitivity. We then applied dimensionality reduction techniques to derive multimodal cortical fingerprints from resing-state functional connectivity and brain microstructure. Research questions Can we use the neural fingerprints of cardiac interoception to predict individual differences over psychiatric variables? Materials and methods Using a novel psychophysical Bayesian approach to quantifying cardiac interoceptive sensitivity and metacognition (the heart rate discrimination task), we use cortical microstructure and whole-brain connectivity profiles to predict participants' performances in type-1 and type-2 decisions levels. We analysed 12 minutes of multi-band resting-state fMRI and quantitative maps indexing cortical myelination and iron concentration from a multi-parameter mapping technique in 545 healthy human participants. We then applied canonical correlation analysis (CCA) to extract the maximally correlated latent dimension of cardioception sensitivity and metacognition on the one side, together with functional connectivity and brain microstructure on the other side. Results We report the functional and microstructural correlates of cardiac interoception. We show that myelination and iron concentration, as well as seed-based insular functional connectivity in the anterior, middle, and posterior insula, differently relate to the psychometric threshold, slope and metacognitive indexes of the heart rate discrimination task. Finally, we explored whether such individual fingerprints could predict psychiatric variables at the individual level. Conclusion Cardiac interoceptive abilities are underpinned by distinct patterns of functional connectomes and brain microstructure. We derive different profiles using microstructural and connectomic profiles and compare their predictive power both in terms of their relationship to interoceptive abilities and self-reported psychiatric symptoms. In particular, we explore the divergent mappings between these variables found in the anteroposterior gradient of the insula.

222. Cardiac and respiratory phase selectively affect early visual potentials at the sensory threshold

Viviana Leupin1, Dr Juliane Britz1

1University Of Fribourg

222. We can investigate neural correlates of consciousness by experimentally dissociating sensation and perception (e.g., sensory threshold stimuli are consciously perceived in 50% of trials) and by measuring the response of the brain to different perceptual outcomes of such a stimulus: when it is consciously perceived, both early sensory (P1), later perceptual event-related potentials (ERPs) (VAN), and post-perceptual (LP) components are stronger than when it is not perceived. The brain is inextricably connected with the body, and cyclic variations of bodily signals, i.e. the cardiac and respiratory phase can likewise influence perceptual awareness: baroreceptor activity during the systolic phase interferes with sensory stimulus processing. Moreover, breathing modulates baroreceptor activation through cardiorespiratory coupling and likewise affects the detection of simple stimuli. To determine the relative influence of brain activity and the cardiac and respiratory phase on conscious awareness, we presented subjects with stimuli (Gabors overlaid with random-dot-noise) at the sensory threshold and compared the ERPs for the same stimulus when consciously perceived and not as a function of the cardiac and respiratory phase. During the systolic phase, we found a positive shift in the posterior electrodes from -100 to 200 ms after stimulus onset. The P1 was modulated as a function of awareness in the sense that it is larger in the aware than the unaware condition in the diastolic but not the systolic phase. Also, the respiratory phase affects the same component in similar ways: it is modulated as a function of awareness during inhalation but not during exhalation. However, neither cardiac nor respiratory phases significantly affected the later perceptual (VAN) and post-perceptual components (LP). While the absence of the P1 modulation as a function of awareness in the systolic phase can be explained by concurrent baroreceptor activation, the mechanisms underlying the modulation occurring during inhalation requires further investigation.

223. Neural Mechanisms of Reward Processing During Online Vickrey Auctions: An Event-Related Potential Study

Alice Newton-Fenner1,2, John Tyson-Carr1, Hannah Roberts1, Katerina Kokmotou1,2,3, Jess Henderson1, Adam Bryne1,2, Danielle Hewitt1, Nick Fallon1, Olga Gorelkina4, Vicente Soto1,5, Yiquan Gu4, Timo Giesbrecht3, Andrej Stancak1,2

1Department of Psychological Sciences, University Of Liverpool, 2Institute for Risk and Uncertainty, University of Liverpool, 3Unilever Research and Development, 4Management School, University of Liverpool, 5Centre for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibáñez

223. Objectives Online retailers often sell products using a socially competitive second-price sealed-bid auction known as a Vickrey auction (VA), an incentivised demand-revealing mechanism used to elicit players’ subjective values. The VA presents a situation of risky decision making, which typically implements value processing and loss aversion mechanisms. Neural outcome processing of VA bids are unknown; this study explores this for the first time using EEG. Research question The aim of this study was to investigate the electrophysiological processes related to absolute and relative wins and losses during a novel competitive Vickrey auction task. Materials and methods Twenty-eight healthy participants bid on household items against an anonymous, computerised opponent. Bid outcome event-related potentials (ERPs) were predicted to differentiate between three conditions: outbid (no-win), large margin win (bargain) and small margin win (snatch). Individual loss aversion values were evaluated in a separate behavioural experiment offering gains or losses of variable amounts but equal chances against an assured gain. Results Processing outcomes of VA bids were associated with a feedback-related negativity (FRN) potential with a spatial maximum at the vertex (251–271 ms), where bargain win trials resulted in a greater FRN amplitude than snatch win trials. Additionally, a P300 potential was sensitive to win vs no-win outcomes and to retail price. Individual loss aversion level did not correlate with the strength of FRN or P300. Conclusion These results show for the first time that outcome processing in a VA is associated with FRN that differentiates between relatively advantageous and less advantageous gains, and a P300 that distinguishes between the more and less expensive auction items. Our findings pave way to an objective exploration of economic decision making and purchasing behaviour involving a widely popular auction.

224. Event-related potentials and functional brain networks in segregating two speech streams with different time-scales of predictability

Orsolya Szalárdy1,2, Brigitta Tóth1, Dávid Farkas3, Gábor Orosz4, Ferenc Honbolygó5,6, István Winkler1

1Institute of Cognitive Neuroscience and Psychology, RCNS, 2Institute of Behavioural Sciences, Faculty of Medicine, Semmelweis University, 3Analytics Development, Performance Management and Analytics, Business Development, Integrated Supply Chain Management, Nokia Business Services, Nokia Operations, Nokia, 4Department of Psychology, Stanford University, 5Brain Imaging Centre, RCNS, 6Institute of Psychology, ELTE Eötvös Loránd University

224. Objectives Whiles acoustic predictability has been shown to affect auditory stream segregation and attentional selection, the effects of linguistic predictability on these processes is yet to be clarified. Our goal was to identify functional brain networks (FC) and event related potentials (ERP) activated while selectively attending to one speech stream in a multi-talker situation by varying the lexically/semantically valid speech units in the target and the parallel stream. Research question We investigated how the brain utilizes predictive cues in speech. Specifically, we tested the effects of the time-scale of linguistic predictability on stream segregation and target-selection/distractor-inhibition. Materials and methods Two speech streams were presented concurrently while the linguistic cues of predictability were varied over four levels. Three conditions delivered natural speech with intact phonotactics and sentence prosody: 1) normal speech, 2) word-salad (randomized word order within each sentence), and 3) pseudo-words (randomized syllable order within each sentence), whereas the fourth condition were spectrally rotated speech. Participants were instructed to attend one stream and respond to the embedded natural cough sounds, which served as targets in the attended and as distractors in the unattended stream. ERPs and FCs were extracted from continuous EEG records and compared across the conditions. Results The target-identification related N2 component’s amplitude significantly increased from the pseudo-word to the word-salad and normal speech conditions. In contrast, no effect of the conditions was observed for the P3 amplitude or for the parameters of behavioral responses. Fronto-parietal functional brain networks were associated with the suppression of the distractor stream. Their oscillation frequencies reflected the duration of the meaningful speech units. Conclusion These results suggest that target identification is affected by linguistic predictability, and the functional brain networks involved in stream segregation/selection reflect the time-scale of the meaningful speech units of the distractor stream. The results are interpreted within the framework of auditory stream segregation and selective attention.

225. Neural mechanisms of contingency leaning: the role of contingency awareness and cognitive control.

Dorota Sznabel1,2, Dr Rüdiger Land1, Prof. Bruno Kopp3, Prof. Andrej Kral1,2

1Department of Experimental Otology, Hannover Medical School, 2Cluster of Excellence 'Hearing4all', 3Department of Neurology, Hannover Medical School

225. According to associative theories, learning proceeds via a gradual process of forming associations between co-occurring stimuli. This process is often considered implicit (i.e. not requiring explicit knowledge about the associations) and automatic (in the sense that conditioned behavior does not engage cognitive control). Here we tested whether contingency learning (CL) in a probabilistic cue-target paradigm is implicit and automatic, and investigated the underlying neural mechanisms. Reaction times (RT) and electroencephalographic measures were recorded from 48 subjects who were asked to respond to target stimuli occurring within sequences of non-targets. Within one visual sequence, targets were predictable due to embedded cue-target contingencies. Another sequence did not include contingencies, rendering targets unpredictable. We examined single-trial relations between behavioral and event-related potential (ERP) measures of CL: the P300 and the contingent negative variation (CNV). We also estimated neural sources of these ERPs. Questionnaire-based post-task verbal reports distinguished 22 “explicit” from 26 “non-explicit” subjects (i.e. aware/unaware of contingencies). The distinction between “explicit” and “non-explicit” subjects was reflected in all measures of CL. Specifically only the explicit group demonstrated shortened RTs to predictable targets (i.e. the behavioral manifestation of CL), an increase in cue-locked P300 amplitudes, and the presence of CNV. Both ERP effects were tightly linked to behavior on a single-trial level, i.e. they occurred exclusively on trials followed by fast-responses. Neural activity within precuneus and mid-cingulate cortex (MCC) contributed to the modulation of cue-locked P300 and CNV, respectively. Precuneus activity contributed also to target-related P300, irrespectively of target predictability or contingency awareness. However, the P300 in response to predictable targets showed strong activation within MCC in explicit subjects – a region implicated in cognitive control. The behavioral data reveal that human CL requires contingency awareness. The ERP results from explicit subjects reveal some of the neural correlates of CL, which rest on collaborative functioning of precuneus and MCC. In conclusion, precuneal-cingular interaction seem to support proactive cognitive control – an essential constituent of CL. Human CL is neither implicit nor automatic, and its neural correlates comprise a fronto-parietal control network.

226. Regulating the accrual of visual information to awareness with alpha entrainment

Mireia Torralba Cuello1, Alice Albertini Drew1, Alba Sabaté San José3, Luis Morís Fernández1, Salvador Soto Faraco1,3

1Multisensory Research Group, Universitat Pompeu Fabra, 2Catalan Institution for Research and Advanced Studies (ICREA), 3Universitat de Barcelona

226. Objectives Endogenous brain processes play a paramount role in shaping perceptual experience, as illustrated by the alternations experienced when watching ambiguous images. In Binocular Rivalry (BR), a phenomenon that arises when two dissimilar images are presented to each of the eyes, perceptual experience consists on a stochastic alternation between each of the images or a patchy combination of both. This process is the result of a competitive process between neural populations and, recently, it was shown that the characteristic duration of individual stable percepts correlated with endogenous activity in the alpha (8-14 Hz) range. In the present study, we aim at establishing a causal link between alpha oscillatory brain activity and perceptual fluctuations in BR dynamics. Research question We propose that alpha rhythmic fluctuations in visual cortex excitability pace the accumulation of sensory information leading to perceptual alternations. In order to establish a causal link, entrained entrain endogenous activity during a BR task with the aim of modulating the typical duration of perceptual alternations. Materials and methods We used BR combined with visual entrainment and electroencephalography in a series of four experiments in humans. The inverse of individual median percept duration was used to evaluate the rate of accrual visual information, endogenous activity was characterized by the dominant frequency in occipital activity during task, and cross-coherence between endogenous activity and visual stimulation was used to assess entrainment at group level. Results Individual alpha frequency and natural alternation rate were correlated, as expected by hypothesis. Furthermore, regulating endogenous brain activity via entrainment produced corresponding behavioural changes in perceptual alternations, specific to the alpha range. Overall, alpha rhythmic stimulation resulted in faster perceptual alternation dynamics, compared to arrhythmic or no stimulation. Conclusion These results may offer a mechanistic account of how visual information is accumulated, via alpha cycles, to promote the emergence of conscious perceptual representations and suggest that models of binocular rivalry incorporating alpha as a pacemaker can provide an important advance in the comprehension of the dynamics of visual awareness.

228. Time-varying functional whole-brain connectivity synchronizes between individuals during movie watching

Başak Türker1, Lorina Naci2, Adrian Owen3, Jacobo Sitt1

1Paris Brain Institute, 2Trinity College Institute of Neuroscience, 3Western University

228. Our interactions with the environment are determined by an interplay between the ongoing neural activity and the neural responses to external stimuli. Indeed, the brain continually processes incoming information, attempting to make sense of it and to produce an appropriate response. In our study, we investigated how sensory information processing influences ongoing brain activity. 15 participants underwent fMRI recordings during movie watching and rest. A second group of 12 participants watched the same movie but in a scrambled order, preventing them from understanding the plot while still viewing every scene. Phase synchronies between 42 brain regions were computed for each fMRI volume during all three conditions, resulting in a 42 by 42 phase-coherence matrix for each volume. Then, these matrices were classified into 4 prototypical ‘patterns’ using k-means clustering. Participants’ brain activity during the scans was expressed as a sequence of the 4 patterns varying in time. First, we hypothesized that some whole-brain connectivity patterns would be associated with a particular experimental condition. Our analyses revealed that certain brain connectivity patterns were predominantly manifested in the movie condition, while others were mainly present in the resting state and scrambled movie condition. Furthermore, we hypothesized that functional connectivity dynamics would be similar across participants during movie watching, when brain activity is driven by the same narrative. We computed a similarity index in order to assess the resemblance between the participants’ pattern sequences. This index measured the co-occurrence of brain patterns between two participants, in comparison to independent brain activity. Synchronization level of each subject is defined as their average similarity index with all the other participants of their group. We found a higher synchronization across participants during movie watching compared to resting state and scrambled movie conditions. Moreover, we predicted an increased synchronization during the most engaging parts of the movie. As expected, the synchronization dynamics across participants were correlated with suspensefulness: more suspenseful scenes induced higher synchronization. These results suggest that processing of the same high-level information elicits common brain activity dynamics among individuals and that whole-brain functional connectivity dynamics track variations in the properties of the processed information.

227. Transient behavioral responsiveness to external information is present across all sleep stages and can be predicted from EEG signal

Başak Türker1, Esteban Muñoz Musat1, Emma Chabani1, Alexandrine Fonteix-Galet1, Jean-Baptiste Maranci1,2, Nicolas Wattiez1, Pierre Pouget1, Jacobo Sitt1, Lionel Naccache1,3, Isabelle Arnulf1,2, Delphine Oudiette1,2

1Paris Brain Institute, 2AP-HP, Hôpital Pitié-Salpêtrière, Service des Pathologies du Sommeil, National Reference Centre for Narcolepsy, 3AP-HP, Hôpital Pitié-Salpêtrière, Département de Neurophysiologie

227. Sleep has classically been considered as a state of disconnection from the environment, with very reduced (or absent) reactivity to external stimuli. However, a recent study showed that, in the specific case of lucid dreaming, participants were able to behaviorally respond to tactile and auditory stimuli by contracting their facial muscles in REM sleep. In the current study, we investigated whether this putative behavioral responsiveness during sleep could generalize to ordinary non-lucid REM sleep and to other sleep stages. 27 participants with narcolepsy - who present excessive daytime sleepiness, a short REM sleep latency, and a high frequency of lucid dreams, and 22 healthy participants went through a lexical decision task while napping. They were instructed to contract either their corrugator or zygomatic muscles depending on the stimulus type (word vs pseudowords). Some participants with narcolepsy reported having a lucid dream upon awakening. We demonstrated that accurate behavioral responses (facial EMG responses) were collectible across all sleep stages in both populations. Moreover, behavioral responsiveness to external stimuli in non-lucid naps was associated with previously-validated electrophysiological markers of higher cognitive state computed prior to the stimulus presentation. Random forest classifiers were able to predict the responsiveness in all sleep stages using EEG marker values. Furthermore, lucid trials were characterized by a higher response rate, a systematic increase in EEG markers regardless of behavioral responsiveness, and the presence of behavioral and electrophysiological signatures of conscious processing. Overall, our findings suggest that sleepers can transiently process external stimuli at a high-cognitive level and react to them across all sleep stages. As these brief windows of reactivity can be predicted from EEG signal, they could be targeted to test the possibility for real-time communication with sleepers across all sleep stages.

229. Hierarchical strategic and non-strategic expectations in language comprehension

Miss Consuelo Vidal Gran1, Prof. Howard Bowman1,2, Dr. Damian Cruse1

1University of Birmingham, 2University of Kent

229. Objectives: Incoming sensory information is affected by hierarchical probabilistic predictions based on context and previous experience. Generating global predictions from the highest level of the hierarchy (top-down processing) is thought to require consciousness, while local (lower-level) predictions proceed pre(un)-consciously. Predictions are particularly important for successful language comprehension. This study investigates the electrophysiological correlates of local and global expectations in semantic processing. Research question: We hypothesize that individuals generate hierarchical semantic expectations that vary in complexity, where local (lower level) expectations are based on stimulus properties, and global expectations require a strategic use of the context in which stimuli are presented. Consistent with predictive coding accounts, the amplitudes of the ERPs will reflect violations of expectation at consecutive levels of the hierarchy – with local violations evident earlier than global violations. Materials and methods: We test an auditory semantic priming paradigm using semantically related and unrelated word-pairs (prime/target) to manipulate local expectations as we simultaneously manipulate global expectations of the validity of the prime (cued by male/female voice). Thus, expectations about the identity of an upcoming target can be influenced by local features (i.e. the prime) and global features (i.e. probability that a related target will follow the prime). Results: We observe an early ERP effect (around 350ms) between related and unrelated targets, consistent with a local prediction error; followed by a late effect (around 550ms) of violations of the global context, i.e. larger error signal for unexpected targets in a high validity context relative to a context with low validity. Conclusion: The early ERP effect is consistent with lower-level ‘local’ prediction errors, whereas the later effect reflects strategic predictions based on global context. This is supported by individuals explicitly reporting the use of strategy while performing the task. Together, these results provide support for a hierarchical model of prediction mechanisms in semantic processing. Furthermore, this paradigm may be beneficial for improving the accuracy of diagnosis of patients with disorders of consciousness, as it differentiates strategic and non-strategic processing -in a similar way to the local-global paradigm- but in the context of the clinically relevant domain of residual language processing.

230. Representation of content in sustained viewing conditions: a case study for consciousness theories

Gal Vishne1, Dr Edden M. Gerber1, Prof Robert T. Knight2, Prof Leon Y. Deouell1

1The Hebrew University of Jerusalem, 2University of California

230. Objectives: Vision research has thoroughly characterized the information content of transient neural responses to stimuli onset. Yet, visual experience is composed of many stationary moments without change, when we still maintain information about our environment. We set out to characterize neural representation of visual content over time, using a passive viewing task with images of variable durations (300-1500ms) and categories. This approach was recently promoted as a method for arbitrating between two prominent scientific theories of consciousness (Integrated Information Theory (IIT) and Global Neuronal Workspace (GNW); COGITATE consortium). Research question: What are the temporal dynamics and spatial profile of visual representation in sustained viewing conditions? Do neural signals represent information persistently even in a passive, changeless setting, and are different neural regions engaged in different temporal dynamics? Materials and methods: We recorded intracranially from 10 patients undergoing epilepsy surgery (1067 electrodes), enabling us both high spatial and high temporal resolution. We measured information content both at the category level (face, object, animal), using multivariate decoding, and at the level of single exemplars, using representational similarity analysis. We used temporal generalization to measure stability over time. Results: First, we show that category information persists throughout the viewing, as a stable pattern of activity across sites, despite a major reduction in response amplitude with time. Regionally, we find sustained category information in occipital and ventral-temporal areas, and onset (200-400ms) category information in prefrontal sites. Second, we find sustained information about the identity of single images, stable throughout the viewing period. Here too, sustained information was present in posterior areas, but we also find transient information in prefrontal areas. These results hold when controlling for the category structure and when focusing on single categories. Conclusion: We find sustained visual information in posterior areas, predicted by IIT, alongside a short-lived “ignition” in anterior areas, including PFC (despite the no-report task), predicted by GNW. These results may suggest that ongoing content information is maintained in posterior areas, while prefrontal regions are more involved in changes in perception. However, as predictions of both theories bear out, it questions whether this approach can arbitrate between the theories.

43. Neural correlates of predictive coding in continuous speaking and listening

Dr. Omid Abbasi1, Mrs Nadine Steingraeber1, Mr Nikos Chalas1, Dr Daniel Kluger1, Prof Joachim Gross1

1University Of Muenster

43. Objectives and research question: Speech production and perception go hand in hand to shape any verbal communication. The underlying neural substrates of speech production and perception are partially shared, but they are also supported by distinct neural networks. To date, most of the information we have about these brain networks is based on either spatially limited invasive studies or studying semi-natural single words and sentences. Here we used magnetoencephalography (MEG) in order to examine the underlying neural substrates and their frequency-specific communication channels driving natural speech production and perception. Methods: Participants (n=30) answered seven given questions (60 seconds each; condition #1) as well as listened to audio-recordings of their own voice from previous sessions (condition #2) while MEG data was recorded (CTF Systems). Amplitude envelope was extracted from the continuous speech signal. Individual MRIs were used to estimate source models per participant. Cortical areas were divided into 230 anatomical parcels according to the parcellation from the Human Connectome Project. For each parcel, the first three SVD components were extracted. We then estimated mutual information (MI) between the speech envelope and all three time series. Next, using a blockwise approach, we estimated the connectivity between the left STG (LSTG) and other parcels using a multivariate nonparametric Granger causality approach (mCG). Results: Our speech-brain coupling results during continuous speech production separated the temporal areas following the speech envelope (in the theta range) from frontal and motor areas preceding the speech envelope (in the delta range). Moreover, the results of the directed connectivity analysis indicate that the feedback signals, connecting higher areas such as motor to STG, represent predictions and are communicated via slow rhythms (below 40 Hz) whereas feedforward signals (reverse direction) represent prediction errors and are communicated via faster rhythms (above 40Hz). Conclusion: The detected negative lag coupling result as well as our connectivity results support the role of the internal forward model in predicting motor programs and the sensory consequences of expected speech output. Our findings bring novel insights into how multiple brain areas interact to produce or perceive speech through different frequency bands.

44. Oscillatory dynamics supporting longitudinal plasticity of action semantics across languages: Evidence from bilingual brain tumor patients

Dr. Lucia Amoruso1,2, Ms Shuang Geng1,3, Ms Polina Timofeeva1,3, Dr. Santiago Gil-Robles4,5, Dr. Iñigo Pomposo5, Dr. Manuel Carreiras1,2,3

1Basque Center On Cognition, Brain And Language (BCBL), 2IKERBASQUE, Basque Foundation for Science, 3University of the Basque Country, UPV/EHU, 4Hospital Quiron, 5BioCruces Research Institute

44. Objectives and research question: Previous evidence suggests that the semantic processing of object and action knowledge is underpinned by partially distinct ventral and dorsal networks involving inferior-temporal and fronto-parietal nodes, respectively. Recently, we find that brain tumor patients with dorsal lesions show a selective longitudinal compensation (post- vs. pre-surgery) during the retrieval of lexico-semantic information about actions (but not objects) indexed by power increases in the beta band. Here, we move one step further and ask whether a similar organizational principle also stands across the different languages a bilingual individual speaks. Materials and methods: we combined a picture-naming task (MULTIMAP) with MEG recordings and longitudinally evaluated highly proficient Spanish-Basque speakers with brain tumors involving fronto-parietal regions in the left hemisphere. We assessed language processing in a longitudinal fashion, namely, comparing performance and MEG activity before and three months after surgery. Results: at the behavioural level, we observed similar accuracy and reaction times across sessions irrespectively of the language at use, suggesting successful compensation and language preservation after tumor resection. At the oscillatory level, we found power increases in beta rhythms (8-25 Hz) following surgery for both Spanish and Basque. Interestingly, these power modulations were observed only for action naming and engaged healthy dorsal ipsi-lesional nodes and contralateral homologues. Conclusion: overall, our results align well with previous evidence showing that object and action knowledge are supported by partially distinct semantic networks. Furthermore, they show that adaptive compensation supporting the access to action-based representations is comparable across languages, suggesting the existence of a similar semantic organization in the bilingual brain.

45. Daytime slow-wave sleep promotes memory consolidation for novel morphology

Viktoria Balla1, Eino Partanen1, Yury Shtyrov2, Miika Leminen4, Piia Turunen1, Alina Leminen1,5

1Cognitive Brain Research Unit, Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, 2Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, 4AI and Analytics Development Unit, HUS Helsinki University Hospital, 5RDI, Laurea University of Applied Sciences

45. Morphemes are defined as the smallest meaningful units of a language that can be used to form new words (derivation, e.g., suffix -ness in darkness) or convey grammatical information (inflection, e.g., plural affix -s in houses). Acquiring novel morphology thus represents an essential but also a challenging aspect of language learning. Emerging neurocognitive evidence suggests that memory traces for novel suffixes can be formed even during a brief learning session, as reflected by rapid neural activation enhancement to the newly learnt items. However, the generalized use of the new suffix may require longer time and involve offline consolidation. While recent evidence emphasizes that memory consolidation considerably benefits from even a short period of sleep, there is scarce evidence of daytime napping effects on the neural correlates of novel morphology acquisition. Addressing this was the goal of the present study, in which we recorded ERPs to novel suffixes during the learning process and introduced a daytime nap period into the learning session. In a within-subject design containing two separate sessions, we trained 21 native Finnish-speaking participants with novel suffixes through a word-picture association task. After this 10-minute training, we used EEG to record brain responses to semantically trained and untrained suffixes, combined with previously unpresented real and pseudoword stems in a 22-minute auditory passive listening task. Additionally, existing Finnish suffixes served as controls. Passive exposure was followed by a 90-minute retention period, containing napping in one session and wakefulness in the other one, after which an 8-minute passive-listening EEG block was repeated. We compared the ERP responses to trained, untrained, and real suffixes before and after the retention period to investigate the effect of sleep versus wakefulness on the consolidation of novel suffixes. Response amplitudes for semantically trained novel suffixes significantly increased after 90 minutes of napping, but only in cases when slow-wave sleep (SWS) occurred. Furthermore, we found that longer time spent in SWS was associated with a larger response enhancement. Overall, our results suggest that a short period of daytime sleep can be beneficial to the acquisition of novel suffixes and highlight the importance of SWS for memory consolidation.

46. Neural speech tracking in the absence of visual input: Dark listening

Evgenia Bednaya1, Bojana Mirkovic2,3, Ms Martina Berto1, Emiliano Ricciardi1, Martinelli Alice1, Alessandra Federici1, Stefan Debener2,3, Davide Bottari1

1IMT School For Advanced Studies, 2Neuropsychology Lab, Department of Psychology, University of Oldenburg, 3Cluster of Excellence Hearing4all, University of Oldenburg

46. Neural activity synchronizes to amplitude modulations of perceived continuous speech. This neural entrainment or speech envelope tracking is typically observed within the language network and modulated by low-level acoustic features, high-level meaningful linguistic units, and engagement. Recent evidence showed that the visual cortex may contribute to speech envelope tracking, although its putative role in the hierarchy of speech processing remains unclear. Here, we tested blindfolded participants (N = 15) who listened to semantically meaningful or meaningless stories, either in quiet or embedded in multi-talker babble noise. We used linear mapping between EEG and corresponding stimuli to estimate temporal response function (TRF) to speech envelope and therefore to assess entrainment. Specifically, we assessed (1) low-level acoustic effects by contrasting TRFs resulting from listening to stories in quiet vs. in noise and (2) high-level linguistic effects by contrasting TRFs resulting from listening to meaningful vs. meaningless stories, both embedded in noise. To better understand the origin of such effects, we performed source modeling of the TRFs, focusing on the visual cortex. Our results showed that envelope tracking was significantly enhanced and delayed for speech embedded in noise as compared to quiet, providing further evidence that entrainment is affected by low-level features and can represent a mechanism to boost comprehension in challenging listening conditions. Higher-level effects on TRFs occurred when semantic information was missing, evidenced by facilitated latencies and reduced amplitudes of earlier occurring peaks when listening to meaningless stories. Source modeling showed that entrainment to speech envelope engages wide networks beyond the auditory cortex, especially as signal-to-noise ratio (SNR) decreases. Furthermore, it revealed that, in the absence of retinal input, the visual cortex participates in envelope tracking of continuous speech. While no clear influence of semantic content was found, the magnitude of such entrainment was affected by low-level speech features. Specifically, a decreased SNR level dampened the visual cortex response, which suggests a suppression mechanism in challenging listening conditions. Altogether, our findings show low-level acoustic and high-level linguistic effects on envelope tracking, involving broad networks of activation, and provide evidence of the visual cortex’s role in entrainment to continuous speech.

47. The effects of cerebellar tDCS on lexical-semantic memory retrieval

Mgr. Dominika Besterciová1, Dr. Martin Marko1, Dr. Rastislav Rovný1, Dr. Igor Riečanský1,2

1Centre of Experimental Medicine, Slovak Academy Of Sciences, v. v. i., 2Department of Psychiatry, Faculty of Medicine, Slovak Medical University in Bratislava

47. In recent years, a contribution of the cerebellum to language functions has been increasingly debated. Our study investigated the cerebellar involvement in lexical-semantic memory using transcranial direct current stimulation (tDCS). Adult healthy participants (n = 136) received either anodal tDCS (n = 45), cathodal (n = 46) or sham tDCS (n = 45). The stimulating electrode (5x7 cm) was placed over the scalp with its anterior border 1-2 cm under the inion and the reference electrode (5x7 cm) was placed over the right arm. Duration of the stimulation was 20 minutes; the current intensity was 2 mA. Prior to and immediately after stimulation, the associative chain test (ACT) was administered. In the ACT, individuals generate word chains according to specific rules (continuous retrieval of semantically related words, continuous retrieval of unrelated words or retrieval of related and unrelated words in alternation). Anodal cerebellar tDCS facilitated continuous retrieval of semantically related words but had no effect in other retrieval conditions. Cathodal tDCS yielded no significant changes in retrieval performance. These findings indicate that the cerebellum is involved in automatic retrieval from lexical-semantic memory, rather than retrieval control. This study was supported by the project VEGA 2/0059/20 and APVV-19-0570.

48. Frequency modulation in spoken-word production

Yang Cao1, Dr Vitória Piai1

1Donders Centre For Cognition

48. Neuronal oscillations occur in the local field potential, which reflects the activity of a neuronal population. Although extensive work has been conducted on amplitude modulations of cortical oscillations, investigations of frequency modulations within a specific band are scarce. The objective of this study is to address the phenomenon of frequency modulation in the brain’s language regions during word production. Alpha- and beta-band power decreases have been consistently found in spoken-word production, using the approach to average power across frequency bins within a canonical frequency band (i.e. alpha band, 8-12 Hz; beta band, 15-25 Hz). These power decreases have been consistently localized to both left lateral-temporal and lateral-frontal lobes (e.g. Piai et al., 2015; Roos & Piai, 2020; Salmelin & Sams, 2002). While the precentral gyrus is relatively a domain-specific region, and primarily for motor-related activity, the lateral temporal region has been considered a multi-functional region, contributing to multiple cognitive processes. Animal studies have suggested that frequency modulations within a frequency band are as meaningful as power modulations, and different frequencies reflect different neuronal populations or processes (e.g. Kilavik et al., 2012). Thus, the planned study will combine the examination of frequency and power modulations in two Regions of Interest in the language production network: superior temporal gyrus (STG; multi-functional), and precentral gyrus (PCG; domain-specific). We hypothesize that for STG, both the peak amplitude and peak frequency will be modulated following stimulus onset compared with pre-stimulus baseline activity (reflecting different functions). By contrast, PCG will only show peak amplitude modulation after stimulus onset (reflecting one function). Electrocorticography signals were recorded when patients undergoing epilepsy monitoring performed spoken-word production tasks. Irregular-resampling auto-spectral analysis (IRASA, Wen & Liu, 2015) will be used to increase the frequency resolution, disentangle rhythmic and arrhythmic components, and to define the peak frequencies and power at peak frequencies for the alpha and beta frequency bands. These parameters will be compared for three time windows: before stimulus onset, after stimulus onset, and after speech onset.

49. Electrophysiological indices of cognitive functioning in people with aphasia

Mr Mateusz Choinski1, Prof Elzbieta Szelag1, Ms Anna Bombinska1, Dr Aneta Szymaszek1

1Nencki Institute Of Experimental Biology, Polish Academy Of Sciences

49. Aphasia is a language impairment resulting from a lesion to the brain. It is also accompanied by deficits in non-language cognitive functions, such as working memory, executive functions and temporal resolution. The assessment of cognitive status of people with aphasia (PWA) usually involves neuropsychological tests, the majority of which require verbal skills, thus, the results may be biased by language difficulties. To overcome this issue, the objective electrophysiological methods may be used, to assess the cognitive capacity of PWA objectively. The aim of the study was to investigate the relationship between P300 and mismatch negativity (MMN) parameters and cognitive functions in PWA. Twenty six patients after stroke participated in the study (age: M = 59.35 years). Several language and non-language cognitive functions were assessed behaviourally. Two electrophysiological tasks were performed: visual Go/No-Go task as well as auditory syllable discrimination task. Shorter P300 latencies were associated with better temporal resolution, psychomotor speed, planning ability, spatial working memory, as well as better word and sentence comprehension and verbal fluency. On the other hand, higher MMN amplitudes corresponded to better psychomotor speed, spatial working memory, phoneme hearing, word comprehension and verbal fluency. The results suggest that studied ERP components are good objective indices of non-verbal and verbal cognitive functions in PWA and can be included in an assessment of cognitive status of these patients. Supported by National Science Centre, Poland, grant number: 2016/21/B/HS6/03775.

50. Physiological correlates of aesthetic experience in music concerts

Anna Czepiel1,2, Dr Lauren K. Fink1,7, Dr Christoph Seibert3, Dr Mathias Scharinger4,5, Dr Sonja Kotz2,6

1Department of Music, Max Planck Institute For Empirical Aesthetics, 2Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, 3Institute for Music Informatics and Musicology, University of Music Karlsruhe, 4Department of German Linguistics, University of Marburg, 5Department of Language and Literature, Max Planck Institute for Empirical Aesthetics, 6Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 7Max Planck-NYU Center for Language, Music, and Emotion

50. Objectives: Music concerts evoke pleasurable aesthetic experiences (AE). Research shows visual information is a contributing factor to this experience: AE (e.g., quality judgements, liking) increases more in audiovisual (AV) than audio only (AO) conditions of music performance, but this effect has been mainly assessed in laboratory settings. Further, results indicating physiological differences between AV and AO music performances are inconsistent. Considering AE as including sensory, emotional, and appreciation (e.g., liking) components, here we aim to specify the link between modality (AO vs. AV), AE, and physiological responses in a naturalistic concert setting. Research questions: (1) Does AE increase more with AV than AO information in a naturalistic concert setting? (2) How is AE reflected in physiological responses comparing AV/AO? Materials and method: In a naturalistic concert hall setting, participants (N = 53) heard piano performances of Messiaen, Beethoven, and Bach twice: in AO and AV versions. Condition order (AO-first vs. AV-first) was counterbalanced across participants. AE (e.g., liking) was measured subjectively via self-reports (Experiment 1 and 2) and more objectively with peripheral responses (skin conductance, heart, respiration, corrugator (‘frowning’) muscle, and zygomaticus (‘smiling’) muscle activity; Experiment 2). Results: AE was significantly higher in the AV condition in both experiments. A Condition by Order interaction (Experiment 2) showed only AO-first participants showed a significant increase in AE. Physiological arousal (i.e., skin conductance and heart rhythm associated with sympathetic activity) was higher in the AO condition. Respiration rate, ‘smiling’, and ‘frowning’ muscle activity were higher in AV condition. Smiling muscle activity was found to be a significant predictor for AE. Conclusion: We replicate and extend previous findings that AV information enhances AE in a more naturalistic setting. We find that certain physiological measures (heart rhythm and skin conductance) may reflect the more sensory component (i.e., increase in arousal in the potentially less predictive AO version), while facial muscles may reflect the liking aspect (i.e., behavioural ratings) of AE. Although we only cautiously attribute (certain) biological responses to AE, we show that a combination of self-report and peripheral measures can assess AE in naturalistic music concert settings.

51. Investigation of Mu Oscillations to Groove Music

Deniz Duman1, Mr. Tommi Kuivamäki1, Prof. Petri Toiviainen1, Dr. Geoff Luck1

1University of Jyväskylä

51. Groove, the popular musical term, is associated with the participatory experiences of desire to move, positive affect, immersion and social connection (Duman, Snape, Toiviainen, & Luck, 2021). Previously, listening to high-groove music was reported to activate motor systems to a greater extent compared to low-groove music (Stupacher, Hove, Novembre, Schütz-Bosbach, & Keller, 2013). A recent study demonstrated enhanced mu activity (near somatosensory areas around 8-12 Hz and its harmonics 18-22 Hz) during passive music listening; reflecting motor inhibition (Ross, Comstock, Iversen, Makeig, & Balasubramaniam, 2022). Best of our knowledge, no study reported mu oscillations to stimuli with varying degrees of groove. Thus, the current study focuses on investigating cortical mu activation to musical stimuli associated with various levels of groove. For this, electroencephalogram (EEG) data were collected from 8 healthy Finnish participants during a passive listening task. Stimuli were selected in two steps: Initially, in an online survey 105 participants listened to 30 short musical excerpts (from various genres of commercial music, with tempo around 120 -/+ 20 BpM) and rated groove-related items (i.e. desire to move, liking and familiarity) for each excerpt. Subsequently, based on the groove ratings, 3 stimuli were selected for each groove levels (low, mid and high) for the experiment described in the current work. During the EEG data collection participants were seated, asked to listen to the presented stimuli and try not to move while their eyes were fixed at a point. Each of the 9 stimuli lasted around 25 seconds and were presented 5 times in randomised order. For the analysis, the data were pre-processed by applying high- and low-pass filters, and removing artifacts with independent component analysis. Subsequently, the data was epoched and spectral decomposition for each stimuli epoch was calculated to investigate spectral power to musical stimuli with various levels of groove. Preliminary analyses demonstrated larger mu power to stimuli that received higher groove ratings. This would indicate that there is a greater motor inhibition to high (compared with low) groove stimuli. Subsequent analyses focus on source decomposition of the mu activity. Further results and the implications will be presented in details.

52. An auditory-reward network processes musical uncertainty and surprise to pleasurable effect

Benjamin Gold1, Marcus Pearce2,3, Ernest Mas-Herrero4, Randy McIntosh5, Catie Chang1, Alain Dagher4, Robert Zatorre4,6

1Vanderbilt University, 2Queen Mary University of London, 3Aarhus University, 4Montreal Neurological Institute, 5University of Toronto, 6International Laboratory for Brain, Music, and Sound Research

52. Enjoying music is one of the most pleasurable human experiences, and it consistently engages central structures of the neural reward system such as the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC). As music unfolds across interweaving patterns of rhythm and sound, it is especially well suited to manipulate expectations and evoke surprise, which have been associated with the activity and synchrony of auditory and reward-related brain areas. We and others have shown that both uncertainty about the musical future and surprise about the musical past modulate NAc activity and liking ratings. In the present study, we extend this research to a network perspective by exploring the functional connectivity (FC) underlying musical information processing and pleasure. During fMRI, 24 participants listened to and rated their liking of 50 naturalistic, real-world musical stimuli characterized with a well-validated model of musical uncertainty and surprise. As in previous studies, we observed an interaction between uncertainty and surprise on liking ratings. FMRI analyses, using regions of interest from the musical pleasure literature, showed that the FC between the mPFC and temporal lobe varied with uncertainty and surprise, following the same pattern as liking ratings and implicating this pathway in the pleasure of musical expectancies. Liking correlated with the NAc’s FC to the temporal lobe and hippocampus, and preliminary analyses suggest that this effect might be greater in listeners more sensitive to musical reward. Together, these results corroborate previous findings and highlight the information transfer between the NAc, mPFC, temporal lobe, and hippocampus as a central feature in the processing and pleasure of musical expectancies.

53. Masking of mouth impairs reconstruction of acoustic speech features and higher-level segmentational features in the presence of a distractor speaker

Chandra Leon Haider1, Nina Suess1, Dr Hyojin Park2, Dr Anne Hauswald1, Prof Nathan Weisz1,3

1University of Salzburg, 2University of Birmingham, 3Neuroscience Institute

53. Multisensory integration enables stimulus representation even when the sensory input in a single modality is weak. In the context of speech, when confronted with a degraded acoustic signal, congruent visual inputs promote comprehension. When this input is masked, speech comprehension consequently becomes more difficult. But it still remains inconclusive which levels of speech processing are affected under which circumstances by occluding the mouth area. To answer this question, we conducted an audiovisual (AV) multi-speaker experiment using naturalistic speech. In half of the trials, the target speaker wore a (surgical) face mask, while we measured the brain activity of normal hearing participants via magnetoencephalography (MEG). We additionally added a distractor speaker in half of the trials in order to create an ecologically difficult listening situation. A decoding model on the clear AV speech was trained and used to reconstruct crucial speech features in each condition. We found significant main effects of face masks on the reconstruction of acoustic features, such as the speech envelope and spectral speech features (i.e. pitch and formant frequencies), while reconstruction of higher level features of speech segmentation (phoneme and word onsets) were especially impaired through masks in difficult listening situations. As we used surgical face masks in our study, which only show mild effects on speech acoustics, we interpret our findings as the result of the missing visual input. Our findings extend previous behavioural results, by demonstrating the complex contextual effects of occluding relevant visual information on speech processing.

55. Investigating the microstructural foundations of cortical speech tracking

Saskia Helbling1,2, Luke J. Edwards2, Kerrin J. Pine2, Daniel Rose2, David Poeppel1,3,4, Nikolaus Weiskopf2

1Poeppel Lab, Ernst Struengmann Institute (ESI) in Cooperation with Max Planck Society, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, 3Department of Psychology, New York University, 4Max-Planck-NYU Center for Language, Music, and Emotion (CLaME)

55. Low-frequency oscillatory activity in auditory cortex synchronises to rhythmic patterns in the envelope of the acoustic input. Speech is quasi-rhythmic and neural activity in auditory cortex follows rhythmic features in the speech envelope, with prominent tracking occurring in the theta frequency range (4-8 Hz) for syllable rates and in the delta frequency range (0.5-4 Hz) for prosodic rhythm. Previous work showed that the synchronisation of low-frequency oscillations and speech envelope is under the influence of top-down control from (pre-) motor and orbito-frontal areas. Here we investigate the microstructural foundations of such top-down control in speech comprehension by relating local cortical myelination, as a proxy of local cell density gleaned from quantitative MRI (qMRI), to the strength of speech tracking during a passive listening task, as assessed by MEG, across participants. We hypothesise that higher myelination in areas linked to top-down control of speech tracking indicates stronger top-down signals and thus predicts stronger speech tracking in earlier auditory areas. In addition, we also expect higher myelination in auditory cortex itself to be correlated to stronger speech tracking. To test these hypotheses, we correlated across 45 healthy participants (1) the sensor-space cerebro-acoustic coherence during passive listening with (2) R1-based myelin estimates from a 3T multi-parameter map protocol for each of the 360 regions of interest defined by the HCP-MMP1 atlas. We show significant correlations between myelination at inferior parietal cortex (IPC) to theta speech tracking strength as well as to power at frequencies previously linked to prediction signals. IPC has been shown to be involved in semantic processing and has been hypothesised to provide semantic constraints during language comprehension. It has further been linked to verbal memory retrieval and violations of memory expectations. Interestingly, we also observed correlations at bilateral hippocampus further implying that the observed correlations could be related to mnemonic functions. In addition, we found the expected positive correlations between myelin at auditory areas and theta tracking strength. Significant correlations between delta coherence strength and qMRI-derived myelination may reflect motor predictions in speech perception.

56. Variability in the temporal distribution of linguistic units in natural speech

Cosimo Iaia1, Mirko Grimaldi1, Dr Alessandro Tavano2

1University Of Salento, 2Max Planck Institute for Empirical Aesthetics

56. Objectives. Speech rhythms across languages converge on similar low frequency (LF) modulations of the speech carrier, suggesting a remarkable degree of regularity. While temporal regularity in input at syllabic level has been clearly documented to drive neural entrainment, a similar degree of regularity in the size of more abstract units cannot be assumed. Here, we compare variance in the temporal distributions of different linguistic levels, from phoneme to syntactic phrases. Research question. How does regularity in unit duration characterize human speech, from phonemic to syntactic levels? Materials and methods. Twenty-three subjects (5 male, mean age = 23.3, std ± 3.5) took part into a behavioral and EEG study. They were asked to listen to the first chapter of two audiobooks in the Italian language, read by a voice actor. Stimuli were presented through two loudspeakers at a comfortable volume (70 dB). Each chapter was roughly 9 min long, segmented into 10 trials. Linguistic levels in the acoustic signal were annotated manually at the phoneme, syllable, word, syntactic phrase and sentence time scales using PRAAT software. Syntactic constituency analysis was performed with Stanza, an nlp library in Python. The duration of each temporal speech unit was extracted, and variance was compared across levels using the coefficient of variation. Results. Preliminary analyses show significant differences in variance between the phonemic/syllabic levels and the word/sentence levels with larger variance for the latter. Importantly, all coefficients were below 1, suggesting limited variance. While durations at phonemic and syllabic levels were highly correlated, no other significant correlation was found. Zooming in as the sentence level, we calculated the coefficient of variation separately for Noun Phrases (NPs) and Verb Phrases (VPs), finding significantly more variance for NPs than VPs. Further analyses are underway to identify the differential import of variance in duration for the hypothesis of neural entrainment across linguistic levels. Conclusion. Although limited in scope and linguistic material, our results suggest that the duration of linguistic units obeys different constraints depending on input hierarchy, with more abstract units showing larger variance, and therefore less likely to be captured via entrainment.

57. Intonation Units evoke a neural response and form ~1 Hz rhythms in spontaneous speech

Maya Inbar1,2,3, Shir Genzer2, Anat Perry2, Eitan Grossman1, Ayelet N. Landau2,3

1Department of Linguistics, Hebrew University of Jerusalem, 2Department of Psychology, Hebrew University of Jerusalem, 3Department of Cognitive and Brain Sciences, Hebrew University of Jerusalem

57. Studies of speech processing investigate the relationship between temporal structure in speech stimuli and neural activity. Such a relationship exists in a variety of frequencies and is termed speech tracking. Speech tracking at ~5 Hz is understood to reflect processing at the syllable level, but despite clear evidence for speech tracking in lower frequencies, it is not well understood what linguistic information is captured in these time scales. We aim to shed light on this topic by studying the neural processing of Intonation Units and their temporal structure. Spontaneous speech is produced in chunks called Intonation Units (IUs). IUs are defined by a set of acoustic cues and are present cross-linguistically. Linguistic theory suggests that IUs pace the flow of information and serve as a window onto the dynamic focus of attention in speech. We measured EEG as participants listened to stories that were recounted spontaneously by 9 different individuals. We transcribed the stories and treated the IUs in them as times of interest for analyzing the EEG response. We find a response that deviates significantly from control – the response measured in time-shuffled data that maintained the association with syllable onsets. This effect appears as early as 50 msec following IU onset. Additionally, we characterize the temporal structure of IUs cross-linguistically. We analyzed audio recordings of spontaneous speech in 6 languages from around the globe. We used IUs as times of interest for analyzing periodicities in the speech envelope, a representation of amplitude fluctuations in speech. Despite the substantial differences between the languages in grammatical, areal, genealogical, and socio-cultural parameters, we find that sequences of IUs in them form ~1 Hz rhythms. We replicate this finding using the stories that were used as stimuli in the EEG experiment. Our results suggest that previous findings of speech tracking at ~1 Hz may reflect processing at the level of IUs. Under the working hypothesis that IUs serve as a window onto the dynamic focus of attention, such a scenario holds the promise of unraveling the neural mechanisms that allows us to share ideas in social interaction.

58. The music complexity affects the late but not early musical syntax processes

Marta Jaśkiewicz1, Piotr Francuz1, Wojciech Bernatowicz2, Paweł Augustynowicz1

1The John Paul II Catholic University Of Lublin, 2The Marie Curie Sklodowska University

58. Experiments on musical syntax typically use similarly designed stimuli. Such sequences of five chords do not have many aspects of music occurring in natural music. There are also studies using natural stimuli derived from classical music. Such stimuli however do not give the full control of variables. The neural answer for such stimuli can not be compared to the answer for the simple stimuli. The project takes into account using simple and complex stimuli which can be compared by observing two event-related potentials: EAN/ERAN and P600/LPC. The research question undertaken in the study is: does stimuli complexity affect early and late stages of musical syntax processing? Ninety six chord progressions were composed as stimuli. All progressions were used for two types of stimuli – simple and complex stimuli. The complex stimuli were similar to simple stimuli but contains additionally the melody set in the highest voice stressed by rhythmical pattern. Additionally, both simple and complex stimuli were presented with (a) congruous and (b) incongruous last chord (according to the rules of musical syntax). Fourteen participants took part in the experiment. The participants were nonmusicians. Results: The EAN potential was observed for incongruous chords (F(1,11) = 19.2; p = 0.001). The effect of Complexity (F(1, 11) = 0.9, p = 0.352) was not statistically significant for EAN. The EAN potential was followed by late positive component showing the differences between congruous and incongruous chords (the main effect of Chord type (F(1, 11) = 13.6, p = 0.004). Also the main effect of Complexity was observed (F(1, 11) = 13.7, p = 0.004). We observed EAN as a response to syntax violation but the complexity of stimuli does not affect the potential. Even during perception of more complex stimuli participants were preattentive as sensitive to syntax violation in complex nad more natural music as during perception of simple sequences. LPC was seen for syntax violation in both simple and complex stimuli but higher amplitudes for simple one show that the sensitivity for such violation is higher when we have just a simple presentation of syntax rules without additional elements of music.

59. Processing of duration and pitch by Estonian and Chinese native speakers

Siqi Lyu1, Nele Põldver1, Kairi Kreegipuu1

1University of Tartu

59. We studied how long-term language experience (one’s native language, L1) affects the brain’s pre-attentional processing of acoustic features (i.e., duration and pitch) using mismatch negativity (MMN), the brain’s ability to automatically discriminate between processing of a frequent and a rare stimulus. Estonian is a quantity language in which the two syllables of a disyllabic word could occur in different ratios, and Estonians use both duration and pitch cues to perceive words. Mandarin Chinese, on the other hand, uses the language-specific pitch patterns, i.e., lexical tones, to distinguish lexical meaning. In this study, both Estonian (N=60) and Chinese (N=60) subjects listened to words in their native language (L1) and a foreign language (L2, Chinese language for Estonian subjects and vice versa). An optimal MMN paradigm was adopted where the deviants differed from the standard in terms of duration, pitch, or both duration and pitch. For the Estonian word stimuli, the Estonian subjects showed a larger MMN to both the duration change and the pitch change than the Chinese subjects. Meanwhile, the Chinese subjects showed a right laterization to both the duration change and the pitch change, suggesting that the Chinese subjects processed the Estonian words as acoustic rather than linguistic information. For the Chinese word stimuli, the Chinese subjects showed a larger MMN with an earlier onset to the pitch difference than Estonian subjects. Instead of eliciting an enhanced MMN in the native Chinese speakers, the duration change elicited comparable MMNs in both groups, suggesting that duration is not stored in the phonological knowledge of the Chinese subjects. Together, our results showed that long-term language experience, i.e., duration and pitch components in the Estonian language and the lexical tone in Mandarin Chinese, has an effect on the brain’s auditory perception abilities.

60. Learning of novel song lyrics in chronic post-stroke aphasia: Behavioural and functional neuroimaging evidence

Dr. Noelia Martínez-Molina1, Sini-Tuuli Siponkoski, Anni Pitkäniemi, Nella Moisseinen, Linda Kuusela, Johanna Pekkola, Ms. Emmi Pentikäinen, Sari Laitinen, Essi-Reetta Särkämö, Prof. Boris Kleber, Prof. Gotffried Schlaug, Aleksi Sihvonen, Prof. Teppo Särkämö 1Helsinki University

60. Objectives: A classical observation in the neurology of aphasia is that some post-stroke aphasia (PSA) patients with severe speech production impairments can retain their ability to produce words through singing, especially when singing familiar songs. Recent neuroimaging evidence suggests that this is structurally linked to left superior and middle temporal cortex. However, the ability to acquire new sung material through training and the neural architecture associated with this has not been studied in PSA. Here, we explore the behavioural and neural learning of novel songs before and after choir-singing training in PSA patients. Research questions: Are PSA patients (i) able to learn novel song lyrics trained over a 16-week choir-singing intervention and (ii) is learning accompanied by functional neuroplasticity changes in the activity of frontotemporal auditory and speech-motor areas during singing production? Materials and methods: This data is from a cross-over (AB/BA) randomized controlled trial where chronic PSA patients (N=30) received a 16-week choir-singing intervention during the first (AB) or second (BA) half of a 10-month follow-up. As part of the intervention, the patients trained singing a novel song, both in the choir and at home. Before and after the intervention, we assessed the verbal production of the lyrics of the trained song and a control (untrained) song behaviourally and in a sparse-sampling fMRI task in which the patients listened, sang along and sang from memory the two novel songs. Results: The production of correct syllables increased for the trained vs. untrained song after the singing intervention (AB) compared to standard care (BA). In fMRI, the AB group showed increased activation for the trained song in the sing along vs. rest condition in the right superior temporal gyrus after the intervention compared to the BA group. Additionally, both groups showed increased post>pre intervention activation in the right post-central gyrus in sing along vs. rest and in the right pre-central gyrus in sing along vs. sing from memory. Conclusion: Our results provides unprecedented evidence for training-induced verbal learning of novel sung material in chronic aphasia coupled with functional neuroplasticity in right frontotemporal auditory and sensorimotor areas associated with vocal motor control.

62. Basal ganglia and cerebellar contributions to auditory rhythm tracking and temporal anticipation

Daniel Mazhari-Jensen1, Antonio Criscuolo Criscuolo1, Dr Michael Schwartze1, Prof Sonja Kotz1,2

1Maastricht University, Faculty of Psychology and Neuroscience, Basic and Applied NeuroDynamics Laboratory, 2Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences

62. Humans readily process and track the rhythm of environmental stimuli and generate temporal predictions to anticipate event onsets. Delta- and beta-band neural oscillations have been consistently implicated in rhythm and sensorimotor processing and further seem to characterize audio-motor coupling in both the perception and action. However, most of the M/EEG literature has focused on cortical substrates of rhythm processing, neglecting the pivotal contribution of subcortical structures such as the basal ganglia (BG) and cerebellum (CE). In the current study, we tested a unique sample of stroke patients with focal lesions in either the BG or CE together with a control group (HC) matched in age, sex, and education. We recorded EEG while participants listened to isochronous auditory sequences and had to detect deviant tones. We tested (i) rhythm tracking capacities by assessing the phase-relationship between the delta-frequency band and tone onsets. Next, we investigated (ii) mechanisms of temporal anticipation in the amplitude envelope of beta-frequency band activity, and (iii) the precise encoding of tone onsets by looking at the N100 jitter in the evoked potentials. CE patients exhibit significant variability (i.e., heteroscedasticity) in the N100 latency, while BG patients increased coherence in the delta-frequency phase before tone onsets. However, they did not show anticipatory beat-frequency modulations compared to CE and HC. These preliminary results highlight the contribution of the CE and BG to rhythm processing and show complementary but diverse influence on delta-beta neural dynamics underlying rhythm tracking and temporal anticipation.

63. Neurophysiological changes in lexical-semantic processing in healthy aging

Pietari Nurmi1, Heidi Ala-Salomäki1, Hanna Renvall1,2, Mia Liljeström1,2

1Aalto University, 2Helsinki University Hospital

63. Comprehension of written language is usually well maintained in older adults (Shafto and Tyler, 2014, Science, 346(6209), 583–588). However, neurophysiological recordings have shown that differences in the underlying neural processing can be observed even when behavioral performance is maintained (Wlotko et al., 2010, Linguistics and Language Compass, 4(8), 623–638). Previous electrophysiological (EEG) studies have, for example, shown that the N400 effect in semantic priming tasks is weaker and slower for older subjects (Kutas & Iragui, 1998, Electroencephalography and Clinical Neurophysiology 108, 456–471). Understanding the underpinnings of this effect in healthy aging is important, as an abnormal weakening of the N400 effect has been shown to predict conversion to dementia in persons with mild cognitive impairment (Iragui et al., 1996, Electroencephalography and Clinical Neurophysiology 100, 392–406). To study written word comprehension in healthy aging, we used magnetoencephalography (MEG) in a semantic priming task tapping into the N400 effect. 49 Finnish-speaking adults, divided into young (22–32 years) and old (62–69 years) age groups, were measured while they evaluated whether word-pairs were semantically related (e.g., banana-orange) or unrelated (e.g., banana-police). The MEG measurement was repeated one week later. Source localization was applied using cortically constrained minimum-norm estimation. A significant N400 effect was observed in both age groups (p<0.05, within-group spatio-temporal cluster-based permutation test), originating mainly from left superior temporal, middle temporal, and middle frontal areas. A difference in the N400 contrast between age groups was observed in the left middle temporal cortex at 250–500ms during the second measurement day (p<0.01). The peak latency of the N400 response measured over the left temporal cortex (single-sensor) in the unrelated condition was slightly shorter (~340ms) for young subjects than for old subjects (~400ms) during both measurement days (p<0.01, between-group t-test). Despite the slower brain responses, old subjects had significantly faster behavioral reaction times (p<0.001) and made a comparable number of errors. This unexpected finding might indicate a difference in cognitive strategies between age groups. Taken together, the results indicate that there are significant age-related changes in neural processes underlying semantic word associations that do not translate into reduced behavioral performance.

64. Lexical parafoveal processing in natural reading predicts reading speed

Dr. Yali Pan1,2, Dr. Steven Frisson2, Prof. Ole Jensen1,2

1Centre for Human Brain Health, University of Birmingham, 2School of Psychology, University of Birmingham

64 The aim of this study is to uncover if mechanisms of covert spatial attention support natural reading in which the eyes scan a sentence. It is debated if upcoming words are processed at the lexical level before saccade to the word; a process referred to as lexical parafoveal processing. The eye-movement literature has found no robust evidence for it. This points to a serial processing model where words are processed one-at-a-time rather than a parallel processing model where two or more words are simultaneously processed. Here we address this question by combining eye-tracking, MEG and ‘rapid frequency tagging’ (RFT) in a natural reading task. Full sentence was presented in which target words of either low or high word frequency were frequency tagged (flickered) at 60Hz. The RTF is non-perceivable but produces a strong signal from visual cortex. We measured the cortical coherence in responses to RFT during pre-target fixation, which reflects parafoveal processing of the target. We found no evidence for fixation difference on words preceding targets. Importantly, RFT-coherence during pre-target fixation was both stronger and earlier when preceding low as compared to high frequency targets. The RFT-coherence difference was negatively correlated with reading speed of the full sentence and predicted a reduction in target fixation. In conclusion, our findings provide novel evidence for parafoveal lexical processing supporting a parallel processing model. Importantly parafoveal processing predicted reading speed. In addition, our approach demonstrates that RFT is a powerful tool to study parafoveal processing as it sheds new light on natural reading.

65. Right-hemisphere recruitment after left-hemisphere stroke: a combined MEG and interhemispheric tractography study

Dr Vitoria Piai1, Irina Chupina1, Dr Xiaochen Zheng1, Dr Maria Carla Piastra2, Dr Joanna Sierpowska3

1Radboud University, Donders Institute, 2University of Twente, 3Unviersity of Barcelona

65. The left hemisphere is dominant for language function in the majority of the population. People with left-hemisphere lesions due to stroke may show global right-hemisphere activity for language, but little is known about right-hemisphere recruitment during language use. Previous studies have mainly used fMRI to elucidate hemispheric changes following stroke, but due to the signal’s poor temporal resolution, it remains unclear when the observed right-hemisphere recruitment happens relative to linguistic stimuli (i.e., during cognitive processing or after a response is given). Moreover, it is largely unknown the extent to which this dynamic recruitment is dependent on white-matter connections between the hemispheres. We hypothesise that right-hemisphere recruitment during language use depends on the location of the lesion and the particular cognitive process required. As such, the integrity of interhemispheric connections is only critical if activity is initially lateralised to the lesioned hemisphere upon stimulus presentation. Individuals with stroke-induced damage and matched controls participated in a combined MEG and tractography study: Twenty-two premorbidly right-handed participants had a chronic stroke in the left hemisphere and four had a chronic stroke in other brain areas. Participants performed two well-established experimental paradigms that measure word-production processes: a context-driven picture naming task and a picture-word interference task. Data acquisition has been completed. According to previous findings, left-lateralised alpha and beta power decreases are found associated with context-driven picture naming, in particular in left posterior temporal and inferior parietal regions. Moreover, left-lateralised modulations of the N400 component are found for picture-word interference, in particular in the middle temporal gyrus. We will use source-level analyses to compare each participant’s hemispheric responses in terms of alpha-beta power in the context effect and the amplitude of the N400m for picture-word interference. Source analyses will be conducted using a FEM-based forward model and beamforming. Tractography on diffusion-weighted imaging data will be used to estimate the integrity of the corpus callosum fibres at four different portions (i.e., genu, anterior midbody, posterior midbody, and splenium). We will relate the electrophysiological hemispheric measures to the integrity of different parts of the corpus callosum to examine the structural constraints on right-hemisphere recruitment.

66. Neural maturation of speech encoding abilities in infants from birth to six months of age

Marta Puertollano1,2, Siham Ijjou-Kadiri1,2, Natàlia Gorina-Careta1,2,3, Teresa Ribas-Prats1,2, Sonia Arenillas-Alcón1,2, Alejandro Mondéjar-Segovia1, M. Dolores Gómez-Roig2,3, Carles Escera1,2

1Institute of Neurosciences, University of Barcelona, 2Institut de Recerca Sant Joan de Déu (IRSJD), 3BCNatal – Barcelona Center for Maternal Fetal and Neonatal Medicine (Hospital Sant Joan de Déu and Hospital Clínic)

66. Language acquisition is a unique expertise that infants are able to master at very early stages of development. Speech perception and its developmental milestones are depicted across the literature for the first months of age in different populations and languages. However, the neural mechanisms underlying these maturational processes are still poorly understood. Here, we use an auditory evoked potential termed frequency-following response (FFR) to unravel the developmental trajectory of the neural encoding of speech sounds during the first six months of age. The FFR is elicited to periodic sounds such as speech or music, and allows evaluating the tracking accuracy of complex sound features in the auditory hierarchy. Moreover, it can be modulated by musical and language exposure and it appears disrupted in children with speech or language impairments and neurodevelopmental disorders, which supports the aim of using this response as a possible biomarker for speech encoding impairment and literacy achievements. The FFR was elicited to a tailored novel stimulus /oa/, which allows analysing specifically the neural encoding of the stimulus envelope and of its temporal fine structure (Arenillas-Alcón et al., 2021 Sci. Rep.). Recordings were obtained in a sample of 54 healthy-term neonates at birth and retested at the age of six months. Six parameters were extracted in the time and frequency domains to characterize the FFR. Results revealed a shortened neural lag and a maturation of the stimulus temporal fine structure neural encoding as a function of age, while no significantly different stimulus envelope encoding was observed across the two time point measurements. To our knowledge, this is the first study describing the striking maturation of the fine structure encoding abilities, already present at the early age of six months. The present study contributes to characterize the neural developmental trajectory behind speech perception abilities during the very early stages of life and supports its use to assess early abnormalities that could be associated to later language impairments. Funding. PGC2018-094765-B-I00 MCIN/AEI/10.13039/50110001103; Fundación Alicia Koplowitz; 2022AR-IRSJDCdTorres; ICREA Academia.

67. Contextual effects on Chinese idiom processing: an ERP study

PhD Student Wei Qi1,2, Prof Hongjun Chen2, Dr Susannah C.S.A. Otieno1, Prof Paavo H.T. Leppänen1

1Department of Psychology, University of Jyväskylä, 2School of Foreign Languages, Dalian University of Technology

67. Background: The linguistic context can modify language processes or facilitate language comprehension during language processing. There is a general agreement that the linguistic context can facilitate the recognition and semantic integration of the metaphorical meaning of an idiom with an implausible literal interpretation. However, much less is known about how the context affects processing of a metaphorical meaning of an idiom with a high literal plausibility. Objective and research question: This study used the brain event-related potentials (ERP) to investigate whether Chinese idioms with a high potential for literal interpretations are processed differently when they are presented in metaphorically and literally biased sentence contexts. Materials and methods: Chinese idioms with high frequency, familiarity and semantic transparency were embedded in three sentence contexts: metaphorical-bias context (MC), literal-bias context (LC) and unrelated context (UC). Participants were requested to judge whether the idiom was semantically congruent or incongruent with the sentence context. Results: Our behavioral results found longer reaction times for the Chinese idioms embedded in the MC than those in the LC. The idioms that followed the UC had the shortest reaction times. ERP results obtained using parameter-free cluster permutation statistics showed larger negativity at 300-420ms, a typical time window for the N400 response reflecting semantic processing, for the idioms in the MC compared to those in the LC. The N400 effect generated by the idioms in the UC was larger than those in the MC or in the LC at the parietal brain areas bilaterally. Additionally, the P600 response, reflecting further context processing, was larger for the idioms in the UC compared to those in the MC at the right centro-parietal brain areas. Conclusion: Our results suggest that the sentence context determines which meaning (literal or metaphorical meaning) of literally plausible Chinese idioms is recognized and accessed. Further, our results showing faster reaction times and smaller semantically related brain response (N400) for the idioms with literal meaning compared to metaphorical counterparts, suggest that less processing effort is required for literal idioms presented in semantically related contexts.

68. Changes in late frontal event-related potentials to self-produced foreign phonemes correlate with improvements in pronunciation

Henry Railo1, Anni Varjonen, Minna Lehtonen, Pilleriin Sikka 1University of Turku

68. The pronunciation of foreign phonemes is assumed to involve auditory feedback control processes that compare vocalized phonemes to target sounds. The electrophysiological correlate of this process is known as the speaking-induced suppression (SIS) of early auditory evoked activity. To gain insight into the neural processes that mediate the learning of foreign phoneme pronunciation, we recorded event-related potentials (ERP) when participants (N=19) pronounced either native or foreign phonemes. Analyses of single-trial ERPs revealed no differences in SIS between foreign and native phonemes in early time-windows (approx. 85–290 ms). In contrast, the amplitude of the fronto-centrally distributed late slow wave (LSW, 320–440 ms) was modulated by the pronunciation of foreign phonemes. The LSW evoked by self-vocalized foreign phonemes shifted towards more positive amplitudes across the experiment, whereas the self-produced native phonemes evoked a constant amplitude LSW. Importantly, the LSW amplitude correlated positively with the improved pronunciation of the foreign phoneme. These results suggest that the LSW may reflect higher-order internal monitoring processes that signal successful pronunciation and enable adjustments to future vocalization.

69. No effect of cerebellar tDCS on semantic prediction

Dominika Besterciova1, Dr. Martin Marko1, Dr. Rastislav Rovny1, Dr. Igor Riecansky1,2

1Centre of Experimental Medicine, Slovak Academy of Sciences, 2Department of Psychiatry, Faculty of Medicine, Slovak Medical University

69. Objectives and research question: The cerebellum is involved in the regulation of behavior in multiple domains (motor, affective, and cognitive). While growing evidence indicates that the cerebellum supports speech and language, its exact role in language processing is yet poorly understood. It has been proposed that an important aspect of the cerebellar function is the capacity to generate predictions in perception and action. Semantic prediction is important for speech production and comprehension. The aim of our study was to test the engagement of the cerebellum in semantic prediction using transcranial direct current stimulation (tDCS). Materials and methods: We administered a sentence completion task to 136 healthy adults prior and immediately after sham (n = 45), anodal (n = 45) or cathodal (n = 46) tDCS of the cerebellum (20 min, 2 mA). Results: We found that this stimulation had no significant effect on completing predictable or unpredictable sentences. Conclusion: These results argue against a significant role of the cerebellum in predictive language processing. (This study was supported by grants VEGA 2/0059/20 and APVV-19-0570.)

70. Form- and meaning-based knowledge benefits on speech perception: an fMRI study

Dr. Carine Signoret1, Dr. Josefine Andin1, Dr. Örjan Dahlström1

1Linköping University

70. Prior knowledge about the phonological form of the words (i.e. form-based) and the semantic coherence of a sentence (i.e. meaning-based) is used to produce an enhanced perceived clarity of noisy spoken sentences. By knowing that these effects are additive but independent in normal-hearing listeners (Signoret et al, 2018), it could be suggested that the neural processing of the effects related to form- and meaning-based knowledge during speech perception might be different. We expect that the benefits contingent on form- and meaning-based predictions arise at different levels of speech processing. While meaning-based knowledge would influence higher levels of speech processing (Alain et al., 2018; Davis et al., 2011), form-based knowledge would influence lower levels (Rysop et al., 2020; Wild et al., 2012). In an fMRI study, 20 normal-hearing participants listened to grammatically correct spoken sentences at different sound quality levels (either clear or degraded by noise-vocoding). Semantic coherence was manipulated to be high (e.g. “His new clothes were from France”) or low (e.g. “His red school was from the newspaper”) and the phonological manipulation was obtained by the presentation of the written text of each spoken word (matching text) or a string of consonants (non-matching text) presented 200 ms before the audio stream. Results on whole-brain analysis showed a main effect of Sound Quality, Text and interaction between Sound Quality and Text replicating previously reported results (Wild et al., 2012). However, a main effect of Coherence, as well as a 3-way interaction, revealed general higher activity for low compared to high coherent sentences in the left IFG. At the intermediate level of sound quality, specifically in non-matching text conditions, higher activity was also observed for low compared to high coherent sentences but in the right MTG. For low-coherent sentences, higher activity was observed in matching than non-matching conditions both in the left IFG and the right STS. Together, these results suggest that both multisensory integration and predictive coding mechanisms play a role in making use of phonological and semantic supports but at different processing levels.

72. Cortical Tracking of Formant Modulations Derived from Silently Presented Lip Movements and Its Decline with Age

Nina Suess1, Anne Hauswald1, Patrick Reisinger1, Sebastian Rösch2, Anne Keitel3, Nathan Weisz1

1Department of Psychology, Centre for Cognitive Neuroscience, University of Salzburg, 2Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University Salzburg, University Hospital Salzburg, 3School of Social Sciences, University of Dundee

72. The integration of visual and auditory cues is crucial for successful processing of speech, especially under adverse conditions. Recent reports have shown that when participants watch muted videos of speakers, the phonological information about the acoustic speech envelope, which is associated with but independent from the speakers’ lip movements, is tracked by the visual cortex. However, the speech signal also carries richer acoustic details, for example, about the fundamental frequency and the resonant frequencies, whose visuo-phonological transformation could aid speech processing. Here, we investigated the neural basis of the visuo-phonological transformation processes of these more fine-grained acoustic details and assessed how they change as a function of age. We recorded whole-head magnetoencephalographic (MEG) data while the participants watched silent normal (i.e., natural) and reversed videos of a speaker and paid attention to their lip movements. We found that the visual cortex is able to track the unheard natural modulations of resonant frequencies (or formants) and the pitch (or fundamental frequency) linked to lip movements. Importantly, only the processing of natural unheard formants decreases significantly with age in the visual and also in the cingulate cortex. This is not the case for the processing of the unheard speech envelope, the fundamental frequency, or the purely visual information carried by lip movements. These results show that unheard spectral fine details (along with the unheard acoustic envelope) are transformed from a mere visual to a phonological representation. Aging affects especially the ability to derive spectral dynamics at formant frequencies. As listening in noisy environments should capitalize on the ability to track spectral fine details, our results provide a novel focus on compensatory processes in such challenging situations.

73. Priming Effects on Metaphor Comprehension in Chinese English Learners: An ERP Study

Doctoral Student Yalin Sun1, Prof Hongjun Chen2, Dr Suzanne Otieno1, Prof Fengyu Cong2, Prof Paavo Leppänen1

1University Of Jyväskylä, 2Dalian University of Technology

73. It has previously been observed that prime words have an impact on figurative language processing. What is less clear, is the possible influence of unconscious primes on metaphor processing. In this study we used brain event-related responses (ERPs) to examine the influence of masked primes with tachistoscopic presentation on the processing of target words presented in sentences in two different languages, native Chinese and foreign English language. The participants were adult Chinese English learners. They were asked to judge whether the metaphors presented with different masked primes (metaphorical/literal/control primes) make sense or not. For Chinese language, parameter-free cluster permutation statistics revealed that clusters at the 240-280 ms time window had higher negative amplitude for the sentences with the metaphorical primes compared to those with the literal primes in the vicinity of at the left fusiform area. For English metaphors, the priming effect resulted in higher positive amplitude for the metaphorical primes compared to the literal primes at the 400-550 ms time window at the central brain areas. The results showed that primes also have an unconscious influence on figurative language processing both in native (Chinese) and foreign (English) language, but that effect is different between the languages in learners of a foreign language. The masked priming (with tachistoscopic presentation) effect on the brain response patterns may be attributed to automatic processing of metaphors.

74. Quantity perception among Estonian kindergarten children with developmental language disorder

PhD student Liis Themas1, Associate Professor of Estonian Phonetics Pärtel Lippus, Associate Professor of Speech and Language Pathology Marika Padrik, Professor of Experimental Psychology Kairi Kreegipuu 1University Of Tartu

74. Previous studies have reported delay in the development of language processing in children with developmental language disorder (DLD; Kujala & Leminen, 2017). More specifically, there is neurophysiological evidence that difficulties in perceiving prosody at young age predict later impairments in language development (Frederich et al., 2004; Weber et al., 2005). At school-age prosody perception remains compromised in children with language impairments (Datta et al., 2010; Shafer et al., 2011, 2005). Estonian three-way quantity distinction, a unique feature of Estonian word prosody, is manifested as complex prosodic structures which combine tonal and durational components (Lippus et al., 2009). There is no neurophysiological data about processing the three-way quantity system by children. The aim of the current study is: (1) to describe neurophysiological differences between children with DLD and their normally developing peers perceiving the three-way quantity distinction with the aid of mismatch negativity (MMN); (2) and to report if neurophysiological data correlates with behavioral results. All children (4.6-6.5-year-olds, DLD group N=30, control group N=30) go through psychometric testing (WPPSI-IV UK version, TTFC-2 Estonian version, Speech and Language Battery of Estonian for 5-6-year-olds) and the DLD group receives a complete EEG examination. AERPs are measured in a passive oddball paradigm with three different sets of stimuli: the standard word alternates with deviant words which have a different quantity degree, a different fundamental frequency contour or longer vowel duration. Further, the children take part in two computerized behavioral tasks: a quantity discrimination task and a lexical decision task. Current research is a part of a longitudinal project. Here we present and discuss preliminary results of the AERPs and behavioral tasks. We hypothesize that MMNs of the DLD group are missing or attenuated and the latencies are delayed. Further, the main localization of the MMNs differs between groups. We expect a mild positive correlation between the results of the neurophysiological and behavioral measurements. For all children discrimination between the second and the third quantity degree is most difficult and both durational and tonal cues are important differentiating between the degrees.

75. Do Chinese-English speakers show hemispheric dominance for metaphor processing in their native or non-native language? Divided-visual-field and ERP study

Xichu Zhu1,2, Prof Hongjun Chen2, Dr Susannah Otieno1, Prof Fengyu Cong2, Prof Paavo Leppänen1

1University of Jyväskylä, 2Dalian University of Technology

75. Background: Previous brain research has found some evidence for right hemispheric dominance of metaphor processing in native language, though conflicting results also exist. The hemispheric dominance of second language metaphorical processing is even more unclear and scarcely studied. Research questions: This study investigated whether Chinese-English speakers processed Chinese and English metaphors, as compared to literal expressions, predominantly at the right or left hemisphere. In addition, the role of familiarity in processing of metaphorical and literal expressions in the first and second language was explored. Materials and methods: This study used brain-event-related potentials with a divided-visual-field paradigm. The participants were asked to perform plausibility judgments of familiar and unfamiliar metaphorical and literal sentences for Chinese (L1) and English (L2) languages. Results: The behavioral reaction time results showed that participants needed longer time to process unfamiliar metaphoric sentences than unfamiliar literal sentences. Overall, the reaction times for unfamiliar sentences were longer than those for familiar sentences in both languages. Moreover, it took longer to process English expressions than Chinese in all sentence conditions which shows an L1 advantage. The EEG results obtained using parameter-free cluster permutation statistics showed a significantly larger N400 response for metaphors than literal expressions in Chinese and a slightly larger N400 response for literal expressions than metaphors in English. Both metaphoricity and familiarity had an effect on the brain response patterns for Chinese and English metaphor processing. However, the brain responses were distributed bilaterally across hemispheres. Conclusion: The results of this study demonstrate a complex hemispheric processing pattern for metaphorical expressions, compared to literal expressions, suggesting, however, no clear evidence for lateralization of metaphor processing. The results also suggest different brain response patterns for metaphor processing between Chinese and English languages.

76. The role of alpha and beta oscillations in naturalistic language processing

Dr Ioanna Zioga1, Dr Hugo Weissbart1, Dr Ashley G. Lewis1, Dr Saskia Haegens1,2, Dr Andrea E. Martin1,3

1Donders Centre for Cognitive Neuroimaging, Radboud University, 2Department of Psychiatry, Columbia University, 3Max Planck Institute for Psycholinguistics

76. During language comprehension, we convert sensory input to abstract structure and meaning. However, little is known with regards to the role of alpha and beta brain oscillations in the encoding of high-level linguistic information during comprehension of naturalistic speech. In this study, we tested whether the functional role that alpha and beta oscillations play in low-level perceptual processing can be generalized to naturalistic speech processing. In particular, alpha oscillations are related to facilitated processing during high cognitive load through inhibition of task-irrelevant networks (Klimesch, et al. 2007), while beta oscillations have been linked to reactivation of content representations (Spitzer & Haegens, 2017). Twenty-five Dutch native speakers listened to stories in both spoken Dutch and French while magnetoencephalography was recorded. We used dependency parsing to identify three dependency states at each word, as the number of 1) newly opened dependencies (corresponding to encoding), 2) dependencies that remained open (maintenance and cognitive load), and 3) resolved dependencies (reactivation). We then constructed linear encoding models to predict alpha and beta power from the dependency features, controlling for low-level linguistic features. Reconstruction accuracy was measured as the correlation between the actual brain signal and the reconstructed signal, following a leave-one-out cross-validation approach. Results showed that reconstruction accuracy was significantly higher in the actual compared to null models (i.e. models in which the actual feature values were replaced with feature values from a different story), especially at left temporal regions. Alpha power was mostly related to maintenance, load, and reactivation, but not to encoding, while beta power was related to every stage of dependency processing, especially to reactivation. The dependency features thus successfully predict alpha and beta power in language-related regions, beyond low-level linguistic features. Reconstruction accuracy was significantly higher for Dutch compared to French stories, suggesting that at least part of the explained variance in alpha and beta power must be related to comprehension in our Dutch native speakers. Overall, this study sheds light on the role of alpha and beta oscillations during naturalistic language processing, providing evidence for the generalizability of these dynamics from perceptual to complex linguistic processes.

187. The Effect of Pausing for Reflection while Reading on Empathy and Creativity

Dr. Erin Clabough1, Maeve Winter1, James Ingersoll2, AJ Willy2

1University Of Virginia, 2Hampden-Sydney College

187. Creativity and empathy are linked together, as it is easier to take another’s perspective if you can imagine their situation, and altruistic acts may be easier to generate. Societal levels of creativity and empathy have been measurably dropping; however, like other teachable skills, creativity and empathy can be practiced and improved. Our study examines the impact of instructing caregivers to pause and engage in a conversation with a child (6-8 years old) while reading a picture book story nightly at bedtime over a 2 week period. The participant’s parents were provided with 7 picture books written by various authors and instructed to read one book a night to the child in a two-week span. Half of the participants were instructed to read the entire book to their child under normal circumstances at bedtime. The remaining participants were instructed to read to a point of conflict within the story determined by the investigators and pause to ask their child two questions written on a label placed inside the book before continuing on with the remainder of the story. At the enrollment visit, children were given a version of the Garton and Gringart empathy as a baseline measurement of both affective and cognitive empathy questions, along with a Wallach and Kogan alternative uses test aimed at measuring creativity. At the follow-up visit 2 weeks later, participants again completed the same empathy and alternative uses tests, as well as a short altruism questionnaire adapted from Litvack-Miller. Data were analyzed using paired t-tests between the group that paused for reflection and the control group. Data will be presented regarding changes in performance for creativity (fluency and originality), empathy (affective and cognitive), as well as any differences on the post-test altruism measure. Our study explores an easy way for parents to implement a daily moment of creativity and empathy practice by using a different way of reading to young children during a recurring nightly routine activity that many families already participate in.

188. The rIFG Integrates Emotion and Cognition - Evidence From an EEG/FEM Beamformer Study

Anya Dietrich1, Edoardo Pinzuti1, Dr Yuranny Cabral Calderin2, Dr Florian Müller-Dahlhaus3, Prof Michael Wibral4, Prof Oliver Tüscher1,3

1Systemic Mechanisms of Resilience, Leibniz Institute For Resilience Research (LIR), 2Neural and Environmental Rhythms, Max Planck Institute for Empirical Aesthetics, 3Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, 4University of Göttingen, Campus Institute for Dynamics of Biological Networks, Department of Data-driven Analysis of Biological Networks

188. The interaction of emotion and cognition in the brain is a highly debated topic. For many decades the two systems were perceived as separable processes yet allowing interactions. Recently, this differentiation has been challenged by more integrative approaches of emotion and cognition, yet without addressing the neurophysiological groundwork. In this study we investigate potential oscillatory mechanisms of emotion-cognition interaction that depend on space, time and frequency via an EEG/FEM beamforming approach in a large cohort (N=103) of healthy human participants. Emotion-cognition interaction was measured via an emotional Eriksen Flanker task, where emotional task-irrelevant images preceded the flanker signal. We found significant activity in the right inferior frontal gyrus (rIFG) both during cognitive and emotional processing and, more importantly, during the interaction of emotion and cognition. This indicates that (i) the rIFG is a general driver for cognitive control, (ii) it also processes emotional interference, and (iii) it integrates emotion and cognition. Further we observed that the strongest activation site for cognitive control, emotional processing, and the integration of both resides in different subdivisions of the rIFG supporting functional segregation and processing gradients in this area. Additionally, we found beta band activity not only to be the mediator of cognitive processing, as described in the literature, but also during emotional processing and especially during the interaction of emotion and cognition. Moreover, we observe that this beta band activity varied in time depending on the emotional or cognitive load. Importantly, the interaction of emotion and cognition in the rIFG reflected by beta band activity is behaviorally relevant as it is correlated to reaction time and accuracy as revealed by Bayesian correlations. Thus, our results show for the first time, that emotion-cognition interaction varies in space, time, and frequency and that the rIFG seems to be a critical hub for the integration of emotion and cognition, adverting this region as potentially relevant in mental health diseases when emotion-cognition integration is distorted or even fails.

189. Brain-body interactions in emotions: perspective matters

Tahnée Engelen, Anne Buot, Julie Grèzes, Catherine Tallon-Baudry 1Cognitive and Computational Neuroscience Laboratory, Department of Cognitive Studies, Ecole Normale Supérieure

189. Experiencing an emotion oneself, in first person perspective, and observing emotions in others, in third person perspective, share substantial physiological and neural similarities. Still, under normal circumstances we do not ‘loose’ our sense of self, and are able to distinguish our own emotions from someone else’s. Neural monitoring of cardiac signals has recently been proposed as a mechanism for such self-other distinction and self-specification in the domains of perception and cognition. Here, we probe whether the same mechanism is at play for emotions – in other words, whether there is a domain-general mechanism of self-other distinction, valid across perception, cognition and emotion. We tackled this question in a paradigm where participants had to rate valence and arousal in response to affective social scenes. Before each trial, a cue indicated whether they would have to report the emotional experience they felt (Self condition), or the emotion expressed by people in the scene (Other condition). During cue, when participants prepared to adopt the Self or Other perspective, we tested whether Heartbeat Evoked Responses (HERs) distinguish between the Self and Other condition. During affective scene presentation, we tested to what extent the known physiological correlates (heart rate, skin conductance response, facial electromyogram) of emotions are affected by perspective. Finally, we analysed whether the self-other discriminating HERs and the affective-related physiological measures independently contribute to subjective experience as rated by the participant. Before having seen any image, HERs significantly differed between the self and other perspective. Additionally, we found evidence that physiological measures (SCR and fEMG) were sensitive to the perspective from which the image was being evaluated. Importantly, we found that changes in bodily signals related to emotions significantly contributed to the ratings of valence and arousal of the participant irrespective of adopted perspective. The HER, however, specifically contributed to the experienced subjective valence when assessing self, but not someone else’s emotions. Our findings demonstrate that perspective permeates measures of emotion on every level; the HER, physiology, and subjective ratings and that the HER related to perspective contributes to our own subjective emotional experience.

190. When Predictive Coding Goes Wrong: Sensorimotor Activation Predicts and Accompanies Illusory Social Perception

Dr. Elisabeth V C Friedrich1, Dr Imme Zillekens2, Dr Anna Lena Biel1, Mr Dariusz O'Leary1, Mrs Eva Victoria Seegenschmiedt1, Mr Johannes Singer1,3, Prof Leonhard Schilbach1,2, Prof Paul Sauseng1

1Ludwig-Maximilians-Universität München, 2Max Planck Institute of Psychiatry, 3Freie Universitat Berlin

190. Objectives: Prior experiences help us navigate social interactions. Seeing a communicative action of one person can – under certain conditions - lead to expectations that are so strong, that we perceive another person responding despite them not actually being present (i.e., seeing a Bayesian ghost). In this study, we aimed to explore the neural correlates of such illusory social perception. Research question: Does sensorimotor brain activation predict and accompany the Bayesian ghost? Methods: Participants watched a light-point agent performing a communicative or individual gesture, followed by either a second masked agent responding to the gesture or noise dots. Participants then had to decide whether the second masked agent was present or if there were only noise dots. EEG was recorded during the experimental task. Results: When observation of the communicative gesture of the first agent was accompanied by increased activation of the sensorimotor cortex, participants were significantly more likely to later respond as having seen the second agent although it was not present (i.e., a Bayesian ghost occurred). This pre-activation of the sensorimotor cortex in alpha and beta frequency bands indicated that participants generated predictions about the second agent’s response. This top-down control outweighed the sensory information perceived in the later time segment and led to seeing a person who was not present. During the appearance of the Bayesian ghost, increased activation of the sensorimotor cortex was indicative of biological movement observation (despite there only being noise dots present) and increased activation of the superior parietal cortex was associated with creating the illusion. Conclusion: Our findings provide striking evidence that we do not merely react to others in social interactions but that our brain anticipates subsequent behavior. These expectations of a certain response to a social action usually facilitate our complex social interactions, but can – under certain conditions - result in seeing a person responding to the social action who is in fact not there. These results are also of importance to the field of psychiatry as they lay the foundation for a better understanding of mental illnesses in which difficulties in social interactions and illusory perception occur.

191. Brain dynamics of recommendation-based social influence on preference change: A magnetoencephalography study

Ms Fatemeh Irani1,2, Ms Sini Maunula4, Dr Joona Muotka1, Dr Matti Leppäniemi3, Ms Maria Kukkonen1, Dr Tiina Parviainen1,2, Dr Simo Monto1,2

1 Department of Psychology, University of Jyväskylä, 2Center for Interdisciplinary Brain Research, University of Jyväskylä, 3School of Business and Economics, University of Jyväskylä, 4Laurea University of Applied Sciences

191. People change their preferences when exposed to others' ideas and preferences in face-to-face interactions as well as across social media. Previous studies suggested that interpersonal influence enters into the procedure of opinion formation in consumer behavior and subjects update their recommendation opinions under the influence of others' recommendations. Out of temperamental and personality characteristics, the trait agreeableness is linked with social conformity and knowledge sharing behavior, and may thus influence both the neural and behavioral manifestations of peer influence during choice behavior. We utilized the high temporal resolution of magnetoencephalography (MEG) to follow cortical activation in individuals (n=30) with low and high agreeableness, when they indicated their recommendations of commercial brands. The recommendations were subjected to peer group feedback, and after the MEG experiment, the participants were asked to re-evaluate the brands. Recommendations changed consistently with conflicting feedback only when peer recommendation was lower than the initial recommendation. On the neuronal level, feedback evoked neuronal responses in the medial frontal and lateral parietal cortices were stronger for conflicting than non-conflicting peer opinions in two time windows after feedback onset: 68–245 ms and 320–998 ms. In time-frequency analysis, conflicting feedback was also associated with increased oscillatory power at the 4-10 Hz band and decreased oscillatory power at 13–30 Hz in medial frontal and parietal cortices, respectively. The change in recommendation behavior, or neural activity associated with the recommendation, was not different between the low and high agreeableness groups. However, the groups showed differences in neuronal oscillations in the alpha-beta band (10-28 Hz) when peer feedback agreed with the recommendation: the high agreeableness group showed higher induced oscillation amplitude mainly in lateral and medial occipital cortices. Our results corroborate earlier findings on the role of conflict monitoring and mentalizing regions in behavioral change and suggest that agreeableness modulates neuronal processing of peer feedback.

192. The impact of problematic Facebook use and Facebook context on empathy for pain processing: An functional near-infrared spectroscopy study

MA Natalia Kopiś-Posiej1,2, Dr Andrzej Cudo2, Dr Paweł Augustynowicz2

1Department of Clinical Neuropsychiatry Faculty of Medicine Medical University of Lublin, 2Department of Experimental Psychology, The John Paul II Catholic University of Lublin, Poland

192. Facebook associates 2.91 billion active users (the data from the fourth quarter of 2021). Except for connecting people from all around the world, Social Media (SM) can lead to social isolation. With the growth of SM, empathy has declined. Empathy engages cognitive and affective processes that support understanding and sharing others’ emotional states. Social neuroscience models of empathy suggest that it can be induced by cues signalling others' pain that activate neural responses in brain regions. Valence-Specific Hypothesis (VSH) proposes that the left cerebral hemisphere is more specialized for processing positive emotions, while the right hemisphere tends to dominate for processing negative emotions. In our study, we used functional near-infrared spectroscopy (fNIRS). We wanted to examine the relation between nonproblematic and problematic Facebook use (Non-PFU/ PFU) and the influence of a cue associated with Facebook on empathy. We used the most common stimuli presented in the empathy paradigm (painful and nonpainful stimuli) presented on a Facebook and newspaper background. We find that cerebral lateralization plays a crucial role in processing emotions. The most important result was in the right anterior prefrontal cortex, active during observation painful and nonpainful stimuli presented on Facebook background, but only in group Non-PFU. We do not observe similar results for the PFU group. This result may suggests that the neural mechanisms operate independently and comprise a set of complex emotion processing networks.

193. The effect of cognitive strategies and facial attractiveness on empathic neural responses

MS Natalia Kopiś-Posiej1,3, PhD Emilia Zabielska-Mendyk3, Professor Michela Balconi2, PhD Irene Venturella2, MS Laura Angioletti2, PhD Paweł Augustynowicz3

1Department of Clinical Neuropsychiatry Faculty of Medicine Medical University of Lublin, 2Research Unit in Affective and Social Neuroscience, Department of Psychology, Catholic University of the Sacred Heart, Milan, 3Department of Experimental Psychology, The John Paul II Catholic University of Lublin,

193. The possibility to empathize with another person is a crucial ability to function in society properly. Empathy allows both sharing and understanding others' feelings. These two critical aspects of empathy are commonly found in literature as emotional and cognitive. Research revealed that emotional empathy is related to modulation in early event-related potentials (ERP) amplitude, and cognitive empathy is linked to later ERP. In the current ERP study, we examined the influences of facial attractiveness on empathic response and the effect of cognitive strategies with setting the participants' attention to attractiveness or pain. Participants (N= 19) viewed photos of physically attractive and unattractive men and women who feel pain. The amplitude of the N2 component was more positive in painful stimulation compared to the non-painful, but only for attractive faces. There were no differences between painful and non-painful stimuli for unattractive faces. The amplitude of the P3 component was more positive in painful conditions than the non-painful one but only when participants performed the pain judgment task. There were no differences in the attractiveness judgment task. This study showed that the attractiveness of a model and drawing participants’ attention to pain constitute an essential modulator of pain empathy.

194. Comparison of the emotional response to spiders, fearful, and disgusting stimuli: fMRI study

Eva Landová1,2, Silvie Rádlová1,2, Jakub Polák1, Kristýna Sedláčková1,2, Anna Pidnebesna2, David Tomeček2, Jaroslav Hlinka2, Daniel Frynta1,2

1Faculty of Sciences, Charles University, Viničná 7, 12844 Prague , 2National Institute of Mental Health, Topolová 748, 25067, Klecany

194. Spiders are common objects of phobias. It is unclear, however, whether they evoke primarily fear or disgust in fearful subjects. We prepared an experiment to examine the neural aspects of emotional priming to spiders either by fear- or disgust-eliciting stimuli. We presented various emotional stimuli to 30 arachnophobics (Aph) and 32 healthy controls (HC) inside the magnetic resonance. There were three measuring sessions; first, we presented the block „neutral“, which included the stimulus categories tarantula spiders, beetles, leaves and daddy-long legs spiders. Second, we presented either the block „fear“ (tarantula, beetle, fear-eliciting snakes, lizards), followed by „disgust“ (tarantula, beetle, disgusting animal carcasses, sleeping animals), or vice versa. In the subsequent analysis, we found stronger activation of the higher-level visual processing areas (both the ventral and dorsal stream) when watching the tarantulas, fear-evoking, and disgusting stimuli, in both Aph and HC. When we analyzed the difference between the groups of respondents, we found that the Aph showed a higher activation of the ventral visual stream when watching the tarantulas. We found no significant difference between the Aph and HC when watching the fear-evoking and disgusting stimuli. Moreover, we analyzed the effect of priming with the fear-eliciting and disgust-eliciting stimuli when watching the tarantula spiders. The poster shows the differences between the Aph and HC respondents and more detailed analyses of each of the priming condition. Keywords: spiders, phobia, arachnophobia, emotions, fear, disgust, fMRI

195. The induced sad mood affects the unconscious and conscious perception of emotional faces

Xueqiao Li1,2, Dr Piia Astikainen1,2

1Department of Psychology, University Of Jyväskylä, 2Centre for Interdisciplinary Brain Research, University Of Jyväskylä

195. The perception of emotional facial expressions plays an essential role in social interactions. However, it is not well known if a sad mood can affect the perception of facial expressions in healthy participants. Here we aim to explore whether induced sad mood compared to neutral mood affects the unconscious and conscious perception of facial expressions in healthy participants. Velten’s mood statements and music, in neutral and sad conditions, were utilized to induce the target mood on two separate days. Sad and neutral faces were presented randomly either in a subliminal condition (for 10 ms which is below the conscious detection threshold) or in a supraliminal condition (for 200 ms which is above the conscious detection threshold) with equal probability in a backward masking task. For each trial, participants were instructed to discriminate the facial expression (sad/neutral) of the target faces by pressing response buttons with the index or middle finger as quickly as possible. Performance of discrimination tasks and continuous electroencephalogram (EEG) were recorded in adult participants (N = 20). The behavioral responses (response times and hit rate) and event-related potential (ERP) in response to sad and neutral faces (latencies and amplitudes of P1, N170, P2, and P3 components) were compared between induced sad and neutral mood conditions. For the subliminal faces, the mood effect was not observed in the ERPs but in behavioral responses. The hit rate for sad faces was higher when participants were in a sad mood than in a neutral mood. For the supraliminal faces, P1 latency was larger in sad mood than in neutral mood. However, the behavioral results did not show any mood effects. The results indicate that induced sad mood affects both the conscious and unconscious perception of facial expressions in healthy individuals.

196. Social dominance and decision making

Wei-hsiang Lin1, Dr Janir da Cruz1, Dr João Rodrigues2, Prof Carmen Sandi2, Prof Michael Herzog1

1Laboratory of Psychophysics, Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 2Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL)

196. Making decisions is one of the most crucial tasks in our daily lives. Several factors possibly affect how one makes decisions. For example, social dominance orientation (SDO), a personality trait reported to be associated with leadership, may play an important role. Here, we investigated how SDO shapes decisions in a variety of decision-making tasks by exploring how several behavioral patterns were associated with the dominance trait. We recruited 146 participants via the online platform Prolific. Each participant completed seven questionnaires to measure their dominance and personality traits as well as six different cognitive tasks. The tasks captured a wide variety of decision-making scenarios such as value-based (lottery choice task), perceptual-based (emotion discrimination task) decisions, and goal-directed behavior (reinforcement learning). Additionally, two control tasks (Go No/Go task and simple reaction time task) were used to measure executive function and motor speed. Firstly, we found a negative correlation between the dominance trait and reaction time of decision-making tasks, suggesting a predisposition for high dominant individuals to act faster. No correlation was found for the control tasks, suggesting that the fast reactions of dominant individuals in decision-making tasks are not merely explained by superior motor ability or increased impulsivity. Additionally, there was no significant relation between dominance trait and accuracy or other decision-related variables, such as risk aversion, reward discounting, or the proportion of making optimal actions in the reinforcement learning framework. Hence, high dominance individuals outperform those of low dominance individuals in making decisions in terms of speed, which does not pertain to their motor or executive abilities. Comparatively, high dominance individuals do not demonstrate superior performance or display unique strategies across a wide range of decision-making scenarios.

198. Multiple large-scale neural networks underlying emotion regulation

Dr. Carmen Morawetz1, Dr. Michael Riedel2, Taylor Salo2, Prof. Simon Eickhoff3, Prof. Angela Laird2, Dr. Nils Kohn4

1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 2Department of Physics, Florida International University Miami, 3Institute for Systems Neuroscience, Heinreich-Heine University Düsseldorf, 4Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center

198. Recent models suggest emotion generation, perception, and regulation rely on multiple, interacting large-scale brain networks. Despite the wealth of research in this field, the exact functional nature and different topological features of these neural networks remain elusive. Here, we addressed both using a recently developed data-driven meta-analytic grouping approach. We identified large-scale neural networks underlying emotion generation, perception and regulation based on convergent brain activation patterns reported during ER via data mining of 385 experiments from 107 published papers. We present empirical evidence for the idea of a multi-component view of ER supported by large-scale brain networks. We applied k-means clustering approach to a large set of previously published experiments investigating emotion regulation (independent of strategy, goal and stimulus type) to segregate the results of these experiments into large-scale networks. To elucidate the functional nature of these distinct networks, we used functional decoding of metadata terms (i.e. task-level descriptions and behavioral domains). We identified four large-scale brain networks. The first two were related to regulation and functionally characterized by a stronger focus on response inhibition or executive control versus appraisal or language processing. In contrast, the second two networks were primarily related to emotion generation, appraisal, and physiological processes. The behavioral profiles associated with the distributed large-scale networks give rise to the assumption that these brain networks play different roles within the ER process. Our results yield new insight into the multicomponent process of ER and provide a coherent framework for studying the functional architecture of ER.

199. Effects of social presence on neural and behavioural aspects of empathy for pain

Pauline Petereit1, Prof. Ulrike M. Krämer1,2

1Department of Neurology, University Of Luebeck, 2Department of Psychology, University of Luebeck

199. Objectives: The current study aimed to investigate the effects of reduced social presence, defined as the degree to which verbal and non-verbal cues about the others’ state are available and to which social interaction is possible, on empathy for others. Research question: How does social presence affect empathic accuracy and neurophysiological signatures of empathy, namely mirror neuron system activity and physiological coupling? Materials and methods: Using empathy for pain as a model paradigm for empathy, 30 participants received electric shocks of varying intensity themselves and subsequently observed others receiving electric shocks. We compared two conditions: presence (participants were directly facing each other) and online (real time video interaction). We measured empathic accuracy towards the other’s pain and recorded neural and physiological responses to other’s as well as one’s own pain. We expected that empathic accuracy, as well as mu suppression over somatosensory cortex, a putative marker of mirror neuron system activity would be lower in the online compared to the presence condition. Results: Presence of the other did not affect empathic accuracy. Mu suppression over the somatosensory cortex tracked the intensity of own but not other‘s pain, and was not affected by the other’s presence. Instead, exploratory analyses showed early (0-500 ms) activity (3-20 Hz), widespread over central, frontal and parietal electrodes that correlated (on trend level) more strongly with the pain intensity in the presence than in the online condition. Moreover, frontal theta was related to both own and the other‘s pain intensity, and parietal beta specifically to the other‘s pain intensity, but social presence did not modulate these neural signatures of empathic experience. Conclusion: Surprisingly, our results indicate that both behavioral and neural aspects of empathy towards others’ pain are preserved in an online interaction. In contrast to former studies, we find no evidence of somatosensory mirror system activity in pain empathy. Instead, frontal theta seems to be a marker of one’s own pain experience, as well as empathic pain experience.

200. Anger processing in traumatic brain injury: an eye-tracking study on attentional bias to angry faces

Nellia Bellaert1, Alice Bodart1, Wivine Blekic1, Laurent Lefebvre1, Mandy Rossignol1

1University of Mons

200. Emotional dysregulation is amongst the most persistent consequences after a moderate to severe traumatic brain injury (TBI). Among these, TBI has been shown to disturb subjective feeling, leading to an angry overreaction to negative events. This overreaction can cause aggressive behaviors that compromise the socio-professional reintegration. However, the origin of this increased anger experience in TBI patients is yet to be defined. Focusing on underlying mechanisms of emotion should allow to better understand the causes of exacerbated anger. According to the Component Process Model of emotion (Scherer et al., 2009), subjective experience of emotions results notably from cognitive processes (e.g., allocation of attention). Mild TBI has been associated with enhanced allocation of attentional resources to threat-related stimuli, which might contribute to affective symptoms such as irritability (Mäki-Marttunen et al., 2015). Nevertheless, the link between attentional bias toward angry faces and subjective feeling of anger has never been investigated in moderate to severe TBI, even though this cognitive process may affect subjective feeling. This study aims to assess these two emotional components in patients with TBI in comparison to controls, in order to examine the degree to which attentional bias to angry faces predict subjective feeling of anger. First, attention allocation is assessed using an eye tracking recording of a Face in the Crowd Task (Pinkham, Sasson & Gur, 2010), in which nine facial expression are displayed simultaneously and participants are asked to decide whether all of the presented faces express the same emotion or one of the faces expresses a different emotion. Second, participants are asked to read scenarios resulting in unpleasant outcomes (Epps & Kendall, 1995) and to rate how angry they would be in that situation, depicting subjective feeling. Scenarios differ according to the character’s actions: benign, ambiguous or hostile. We hypothesized that, in TBI patients, higher levels of subjective anger in response to scenarios will be associated with enlarged attentional bias to angry faces. Testing are currently in progress and results will be presented at the conference. Our results would allow to determine whether targeting attentional bias could be useful for treatment of anger issues following TBI.

201. Minority status, ethnicity, and prejudices: a systematic meta-analysis on fMRI studies

Dr Aino Saarinen1, Prof Liisa Keltikangas-Järvinen1, Prof Niklas Ravaja1

1University Of Helsinki

201. Background: Prejudices toward ethnic groups and ethnic discrimination constitute major problems around the world. Previous research has found evidence for ethnic in-group bias: the brain processes differently ethnic in-group vs. out-group members. Two crucial questions, however, have remained open: (1) whether neural in-group bias is different in ethnic minority vs. majority members, and (2) whether neural in-group bias is differently expressed toward different ethnicities. Objective: A systematic coordinate-based meta-analysis of functional magnetic resonance imaging (fMRI) studies was conducted to investigate neural inter-group biases toward ethnic groups (i.e., BOLD responses toward ethnic in-group vs. out-group). First, we investigated neural in-group bias in minority members (toward majority members) and in majority members (toward minority members). Second, we examined neural in-group bias toward White target individuals (in non-White participants), toward Black target individuals (in non-Black participants), and toward Asian target individuals (in non-Asian participants). Results: First, we found that neural in-group bias was differently evident in minority and majority members. Second, there were differences in neural in-group bias toward various ethnic groups. Discussion: The findings provide novel implications for theory and prejudice-reduction interventions.

202. Chronotype and time-of-day effects on face processing: Early ERP correlates

Isabel M Santos1,2,3, André Silva1, Pedro Bem-Haja1,3, Paulo Rodrigues4, Fábio Monteiro4, Pedro J Rosa5, Diâner F L Queiroz1, Catarina Rosa1,3, Carlos F Silva1,2

1University of Aveiro, 2William James Center for Research, 3CINTESIS.UA, 4University of Beira Interior, 5HEI-Lab, University Lusófona of Humanities and Technology

202. Objectives: Face recognition is a pervasive and important ability in daily life. Although familiar face recognition is seemingly easy and efficient, recognition of unfamiliar faces is difficult and highly error prone, and can be affected by various situational and individual variables. Our objective was to explore whether chronobiological variables can influence face recognition. Research question: The present study sought to understand if chronotype (individual preference for the morning or evening period) and the time-of-day when the task was performed (in synchrony or asynchrony with the preferred time) influence performance and early ERP correlates of face processing. Materials and methods: Thirty-two participants (16 evening-types, 16 morning-types, assessed with the Morningness-Eveningness Questionnaire) performed the tasks twice, at their peak and off-peak times (7:30am and 7:30pm), with a one-week interval between sessions, while their EEG was recorded. One task was a modified version of the Glasgow Face Matching Task (GFMT), consisting on the presentation of 80 sequential pairs of faces, and participants were required to indicate whether the second face of each pair was the same or different from the first face. The other task was a Famous Face Recognition Task, where participants saw 96 randomly presented facial photographs (half famous, half non-famous, with ovals covering hair and external face features) and were asked to indicate whether each photo was of a famous or a non-famous individual. Time-of-first session and the order of the tasks were counterbalanced between participants. All stimuli were different between sessions. Results: Although no significant chronotype or time-of-day effects were observed on behavioural performance in either task, results showed a significant time-of-day x chronotype interaction on the P100 component amplitude for both tasks. Morning-types registered higher amplitudes in the evening session, compared to the morning session, regardless of type of stimuli. Response accuracy was strongly and positively correlated with P100 amplitudes for both morning and evening sessions. No interaction between time-of-day and chronotype was found for the N170 component in either task. Conclusion: These results suggest an early visual attentional asynchrony effect only for morning-types. On the other hand, no (a)synchrony effects were evident on more face-specific processing stages.

203. Meditation Aided With 40 Hz Binaural Beats Enhances The Cognitive Function And Mood State

Ms. Rubina Shakya1

1Kathmandu University School Of Medical Sciences, 2Dhulikhel Hospital

203. The exposure of constant stress stimuli in our daily lives is causing deterioration of neural connectivity in the brain. Interestingly, the improvement in larger-scale neural communication has been argued to rely on brain rhythms, which might be sensitive to binaural beats of particular frequency bands. The theoretical idea behind neural entrainment is that the rhythmic oscillatory activity within and between different brain regions can enhance cognitive function and mood state. So, we aimed to investigate whether the binaural beats of 40 Hz could enhance the cognition and the mood stability of the medical students at Kathmandu University of age 18-25 years old, which possibly, in the long run, might help to enhance their work productivity. The participants were asked to focus on the auditory stimuli of binaural beats with 200 Hz on the right side and 240 Hz on the left side of the headset for 15 minutes, every alternative day of three consecutive weeks. The Stroop’s test and the Brunel Mood Scale (BRUMS) were applied to assess the cognitive function and the mood state, respectively. The binaural beats significantly decreased the reaction time for the incoherent component of Stroop’s test in both male and female participants. For the mood state, scores of all positive emotions except ‘Calmness’ were significantly increased in the case of males. Whereas, scores of all positive emotions except ‘Vigor’ were significantly increased in the case of females. The results suggested that binaural beats of 40 Hz could help in improving cognition and mood states.

204. The role and possible mechanism of prefrontal cortical GABAergic transmission impairment in MCI with depression

Dr. Shu Shu1, Ms. Siyi Xu1, Dr. Yun Xu1

1Department of Neurology, Nanjing Drum Tower Hospital, Affiliated of Nanjing University Medical School

204. Background: Mild cognitive impairment (MCI) is a clinical condition between normal aging and dementia, which is considered to be a progenitor stage of Alzheimer's disease (AD). Clinical studies indicated that depression was one of the key risk factors in promoting the progression of MCI to AD, but little is known about the critical brain regions and mechanisms of MCI with depression. Methods: In our previous work, we found that young APP/PS1 mice could be a proper mice model of MCI, which had been verified that 2-3 months old APP/PS1 mice had short-term memory impairment and depressive-like behavior. Here, we used 2-3 months old APP/PS1 mice as MCI with depression model, behavioral test, whole-cell recording, optogenetics and molecular biology methods. Results: A small amount of Aβ deposition, impaired synaptic inhibitory transmission and increased excitability of pyramidal neurons were detected in the prefrontal cortex (PFC) of these mice, suggesting that PFC plays an important role in MCI with depression. After increasing GABA transmission by optogenetic stimulation, short-term memory deficits and depressive behaviors were rescued, remarkably. Conclusion: Our results suggested that impaired GABA transmission in PFC might be the pathophysiological mechanism of MCI leading to depression-like behavior. The role of prefrontal cortical inhibitory dysfunction in MCI with depression and its mechanisms would provide new ideas and strategies for MCI with depression treatment and is hoping to delay the progression from MCI to AD.

205. The brain automatically categorizes discrete auditory emotion expressions

Siddharth Talwar1, Francesca Barbero1, Roberta Calce1, Olivier Collignon1,2,3,4

1Institute of research in Psychology (IPSY) & Institute of Neuroscience (IoNS), University of Louvain (UCL), 2Center for Mind/Brain Sciences, University of Trento, 3School of Health Sciences, HES-SO Valais-Wallis, 4The Sense Innovation and Research Center

205. Emotion expressions delivered through voices are vital information for interpersonal communication. How the brain discriminates separate emotions delivered through voices remains however poorly understood. To fill this knowledge gap, we rely on electroencephalographic (EEG) recordings in humans combined with a frequency tagging approach to tag neural responses to specific emotion expressions. We selected five “primary” emotion categories (Anger, Fear, Disgust, Happiness, Sadness) vocalized by professional actors and actresses. Twenty-four adult participants listened to a stream of heterogeneous emotional sounds presented periodically to elicit a brain response at the same frequency in the EEG spectrum (2.5 Hz). Importantly, sequences were created so that a specific emotional category (eg fear) appeared at each third sound (0.833 Hz). This oddball presentation rate elicits an additional response in the EEG spectrum only if the brain discriminates a specific emotional category (eg fear) from other emotional categories (eg happy, disgust, anger, sad) and generalizes across heterogeneous exemplars of the “fear” category. To avoid evoking responses caused by differences in acoustic features, stimuli were matched for harmonicity to noise ratio, center of gravity, pitch and envelope. Additionally, participants were presented with a scrambled version of the stimuli with identical spectral content but disrupted intelligibility. We observed a strong brain response at 2.5 Hz, corresponding to the general rate of sound presentation, for both intact and scrambled sequences. Crucially, we observed a peak in the EEG spectrum at the emotion presentation rate (0.83 Hz) in the intact sequence only. The absence of response at the oddball frequency in the scrambled sequence in conjunction to our stimuli matching procedure and the topography observed in the intact sequence suggest that the brain response elicited by a specific emotion relates to the process of higher-order categorization which is at least partially independent from the low-level acoustic features of the sounds. Our results indicate that the fast periodic oddball auditory paradigm is a promising indicator of the brain’s ability to categorize non-verbal vocal emotion expressions objectively (behavior-free), rapidly (few minutes of recording time) and robustly (high signal to noise ratio), making our technique particularly suited for testing infants or clinical populations.

206. Neural and behavioral correlates of empathy for pain in Tourette syndrome

Ronja Weiblen1,2, Carina Robert1, Marcus Heldmann1,3, Thomas Münte1,3, Alexander Münchau4, Kirsten Müller-Vahl5, Ulrike M. Krämer1,3

1Department of Neurology, University of Lübeck, 2Department of Psychiatry and Psychotherapy, University of Lübeck, 3Department of Psychology, University of Lübeck, 4Institute of Systems Motor Science, University of Lübeck, 5Clinic of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School

206. Objectives: In addition to the defining features of motor and vocal tics, patients with Tourette syndrome (TS) show diverse symptoms of altered social behaviors, such as echophenomena, coprophenomena, emotional dysregulation and difficulties in social cognition tasks. Furthermore, they report increased personal distress in emotional situations. It has been suggested that these symptoms reflect increased mirroring or sharing of others’ experience, possibly together with decreased mentalizing about others. We addressed this question using an empathy for pain paradigm together with EEG recordings, focussing on mu suppression over the sensorimotor cortex functioning as the putative neural marker for the mirror neuron system (MNS). Research Question: Do patients with TS show signs of increased mirroring in an empathy task? Methods: Fifty participants (25 age-, gender and education matched healthy controls, 25 TS) underwent the empathy for pain paradigm, while we measured EEG. Pictures of hands and feet in painful or neutral situations were presented in two conditions: normal pain sensitivity of the actor in the picture versus enhanced pain sensitivity. Participants were asked to rate the painfulness for the actor as well as for themselves in a subset of the trials. Furthermore, we tested the frequency of echophenomena and collected extensive clinical data. Changes in mu suppression during the observation of the pictures, as well as pain ratings were compared between groups and were correlated with the occurrence of echophenomena, self-reported empathy and clinical measures. Results: Analysis of the pain ratings revealed the expected effects of experimental manipulations but did not show group differences. Healthy controls exhibited the predicted increase of mu suppression while watching painful compared to neutral actions. However, TS patients did not show this effect. Mu suppression correlated with self-reported empathy, while pain ratings correlated with measures of tic severity. Conclusion: Our results do not support the predicted heightened empathy for pain in TS. On the contrary, TS patients showed less pain-related mu suppression compared to controls, while there were no behavioral group differences. Our results question the hypothesis of an overactive MNS in TS and highlight the need for more research into social cognition in patients with TS.

207. Oxytocin reduces romantic rejection-induced pain as revealed by decreased frontal-midline theta oscillation

Xukai Zhang1,2,3, Peng Li2, Susannah C.S.A. Otieno1, Hong Li3, Paavo H.T. Leppanen1

1University Of Jyväskylä, 2Shenzhen University, 3South China Normal University

207. BACKGROUND: Romantic rejection is a commonly intense distress experience that can profoundly affect human wellbeing. Oxytocin (OT), a neuropeptide, has been shown to reduce physical pain as well as to regulate negative emotions. However, whether OT alleviates the intense social pain, for example related to romantic rejection, and whether this can be observed in brain activation, remains unknown. Here, we tested the pain-reducing effect of OT on brain activation for social pain and investigated its role in the outcome evaluation stage of social decision-making in the romantic domain. METHODS: A total of 61 healthy participants underwent electroencephalographic (EEG) recordings in a double-blind and placebo-controlled design study. Here, we used a novel online speed-dating task to investigate the role of OT in romantic decisions, in which participants meet and choose potential romantic partners online and receive feedback. We focused on the outcome evaluation stage (i.e., receiving feedback from the partners) and measured the theta oscillation of brain activity during this stage. Time-frequency analysis was used to capture the frontal-midline theta oscillation (4-8 Hz), which is associated with social pain. Additionally, a self-reported pleasantness rating for four possible romantic outcomes (Acceptance, Rejection, Unrequited and Disinterest) was measured after a novel online speed-dating task. RESULTS: Consistent with previous studies, participants in the placebo (PLC) group showed greater theta power when receiving the romantic rejection from their potential romantic partners compared to other conditions (Acceptance, Unrequited and Disinterest). We also found that participants with higher theta power showed greater rejection distress in the PLC group. However, OT significantly reduced the romantic rejection induced theta power in the OT group compared with the PLC group. Further, there was no correlation between theta power and rejection distress in the OT group. Furthermore, the group difference in the frontal-midline theta oscillation was source-localized in the brain areas overlapping with those related to physical pain (i.e., somatosensory cortex, anterior cingulate cortex, frontal pole, and supplementary motor area). CONCLUSIONS: OT reduces the theta power triggered by romantic rejection and reduces the association between theta oscillation and rejection distress, which likely reflects the pain-reducing effect of OT on social pain.

258. Detrended fluctuation analysis in the presurgical evaluation of parietal lobe epilepsy patients

Sami Auno1,2,4, Leena Lauronen1,2, Juha Wilenius1,2,5, Maria Peltola1,2, Sampsa Vanhatalo2,4, Matias Palva3,4

1Epilepsia Helsinki, University of Helsinki and Helsinki University Hospital (HUH), 2Department of Clinical Neurophysiology and BABA center, Children’s Hospital, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital (HUH), 3Department of Neuroscience and Biomedical Engineering, Aalto University, 4Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 5BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital

258. Rationale Epilepsy surgery is considered for selected patients with refractory epilepsy. Meticulous presurgical planning is imperative for a successful surgery, yet current methods are often inadequate for unambiguous identification of epileptogenic zone (EZ). This is especially problematic in extratemporal epilepsies. New methods are needed to further improve surgery outcomes. Local cortical excitation/inhibition balance is reflected in long-range temporal correlations (LRTC) of neuronal oscillations, which could provide novel tool for EZ localization. Here we hypothesized that EZ could exhibit excessive excitability and hence aberrant LRTCs. Methods Ten patients who had undergone parietal lobe epilepsy surgery, and who had pre-operative MEG and pre- and post-operative MRIs, were selected. LRTCs were evaluated with detrended fluctuation analysis (DFA) of source modelled interictal MEG data, and the DFA scaling exponents were estimated for cortical parcels. DFA exponent maps were visually inspected by three clinical neurophysiologists, who assessed the most likely EZ location based on the largest exponents. Additionally, DFA exponents were compared against the resection area and locations of inter-ictal epileptiform discharges (IEDs). Results Visual inspections showed lateralization accuracy of 83% in patients with focal cortical dysplasia (FCD), and 69% in all patients. The operated hemisphere and lobe were identified correctly in 42% of the FCD patients and in 29% of all patients respectively. DFA exponents were highest near EZ and lower elsewhere in the cortex in FCD patients. DFA exponents had significant anatomical correlation with IED locations in FCD type II patients. Conclusion DFA is a potential new approach for presurgical evaluation of epilepsy.

259. The maladaptive embodied brain: inter-individual psychopathology profiles reveal finger-prints of brain body interaction.

Dr Leah Banellis1, Dr Nicolas Legrand1, Dr Niia Nikolova1, Prof Micah Allen1

1Center of Functionally Integrative Neuroscience, Aarhus University

259. Objectives Psychiatric symptoms are traditionally associated with neurological dysfunction. However, emerging evidence suggests mental health profiles are not only a consequence of dysfunctional brain dynamics, but also arise from neuronal interactions with interoceptive bodily signals. The contribution of embodied mechanisms to psychopathology has been demonstrated in broad mental health conditions including anxiety, depression and ADHD. We aimed to identify brain-body phenotypes indexing psychiatric symptom dimensions using canonical correlation analysis of multimodal neuroimaging data. We expected functional connectivity in regions of the central autonomic network in high and low heart rate variability (HRV) states to correlate with arousal-inducing psychiatric symptom dimensions such as anxiety and ADHD. Research questions Can we characterise autonomic connectome fingerprints of psychiatric symptom dimensions? Materials and methods ~500 participants completed a comprehensive battery of psychiatric symptom and lifestyle inventories, as well as resting-state fMRI and physiological recordings (i.e., electrocardiogram, electrogastrogram, and respiration). First, we conducted exploratory factor analysis on psychiatric inventory responses to identify concrete symptom dimensions. To indicate cardiovagal output, we calculated the high frequency index of heart rate variability, which was inputted as a regressor for resting-state fMRI. This determined a network of correlated fMRI activity with the high frequency HRV index. Finally, using canonical correlation analysis we identified correlated dimensions of autonomic functional connectivity with psychiatric symptom dimensions. Results We found evidence for functional correlates of autonomic connectivity patterns with specific psychiatric symptom dimensions. This included distinct connectivity profiles for each latent psychiatric construct. Furthermore, we identified functional connectomic patterns within regions of the anterior and posterior insula. These insula connectivity profiles also determined predictions of distinct mental health symptoms. Conclusion We present findings of autonomic connectome fingerprints of psychopathology. These brain-body fingerprints may be utilised as biomarkers for broad psychiatric symptom dimensions.

260. A new measure of transcallosal conduction delay shows the importance of asymmetry in bimanual

PhD Marta Bortoletto1, PhD Laura Bonzano2, PhD Agnese Zazio1, PhD Guido Barchiesi1, Eleonora Marcantoni1, PhD Ludovico Pedullà3, Prof Roberto Gasparotti4, prof Carlo Miniussi1,5, prof Marco Bove3,6

1Neurophysiology Lab, Irccs Istituto Centro San Giovanni Di Dio Fatebenefratelli, 2Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa , 3Department of Experimental Medicine, Section of Human Physiology, University of Genoa, 4Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Section of Neuroradiology, University of Brescia, 5CIMeC, Center for Mind/Brain Sciences, University of Trento, 6Ospedale Policlinico San Martino-IRCCS

260. Objectives: Conduction delay over long-range connections is a crucial feature in the communication of distributed neural networks that may impact the efficacy of signal transmission between distant areas in healthy and pathological brains. In the motor system, it has been proposed that the transcallosal connection between motor areas may affect bimanual coordination. However, the limitations of current techniques in providing non-invasive measures of conduction delay hinder our understanding of its role in shaping behavior. Research question: Here, we aimed at validating a directional measure of transcallosal conduction delay (TCD) between motor areas from TMS-evoked potentials (TEPs) and at testing how TCD affects bimanual coordination. Materials and methods: In two studies, we adopted a concurrent validation approach in which TEPs were related to well-established indicators of transcallosal connections to test if latency and amplitude of early TEP components may reflect strength and conduction delay of transcallosal connection. To individuate the TEP component that represents the response of the contralateral M1 after transcallosal signal transmission, we tested the relationship between: (a) DTI-derived mean diffusivity of the corpus callosum (CC) and the latency of TEPs (Study 1); (b) the amplitude of TEPs and the ipsilateral silent period (iSP) (Study 1 & 2). Then, we explored the behavioral relevance of TCD, by testing the relation between TEPs latency and the difference in the timing of tapping between right and left hand (Inter-hand interval, IHI) in a bimanual finger opposition task. Results: The TEP component M1-P15 was associated with the mean diffusivity of the body of the CC, which connects the motor cortices, (Study 1) and with the iSP, a peripherical measure of transcallosal inhibition (Study 1 & replication in Study 2). Moreover, M1-P15 latency, as index of TCD, was a predictor of bimanual coordination in study 1, but this effect was not replicated in study 2. Conclusion: Early TEPs like the M1-P15 can measure signal transmission through callosal fibers and their latency reflects the TCD. As a new methodology to measure TCD, M1-P15 can be employed in future studies to understand inter-hemispheric effective connectivity in the motor system and its relation to motor behavior.

261. Dynamics of Cortical Neural Processing under Sensory-Perceptual and Auditory-Cognitive Load in Young Listeners

Brilliant Brilliant1, Yifat Yaar Soffer2,3, Prof Yael Henkin2,3, Prof Andrej Kral1

1Institute of AudioNeuroTechnology and Department of Experiment Otology, ENT Clinics, Hannover Medical School, 2Department of Communication Disorders, Sackler Faculty of Medicine, Tel Aviv University, 3Hearing, Speech, and Language Center, Sheba Medical Center

261. Most communication in everyday life takes place in adverse listening conditions. The impact of sensory-perceptual (S-P) (e.g., background noise, competing talkers) and/or auditory-cognitive (A-C) loads (i.e., the burden posted by the task requirement related to specific cognitive functions, such as working memory and attention) on this process remains unclear. In this study electroencephalographic recordings (58 active-channels) have been obtained from young normal hearing adult listeners to identify the neural markers related to specific S-P and A-C load effects. Two auditory tasks, a vowel identification task and an auditory Stroop task, were presented in two listening conditions, quiet and noise. Time-frequency representations using wavelet analysis were derived and both evoked and induced responses were analyzed. Stimuli evoked responses mainly in delta-theta bands. In addition to this evoked activity, alpha desynchronization and theta and beta synchronizations were observed in the induced domain, indicating extensive post-perceptual processing even after the behavioral response. These post-perceptual manifestations were not evident in the evoked potentials. Comparison between the impact of S-P and A-C load separately revealed that higher S-P load (noise vs. quiet condition decreased the evoked theta power and induced activations in alpha and beta frequency band. Higher A-C load (auditory Stroop task vs. vowel identification task) resulted in increased, long-lasting (up to 2 seconds) theta activity. Taken together, the present methodology exposed neural markers in frequency domain of high-level auditory processing during an adverse listening condition. *Brilliant and Yaar-Soffer contributed equally to the study

262. Cortical oscillatory changes during cognitive effort to achieve a reward or avoid a loss.

Mr. Adam Byrne1,2, Ms. Danielle Hewitt1, Ms. Jessica Henderson1, Ms. Alice Newton-Fenner1,2, Ms. Hannah Roberts1, Dr. John Tyson-Carr1, Dr. Timo Giesbrecht3, Dr. Andrej Stancak1,2

1Department of Psychological Sciences, University of Liverpool, 2Institute for Risk and Uncertainty, University of Liverpool, 3Unilever Research and Development

262. Objectives. Losses have been found have greater subjective value than gains of equal nominal value in decision making tasks. Previous studies showed that when participants were incentivised during an effortful task to avoid a loss or achieve a gain, task performance was not better when anticipated losses were compared to gains. We explored how the subjective value of losses and gains affected performance and oscillatory changes in the sensorimotor and frontal cortices in the alpha-, beta-, and theta-bands during motor preparation in a sustained vigilance reaction time (RT) task while participants were incentivised with monetary gains, losses, or withno reward. Research question. We asked if amplitude decreases of cortical oscillations in a 1-second window preceding motor response in a sustained vigilance task would be stronger if the incentive was to avoid a monetary loss compared to achieving a monetary gain. Methods. Participants performed a series of speeded RT responses while expecting a monetary reward (5p and 10p), avoiding a monetary loss (-5p and -10p), or receiving no incentive (0p) if they responded faster than their median RT. Pre-movement alpha-, beta-, and theta-band power in each condition was analysed using the event-related desynchronization method (ERD), and the subjective value of effort was evaluated using a cognitive effort discounting task with gain and loss conditions. Results. RTs were faster in both gain and loss conditions as larger gains/losses were offered. Alpha- and beta-band ERD over the contralateral sensorimotor region over the frontal electrodes was stronger in trials offering gain or avoiding a loss compared to no-reward, however, ERD was not different in loss and gain trials. The subjective value of effort obtained in the discounting task revealed that participants were more willing to expend a greater effort when they were motivated with losses compared to gains; the value of effort was not associated with ERD patterns though. Conclusions. Results provide an explanatory basis for the absence of differences between anticipated losses and gains of equal nominal values in motor performance during a sustained vigilance task as these two different types of incentives produced similar pre-movement ERDs.

263. Replicability of the brain map of natural frequencies during resting state

Dr. Almudena Capilla1, Ms. Andreea Olteanu1, Mr. Martín García-Montes1, Ms. Marta García-Huéscar1, Dr. Pablo Campo1

1Universidad Autonoma De Madrid

263. Neural oscillations are fundamental for effective brain communication. However, despite their relevance, some critical information is still missing. In this study, we aimed to shed light on one basic but outstanding question: which are the typical or natural frequencies of the human brain at rest? With this aim, we developed an algorithm to extract the natural frequencies of the human brain on a voxel-by-voxel basis. Critically, we assessed the replicability of this algorithm by applying it to two independent sets of magnetoencephalography (MEG) data. On the one hand, we tested the algorithm on a sample of 128 healthy participants acquired by a CTF system with 275 axial gradiometers, obtained from The Open MEG Archive (OMEGA; https://www.mcgill.ca/bic/resources/omega). On the other hand, we applied the same analysis pipeline to a sample of 89 healthy volunteers recorded by a whole head MAGNES 3600 (4D Neuroimaging) system with 248 magnetometers from the Human Connectome Project (HCP; http://www.humanconnectomeproject.org). The algorithm employed to estimate the natural frequencies across the brain consisted of the following steps: (1) reconstruction of source-level time series, (2) computation of power spectra at different time points, voxels, and participants, (3) k-means clustering of power spectra, and (4) identification of the peak frequency of the most characteristic power spectrum for each voxel. Our results showed a consistent pattern of oscillatory activity, which was organized according to both a medial-to-lateral and a posterior-to-anterior gradient of increasing frequency. Thus, medial fronto-temporal regions were characterized by slow oscillations in the delta and theta ranges. The alpha rhythm was typical of posterior brain regions, both default mode network-related areas (e.g., precuneus) as well as visual and auditory sensory cortices. Finally, parietal, motor, and lateral prefrontal regions were characterized by beta-band activity. Importantly, the natural frequency maps derived from the two independent datasets showed a strong correlation, demonstrating the replicability of the algorithm. In conclusion, our results suggest that the human brain has a characteristic oscillatory pattern during resting state, which is highly consistent and organized in a region-specific manner. Funded by PGC2018-100682-B-I00 (MCIU/AEI/FEDER, UE).

265. Hierarchically nested networks optimize audiovisual speech processing

Msc. Nikos Chalas1, Prof Diana Omigie3, Prof. David Poeppel4,5, Prof. Virginie van Wassenhove2

1Institute for Biomagnetism and Biosignal Analysis, University of Münster, P.C., D-48149, 2CEA, DRF/Joliot, NeuroSpin; INSERM, Cognitive Neuroimaging Unit; CNRS; Université Paris-Saclay, 3Department of Psychology, Goldsmiths University London, , 4Department of Psychology, New York University, 5Ernst Struengmann Institute for Neuroscience

265. In speech perception, the natural asynchronies between sound and vision may not hinder but actually assist a listener’s comprehension: seeing the speaker’s mouth initiates predictions about the ‘what’ and ‘when’ of the upcoming acoustics. Sensitivity to the temporal statistics of audiovisual speech signals is thus of utmost importance for successful predictive coding. Here, we characterized large-scale oscillatory dynamics during the processing of (naturally and artificially) desynchronized audiovisual speech with magnetoencephalography (MEG). First, we report that the amplitude of the auditory phase-locked responses parametrically decreases with increased with natural synchrony; this pattern was asymmetrical, consistent with the temporal window of integration in audiovisual speech. Second, we show that the temporal statistics of audiovisual speech affect large-scale oscillatory networks at multiple spatial and temporal resolutions. The use of direct phase information transfer and a novel bipartite network analysis revealed a strong nestedness in the oscillatory networks. High-frequency activity patterns (β, γ) were spatially nested in the low-frequency (δ) networks. Altogether, our findings suggest that the endogenous regulation of phase coupling in speech processing provides temporal adaptability to external temporal statistics, while preserving the integration constants essential for speech processing.

266. An individualized and comparative approach to the neurophysiology of beat and rhythm processing

Antonio Criscuolo1, Prof. Michael Schwartze1, Prof. Molly J. Henry2, Prof Hugo Merchant3, Prof Sonja Kotz1,4

1Maastricht University, 2Max Planck Institute for Empirical Aesthetics, 3Instituto de Neurobiología, UNAM, 4Max Planck Institute for Human Cognitive and Brain Sciences

266. Comparative and translational research in beat and rhythm processing tries to unravel the neurocognitive dynamics that enable us to process and predict environmental rhythms. Macaque monkeys share basic temporal processing capacities but seem to fail in denoting a beat (i.e., to extract metrical structures). Through rhythm tracking we quantified the phase-relationship between neural activity and tones onsets (Fig.1-3, A-C). Next, we focused on subjective rhythmitisation: the human disposition to perceive subjective accentuations of tones when listening to isochronous equitone sequences. We examined an individual’s metric grouping strategy by using time-locked responses in the beta- and mu-band and modelled endogenous tendencies to switch between binary, triplet, and combined beats in time independently from task instructions (Fig. 4). This single-subject and -trial approach confirms that humans and macaque monkeys reliably use comparable rhythm tracking and metric grouping strategies. The current observations provide crucial evidence for rhythm cognition and potentially lend support for endogenous beat perception in non-human primates, thus strengthening Darwin’s notion of shared basic rhythm capacities.

267. The role of beta oscillations in mental time travel

Dr Mariano D'Angelo1,2, Prof Francesca Frassinetti1, Dr Marinella Cappelletti3

1University of Bologna, 2Karolinska Institutet, 3Goldsmiths, University of London

267. The brain is a time machine that processes short interval timing but that also allows projecting the self in the past and in the future, i.e., to mentally time travel (MTT). Beta oscillations index temporal timing of milliseconds, such that higher power is associated to longer durations. Moreover, activity in the posterior parietal cortex index milliseconds temporal intervals, such that higher power accounts for longer durations. Here, we clarify to what extent MTT, which spans across years, relies on parietal beta oscillations, like short interval timing. To this aim, participants (N=30 healthy adults) performed a novel MTT task while they received transcranial Alternating Current Stimulation (tACS) over the bilateral parietal cortex to test the role of target beta and control alpha oscillations, in addition to a non-stimulation control condition. Participants see faces of different ages. Each face was presented with a phrase describing a life event, happening in middle age. Participants were required to perform a 2-alternative forced choice task: in the ‘Past condition’, they indicated if it is likely or unlikely that the person has lived the life event 10 years ago; in ‘Future condition’ that the person will live the event in 10 years. Relative to control conditions, beta-tACS corresponded to an underestimation of temporal distances during past MTT, such that participants indicated younger faces as more likely to have lived the events 10 years ago. No modulation was found for the future MTT. In Experiment 2, the same group of participants performed a time reproduction task, i.e., they copied the duration of seconds-long visual events as accurately as possible. Participants who overestimated short seconds-long temporal intervals in the time reproduction task, also overestimated temporal distances in the past mental time travel and displayed a stronger beta-tACS effect. These results indicate that beta oscillations constitute a common computational mechanism for both seconds-long intervals and longer temporal distances involved in the past MTT. Moreover, beta tACS unsuccessfully modulate future MTT, probably because the correct computation of temporal distances is likely to be more relevant for the past relative to the future.

271. Multifractal characterization of the critical Landau-Ginzburg model for cortical dynamics

Merlin Dumeur1,2,3, Dr Sheng H. Wang2,4, J. Matias Palva2,4,5, DRF Philippe Ciuciu1,3

1CEA, DRF, Joliot, NeuroSpin, Paris-Saclay University, 2Department of Neuroscience and Biomedical Engineering, Aalto University, 3Inria, MIND team, Paris-Saclay University, 4Neuroscience Center, Helsinki Institute of Life Science, Helsinki University, 5Centre for Cognitive Imaging (CCNi), Institute of Neuroscience and Psychology, University of Glasgow

271. Scale invariance describes features which are preserved over several spatial or temporal scales. Multifractal analysis is a mathematical framework that has been primarily developed to address turbulence phenomena in statistical physics. It allows us to characterize statistical scale-invariance in data. This technique has shown interesting results when applied to electrophysiological data, but clear interpretation has remained difficult because of the absence of a clear link between observed statistical properties of the recorded signal and cortical dynamics. The critical brain hypothesis refers to the proposed idea that the brain is comparable to a complex dynamical system operating near a critical point. This provides a compelling framework for understanding scale invariance in brain activity recordings, which motivates efforts to uncover any relation between multifractality and critical/bistable dynamics. Here we use multifractal analysis to analyze the scale-invariant properties of the recently proposed Landau-Ginzburg model of cortical dynamics, with the aim to derive a principled way to use this tool on electrophysiological recordings. Preliminary results indicate that significant multifractality is present in the transition between critical and bistable dynamic regimes. These results provide a better understanding of the underlying mechanisms creating multifractal scaling in neuronal activity models. It is expected to enable the interpretation of multifractality in electrophysiological recordings as an indicator of the underlying cortical dynamics.

319. Distinct beta frequencies reflect distinct contextually-defined categories

Dr. Elie El Rassi1, Yi Zhang, Dr. German Mendoza2, Prof. Hugo Merchant2, Prof. Saskia Haegens1,3

1Donders Institute For Brain, Cognition And Behaviour, 2Universidad Nacional Autónoma de México, 3Dept. of Psychiatry, Columbia University

319. Beta oscillations are involved in a variety of cognitive functions beyond their traditional sensorimotor role. Based on prior findings of content-specific beta synchronization during working memory and decision making, we hypothesized that beta activity supports the activation and reactivation of cortical representations by mediating neural ensemble formation within and between brain regions. We here found that beta activity in monkey dorsolateral prefrontal cortex (dlPFC) and in pre-supplementary motor area (preSMA) reflected the content of a stimulus in relation to the task context, regardless of its objective properties. In multiple versions of a categorization task, we changed a categorical boundary between sessions, such that a stimulus which belonged to one of two categories during one session could belong to the other category during the next session. During a delay in which monkeys had to hold their categorical decision in mind, we found that two distinct beta-band frequencies were consistently associated with the same two relative categories, and that activity in these respective bands predicted the animals’ responses. We characterized beta at these frequencies as transient bursts with distinct temporal profiles. We further showed that dlPFC and preSMA were connected via these distinct frequency channels, with dlPFC driving the frequency separation, a result supported by granger causality and spike-field coherence analyses. In sum, these results provide support for the role of beta in forming neural ensembles, and further show that such ensembles might synchronize at different beta frequencies.

323. Investigating Differences in Frequency Characteristics in the Default Mode Network with Empathy-Related stimuli vs Resting State

Ms Shubhangi Gautam1, Mr Krishna Gurugubelli1, Mr Anil Vuppala1, Mrs Kavita Vemuri1

1IIIT Hyderabad

323. We investigate frequency characteristics in areas supporting the Default Mode Network (DMN) in an empathy task (watching movies) and resting state. A novel single frequency filter (SFF) with higher spectro-temporal resolution was applied. By correlating subjective ratings of empathy for the tasks and the neural activations, the aim was to examine possible markers in DMN as empathy traits. The fMRI data collected from 15 (only 8 were considered for this analysis, age 23-28 years college students) as they viewed 5-8 minutes movie clips and in resting state. Post-scan the participants empathy rated the three clips. Post pre-processing (in SPM12), group ICA method was applied (GIFT toolbox) and an IC with DMN was identified for each session. Six voxels from each DMN network areas (bilateral IPL, Precuneus, ACC, PCC, mPFC) were extracted by applying a mask (AAL atlas) from the task scans while four voxels for resting state with a threshold (p > 0.05 for ACC,MPFC and p > 0.01 for other regions ). For each voxel, time series signal was normalized and the SFF applied. We specifically look at 0.0-0.25 Hz (Tr = 2s) frequency range. These low frequency fluctuations have been further divided into two distinct frequency bands - band 1(0.01-0. 1Hz), studied for RS and band 2 (0.1-0.25 Hz) to observe the differences. The PSD amplitude from the group ICA’s DMN IC highlighted a higher power contribution at lower frequencies, a steeper decrease of power with frequency in RS compared to task DMN. The average PSD amplitude at each region across participants reveals that task -band 1 had a reduction in power at each frequency while RS regions had higher amplitude at band 2. PSD peaks were identified as a function of frequency and K-means clustering applied by partitioning into four clusters – cluster 1,2 (LF and high amplitude) while clusters 3,4 (HF and low amplitudes). We found that participants who had given higher empathy rating fell into cluster 1,2 while those with lower ratings fell into cluster 3,4. These findings indicate DMN and individual region’s frequency characteristics could be a potential empathy trait marker.

324. Functional, effective, and structural connectivity within the extinction network

Carlos Alexandre Gomes1,2, Franziska Labrenz2, Tamas Spisak2, Adeel Razi3, Dominik Bach4, Robert Kumsta1, Dagmar Timmann2, Nikolai Axmacher1

1Ruhr University Bochum, 2University of Duisburg-Essen, 3Monash University, 4University College London

324. Extinction learning refers to the gradual decrease in the conditioned response to a conditioned stimulus (CS) without reinforcement, and it is believed to be a central mechanism during exposure-based therapies. Even though some studies have identified brain regions associated with extinction learning (e.g., Phelps et al. 2004), there is hardly a consensus regarding which of these brain regions are most critical during this effect (e.g., Fullana et al., 2018). Furthermore, connectivity studies on extinction learning, as well as evidence of a brain-behaviour relationship, remain scarce. Therefore, the main aim of our project is to identify functional and structural connectivity patterns of the extinction network, and also to understand how these patterns allow predicting inter-individual differences in the efficacy of extinction learning across a range of paradigms. In this ongoing multi-site study, we analysed 546 resting-state fMRI and 514 DTI datasets from healthy adults. Participants performed a task that involved an extinction learning phase (e.g., fear conditioning). Each participant was tested in one of three locations/MRI systems within Germany, depending on the study the participant was assigned to. Critically, however, all studies used identical resting-state fMRI and DTI sequences. For the analysis of resting-state fMRI we computed several functional and effective connectivity metrics (e.g., correlation-based, dynamic time warping, spectral DCM). For structural connectivity, we applied probabilistic tractography to construct ROI-to-ROI connectivity matrices. Although preliminary, our results indicate interesting, but intricate, connectivity patterns among the different brain regions within the extinction network, namely, the hippocampus, amygdala, cerebellum, ventral medial prefrontal cortex, and anterior cingulate cortex (ACC). Some of these connections were shown to be inhibitory (e.g., ACC to hippocampus) whereas others appear to be excitatory (e.g., Amygdala to ACC). Physiologically, we found a significant fear learning effect, as revealed by larger skin conductance responses for reinforced CS relative to non-reinforced CS. Our preliminary results suggest a complex interaction among the most critical brain regions believed to comprise the extinction network. We are currently examining how these functional and structural connectivity patterns relate to the physiological measures of learning efficacy.

325. Investigating endogenous delta oscillations in human MEG

Mr Harish Gunasekaran1, Dr Leila Azizi1, Prof Virginie van Wassenhove1, Dr Sophie K. Herbst1

1Cognitive Neuroimaging Unit, INSERM, CEA, CNRS, Université Paris-saclay, Neurospin, 91191 Gif/Yvette.

325. To interact with a dynamic environment, anticipating “when” an event occurs is crucial to perform the desired actions at the right time. Recent lines of research have suggested that such temporal predictions could be implemented through the entrainment of slow neural oscillations (e.g. delta, 0.5 – 4 Hz). Entrainment by the temporal regularities in the environment would thus tune brain dynamics to the predicted onsets of relevant events. However, it is difficult to assess whether entrainment truly results from an a priori endogenous delta oscillation, or whether oscillatory brain dynamics merely reflect the exogenous rhythmic input. To establish whether endogenous delta oscillations can be seen in human brain activity, we re-analyzed an MEG dataset (N = 23) collected for a different experiment. We chose three conditions devoid of external stimulation, yet varying in the amount of internal rhythmic behavior: 1. Resting state (no rhythmic behavior), 2. Motor tapping (overt rhythmic behavior), and 3. Internal counting (covert rhythmic behavior). Combining spectral analyses with a fine-grained peak detection algorithm, we were able to detect spectral peaks in the delta frequency-range. Additional analyses are being carried out to establish whether those peaks can be interpreted as endogenous oscillations.

272. Distinct frequency channels for maintaining feature specific information in visual working memory

Mr Hamed Haque1,2, Dr Sheng H Wang1,3, Dr Felix Siebenhühner1, Prof J. Matias Palva1,3, Prof Satu Palva1,4

1University Of Helsinki, 2BioMag Laboratory, 3Aalto University, 4University of Glasgow

272. Objectives: Visual working memory (VWM) sustains visual information online for future usage. This information can be maintained as single features as well as coherent object representations. However, the systems-level mechanisms and interareal networks that underlie the maintenance of these representations in VWM are not well understood. We investigated whether differences in phase synchronization would be used to differentiate specific visual features and object representations. Research question: What functional role does large-scale synchronization of neuronal oscillations carry in the maintenance of visual information in VWM? At which frequency bands does interareal synchronization code for feature-specific information and what are the anatomical patterns of the brain networks underlying this representation of visual information? Materials and methods: We recorded concurrent magneto- and electroencephalography (MEEG) from 20 healthy human participants during a delayed-match-to-sample task in which the participants memorized different features (Shape, Color, or Location) or feature conjunctions (Color-Location, or Shape-Color-Location) with 800 trials for each of the 5 conditions. We then estimated phase synchronization and cross-frequency synchronization among 400 cortical parcels and 38 frequencies (between 3 to 120 Hz) from source-reconstructed MEEG data. Graph theory was used to characterize the networks during the maintenance period. Statistical and classification analysis were performed on these networks. Feature-specific graphs and graphs shared across all three features were extracted. Results: Working memory maintenance of all features and feature conjunctions was characterized by sustained increase in delta and alpha synchronization and decrease in theta and beta synchronization. The anatomical patterns of alpha and beta synchronization were feature-specific while the delta and theta synchronization patterns were shared across features. Alpha synchronization was also correlated with individual behavioral performance and was predictive of the memorized feature of each trial through using a multivariate classifier. Cross-frequency synchronization between alpha and beta was also observed for all conditions. Conclusion: Concurrent synchronization in multiple frequency bands characterize the maintenance of feature information in visual working memory and this synchronization does not reflect the inhibition of individual features. Alpha and beta synchronization of different visual features exhibit unique feature-specific patterns and may therefore underlie the coordination and maintenance of visual information in working memory.

326. Differences in Theory of Visual Attention Cognitive Functions between Video and Non-Video Gamers are Associated with Differential Alpha Amplitude Modulations

Yannik Hilla1, Fabian Link1, Prof Paul Sauseng1

1Ludwig-Maximilians-Universität, Department of Psychology

326. Video gaming has been frequently related to improvements in cognitive processing. An explanation for this may be that playing video games enhances a cognitive function which several cognitive processes share. Attentional control, the ability to focus on processing relevant information while simultaneously suppressing irrelevant information, may be a promising candidate here. We investigated this theory by relating alpha power modulations as a measure of attentional control to inter-individual differences in theory of visual attention (TVA) cognitive functions between video- and non-video game players. In detail, we recruited 46 video- and 36 non-video game players to perform a visual short-term memory paradigm while their brain activity was measured using electroencephalography. Their task was to memorize two white shapes that were depicted on an invisible circle either in the left or right visual field at one of three different exposure durations (either with or without black shapes as distractors). We modeled their visual short-term memory capacity (K), speed of information processing (C), sensory threshold of conscious perception (t0), top-down control (alpha) and visuospatial attention (spatial bias) based on performance differences between conditions using TVA algorithms. Moreover, we computed difference values contrasting alpha power asymmetry indices of each hemisphere and conditions with and without distractors to operationalize the role of hemispheric dominance and attention functions in attentional control. Then, we related attentional control measures to TVA cognitive functions using generalized additive models and determined the significance of their fit using Akaike information criterion and Bayes factor values. There were significant model fits between TVA K, C and attentional control values predominantly in video game players; and between TVA spatial bias, alpha and attentional control values rather in non-video game players. Model fits were strongest for right hemispheric attentional control measures in response to memory displays with targets only than targets and distractors. Therefore, video game players might deploy attentional control to enhance encoding of relevant information while non-video game players might use it to orient visuospatial attention. Thus, our results indicate that inter-individual differences in cognitive processing between video and non-video game players may indeed be associated with differential deployment of attentional control.

327. High excitability and attenuated long-range temporal correlations predict Alzheimer’s disease progression

Dr Ehtasham Javed1, Ms Isabel Suárez-Méndez2,3, Dr Gianluca Susi2,3, Dr Juan Verdejo Román4, Prof Matias Palva1,5, Prof Fernando Maestú2, Prof Satu Palva1,6

1Neuroscience Center, HiLIFE-Helsinki Institute of Life Science, University of Helsinki, 2Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, 3Department of Structure of Matter, Thermal Physics and Electronics, Complutense University of Madrid, 4Department of Personality, Evaluation and Psychological Treatment, University of Granada, 5Department of Neuroscience and Biomedical Engineering, Aalto University, 6Centre for Cognitive Neuroimaging, Institute of Neuroscience & Psychology, University of Glasgow

327. Objective: We aim to characterize at-risk individuals of Alzheimer’s disease using criticality measures. Background: Alterations in local and inter-areal oscillatory dynamics have been increasingly linked with continuous neural degeneration in Alzheimer’s disease (AD). Contemplated by both animal and computational models, it is hypothesized that loss of excitation/inhibition (E/I) balance triggers the development of disease, which is reflected in alterations of the brain oscillatory activity. Hypothesis: Brain criticality is primarily thought to be controlled by the E/I ratio so that critical dynamics emerge at balanced E/I. We thus tested E/I balance hypothesis expecting any imbalance in E/I would lead to pathological function, that is, AD-related oscillatory alterations and aberrant brain critical dynamics. Material and Methods: We analyzed MEG data recorded from 85 preclinical (SCD: Subjective Cognitive Decline) and 142 prodromal (MCI: Mild Cognitive Impairment) participants, and 116 neurotypical controls (HC) of similar age ranging from 57 to 87 years. The source-space data were reconstructed from sensor-space MEG data using native forward and inverse models, and collapsed to Schaefer’s 400 cortical parcels. We then quantified brain activity using long-range temporal correlations–hallmark of systems with critical or near-critical dynamics–, and E/I measure; fE/I: estimated ratio of excitation and inhibition from neural oscillations. Results: We found attenuation in LRTCs and elevated fE/I values with the disease progression. Importantly, similar frequencies, that is, high-theta (7-8 Hz), alpha (8-12 Hz), beta (12-30) and low gamma (30-40 Hz) were observed marking between-group differences for both criticality metrics. Conclusion: The results indicate robustness of both measures in distinguishing individual with SCD and MCI, and from NC. Frequency specific alterations i.e. SCD differences compared to NC are in frequency range of 7-12 Hz, and between SCD and MCI, latter had considerably lower LRTC values and increased fE/I for frequencies of 12-22 Hz, highlight their potential as biomarker to classify individuals in a disease continuum.

329. Alzheimer's Disease as an Example of Desinchronization of Functioning and Collection of Neurocognitive Patterns–Potential Resources for the Development of AI

PhD Candidate Anna Kaszyńska1

1SWPS//Polish-Japanese Academy of Information Technology

329. The poster is focused mostly on the potential development of Artificial Intelligence by extracting fixed patterns and regularities that enable the improvement and refinement of advanced analyses in the field of artificial neural network learning. Poster is conducted through the prism of the neurocognitive view of Alzheimer's disease as a potential set of neurocognitive patterns constituting a potential source of resources for the development of artificial intelligence (especially biomedical field). It is closely related to encephalography, both used to detect pathological dementia changes, and the analysis of brain activity itself, showing the existence of repeated regularities. These patterns, corresponding to the astrophysical Lagrandrean mapping analysis, seem to have the potential to develop artificial intelligence. Especially, following the idea of perceiving Alzheimer's disease as a global desynchronization of functioning, global neurodegenerative changes may provide potential resources that, through mathematical and algebraic transformations, may serve as a foundation for the development of artificial intelligence (following the example of deep learning and microbiology features regarding, for example, proteins and Boltzmann theorem). (These hypothetical assumptions based on scientific studies correspond directly to my research that is carried out in the Centre of the Neurocognitive Research at SWPS is focused on resting state EEG according mostly to theta and gamma bands in the context of the cross-frequency coupling, entropy or LZC analysis. I emphasis memory processing and memory information maintenance among past marijuana users and poly drug users. My hypothesis is based on the scientific evidence and observations regarding aspects of Alzheimer’s disease, medical marijuana, deep learning (in the context of pattern recognition in the filled of microbiology on one hand and astrophysics on the other - as a comparison of micro and macro cosmos patterns that can be revealed through mathematical/logical analysis). I consider the possibility of the similarities between control group and past marijuana users as well as between poly drug users and Alzheimer’s disease patients. Moreover, I highlight theta and gamma bands due to their different features, responsibilities, and participation in both memory performance as well as in the presence of desynchronization in neurodegenerative diseases).

330. Coupling of pupil- and neuronal population dynamics reveals diverse influences of arousal on cortical processing

Christian Keitel1, Thomas Pfeffer2,3, Daniel Kluger4,5, Anne Keitel6, Alena Russmann3, Gregor Thut7, Tobias Donner3, Joachim Gross4,5,7

1University of Stirling, Psychology, 2Universitat Pompeu Fabra, Center for Brain and Cognition, Computational Neuroscience Group, 3University Medical Center Hamburg-Eppendorf, Department of Neurophysiology and Pathophysiology, 4Institute for Biomagnetism and Biosignal Analysis, University of Münster, 5Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, 6University of Dundee, Psychology, 7Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow

330. Fluctuations in arousal, controlled by subcortical neuromodulatory systems, continuously shape cortical state, with profound consequences for information processing. Yet, how arousal signals influence cortical population activity in detail has so far only been characterized for a few selected brain regions. Traditional accounts conceptualize arousal as a homogeneous modulator of neural population activity across the cerebral cortex. Recent insights, however, point to a higher specificity of arousal effects on different components of neural activity and across cortical regions. Here, we provide a comprehensive account of the relationships between fluctuations in arousal and neuronal population activity across the human brain. Exploiting the established link between pupil size and central arousal systems, we performed concurrent magnetoencephalographic (MEG) and pupillographic recordings in a large number of participants, pooled across three laboratories. We found a cascade of effects relative to the peak timing of spontaneous pupil dilations: Decreases in low-frequency (2-8 Hz) activity in temporal and lateral frontal cortex, followed by increased high-frequency (>64 Hz) activity in mid-frontal regions, followed by monotonic and inverted-U relationships with intermediate frequency-range activity (8-32 Hz) in occipito-parietal regions. Pupil-linked arousal also coincided with widespread changes in the structure of the aperiodic component of cortical population activity, indicative of changes in the excitation-inhibition balance in underlying microcircuits. Our results provide a novel basis for studying the arousal modulation of cognitive computations in cortical circuits. [CK and TP contributed equally to this work and share first authorship; TD and JG share senior authorship.]

331. Motor theta networks during response generation in aging

Porf. Vasil Kolev1, Prof. Michael Falkenstein2, Prof. Juliana Yordanova1

1Institute of Neurobiology, Bulgarian Academy of Sciences, 2Institute for Work, Learning and Aging

331. Objectives. It has been suggested that a distributed oscillatory system in the brain operating in the theta frequency range plays a major role in coordinating motor actions (Duprez et al., 2019; Yordanova et al., 2020). In this distributed theta system, a central coordinating (“hubbing”) function has been attributed to the medial frontal regions. Also, theta activity at motor cortical regions is closely associated with medial frontal theta activity, possibly in relation with movement regulation, monitoring and control. The objective of this research was to explore the effects of aging on the motor theta network during response generation. Methods. Response-related potentials (RRPs) were recorded from young and older adults while they performed a four-choice reaction task in two modalities (visual and auditory). RRPs of right-hand correct responses were analyzed in the time-frequency domain. Spatial synchronization of response-related theta oscillations was assessed using phase-locking value (PLV). Effects of aging were analyzed for a) the connectedness of the contra-lateral motor cortex (C3) with other cortical regions, and b) the connectedness of the medial frontal cortex (FCz) with other cortical regions. Results. In young adults, the synchronization of the activated left motor cortex (C3) was strongest with fronto-central and frontal areas in the same left hemisphere. In contrast, in older adults, the synchronization of the activated motor cortex was strongest with left-hemisphere centro-parietal regions. The synchronization of the medial frontal cortex (FCz) was strongest with contra-lateral sensorimotor regions, but it did not differ between young and older adults. Conclusion. Aging is associated with a reorganization of the functional connections between the activated motor cortex and other cortical regions involved in motor response generation, which may have implications for aging-related performance slowing. Supported by the National Research Fund, Sofia, Bulgaria (Project DN13-7/2017).

332. Effects of age and dopamine D1 receptor availability on the differentiation of striato-cortical functional connectivity

Dr Saana Korkki1, Dr Kristin Nordin1,2, Mr Robin Pedersen2, Dr Jarkko Johansson2, Dr Anna Rieckmann2,3, Dr Alireza Salami1,2

1Karolinska Institute, 2Umeå University, 3Max Planck Institute for Social Law and Social Policy

332. The striatum can be parcellated into functionally-distinct subdivisions based on its cortical connections. In younger adults, different subdivisions of the caudate have been shown to preferentially couple with two large-scale cortical association networks: the fronto-parietal network (FPN) and the default-mode network (DMN). Prior work indicates an age-related reduction in the specificity of caudate subregional connectivity to these cortical networks, with such decreases further predicting loss of memory function in older age. One potential factor contributing to age-related dedifferentiation of striato-cortical connectivity may be reduced integrity of the dopaminergic system, a neurotransmitter critical for maintaining the specificity of neural processing. Here, we examined age-related differences in resting state functional connectivity of striatal subregions with the cortical FPN and DMN in a large lifespan sample of healthy adults (N = 180, aged 20-79) from the DyNAMiC study. All participants also underwent positron emission tomography (PET) assessment of D1 receptor availability with the radioligand [11C]SCH23390. Consistent with prior findings, we observed an age-related reduction in the specificity of central lateral caudate connectivity with the FPN and DMN. Moreover, across the lifespan, variation in caudate D1 receptor availability was associated with the degree of functional connectivity differences between the lateral caudate and the two cortical targets. These findings align with previous accounts of age-related dedifferentiation of brain function, and suggest a role for decreased dopamine system integrity in reduced specificity of striato-cortical connectivity in older age.

333. Neuronal synchrony in the gamma-band mediates temporal attention

Dr. Shrikanth Kulashekhar1,2,3, Hamed Haque2, Matias Palva2,4,5, Satu Palva2,4

1International School for Advanced Studies (SISSA), 2Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 3BioMag Laboratory, HUS Medical Imaging Center, 4Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, 5Department of Neuroscience and Biomedical Engineering, Aalto University

333. Temporal attention, the process of attending to the temporal property of a stimulus, has been shown to increase the overall perception and estimation accuracy of temporal information. Studies on timing in humans using functional magnetic resonance imaging (fMRI) have revealed a positive correlation between temporal attention and neuronal activity in the sensory and motor areas, parietal and corticostriatal cortices. While the brain regions involved in the attentional processing are fairly well known, the systems-level mechanisms coordinating the distributed neuronal activity have remained elusive. It has been suggested that synchronized oscillations could regulate communication in neuronal networks and hence serve such coordination. However, the role of synchronized oscillations in temporal attention has remained largely unknown. We recorded human neuronal activity using magnetoencephalography (MEG) during a visual, temporal discrimination task. In the time condition, a cue instructed the subjects to orient their attention to, and compare the stimuli durations. While in the colour condition they attended and compared to the colours of the dynamic visual stimuli. To address the functional significance of neuronal synchronization we identified frequency specific, large-scale synchronized networks from source reconstructed MEG data. Temporal attention was associated with sustained synchronization in the gamma-band (45–80 Hz). We found the synchronization in the sensory and motor areas, including the frontal opercula, an area previously shown to be parametrically modulated by temporal attention. The results thus suggest that gamma-band phase synchronization could regulate the coordination and maintenance of temporal attention in brain areas previously associated with temporal processing.

322. How did you sleep last night? The influence of sleep on functional connectivity in healthy adults

Miss Alejandra García-Colomo1, Mr Alberto Nebreda Pérez1, Mr Ricardo Bruna1, Mr Martín Carrasco2, Miss Jaisalmer De Frutos Lucas1, Mr David Lopez Sanz1, Mr Fernando Maestu Unturbe1

1Universidad Complutense De Madrid, 2Universidad Politécnica de Madrid

322. Normal aging is often associated with cognitive decline in different domains and physiological alterations, such as volume losses, neurochemical alterations, electrophysiological activity changes and even beta amyloid deposition. These age-related changes have been associated with sleep disturbances. The default mode network (DMN) encompases different areas involved in memory function, emotional processing and attention, and has been thoroughly studied in patients with mild cognitive impairment, Alzheimer’s disease and other dementias. These patients present structural and functional alterations in these regions, which have been associated with the experienced cognitive deficits. Interestingly, functional connectivity in the DMN is also deeply affected by sleep alterations, such as disruptions, and, conversely, changes in its connectivity have been shown to affect sleep parameters such as onset. In the present study, we investigated the relationship between self-reported measures of sleep quality and the intra-network functional connectivity of areas belonging to the DMN during resting-state recorded using magnetoencephalography (MEG). The sample for this study was composed of 81 healthy adults. All participants completed the Pittsburgh Sleep Quality Index and underwent a 5-minute resting-state MEG scan with their eyes closed. Connectivity strength was calculated at the source-level using PLV considering only the sources corresponding to areas of the DMN. The influence of sleep quality over the connectivity strength was evaluated using ANOVA. Results show that connectivity strength between 10-12Hz is affected by sleep quality in areas of the DMN such as the left hippocampus (F=4.51; p=0.037), the right inferior parietal lobe (F=4.31; p=0.041) and a trend towards significance is seen in the left right inferior parietal lobe (F=3.83; p=0.054). The present results are consistent with previous studies and support the importance of a good sleep quality for the proper functioning of the brain even in healthy adults. Given the relationship between sleep, aging and physiopathological processes associated with the development of AD and other forms of dementia, the study of sleep could constitute both an early biomarker and a field for intervention.

269. Topographic changes of brain frequency rhythms throughout life: a MEG study

PhD candidate Sandra Doval1, Dr Pablo Cuesta2, Dr Ricardo Bruña2, PhD candidate Lucía Torres-Simón1, PhD candidate Brenda Chino3, PhD candidate Inés Abalo Rodríguez1, Ms Ignacio Taguas Garzón1, Prof Fernando Maestú1, Dr David López-Sanz1

1Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Complutense University of Madrid , Faculty of Psychology , 2Department of Radiology, Rehabilitation and Physiotherapy, UCM, Faculty of Medicine,, 3Institute of Neuroscience, Autonomous University of Barcelona

269. There are multiple evidences proving how brain oscillations at different frequencies underlie multiple processes of key relevance for human performance. These processes seem to depend directly on the synchronized activity at different frequencies of the brain tissue along the cortical surface. Regarding this topic, numerous studies have shown that different brain regions show a natural tendency to synchronize its neuronal activity at different frequencies, the so-called “natural frequencies”. However, there are few studies regarding the topographic distribution of natural frequencies and its evolution during development and aging. The main objective of this study was to properly describe natural frequencies’ topographical distribution throughout life. For that reason, brain activity of 792 healthy people, (13-80y/o) have been characterized, using Magnetoencephalography. After signal pre-processing, the activity of each subject in each of the 1202 cortical sources was reconstructed and their relative power was calculated. The natural sources that generate each brain rhythm, as well as its modification through the life continuum were studied by conducting Pearson’s correlations between relative source contribution (z-value) and age (z-values were used to weight the relative importance of each source in each band to estimate natural generators, whereas rho values indicate how sources change its contribution throughout maturation). Results showed a specific topographic distribution of the generators for each band, which was modified through life. In addition, there were topographical changes for each band. For slow waves (< 8Hz) their main generators increase their importance with age. For alpha and gamma their main generator, decreased its relevance in the life continuum increasing towards more anterior-temporal regions for both. As a conclusion, responsible areas of the generation of the different brain rhythms replicate previous literature reports. In the specific case of gamma, which has been scarcely studied in the resting-state literature, we found a high involvement of frontal areas in its generation. There are significant topographical changes in the distribution of natural frequencies for all bands. This implies that normative development and aging are characterized by modifications in the predominant oscillations in the different areas of the cortical surface.

341. Analysis of multilayer functional connectivity networks for the diagnosis of Mild Cognitive Impairment.

Mr. Ignacio Taguas1, PhD candidate Sandra Doval1, Prof Fernando Maestú1, Dr David López-Sanz1

1Complutense University Madrid

341. Objectives Resting-state magnetoencephalography (MEG) is a widely used technique to study functional connectivity (FC) disruption in Alzheimer’s Disease (AD) and Mild Cognitive Impairment (MCI), a prodromal stage of AD. Traditionally, MEG signals are decomposed by frequency, and the networks corresponding to each frequency range are studied independently. However, the interplays between the different frequency bands have rarely been studied. Research question In the present study, we used MEG to construct multi-frequency networks, to check whether the previous results obtained using frequency-specific networks are also applicable when assessing the interactions between different frequencies. Materials and Methods To this end, we performed eyes-closed resting-state MEG in 105 MCI patients and 248 controls. Cross-frequency brain networks were constructed by calculating the amplitude envelope correlation between 90 regions of interest in five frequency bands (delta, theta, alpha, beta and gamma), considering both intra and inter band connections. As a result, a single network was constructed for each subject, with each ROI represented in all bands. Subsequently, we calculated three centrality measures (node strength, closeness centrality and eigenvector centrality), and compared both groups accounting for the variability derived from gender, age and schooling years. Results Node strength and closeness centrality showed a decrease in the connectivity of the ROIs in the frontal lobe of MCI patients with respect to controls. Eigenvector centrality, on the other side, showed that these frontal ROIs are connected to more important ROIs in MCI patients, while temporoparietal ROIs are connected to less central ROIs with respect to controls. Conclusion These results are consistent with previous literature, showing that the changes in FC in the brain already described for frequency-specific networks are maintained when considering interactions between frequency bands. Furthermore, these results prove the validity of the methodology we have implemented for the topological analysis of cross-frequency networks, providing a simple procedure to study global brain network connectivity.

257. Inhibitory control functional connectivity associated with predisposition to alcohol binge drinking in adolescents: a longitudinal MEG study

Dr Luis Antón-Toro1, Msc Alberto Del Cerro-León1, Msc Danylyna Shpakivska1, Marcos Uceta2, Dr. Ricardo Bruña3, Dr. David Lopez-Sanz1, Dr. Fernando Maestú1, Dr. Luis Miguel García-Moreno4

1Department of experimental psychology, University Complutense Of Madrid, 2Universidad politécnica de Madrid, 3Department of Radiology, University complutense of Madrid, 4Department of psicobiology, University complutense of Madrid

257. Background: Binge drinking (BD) is a widespread habit among adolescents, leading to detrimental consequences on the functional integrity of the brain. However, evidence for the relationship between inhibitory electrophysiological networks and predisposition to alcohol consumption is scarce at present. Aims: To analyse the relationship between functional connectivity (FC) during the inhibitory task and future alcohol consumption, as well as the impact of BD on these functional networks. Methods: In a first stage, before the onset of BD, the electrophysiological activity of 67 non-consuming adolescents (age=14.5±0.90) was recorded by MEG during a Go-noGo task. Two years later, in a second stage after BD initiation, 30 participants (age=16.67±0.77) completed the second phase under the same recording conditions. In addition, each participant's alcohol consumption was measured in standard alcohol units (SAU; 1 SAU = 10 mg ethanol). FC was calculated in source-space in both stages, using Phase Locking Value. Subsequently, the symmetric percentage change (SPC) of the FC between both stages was calculated. Finally, we performed a Spearman correlation analysis between the FC or SPC of each cortical source and the SAU levels. We used a cluster-based permutation test to calculate which brain regions showed significant relationships before and after BD. Results: Before BD onset, we found two positive clusters in the beta band, the first in the right prefrontal pole (p=0.006), the second in the right temporal lobe (p = 0.014). After BD onset, we found three negative clusters in the beta band. The first in the prefrontal pole (p = 0.002), the second in the right temporal pole (p = 0.006), and the third in the right temporo-parietal junction (p = 0.014). In addition, we found a negative cluster in the gamma band, in the left orbital cortex (p = 0.028). Conclusion: Higher beta FC in executive control networks is associated with higher future alcohol consumption. A smaller longitudinal change of FC in these networks was associated with higher alcohol consumption. These results evidence the relationship between FC levels and the risk of developing BD behaviours, as well as the neglectful impact of alcohol intake on the maturation of cortical networks.

268. Alcohol binge drinking and gamma band evolution during adolescence

Mr Alberto Del Cerro-León1, Dr Luis Fernando Antón-Toro1, Mrs Danylyna Shpakivska1, Mr Marcos Uceta2, Dr Pablo Cuesta3, Dr Ricardo Bruña3, Dr David López-Sanz1, Dr Fernando Maestú1, Dr Luis Miguel García-Moreno4

1Department of Experimental Psychology, Universidad Complutense De Madrid, 2Universidad Politécnica de Madrid (UPM), 3Department of Radiology, Universidad Complutense de Madrid (UCM), 4Department of Psychobiology, Universidad Complutense de Madrid (UCM)

268. Background: Alcohol Binge drinking (BD) has become a widespread habit among adolescents despite its detrimental consequences on brain integrity, especially over the executive control networks. However, the latest evidence suggests that prior differences may predispose some individuals to initiate alcohol consumption. Objectives: We aim to describe the relationship between brain activity power during inhibitory control task and future alcohol consumption, before and after BD onset. Materials and methods: The electrophysiological activity of 67 non-consuming adolescents (age=14.5±0.90) was recorded by a MEG during a Go-noGo task. Two years later, a total of 30 participants (age=16.67±0.77) completed the second phase of the study, where brain activity was again recorded under the same conditions. This activity measures were transformed into the source-space and the frequency power was calculated for inhibitory condition. In addition, Alcohol consumption of each participant were measured in standard alcohol units (SAU; 1 SAU = 10mg ethanol). Subsequently, we performed a Spearman’s correlation analysis between spectral power of each cortical source and SAU levels and a cluster-based permutation test (CBPT) to observe brain regions with pre-BD and post-BD significant relationships. Results: For pre-BD analysis, we found a parietal cluster in gamma band with positive correlation with future consumption levels. Regarding post-BD, we observed a similar parietal cluster in gamma band with negatively correlations with the rate of pre-post change in gamma power. Conclusion: A higher gamma band potency in parietal regions could be a risk marker for the development of alcohol BD during adolescence. Moreover, functional changes in these regions during adolescence seem to be affected by to consumption levels.

264. Diachronic evolution in oscillatory activity in non-pathological development measured by MEG

Phd Candidate Sandra Doval1, Dr Pablo Cuesta2, Dr Ricardo Bruña2, PhD candidate Lucía Torres-Simón1, PhD candidate Brenda Chino3, Ms Ignacio Taguas Garzón1, PhD candidate Inés Abalo Rodríguez1, Prof Fernando Maestú1, Dr David López-Sanz1

1Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Complutense University of Madrid , Faculty of Psychology , 2Department of Radiology, Rehabilitation and Physiotherapy, UCM, Faculty of Medicine,, 3Institute of Neuroscience, Autonomous University of Barcelona

264. Nowadays, numerous studies use modulations in different frequency bands’ power as potential biomarkers for several pathologies. However, very little is known about the typical diachronic evolution of these markers during development and aging. Our main objective was to detail characterize, the profile of electrophysiological evolution in healthy development, and to properly describe how brain activity changes due to the healthy maturational process. To this aim, brain activity of 792 healthy people, (13-80y/o) were acquired, using magnetoencephalography. After signal pre-processing, the activity of each subject was reconstructed in the source space, and relative power was calculated. The adjustment of the power change through life was evaluated for each classical band, considering three possible fitting models (linear, quadratic, and cubic) by using multiple regression analysis, and Likelihood-ratio-test to evaluate the best adjustment (FDR-correction, q=0.05). Then, to analyze the potential relation between cognitive scores and power in each band, partial correlations were applied between performance in each cognitive domain and power in each source and band (corrected by age) estimating the potential correlation (rho-values) between each band power and cognitive performance. Significant power modulations as a function of age were observed in each band through life following different statistical adjustments depending on the frequency band and cortical region analyzed. Although there were regions in which a linear model could give better explanation of changes across life continuum, mainly, complex adjustments gave a significantly better explanation of the diachronic changes. As a conclusion, there was a highly significant relation between age and the different cerebral rhythms power, which is not strictly linear in most cases. Furthermore, that evolution depends on the topographical region as well as the band considered. Regarding the relationship between power and cognitive performance, we observed that a more intense slow wave activity (i.e. delta and theta) and a less pronounced fast wave activity were associated to an overall better cognitive performance. Supporting the notion that the changes we described in the resting-state power spectrum during normal aging represent a sign of brain activity deterioration rather than a compensatory attempt as they are accompanied by worse performance in all cognitive domains.

273. Influencing factors of reduced reward sensitivity and altered MEG connectivity after stroke

Johanna Maas1,2, Franziska Wagner1,2, Jenny Rogenz1,2, Laura Opitz1,2, Alexander Schmidt1,2, Carsten M. Klingner1,2, Stefan Brodoehl1,2

1Hans Berger Department of Neurology, Jena University Hospital, 2Biomagnetic Center, Jena University Hospital

273. Stroke is the second leading cause of death worldwide and one of the most common causes of acquired disability in adulthood. For most patients, neurological rehabilitation with a focus on relearning skills plays a crucial role. Better learning outcome can be achieved in stroke patients through reward. Yet there has been little work examining whether and to what extent cerebral reward processing differs between stroke patients and healthy individuals and the impact of potential alterations on learning processes. The hypothesis that stroke patients exhibit altered reward processing due to network changes was tested. Furthermore, potential factors influencing this alteration were assessed. To investigate this, a group of stroke patients with first-time ischemic lesion in the mediastinal stromal area (n=47) was compared to a group of age-matched healthy subjects (n=26). The group of stroke patients was further divided into subgroups based on potential influencing factors such as NIHSS score, stroke size, and localization, which in turn were compared to each other. Magnetoencephalography (MEG) measurements were conducted during which the subjects performed the well-established reward paradigm Monetary Incentive Delay task. The reaction times during the paradigm were recorded. Connectivity analyses were performed using the MEG data. The stroke patients showed a significantly lower reward sensitivity. They required a greater monetary incentive than the healthy subjects to increase their reaction speed compared to the control condition without reward prospect. The factor whose impact on this decrease in sensitivity was found greatest so far was the NIHSS score. The evaluation of the comparison of some remaining subgroups and the results of the connectivity analyses are still pending. As reward sensitivity decreases with increasing NIHSS score, stroke patients might need a greater amount of reward to achieve satisfactory outcomes in learning processes during recovery. In the course, the influence of further factors such as the size and the localization of the lesion on reaction speed and network connectivity will be investigated to approach the patients more individually during rehabilitation.

334. The role of pre-stimulus alpha rhythms in non-retinotopic feature integration

Maëlan Q. Menétrey1, Prof. Michael H. Herzog1, Dr. David Pascucci1

1Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL)

334. What is the link between spontaneous neuronal oscillations (i.e., non-evoked activity) and perception? Often, the phase or power of alpha activity is proposed to modulate perception. The majority of work has focused on the unecological presentation of single stimuli at threshold. Here, we investigated the relation between pre-stimulus electroencephalography (EEG) rhythms and non-retinotopic integration of visual features in the sequential metacontrast paradigm (SQM), where information needs to be integrated across space and time. In the SQM, participants discriminate the offset of a central line followed by a stream of flanking lines. Metacontrast masking makes the central line invisible, but its offset can be perceived in the motion stream. When a second line in the stream has an offset in the opposite direction, the two offsets integrate. Using linear discriminant analysis, we isolated electrodes carrying information about the reported offset in the stream. Pre-stimulus alpha activity at these electrodes was predictive of the reported percept: increases in alpha power led to more frequent reports of the first offset, decreases in alpha power to more frequent reports of the second. These results indicate that spontaneous alpha rhythms may modulate the relative weighting of visual features embedded in a continuous stream.

335. Meso-scale oscillatory architecture of a human cortex

Vladislav Myrov1,2, Joonas Juvonen1,2, Gabriele Arnulfo1,3, Felix Siebenh Hühner2, Satu Palva2,4, J.M. Palva1,2,4

1Department of Neuroscience and Biomedical Engineering, Aalto University, 2Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland, 3Department of Informatics, Bioengineering, Robotics and System engineering, University of Genoa, 4Center for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow

335. Neuronal oscillations play central mechanistic roles in cognitive processes. The presence of oscillations is typically quantified with power spectrum analysis that measures oscillations’ amplitudes but does not directly quantify rhythmicity. To directly estimate the rhythmicity of a signal, we advance a novel method, phase-autocorrelation function (pACF), which is a direct measure of rhythmicity and robust against variations in amplitude. In this study we analysed stereoelectroencephalography (SEEG) data from a cohort of 67 subjects with drug resistant focal epilepsy undergoing presurgical clinical assessment and resting state magnetoencephalography (MEG) data from a cohort of 54 subjects. A single subject inspection revealed significant phase autocorrelations in anatomically well-delineated brain areas and only a few narrow frequency bands. These peaks were also observed in power spectra, but imperfect assumptions about the underlying baseline decay function confound frequencies around frequency peaks. SEEG and MEG analysis showed that brain areas show significant oscillatory activity, but so that most areas exhibit oscillations exclusively in a single frequency band. Alpha and beta are the predominant modes of oscillatory activity in the human brain in general. Auditory and visual systems are most active in the low-alpha frequency band, while the somatosensory region has the dominant mode in the high-alpha and beta frequency bands. Both computational modeling and SEEG and MEG experimental findings showed that pACF is strongly and positively correlated with inter-areal phase synchronization. Additionally, we found that Major Depressive Disorder is characterized by loss of pACF in the low-alpha frequency range and is correlated with depression symptoms in the alpha band. Phase autocorrelation is a model-free approach not limited by strict assumptions. The use of pACF allows us to directly quantify and compare signals’ oscillatory power rather than indirectly via amplitude-based metrics. Due to its amplitude-independent nature, pAFC separates oscillatory peaks better than PSA, is less-prone to amplitude fluctuations, and better at revealing the true oscillatory nature of signals.

336. The role of brain segregation and integration in maintaining verbal fluency in healthy ageing – a secondary EEG data analysis

Ms Elise J. Oosterhuis1, Dr Neil Bailey2,3, Dr Kate Slade1, Dr Patrick J.C. May1, Dr Helen E. Nuttall1

1Department of Psychology, Lancaster University, 2Epworth Centre for Innovation in Mental Health, Epworth Healthcare, 3Monash University, Department of Psychiatry, Central Clinical School

336. Ageing leads to word-finding difficulties, reflected in age-related decreases in verbal fluency. Further, verbal fluency might be an early marker for dementia. This study aimed to investigate the relationship between age-related decreases in verbal fluency and functional brain networks, specifically segregation and integration (i.e., communication between neighbouring and distant brain regions, respectively). We hypothesised that decreased network segregation is related to word-finding performance in older adults, but not in younger adults. The current secondary data analysis included 106 right-handed younger and older adults (N=53 per group) from the Leipzig Study for Mind-Body-Emotion Interactions (Babayan et al., 2019). The subset of participants used had no history of alcohol nor substance abuse, and no depression. Participants had completed a category and letter fluency task. We estimated functional networks from eyes-closed resting-state electroencephalography (EEG) recordings using the debiased weighted Phase Lag Index, filtered with the Orthogonal Minimum Spanning Tree algorithm. Segregation and integration were measured through the clustering coefficient (CC), modularity, path length (PL), and small-worldness (SW). Multiple linear regression analyses indicated that CC and modularity were positively related to letter fluency in the delta band. CC was negatively related to letter fluency in the alpha band and PL was positively related to letter fluency in the delta band. In the theta band, the effect of PL on letter fluency was greater in older adults. For category fluency, the effect of CC was lower in the beta band and higher in the delta band in older adults. These results indicate that segregation and integration are related to word-finding in older adults in a way that is specific to EEG frequency band. Therefore, maintaining word-finding in older adults may involve both short-and long-ranged brain connections. Babayan, A., Erbey, M., Kumral, D., Reinelt, J. D., Reiter, A. M. F., Röbbig, J., Schaare, H. L., Uhlig, M., Anwander, A., Bazin, P.-L., Horstmann, A., Lampe, L., Nikulin, V. V., Okon-Singer, H., Preusser, S., Pampel, A., Rohr, C. S., Sacher, J., Thöne-Otto, A., … Villringer, A. (2019). A mind-brain-body dataset of MRI, EEG, cognition, emotion, and peripheral physiology in young and old adults. Scientific Data, 6(1), 180308. https://doi.org/10.1038/sdata.2018.308

274. Brain network mechanisms for preserving reward sensitivity in healthy aging

Laura Opitz1,2, Jenny Rogenz1,2, Johanna Maas1,2, Alexander Schmidt1,2, Dr. med. Stefan Brodoehl1,2, Dr. med. Carsten M. Klingner1,2, Dr. med. Franziska Wagner1,2

1Hans Berger Department of Neurology, Jena University Hospital, 2Biomagnetic Center, Jena University Hospital

274. Deliberately or unconsciously, individuals tend to pursue rewards leading to happiness. As the term reward includes basic needs such as food, sleep, or social contact, the reward system exerts a paramount role in controlling our daily behavior. Therefore, its functional integrity remains indispensable across the lifespan. Previous research showed that reward system function is better preserved in the elderly than most cognitive functions. To investigate the compensatory mechanisms providing reward system stability in aging, we employed a well-established reward paradigm (Monetary Incentive Delay Task) in groups of young and old participants while undergoing EEG measurement. As a new approach, we applied EEG connectivity analyses to assess cortical reward-related network connectivity. At the behavioral level, our results confirm that the function of the reward system is preserved in old age. The mechanisms identified for maintaining reward system function in old age do not fit into previously described models of cognitive aging. Overall, older adults exhibit lower reward-related connectivity modulation, a higher reliance on posterior and right-lateralized brain areas than younger adults, and connectivity modulation in the opposite direction than younger adults, with usually greater connectivity during non-reward compared to reward conditions. We suggest that the reward system has unique compensatory mechanisms distinct from other cognitive functions, probably due to its etymologically very early origin. In summary, this study provides important new insights on cortical reward network connectivity in healthy aging.

348. Mouse-model for gaining mechanistic insights of human resting-state oscillatory brain dynamics

Paula Partanen1, K Kim, JM Palva, S Palva 1University of Helsinki

348. In vivo electrophysiology with head-fix awake behaving mouse has emerged as a novel approach to study large-scale brain dynamics to that in human EEG and MEG. However, little is known of the mechanistic basis influencing the emerge of large-scae network dynamcis. Here we taken an advantage of novel platform for measuring electrophysiological activity from awake head-fixed mouse to identify mouse oscillatory default mode network (DMN) and how these dynamics are regulated by modulations of neuronal excigtability. We have measured local field potentials (LFP) using two electrocortical (ECoG) grids over cortical surface and LFP and multi-unit activity with two laminar probes from subcortical structures. Here we show that DMN is characterized by icnreased alpha oscillations similarly to that in human particpants.

337. Global brain dynamics under visual entrainment

Maëlan Menétrey1, Garance Merholz2, Dr David Pascucci1

1ecole polytechnique fédérale de lausanne (EPFL), 2University of Iceland

337. Cognitive and perceptual functions depend on the momentary dynamics of the brain. A typical approach to investigate these dynamics is through the so-called method of entrainment. In entrainment, a rhythmic stimulation (e.g., a periodic visual or auditory stimulus) leads to the mutual resonance between an external source and the activity of the brain: a light flickering at 10 Hz induces a 10 Hz oscillatory dynamic in the brain. It is often assumed that there is a one-to-one correspondence between the inducer rhythm and the process entrained in the brain. For example, performance in various cognitive and perceptual tasks is typically measured at the peaks and throughs of an induced rhythm, under the idea that the two are linked to distinct states in the brain (e.g., excitatory, or inhibitory cycles of activity). Yet, the actual effect of these periodic stimulations, which are rarely encountered in nature, remains largely unexplored. Here, we use electroencephalography (EEG) and visual entrainment to evaluate changes in global brain states and directional activity flows during rhythmic visual stimulation. In the entrainment paradigm, participants were presented with an oval flash around the center of the visual field. The luminance of the oval changed either periodically (10 Hz) or randomly for ~1.5 s. When comparing the two conditions, a strong phase synchronization at 10Hz and in the harmonics was found in the entrainment condition. In contrast, participants showed mixed effects in power. In further investigations, we will compare the temporal dynamics of micro-states observed as well as the dominant EEG topographies and the time-varying structure of lagged dependencies amongst EEG signals at different electrodes. The outcome of this work will eventually provide a more in-depth characterization of the dynamics of brain activity under entrainment, aiding the understanding of this phenomenon and the interpretation of entrainment results.

276. Altered Excitation-inhibition balance in rapid eye-movement sleep behavior disorder patients

Monica Roascio1, Vladislav Myrov2,3, Felix Siebenhühner2,4,5, Matias Palva2,3,4,6, Dario Arnaldi7,8, Gabriele Arnulfo1,2

1Department of Informatics, Bioengineering, Robotics and System engineering, University of Genoa, 2Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 3Department of Neuroscience and Biomedical Engineering, Aalto University, 4Doctoral Program Brain & Mind, University of Helsinki, 5BioMag Laboratory, HUS Medical Imaging Center, 6Center for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, 7Clinical Neurology, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Children's Sciences, University of Genoa, 8IRCCS Ospedale Policlinico San Martino

276. Alterations in the excitation/inhibition (EI) balance constitute a candidate pathophysiological mechanism contributing to neurodegenerative diseases. Conversely, EI balance is essential for information processing in healthy brains. It has remained unclear whether EI imbalance is already present in the Rapid eye-movement sleep Behaviour Disorder (RBD), a prodromal stage of ɑ-synucleinopathies as Parkinson’s disease. Here, we analyzed how neuronal fluctuations and EI balance change in a longitudinal cohort of patients with idiopathic RBD (iRBD). We recorded resting-state electroencephalography (EEG) in a longitudinal cohort of RBD patients (N=59 at baseline, N=31 at first follow-up, N=9 at second follow-up), and 46 healthy subjects. Seventeen RBD patients converted to an ɑ-synucleinopathy with disease progression (pRBD) and the remaining N=42 remained stable with the disease progression (sRBD). We quantified Long-range temporal correlations (LRTCs) by using Detrended Fluctuation Analysis (DFA) with a fitting interval of 2-25 seconds. Moreover, we investigated the EI balance by estimating functional EI ratio (fEI), a measure that correlates the amplitude profiles and the LRTCs of a given neural network. We thus computed the fEI for windows of 5 seconds with 80% overlap. We first tested for group effects of DFA or fEI changes using a Kruskal-Wallis test and we investigated pairwise comparison using the Wilcoxon rank-sum test across frequencies (N=30 wavelets - 2-70Hz, Benjamini-Hochberg with ɑ=5%). We observed that the LRTCs were significantly stronger in RBD patients compared to healthy subjects in the low-frequency range (2-8Hz). Moreover, the LRTCs were significantly weaker in pRBD patients than in sRBD patients at baseline in the gamma band (50-70Hz). We observed a significant difference in fEI values in sRBD and pRBD at baseline at theta-band (7Hz) and above 40Hz. Our results suggest that large-scale brain networks of sRBD patients operate in near a critical regime on the sub-critical side, whereas networks of pRBD patients operate closer to a critical regime. Surprisingly, LRTCs were anti-correlated with phenoconversion suggesting the existence of a non-linear relation between EI imbalance and LRTCs in RBD patients. Altogether these results might reflect the pathophysiological mechanism linked to the on-going neurodegeneration process.

338. Human concurrent intracranial EEG and fMRI reveals multiple temporally independent but spatially similar connectome trajectories across timescales

Parham Mostame, Jonathan Wirsich, Thomas Alderson, Ben Ridley, Serge Vulliemoz, Maxime Guye, Louis Lemieux, Sepideh Sadaghiani1

1University of Illinois at Urbana-champaign

338. OBJECTIVES AND RESEARCH QUESTION The large-scale organization of functional connectivity (FC), the functional connectome, continuously undergoes reconfigurations between distinct spatial patterns, as has been demonstrated separately in fMRI and electrophysiological studies. Such neural flexibility is thought to enable meeting ever-changing processing demands. However, the relationship between connectome spatial reconfigurations over the temporal range of FC, from infraslow timescales of fMRI to rapid oscillation-based timescales of electrophysiology, remains unknown. MATERIALS AND METHODS We studied the cross-modal convergence/divergence of connectome dynamics frame by frame during resting wakefulness in rare concurrent intracranial EEG and functional MRI (iEEG-fMRI; 9 human neurosurgical patients), generalizing to whole-brain connectomes from source-localized scalp EEG-fMRI (26 healthy humans). RESULTS Hemodynamics- and electrophysiology-derived connectome dynamics intermittently showed frequency-specific periods of spatially similar patterns across modalities. The occurrence rate of such periods of convergence was not statistically higher than when the two modalities were compared at all non-overlapping timepoints, demonstrating temporal independence across data modalities (i.e. asynchronous association). Clustering these converging spatial patterns revealed that several recurrent connectome states are spatially shared over a wide range of timescales revealed by the two modalities. Further, the periods of spatial convergence across fMRI- and iEEG states of different frequencies occurred at mostly non-overlapping timepoints. CONCLUSION Given the asynchronous and multi-frequency association between fMRI and iEEG connectome states observed here, these modalities may be envisaged as capturing distinct aspects of FC, rather than intermodal measurements of the same phenomenon. Infraslow fluctuation-based FC (fMRI) and oscillation-based FC of various frequency bands (EEG) constitute multiple dynamic trajectories through a shared state space of discrete connectome configurations. The multitude of flexible trajectories may concurrently enable FC across multiple independent sets of distributed brain regions.

275. The role of beta-band oscillations in interhemispheric interaction

Judith Sattelberger1, Prof Matias Palva1,2, Prof Satu Palva1,3

1Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 2Department of Neuroscience and Biomedical Engineering, Aalto University, 3Centre for Cognitive Neuroimaging (CCNi), Institute of Neuroscience and Psychology, University of Glasgow

275. Background: How is visual information integrated and stored in visual working memory (VWM)? Fast beta/gamma and slow alpha/theta oscillations are thought to form cortex-wide networks underlying the integration of sensory processing and executive functions, respectively. Specifically, posterior beta-band synchrony increases with information load and is tightly linked to object features maintained in VWM. Behavioral studies show that while the left and right hemispheres possess independent resources to maintain feature information, VWM capacity is highest when stimuli are presented in both hemifields, an effect called the bilateral field advantage (BFA). This might be due to resources being recruited from both hemispheres concurrently. Thus, we propose that interhemispheric beta-band synchronization underlies and predicts higher VWM capacity in the bilateral visual hemifield than in either unilateral hemifield. Methods: To test this hypothesis, we will record high-density EEG (256 sensors) of 20 subjects during a lateralized change detection task, in which two to six differently colored squares are presented either in a single hemifield (unilateral condition) or across both visual hemifields (bilateral condition). The participants are asked to memorize color and location information of all squares and to indicate if there was a change in any feature after a delay period. We will then identify the synchrony networks in each frequency band associated with sensory and executive processing that emerge within and across hemispheres during VWM maintenance with the use of source modelling and graph theory. Expected results and implications: We expect to find an advantage for trials of the bilateral condition that is reflected in (1) higher behavioral efficiency and (2) increased beta-band power and strengthened interhemispheric phase synchrony in posterior sites. Furthermore, we expect to reproduce previously discovered networks of VWM processing in the theta, alpha and gamma band. Taken together, this will lead to a better understanding of feature binding in VWM and the role of interareal synchrony in human cognition as a whole.

339. Altered phase synchrony and cross-frequency coupling in early cognitive decline

Dr Felix Siebenhühner1, Dr Ehtasham Javed2, Prof Fernando Maestu3,4, Dr Juan Verdejo Román3, Dr Gianluca Susi3,5, Isabel Suárez Méndez3,5, Prof Matias Palva1,2,6, Prof Satu Palva1,6

1Neuroscience Center, Helsinki Institute of Life Science, Helsinki University, 2Department of Neuroscience and Biomedical Engineering, Aalto University , 3Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, 4Department of Experimental Psychology, Cognitive Processes and Logopedics, Complutense University of Madrid, Madrid, Spain, 5Department of Structure of Matter, Thermal Physics and Electronics, Complutense University of Madrid, 6Centre for Cognitive Neuroimaging (CCNi), Institute of Neuroscience and Psychology, University of Glasgow

339. Objectives: To investigate whether neuronal synchronization is altered in early stages of cognitive impairment. Research question: Mild cognitive impairment (MCI) often precedes Alzheimer’s disease (AD) and may itself be preceded by subjective cognitive decline (SCD). We hypothesized that these forms of early cognitive decline might be accompanied by abnormal neuronal synchronization that could be detected with electrophysiological methods and possibly used to predict progress towards AD. Materials and methods: In a first study, we recorded 3-min resting state magnetoencephalographic (MEG) data from 142 subjects with MCI, 85 with SCD and 116 healthy controls (HC) of the same age range. For 45 MCI patients, a second MEG set was recorded 2 years later. Of these subjects, those (N=23) whose symptoms had worsened were classified with progressive MCI (pMCI), the others with stable MCI (sMCI). We used source reconstruction and collapsed source activity into 400 cortical parcels of the Schaefer parcellation. We then estimated phase synchronization and cross-frequency coupling (CFC) between pairs of parcels. Results: In the first dataset, we found that global phase synchrony (PS) in a range from 5 to 20 Hz was significantly reduced in the MCI cohort compared to HC, and in SCD even more so. Similar results were found for 1:2 alpha:beta cross-frequency phase synchrony (CFS) and 1:2 alpha:beta and 1:3 alpha:gamma phase-amplitude coupling. In the second dataset, we observed that in both the early and late measurements, sMCI and pMCI cohorts in both PS and CFC showed substantial differences in the alpha peak, which was centered around 10 Hz for sMCI, but between 8 and 9 Hz for pMCI. Conclusion: These results indicate that phase synchronization and cross-frequency coupling are altered already early in cognitive decline. Interestingly, the reduction of PS and CFC was larger in SCD than in MCI, suggesting that the proposed trajectory from SCD to MCI may be U-shaped rather than monotonic. In the longitudinal study, subjects with progressive MCI were found to exhibit slowed alpha peak frequency already at the first measurement, indicating that alpha peak frequency might be used to predict progression of the disease.

340. Human visual gamma for color stimuli: When L-M cone contrast is equalized, red is not special

Benjamin J. Stauch1, Dr. Alina Peter2, Isabelle Ehrlich3, Zora Nolte1, Prof. Pascal Fries1

1The Ernst Strüngmann Institute (ESI) For Neuroscience In Cooperation With Max Planck Society, 2McGovern Institute for Brain Research, MIT, 3Department of Psychology, Goethe University Frankfurt

340. Strong gamma-band oscillations in primate early visual cortex can be induced by homogeneous color surfaces. Compared to other hues, particularly strong gamma oscillations have been reported for red stimuli. However, precortical color processing and the resultant strength of input to V1 has often not been fully controlled for. Therefore, stronger responses to red might be due to differences in V1 input strength. We presented stimuli that had equal luminance and color contrast levels in a color coordinate system based on responses of the lateral geniculate nucleus, the main input source for area V1. With these stimuli, we recorded magnetoencephalography in 30 human participants. We found gamma oscillations in early visual cortex which, contrary to previous reports, did not differ between red and green stimuli of equal L-M cone contrast. Notably, blue stimuli with contrast exclusively on the S cone axis induced very weak gamma responses, as well as smaller event-related fields and poorer change-detection performance. The strength of human color gamma responses could be well explained by the strength of thalamic input induced by each hue and does not show a clear red bias when this input strength is properly equalized.

328. Classification of preclinical and prodromal stages of Alzheimer’s disease based on criticality and excitation/inhibition measures

Phd Gianluca Susi1,2, PhD student Isabel Suárez Méndez1,2, PhD Ehtasham Javed3, PhD Felix Siebenhühner3, Prof J.Matias Palva3,4, Prof Satu Palva3,5, Prof Fernando Maestú1,6

1Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, 2Department of Structure of Matter, Thermal Physics and Electronics, Complutense University of Madrid, 3Neuroscience Center, HiLIFE-Helsinki Institute of Life Science, University of Helsinki, 4Department of Neuroscience and Biomedical Engineering, Aalto University, 5Centre for Cognitive Neuroimaging, Institute of Neuroscience & Psychology, University of Glasgow, 6Department of Experimental Psychology, Cognitive Processes and Logopedics, Complutense University of Madrid

328. Objective: To evaluate the potential of criticality and excitation/inhibition measures extracted from magnetoencephalography (MEG) data, combined with volumes from magnetic resonance imaging (MRI), to distinguish between diagnostic categories ranging from normality to early phases of Alzheimer’s disease (AD) continuum: healthy controls (HC), subjective cognitive decline (SCD) and mild cognitive impairment (MCI). Research question: We hypothesize that brain criticality and excitation/inhibition measures can be proficiently used to classify between these diagnostic categories, both alone and combined with medial temporal lobe volumes (MTLv). Material and methods: We obtained MEG and MRI data from 343 participants (nHC=116, nSCD=85 and nMCI=142). Sensor-space MEG data was source-reconstructed and collapsed to Schaefer’s 7-network parcellation. MTLv were extracted from the segmented MRI data. Long-range temporal correlations (LRTC) and functional excitation/inhibition ratio (fE/I) features in θ, α, β, γ frequency bands, and MTLv, were extracted and used to train a k-nearest neighbors classifier (k=10) to distinguish between HC-SCD, HC-MCI, SCD-MCI individuals. Model performance in predicting new data was estimated using leave-one-patient-out cross-validation, considering AUC and accuracy. We considered the full set of features (56 functional and 6 volumetric), and then reduced the data dimensionality using the minimum redundancy maximum relevance algorithm. Through the extension to kernelSHAP algorithm we finally evaluate the importance of these features for the model outcome. Results: When the full set of features was considered the classifier was able to distinguish between HC-SCD with AUC=0.83 (Acc=0.76), between HC-MCI with AUC=0.86 (Acc=0.77), and between SCD-MCI with AUC=0.86 (Acc=0.81). After applying feature selection (reduced dataset), the classification improved noticeably (HC-SCD: AUC=0.86, Acc=0.79, 21 features; HC-MCI: AUC=0.88, Acc=0.82, 7 features; SCD-MCI: AUC=0.87, Acc=0.81, 14 features). Shapley values concerning the reduced dataset highlighted that fE/I (mainly in γ and θ bands) present higher order of importance for differentiation between HC-SCD and SCD-MCI, while MTLv for differentiation between HC-MCI. Conclusions: Brain criticality and E/I measures represent valuable tools to distinguish between individuals presenting different degrees of symptom severity, e.g., in the context of clinical trials where personalized treatment and sample recruitment are common practice.

342. Effects of temporal interference stimulation on mental rotation and individual alpha frequency

Carsten Thiele1, Stefan Repplinger1, Dr. Aiden Haghikia1, Dr. Tino Zaehle1, Dr. Philipp Ruhnau1,2

1Universitätsklinikum Magdeburg, 2University of Central Lancashire

342. Objectives: Recent research developed temporal interference stimulation (TI) as an instrument to modulate neuronal activity in rodents. This novel method of non-invasive, transcranial electrostimulation uses interfering electric fields of alternating currents to target deeper brain areas than other methods of transcranial electrostimulation would allow. In theory, the neuromodulation via TI is acting in a similar way to transcranial alternating current stimulation (tACS), that is, through entrainment of neuronal oscillations. Previous research showed that tACS in the alpha range results in brain activity changes in the alpha band after stimulation, which is reflected in larger alpha power increases post-stimulation compared to baseline in tACS compared to control (sham) groups. Furthermore, significant changes in behavioral performance in a mental rotation task comparing tACS and sham were observed. Research question: In this study, we set out to find empirical evidence for similarities and differences in stimulation effects caused by TI and tACS on mental rotation ability and resting alpha activity. Materials and methods: We combined electrophysiological recordings via EEG as well as a mental rotation paradigm while administering either TI, tACS or a sham stimulation at subjects’ individual alpha frequencies (IAF). Results: Participant’s accuracy in the mental rotation task improved over the course of the experiment. This improvement was significantly larger in the tACS group compared to sham, replicating previous findings, as well as compared to the TI group. There was no difference in improvement rates between TI and sham groups. Resting IAF power increased from a baseline measurement to post-stimulation in all groups, yet no significant differences in these increases could be observed. Numerically the effect was the strongest in the TI group, followed by tACS and sham. Conclusion: While the results replicate that tACS improves performance in a mental rotation task, TI did not show such an effect. This indicates that TI at present and within feasible intensities is insufficient to interact with cortical alpha, which is involved in mental rotation processes. We did not observe significant changes in resting alpha. Future research needs to determine if TI can be applied with higher intensities, to increase chances of neuromodulation in humans.

343. Motor learning induces frequency-specific changes to large-scale brain network connectivity during post-learning sleep

Simon Titone1,2, Dr. Jessica Samogin1, Prof Phillippe Peigneux3, Prof Stephan Swinnen1,2, Prof Dante Mantini1, Prof Genevieve Albouy1,2,4

1Department of Movement Sciences, Motor Control and Neural Plasticity Research Group, KU Leuven, 2LBI – KU Leuven Brain Institute, 3Neuropsychology and Functional Neuroimaging Research Group (UR2NF) at the Centre for Research in Cognition and Neurosciences (CRCN), Université Libre de Bruxelles (ULB), 4Department of Health and Kinesiology, College of Health, University of Utah

343. Objectives and research question: Magnetoencephalographic research has shown decreases in delta-band seed-based functional connectivity (FC) between motor, frontal and parietal seeds during sleep following motor sequence learning (MSL). As our previous research indicates that the examination of connectivity patterns at a network-level can bring additional insights into motor function, the goal of the present study was to assess, using high-density electroencephalography (hdEEG), whether MSL affects FC during subsequent sleep within and between large-scale cortical networks. Materials and methods: After completing a habituation night in the sleep laboratory, 23 healthy participants (13 F; mean age: 23.5 ± 3.5 y) were invited for 2 experimental sessions (task and control sessions) including nocturnal recordings. During the task session, participants were trained on a MSL task in the evening and retested the next morning after a night of sleep recorded with hdEEG. The control session only included sleep recordings (no task prior to sleep). Sleep EEG data from 5-minute episodes of stage NREM2, NREM3 and REM sleep from the first sleep cycle recorded in both the task and control nights were analyzed. Oscillatory activity in the delta-(1-4Hz), theta-(4-8Hz), alpha-(8-12Hz), sigma-(12-16Hz) and beta-(16-30Hz) bands was source-localized for each sleep stage. FC was then assessed from the source-reconstructed signal within the motor network-(MOT) and between MOT and the default mode-(DMN), dorsal attention-(DAN), ventral attention-(VAN), language-(LANG) and visual-(VIS) networks. FC metrics were compared between the control and task nights for each sleep stage. Results: Our behavioral data indicate significant gains in performance speed after a night of sleep (F(1,22) = 10.84, p = 0.003). EEG data analyses revealed that NREM3 sleep sigma band connectivity within the motor network (F(1,22) = 5.41, puncorr = 0.03, pFDR = 0.208) and between MOT-DAN (F(1,22) = 6.29, puncorr = 0.02, pFDR = 0.208) and MOT-DMN (F(1,22) = 5.79, puncorr = 0.025, pFDR = 0.208) was lower during the task as compared to the control night. Conclusion: Our preliminary results suggest that sigma-band connectivity within and between large-scale cortical networks is reorganized during slow-wave sleep following motor sequence learning.

344. Maternal treatment with antiepileptic drugs during pregnancy affects sleep-related brain dynamics in newborns

Anton Tokariev1,2, Mari Videman3, Susanna Stjerna1, Sampsa Vanhatalo1,2

1BABA Center and Department of Clinical Neurophysiology, Children’s Hospital, Helsinki University Hospital and University of Helsinki, 2Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 3Department of Pediatric Neurology, New Children's Hospital, University of Helsinki and Helsinki University

344. The early structural wiring of human brain takes place in utero, and it is guided by the endogenous brain activity, which is sensitive to many environmental effects, such as maternal drug treatments. Here, we studied the effects of in utero exposure to antiepileptic drugs (AED) on the early brain activity, and especially the sleep-related dynamics of newborn brain networks. We analysed 19-channel EEG from two groups of infants: i) exposed to AED (N=52), and ii) healthy controls (HC, N=68). Infants in both groups were born full-term at 40.2±1.7 weeks (median ± IQR) and EEG was recorded at age of 42.2±1.3 weeks. Next, we selected 3-minutes-long artifact-free epochs of EEG during active (AS) and quiet sleep (QS). These epochs were transformed into cortical signals (N=58 parcels) using infant head model and dynamical statistical parametric mapping. Resultant cortical activity was filtered into low/high delta (0.4–1.5/1.5–4 Hz), theta (4–8 Hz), alpha (8–13 Hz) frequency bands, and frequency-specific phase connectivity between parcel was assessed with weighted phase lag index. Finally, we tested group-by-sleep interactions (transitions between AS and QS in AED vs. HC) using network-based statistics. Significant changes in connectivity during sleep transitions were compared to neurocognitive performance at term-equivalent age and two years. We found that AED changes the sleep-related dynamics of brain networks. One large-scale pattern was observed in high delta band (p=0.012, t-test) and another one was detected in neighbouring theta band (p=0.008, t-test). Connectivity strength in both networks increased in AED infants when transiting from AS to QS, while HC showed an opposite effect. Comparison of these networks in the AED infants to clinical performance showed significant correlations: At term age, the theta frequency networks correlated significantly with neurological performance (Spearman’s R=−0.36, p=0.015), while at two years of age, the strength of high delta networks correlated with the fine motor scores (Spearman’s R=0.42, p=0.005). Our results show that prenatal AED exposure affects dynamics of infant brain networks and these changed networks associate with immediate and later neurocognitive performances. This study also suggests that analysis of cortical-level networks holds promise for disclosing clinically informative effects of early exposure to pharmacological therapies.

345. What is the role of frontoparietal attention network (de)synchronization underlying working memory and attention? An HD-tACS study

Mr Olof Van Der Werf1,2, Prof Dr Alexander Sack1,2,3, Ms Patricia Mendes4, Dr Tom De Graaf1,2, Dr Teresa Schuhmann1,2

1Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 2Maastricht Brain Imaging Centre (MBIC), Maastricht University, 3Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Brain and Nerve Centre, Maastricht University Medical Centre+ (MUMC+), 4Faculty of Health, Medicine and Life Sciences, Maastricht University

345. The frontoparietal attention network is involved in visual attention and working memory. Communication within such a network is thought to occur through oscillatory coherence, where synchronisation fosters and desynchronisation hampers neural signalling. Several recent studies applied dual-site transcranial alternating current stimulation (tACS) to uncover the causal role of frontoparietal oscillatory coherence in working memory. Yet, its role in visuospatial attention is still largely unknown; for example, both theta (4-8 Hz) and alpha (8-12 Hz) frequency bands have been associated with visuospatial orienting and reorienting of attention. Furthermore, existing tACS studies share a major limitation: electric field modelling suggests that the stimulated area differs between in-phase versus out-of-phase stimulation. In this single-blind, sham-controlled experiment, we will study the role of frontoparietal (de)synchronisation underlying visuospatial attention and working memory. We hypothesise that visuospatial attention will be affected by alpha and theta band (de)synchronisation and working memory only by theta (de)synchronisation, where synchronisation improves, and desynchronisation hampers performance, compared to sham. We aim to include 31 participants (effect size f = 0.25, power 1 − β = 0.95) in four experimental sessions, one for each combination of phase lag (in-, out-of-phase) and frequency (6 Hz and 10 Hz). We will apply tACS (2mA, peak-to-peak) using two 4-by-1 electrode hubs, centred over FC2 and P4 (10-20 system). Separate stimulators ensure that current flows largely within, not between, each electrode hub. Sessions will consist of 15-minute baseline (sham, ramp-up and ramp-down of 30s), followed by two 15-minute stimulation blocks. We will test working memory performance using a two-back task; outcome measures are d’ and reaction times (RT) on hits. We test visuospatial attention using an endogenous cueing task; outcome measures are spatial bias (RT left – RT right), orienting (RT valid – RT neutral) and reorienting (RT invalid – RT valid). We use an eye tracker to exclude trials with blinks / saccades in the attention task. After data pre-processing, we will conduct a Repeated Measures ANOVA to assess differences between experimental groups (6 Hz in-phase, 6 Hz out-of-phase, 10 Hz in-phase, 10 Hz out-of-phase, sham) in the outcome measures characterising working memory and attention.

346. Functional dissociation of hippocampal and neocortical ripples: From information transfer to consolidation

Dr. Frank van Schalkwijk1, Dr. Janna Lendner1,2, Prof. Dr. Jack Lin3,4, Dr. Dr. Randolph Helfrich1

1Hertie-institute For Clinical Brain Research, Center For Neurology, University Medical Center Tübingen, 2Department of Anesthesiology and Intensive Care Medicine, University Medical Center Tübingen, 3Department of Neurology, UC Irvine, 4Department of Biomedical Engineering, Henry Samueli School of Engineering, UC Irvine

346. Objectives. The hippocampal sharp-wave ripple is a key component of the hippocampal-neocortical dialogue that supports sleep-dependent memory consolidation. Previously, ripples were thought to be exclusively expressed in the medial temporal lobe. Recent findings indicated that ripples are a widespread cortical phenomenon. To date, it remains unclear if neocortical ripples fulfill a functionally similar role as their hippocampal counterparts. Specifically, it remains unknown how widespread ripples support memory reactivation, transfer, and consolidation. Research questions. What is the functional relevance of cortical ripples and how do they support the hippocampal-neocortical dialogue? First, we quantified morphological similarities between ripples recorded from the prefrontal cortex and medial temporal lobe. Second, we evaluated their spatiotemporal network connectivity profiles. Finally, we dissected the precise functional role for information transfer of hippocampal and neocortical ripples. Materials and methods. We conducted full-night sleep recordings in pharmacoresistant patients with epilepsy undergoing invasive recordings prior to resective surgery (N=14; mean age=36.79 ± 13.28y, range 19-58y; 64% female). Intracranial electroencephalography was recorded using implanted depth electrodes as part of pre-surgical invasive monitoring as well as scalp EEG. Results. Strong functional dissociations were observed between cortical and hippocampal ripples despite identical ripple morphology, connectivity profiles, and preferred phase coupling to slow oscillations and spindles. Our results revealed a stereotypical, low dimensional network response upon hippocampal ripples, which triggered directional information transfer from the medial temporal lobe to prefrontal cortex. In contrast, cortical ripples actively blocked information transfer from the hippocampus and disengaged network interactions to support local consolidation of newly received information within neocortical loops. Conclusion. Widespread ripple oscillations exhibit a uniform morphology, but support highly distinct functional roles. Here we report that hippocampal ripples initiate hippocampal-neocortical directed information transfer, whereas cortical ripples shut down this communication pathway; thus, preventing additional input during local information consolidation. Consequently, the temporal coordination of hippocampal and cortical ripples reflects an inherent feature to facilitate a dynamic hand-off between information transfer and consolidation.

347. Training parents for an early emotional contact changes cortical networks in their preterm infants

Pauliina Yrjölä1,2,3,4, Michael Myers5,6,7, Martha Welch5,6,7, Nathan Stevenson8, Anton Tokariev1,2,3, Sampsa Vanhatalo1,2,3

1BABA center, Department of Clinical Neurophysiology, Children’s Hospital, Helsinki University Hospital and University of Helsinki, 2Department of Physiology, University of Helsinki, 3Neuroscience center, Helsinki Institute of Life Science, University of Helsinki, 4Department of Neuroscience and Biomedical Engineering, Aalto University, 5Department of Psychiatry, Columbia University College of Physicians & Surgeons, 6Department of Pediatrics, Columbia University College of Physicians & Surgeons, 7Department of Developmental Neuroscience, New York State Psychiatric Institute, 8Brain Modelling Group, QIMR Berghofer Medical Research Institute

347. Objectives It is well established that prematurity is linked to neurodevelopmental compromise, constituting a key challenge in neonatal medicine. While treatments employing environmental enrichment (EE) have shown positive effects on neurodevelopmental outcomes, the underlying neurobiological effects on cortical networks remain largely unknown. The objective of this work is to investigate how improving parent-infant connection with bedside counseling affects electroencephalographic (EEG) connectivity networks. Research question Which cortical networks are affected by EE? Are those effects linked to later neurodevelopmental outcomes? Is an EE intervention able to restore normal cortical network development? Materials and methods High-density scalp EEG (N=128 channels) was recorded at term-equivalent age (40±1.6 weeks) from preterm infants in a trial of Family Nurture Intervention (FNI), which aims to enhance early parent-infant emotional connection. Infants received either FNI (N=59) or standard care (SC, N=50) and were born at gestational age of 31±2.4 weeks. Findings were also compared to clinical EEG recordings (N=19 channels) from healthy term controls (HC, N=67). 5-minute epochs of active (AS) and quiet sleep (QS) were extracted, prefiltered from 0.4-40Hz, and down-sampled to 100 Hz. These data were filtered into narrow frequency bands and reconstructed to source activity. Pairwise connectivity was computed with weighted phase-lag index, and the resulting functional networks were statistically compared between infant groups. Networks with significant group differences were correlated to later neurodevelopmental outcomes (Bayley) and compared to the networks of HC infants. Results We found significant frequency-specific group differences, most prominently at alpha (~11Hz) frequency. The strength of the alpha frequency network correlated to neurodevelopmental scores in both AS (Cognition: p=0.006, rho=-0.39) and QS (Cognition: p=0.03, rho=-0.31; Language: p=0.02, rho=-0.42). Strikingly, the mean connectivity in networks of the FNI infants was comparable to those found in the HC infants, whereas they were significantly different from the networks seen in the SC infants (p<0.001). Conclusion This work shows that consulting parents in improving parent-infant connection may affect early development of cortical networks. This effect links to neurodevelopmental outcome, and moreover, the networks in the FNI infants appear to exhibit diminished prematurity-related effects. Thus, EE interventions may improve early neurodevelopment in preterm infants.

245. Phonological information can modulate orthographic processing already at the earliest stages of visual processing: An electrophysiological study

Dr Luís Faísca2, Dr Alexandra Reis2, Dr Filomena Inácio2, Dr Susana Araújo1

1Faculty of Psychology, University of Lisbon, 2Center for Biomedical Research, University of Algarve

245. For a skilled reader it takes only approximately ¼ second to identify a word. This remarkable speed depends on a visual specialized system for letters over symbol strings in the left ventral occipitotemporal cortex (including the visual word form area) and is signaled by the N1 electrophysiological component. The letter specialized system develops rapidly in the brain, allied with letter knowledge, and will serve automatic visual word recognition. This study used event related potentials (ERPs) to investigate the underlying processes of the letter-string N1 effect. While the bottom-up selectivity of N1 to visual-orthographic properties is well-established, it is still under debate if the N1 effect is open to top-down influences from language. Thus, we aimed to clarify whether online processing at the phoneme level can feed back to the visual system during letter processing. For this, we asked 42 typical adult readers (mean age[±SD] = 21.7 [±3.0] years) to perform an one-back task (visual immediate repetition detection), in which we orthogonally manipulated the stimulus lexical status (words vs. pseudowords) and the spelling-to-sound consistency at the sublexical level ((pseudo)words that can only be sounded out in one way vs. contain ambiguous grapheme-to-phoneme mapping). Results showed a predominant left-lateralized N1 for letter strings, as a signature of fast, automatic orthographic processes in expert-like readers. In addition, we found amplitude modulations in the visual N1 ERP component for different levels of spelling-to-sound consistency, specifically, inconsistent stimuli (vs. consistent) yielded smaller N1 over posterior sites. Especially for words, this effect of consistency was stronger in the dominant language hemisphere. Thus, phonology, manipulated in terms of inconsistency in the spelling-to-sound mappings, can affect the visual recognition of print already at the earliest stages of visual processing (< 200ms). Our results seem compatible with an interactive account in which higher-level top-down (phonological) and visual bottom-up orthographic information interacts in an automatic fashion for visual word recognition.

231. Does the respiratory cycle modulate visual perception? An exploratory study in the domains of emotional face perception and motion discrimination.

Md, Phd.-student Malthe Brændholt1, Prof Micah Allen1,2

1Center of Functionally Integrative Neuroscience, Aarhus University, 2Cambridge Psychiatry, University of Cambridge

231. Objectives The view that bodily, cognitive, and neural states are closely coupled is gaining increasing interest in cognitive neuroscience. Breathing constitutes a fundamental visceral rhythm maintaining homeostasis in the body. Recent evidence suggests that stimuli in a variety of modalities are perceived differently relative to the inspiratory-expiratory breathing cycle. In particular, previous work found that emotional stimuli may be particularly susceptible to respiratory phase. To expand on these findings, we examined whether the respiratory cycle influences perceptual performance for emotional face and visual motion stimuli. Research question Is perceptual decision making coupled to the breathing cycle and is this coupling specific to emotional stimuli? Material and methods We probed breath-behavior coupling in healthy human participants in two perceptual domains using 1) a Face Affect Discrimination Task 2) a Visual Motion Discrimination Task. In each case, participants viewed a brief stimulus presentation and then responded as to whether the face was happy or angry, or the dot motion upward or downward. All stimuli were presented at peri-threshold intensity values, where thresholds were determined using an adaptive staircase. To control for possible respiratory-locked head motion, all participants completed the experiment using a fixed chin rest. Respiratory movements were recorded using a respiration belt. 40 healthy participants participated in an exploratory discovery sample, with 320 trials each per stimulus condition. Results We used permutation-based statistical tests measuring the degree of coupling between the respiratory cycle and perceptual behavior, using the Watson u-test and Modulation Index, respectively. We did not find robust emotion related effects of the respiratory cycle, either for reaction time or choice. For dot motion accuracy, we observed a significant (p < 0.05) respiratory cycle effect on the distribution of hits and misses. Conclusion Our study suggests that, in the emotional domain at least, respiratory-modulated behavioral effects may not be as robust as previously anticipated. Future exploratory analyses will investigate perceptual sensitivity and bias measures binned across inspiratory and expiratory phases of breathing, as well as sinuosidal time-frequency analyses to probe for possible alignment of infra-slow respiratory and reaction time rhythms in both modalities.

249. A study on the relationship between history effects in perceptual decisions and brain rhythms

Gizay Ceylan1, Dr David Pascucci1

1EPFL

249. Perceptual decisions can be highly variable, even in response to the same stimulus. This variability is partly due to the effect of the temporal context and the intrinsic dynamics of the brain. In this work, we sought to characterise the relationship between the two by leveraging high-density electroencephalography (EEG) recordings and the phenomenon of serial dependence. In serial dependence, visual decisions are biased towards features of stimuli seen before. We have previously shown that serial dependence originates from the persistence of elementary visual representations required by a task and may involve high-level processing stages, beyond perception. Here, we replicate these findings in a multi-session experiment with both psychophysics and EEG. In the behavioural task, participants were presented with a cloud of moving dots and a contrast pattern, fused into a single stimulus. In randomly interleaved trials, participants were asked to reproduce either the direction of the dots motion or the orientation of the contrast pattern. Serial dependence occurred systematically and independently of the relevant feature: in reproducing the orientation of the contrast pattern, participants were biased by the previously reported motion direction and vice versa. This result was consistent within subjects and between sessions. In the EEG session, we evaluated the size of the bias as a function of the power of pre-stimulus brain rhythms at multiple frequencies. Our preliminary results suggest that prior visual representations interfere more with current decisions depending on the energy power at low-frequency rhythms, suggesting an interplay between temporal context and the momentary state of the brain, right before the onset of a stimulus.

250. Spontaneous slow fluctuations in oscillation amplitudes orchestrate conscious visual perception: A source-reconstructed time series analysis

Dr Gabriela Cruz1, Prof Satu Palva1,2, Prof Matias Palva1,2,3

1Institute of Neuroscience and Psychology, University Of Glasgow, 2Neuroscience Centre, Helsinki Institute of Life Science, University of Helsinki, 3Department of Neuroscience and Biomedical Engineering, Aalto University

250. The human brain exhibits infra-slow (0.01-0.1 Hz) and slow (0.1-1 Hz) fluctuations in neuronal excitability. Previous research suggests such slow fluctuations as well as faster pre-stimulus activities plays a role in sensory processing and perception. However, the roles of slow fluctuations in visual perception and, in particular, the underlying neural networks have remained incompletely understood. The current study aims at unveiling the functional significance of ongoing slow fluctuations for visual conscious perception in task-engaged subjects, in source reconstructed MEG data. Twenty subjects undertook a visual continuous performance task where they reported perceived visual stimuli in a stream of stimuli presented at a constant contrast yielding ~50% detection rate. We found that visual perception was correlated with the phase of slow pre-stimulus fluctuations, particularly in brain regions that conform task-related networks. Spatio-temporal structure of the perceptual-processing-biasing slow fluctuations was distinct from that of faster oscillations. This finding supports the idea that fluctuations below 1Hz could reflect network-scale excitability regulation that plays a role in orchestrating cognitive functions.

251. From deep to shallow rooting approaches in schizophrenia research

Mr Dario Gordillo1, Janir Ramos da Cruz, Aline Cretenoud, Ophélie Favrod, Andreas Brand, Simona Garobbio, Albulena Shaqiri, Wei-Hsiang Lin, Ekaterine Berdzenishvili, Patrícia Figueiredo, Maya Roinishvili, Eka Chkonia, Michael H Herzog 1EPFL

251. The prevailing approach in schizophrenia research usually focuses on one experimental paradigm revealing clear-cut atypical effects in patients compared to healthy controls. Thereon, in-depth studies are carried out to understand in great detail what are the cognitive, neural, and genetic underpinnings of the abnormality. An implicit or explicit assumption is that the paradigm taps into common and representative aspects of schizophrenia. We show that this assumption may not necessarily hold true. First, we tested 68 schizophrenia patients and 60 healthy controls with a battery of visual paradigms from which we extracted 34 features, covering a wide range of functions of the visual system. Patients showed significant deficits in 14 of these visual features, compared to controls. To understand to what extent the 34 features relate to each other, we correlated these features. We found that the correlations were very weak. Second, we analyzed resting-state EEG data of 121 patients and 75 controls using multiple techniques from which we extracted 194 EEG features. We found that 69 of these EEG features showed significant group differences, suggesting that they tap into important deficits. Yet, the correlations between these 69 EEG features were very weak. Based on these results, we ask the question to what extent a single feature captures truly representative aspects of schizophrenia. Instead, it may well be that each paradigm taps into roughly independent aspects of schizophrenia. We propose that future studies should consider multiple features extracted from the same and different paradigms. In contrast to the prevailing deep rooting approach, such a shallow rooting approach would be more aligned with the heterogeneity of schizophrenia, which even though well recognized, is not always fully considered.

252. Differentiating cognitive states and task demands by aperiodic electrophysiological markers in humans

MSc Christopher Höhn1, Dr. Michael Hahn2, Assoc. Prof. Dr. Kerstin Hödlmoser1,3

1Laboratory for Sleep, Cognition and Consciousness Research, Department of Psychology, University of Salzburg, 2Hertie-Institute for Clinical Brain Research, University Medical Center Tübingen, 3Centre for Cognitive Neuroscience Salzburg (CCNS), University of Salzburg

252. Human brain activity dynamically changes between cognitive states and with different arousal levels and cognitive demands. Recent evidence suggests that consciousness and arousal can be inferred by scale-free neural activity in the human EEG. Specifically, the spectral exponent from the power spectrum and neuronal complexity can distinguish between wakefulness, natural sleep and anesthesia. Importantly, both parameters have also been linked to behavioral task performance. Here, we utilized these two electrophysiological markers to investigate whether they additionally distinguish tasks with varying cognitive demands in addition to differentiating sleep-states from wakefulness. We recorded full-night polysomnography from 28 healthy male subjects (21.54 ± 1.90 years) on three occasions in a within-subjects design. Additionally, subjects performed multiple cognitive tasks, including an auditory Go/Nogo task, a declarative learning task and baseline resting sessions (with opened and closed eyes). We computed neuronal complexity using the Lempel-Ziv-Welch algorithm and spectral slopes (exponents) of the EEG power spectra by applying robust linear fits in log-log space between 30-45 Hz for each task and per sleep stage. We found a general (i.e. independent from recording day or task) increase in neuronal complexity and a flattening of the spectral slope over the evening. Interestingly, only the neural complexity showed an additional reset to baseline level after a night of sleep. No modulation of complexity by the performed cognitive task was present. However, an increase in task demands led to a significant flattening of the spectral slope. Both, spectral exponent and neuronal complexity were modulated by sleep-stages, showing decreasing complexity and steeper slopes with deeper sleep stages (from N1 to N3). However, only the spectral exponent was sensitive enough to distinguish REM sleep from other sleep stages and wakefulness. Critically, all of these results were highly stable as they emerged across all three recordings per subject. Our findings suggest that neuronal complexity and spectral exponent can serve as informative and intra-individually robust electrophysiological markers of altered arousal states and task demands, which are easily accessible with scalp-EEG recordings. The trajectories of both parameters across the evening and the subsequent reset after sleep in neuronal complexity further suggest a possible circadian modulation.

253. Long-term temporal structure and scale-freeness of high-level perception

Mr Martin Irani1,2,3, Mrs Yuetian Li1,3, Dr. Richard Bidó-Medina1,4, Mr. Maximilian Egan1,3, M Chris L. Perriello1,3, Mr Runhan Yang1, Mrs Laura Pritschet1,5, Mr Ezra Winter-Nelson1,6, Dr. Thomas H. Alderson1, Dr. Wendy Heller1, Dr. Sepideh Sadaghiani1,2,3

1Beckman Institute, University of Illinois at Urbana-Champaign, 2Neuroscience Program, University of Illinois at Urbana Champaign, 3Department of Psychology, University of Illinois Urbana-Champaign, 4Harvard Medical School, 5University of California Santa Barbara, 6University of Texas at Dallas

253. The brain continuously undergoes distinct states over time in order to flexibly adapt to changing external constraints. Dynamic systems such as this commonly exhibit criticality; a regime poised between order and disorder that gives rise to maximum variability in spatiotemporal patterns. A characteristic suggestive of a critical system is to exhibit patterns that are invariant across timescales, a property usually referred to as scale-freeness. Previous studies have reported that sequences of perceptual outcomes during presentation of ambiguous stimuli show scale-free properties. Criticality, indexed by scale-freeness, may be prompt to flexible perception which, in turn, supports adaptive behavior under ambiguous circumstances. However, prior observations have been confined to low-level stimuli (e.g., signal detection), and it remains unclear whether high-level perceptual decisions (e.g., object perception) are likewise scale-free. To this end, we used scalp full-band EEG recordings (N=38) during an emotional valence perception task, where subjects were instructed to indicate whether an emotionally ambiguous face image (determined by a threshold procedure on each subject) was perceived as sad or neutral. Subjects also performed an object perception task (N=34), where they viewed the Rubin’s vase-face ambiguous figure and were instructed to indicate whether they perceived either a face or a vase. We found that response time series showed significant long-term autocorrelations with respect to the null model, confirming that perceptual outcomes at any given moment depends on perception of prior stimuli. We then assessed the temporal structure of this dependence in terms of its scale-free properties using Detrended Fluctuation Analysis (DFA). Hurst exponents were greater than 0.5 and significantly different than the null model, confirming the presence of scale-free behavior in both tasks. Taken together, our findings suggest that scale-free temporal dependencies govern not only low-level but also higher-level perceptual processes. Scale-freeness extending across all levels of perception may arise from an underlying scale-free neural process. Flexibility of higher-level perception, supported by critical dynamics, may be crucial for resolving uncertainty encountered in everyday visual settings.

254. Comparing Response Inhibition and Interference Resolution using 7T MRI

Scott Isherwood1, Pierre-Louis Bazin1,3, Steven Miletic1, Anne Trutti2, Desmond Tse4, Niek Stevenson1, Riley Innes1, Anneke Alkemade1, Sarah Habli4, Pål-Erik Goa4, Asta Haberg4, Birte Forstmann1

1University Of Amsterdam, 2Norwegian University of Science and Technology, 3Max Planck Institute for Human Cognitive Brain Sciences, 4Leiden University

254. Response inhibition and interference resolution are two of an array of complex cognitive control processes. Response inhibition is commonly studied using the stop signal task, where the main contrast of interest is the failed stop > go trials (SST; Logan et al., 1984). Interference resolution describes a broad class of high-level reasoning abilities, used to resolve conflicting stimuli in the environment. The multi-source interference task (MSIT; Bush et al., 2003) is a commonly used task developed to investigate interference resolution, where the main contrast of interest is the incongruent > congruent trials. 32 participants were scanned in one functional magnetic resonance imaging (fMRI) session on a 7 Tesla Siemens TERRA. Each participant completed 200 trials of two tasks: the visual SST and MSIT. The functional data was collected using a single echo 2D-EPI BOLD sequence (TR = 1380ms; TE = 14ms; voxel size = 1.5mm isotropic). All MRI data were preprocessed using fMRIprep (Esteban et al., 2019; 20.2.6). This pipeline included realignment, slice timing, susceptibility distortion and head motion correction. The data were spatially smoothed using a Gaussian smoothing kernel (FWHM = 1.5mm). Whole-brain GLMs were calculated using FSL FEAT (Jenkinson et al., 2012). FLAME1 was used to calculate group-level results (Woolrich et al., 2004). Subsequently, statistical parametric maps (SPMs) were made to interpret the results, where all p-values were corrected for the false discovery rate (FDR) and a critical value of q < 0.05 was used. In contrast to previous meta-analytic and inter-individual findings, here we find common subcortical substrates within both the response inhibition and interference resolution tasks. Maximum z-values are given for the main contrasts of the SST and MSIT tasks, respectively. In line with previous work, we do see that the bilateral supplementary motor area (z=4.93,4.74), bilateral insula (z=6.87,6.01) and left inferior frontal gyrus (z=6.11,5.32) are recruited in both tasks. Other overlapping activations include but are not limited to the thalamus (z=5.22,4.22), substantia nigra (z=4.77,4.13), and subthalamic nucleus (z=4.91,4.19). This work exemplifies the necessity for ultra-high field MRI scanners and tailored sequences (Miletic et al., 2020) to accurately investigate cognition on a whole-brain level.

256. Neurally-informed modelling of ageing effects on the speed-accuracy trade-off

Cian Judd1, Dr Jessica Dully1, Prof Simon Kelly2, Dr David McGovern3, Dr Elaine Corbett1,2, Prof. Redmond O'Connell1

1Trinity College Institute Of Neuroscience, 2University College Dublin, 3Dublin City University

256. Objectives and Research Question When instructed to prioritise speed over accuracy in decision making, older adults tend to make smaller adjustments to their choice behaviour compared to younger adults. Behavioural modelling suggests this may be due to less pronounced adjustment of decision bounds across conditions and a general preference for a more cautious response style. However, this work has relied on standard models which overlook important algorithmic elements and adjustments that have been identified in recent neurophysiological research. The current study aimed to leverage neurally-informed modelling to investigate ageing’s effects on speed-accuracy adaptation. Materials and methods 30 older adults and 30 young adult controls performed a random dot-motion task, while EEG signatures of evidence accumulation and motor preparation were recorded. Results and Conclusions Both groups adapted their behaviour in response to speed pressure, with young adults showing a more substantial reduction in reaction time. However, there was no group difference in the number of points scored. Consistent with previous modelling studies, both groups exhibited increased starting levels of motor preparation under speed pressure but the adjustments were significantly smaller in the older group. These prestimulus motor adjustments were used to constrain a sequential sampling model which also included dynamic within-trial bound adjusmtents (‘urgency’) based on the observation that motor preparation exhibited substantial build-up prior to evidence onset. This neurally-constrained model indicated age differences in the dynamic adjustment of decision bound, with only young adults significantly adapting their urgency rate across conditions. Young adults adapt their bounds three times as strongly under speed pressure, with a more consistent setting of bounds potentially allowing older adults to achieve an equal number of points on the task. We also report an exploratory, model-based approach for accounting for behaviourally-irrelevant differences in EEG signal amplitudes when comparing decision signals between groups. Overall the project highlights the potential exciting applications of neurally constrained modelling for enabling more accurate group comparisons.

113. Neurally informed insights into perceptual learning in decision making tasks

Cian Judd1, Dr Elaine Corbett2, Prof Redmond O'Connell1

1Trinity College Institute Of Neuroscience, 2University College Dublin

113. Objectives and Research Question Research in psychophysics has indicated that behavioural improvements arising from training on perceptual tasks are attributable to reductions in internal noise. In parallel, mathematical modelling studies within the decision-theoretic framework have tended to point to alternative accounts including increased drift rates and reduced non-decision times and boundary separation. However, these models fix within-trial noise as their scaling parameter, thus preventing it from accounting for any learning effects. EEG derived markers of decision making may be useful in enabling us to inform and constrain decision models and examine changes in within-trial noise over learning. Materials and Methods Sixteen participants completed an Equivalent Noise Estimation of internal noise and five blocks of a two-forced choice random-dot motion task across three sessions while 128-channel EEG was recorded. In each block a set of identical stimuli were presented interleaved with 90 novel trials, giving 15 passes of identical stimulus (5 each of 3 days). Results and Conclusions Participants showed significant increases in accuracy by session, but not within a session, while reaction time reduced over the course of a session, but did not lower significantly across blocks in one day. A significant reduction in psychophysical estimates of internal noise was also seen across sessions. Analysis of neural indices of decision making showed increased pre-stimulus build-up of the decision signal by session. Analysis of the contingent negative variation as a marker of urgency suggested significantly more pre-stimulus CNV build-up in earlier sessions. Current work is using this neural data to constrain standard diffusion models, enabling us to assess the impact of perceptual learning on model-estimates of internal noise.

232. Neural rhythmic representation of intergroup bias: comparing political right and left

Annika Kluge1, Eliyahu Adler1,2, Dr Jonathan Levy1,3

1Aalto University, 2The Hebrew University of Jerusalem, 3Interdisciplinary Center Herzliya

232. It is widely debated whether the two political wings, right and left, are symmetrically polarized or differ fundamentally and asymmetrically. Several neuroimaging and electrophysiological studies have examined this question but neural rhythmical activity has been largely overlooked. Framed in the political turbulence of Israel, our study has utilized magnetoencephalography (MEG) to investigate neural oscillations representing intergroup bias and the possible neural differences between political wings. We sampled 79 Israeli adults who underwent the Implicit Association Test (IAT) during MEG recording. The only rhythm associated with intergroup bias in earlier studies has been the alpha rhythm and our findings confirmed that. Further, this effect appeared in the rightist group but not in the leftist and was significantly different between the two groups at the neural level. This study has implications for the neuroscience of political ideology.

233. Respiration aligns perception with neural excitability

Dr Daniel Kluger1, Elio Balestrieri1, Prof Niko Busch1, Prof Joachim Gross1,2

1University Of Münster, 2University of Glasgow

233. Recent studies from the field of interoception have highlighted the link between bodily and neural rhythms during action, perception, and cognition. The mechanisms underlying functional body-brain coupling, however, are poorly understood, as are the ways in which they modulate behavior. We acquired respiration and human magnetoencephalography data from a near-threshold spatial detection task to investigate the trivariate relationship between respiration, neural excit-ability, and performance. Respiration was found to significantly modulate perceptual sensitivity as well as posterior alpha power (8–13 Hz), a well-established proxy of cortical excitability. In turn, alpha suppression prior to detected versus undetected targets underscored the behavioral benefits of heightened excitability. Notably, respiration-locked excitability changes were maximized at a respiration phase lag of around –30° and thus temporally preceded performance changes. In line with interoceptive inference accounts, these results suggest that respiration actively aligns sampling of sensory information with transient cycles of heightened excitability to facilitate performance.

234. Relationships between local and global oscillatory measures of connectivity and structural connectivity in the healthy population

Emily Lambe1, Dr Eirini Messaritaki1, Prof Krish Singh1

1Cardiff University

234. Objectives Understanding relationships between the brain’s local and global dynamics is important in both health and disease and required for the attribution of cognitive functioning. Magnetoencephalography (MEG) allows us to quantify local functional connectivity, reflected in high frequency oscillations, and global functional connectivity processes, reflected in the lower frequencies. Previous literature suggests that individuals with strong local gamma connectivity also have strong global connectivity, such that the amplitude of local and global oscillatory measures is correlated. Relationships between the brain’s structure and function are also of considerable interest. Therefore, how individual variability in the structural connectome is related to individual variability in local and global connectivity will also be assessed. Research questions The aim of this work is to 1) further define physiologically informed inter- and intra-areal oscillatory relationships by investigating relationships between local and global measures, and 2) explore how functional connectivity relates to the structural connectome by investigating local connectivity and structural connectivity relationships. Improved understanding of these relationships will provide a perspective from which to better explore associated cognitive mechanisms and their disruptions in disease. Materials and methods MEG recordings were obtained from 183 healthy individuals during the resting state and a visual paradigm. Beamformer analysis was used to localise the signals in the brain. Analysis of the gamma signal in the visual cortex and amplitude-amplitude connectivity across the brain between 90 cortical areas (defined via the Automated Anatomical Labelling atlas) was conducted. Diffusion magnetic resonance imaging (dMRI) data were collected from the same participants, and used to perform tractography and calculate the structural brain networks of the participants, using the same 90 cortical areas. Relationships between the structural and functional networks were investigated with regression analysis. Conclusion Investigating functional measures, we observed that the visual gamma amplitude was negatively associated with connectivity within an occipital resting-state network in the alpha band. Investigating structural connectivity in relation to local oscillatory measures, we observed a negative relationship between visual gamma frequency and components of the structural networks weighted by measures related to myelination and axonal packing. These findings give further insight into the processes that underpin cognition.

235. Fatigability-related spectral power changes in people with multiple sclerosis

Stefanie Linnhoff1, Aiden Haghikia1, Tino Zaehle1

1Department of Neurology, Otto-von-Guericke University

235. Objectives: Fatigue is a multidimensional and challenging symptom of many neurological diseases, such as multiple sclerosis (MS). There is increasing evidence that fatigue can manifest itself as subjective fatigue with a trait or state characteristic as well as a performance fatigability - an objectively measurable performance decline with time on task [1]. However, in the absence of valid and reliable objective parameters to assess fatigability, the current fatigue diagnosis is still purely subjective. Analyzing task-related oscillatory brain activity is an effective way to monitor attention decline. Thus, the link between cognitive fatigability and spectral power changes has been repeatedly demonstrated in healthy subjects, such as increased frontal theta and occipital alpha activity [2,3]. Yet, associations between subjective trait and state fatigue and performance fatigability remain ambiguous and inadequately investigated. Research Question: This study systematically investigated fatigability-related spectral power changes and their associations with subjective trait and state fatigue in both, chronically fatigued and healthy individuals. Materials and Methods: We enrolled 21 people with MS and 21 age- and gender-matched healthy controls. Before and after participants performed a 30-minute cognitively exhaustive task, resting-state EEG data with eyes open and closed were recorded, and spectral powers were assessed. Subjective state fatigue was repeatedly measured via visual analog scales. In addition, trait fatigue scores were assessed via self-reported questionnaires. Results and Conclusions: The task was subjectively exhaustive for both groups. As hypothesized, the MS group had a greater increase of subjective state fatigue and fatigability systematically modulated frontal theta and occipital alpha power differently in both groups. Furthermore, correlational analyses indicate an association between subjective fatigue and objective parameters of fatigability. These findings might help improve the understanding of the neural mechanisms underlining cognitive fatigability and complement the subjective fatigue diagnostic with quantitative objective methods. References [1] Linnhoff, S., Wolter-Weging, J., & Zaehle, T., Clin Neurophysiol, 132(7), 1721-1732 (2021) [2] Wascher, E., Rasch, B., ... & Gutberlet, I., Biol Psychol, 96, 57-65. (2014) [3] Clayton, M. S., Yeung, N., & Kadosh, R. C., Trends Cogn Sci, 19(4), 188-195. (2015)

236. Does dynamic urgency facilitate perceptual decision making in continuous monitoring contexts?

Mr Harvey McCone1,2, Mr Richard Halpin2, Prof Redmond O'Connell1,2

1Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, 2School of Psychology, Trinity College Dublin

236. Background Recent modeling and neurophysiological research on perceptual decision making has highlighted the role of dynamic urgency processes that serve to expedite choice commitment when participants are faced with a response deadline. This work has focussed almost exclusively on scenarios in which participants know exactly when choice-relevant information will appear. In continuous monitoring contexts, participants are faced with considerable temporal uncertainty, and it is not clear whether urgency processes can be effectively implemented in such contexts. Experimental Procedures To investigate this question, we will record electroencephalography (EEG) while human participants perform a continuous monitoring random dot motion task. Twenty-five participants will monitor a continuously presented cloud of randomly moving dots for intermittent periods of coherent leftward or rightward motion, reporting the direction of motion by making mouse clicks. Coherent motion will be presented at one of two coherence levels, and there will be three randomly interleaved inter-target intervals. In alternating blocks, participants will perform the task under conditions of relative speed or accuracy emphasis. Analysis Pipeline To test the degree to which urgency is invoked on this task, we will examine previously characterized neural signatures of urgency (effector-selective mu/beta-band activity (8-30 Hz) and the Contingent Negative Variation, CNV) while tracing evidence accumulation via the Central-Parietal-Positivity (CPP). Hypotheses Based on previous preliminary findings, we hypothesize that urgency signals will begin building in advance of target presentation, peaking at the time of response. It is hypothesized that response times will be faster, false alarm rate will be higher, and miss rate will be lower under speed pressure. Similarly, we hypothesize that the slope of the urgency signals will increase prior to target onset and response selection under speed pressure. Power Analysis A power analysis conducted using G*power indicated that a sample of twenty-five participants is required to detect an effect size of f = 0.3. Pilot Data Behavioural results from eight participants (3 female, mean age = 24.63 years, range: 21-29 years) indicate that participants responded faster, committed more false alarms, and missed fewer targets in the speed condition.

246. Modulating locus coeruleus activity via volitional control of pupil diameter

Sarah Meissner1, Marc Baechinger1, Jenny Imhof1, Angela Wandel1, Adrian Taubner1, Nicole Wenderoth1,2

1Neural Control of Movement Lab, ETH Zurich, 2Future Health Technologies, Singapore-ETH Center

246. Objectives: The locus coeruleus (LC) in the brainstem is the principal source of noradrenergic projections across the brain and is involved in the control of various behaviors. Interestingly, there is ample evidence for a link between LC activity and non-luminance dependent pupil size changes. Building on this evidence, we investigated whether changes in pupil size (i) can be volitionally induced via pupil-based neurofeedback (pupil-NF) training, and (ii) are indeed linked to activity changes in the LC and interconnected areas. Methods: 52 healthy volunteers (19-47 years) received pupil-NF training to learn to volitionally increase and decrease pupil size. Pupil size was measured by means of an eye-tracker and fed back to the participants during training. 27 control participants (19-40 years) received the same amount of training and instructions on mental strategies but no veridical pupil-NF. To further explore the link between pupil size changes and LC activity, 25 of the participants receiving veridical pupil-NF underwent two follow-up session combining pupil-NF with 3T fMRI to measure BOLD responses during volitional pupil modulation. First-level analyses involved the construction of a general linear model contrasting blocks of pupil size increase vs. decrease and using measured pupil diameter as regressor of interest, respectively. Results: Participants were able to learn to self-modulate their pupil size (rm-ANOVA, main effect training session; p < .001). Such self-modulation was clearly reduced in control participants who did not receive veridical pupil-NF (main effect group; p < .001). Preliminary analyses of our fMRI data further revealed that pupil self-modulation may indeed be linked to activity changes in the LC and interconnected areas including the anterior cingulate cortex and the thalamus: we found higher BOLD responses during blocks of volitional pupil size increase than decrease as well as a correlation between measured pupil size and BOLD responses in similar areas throughout the task. Conclusion: Our findings suggest that healthy volunteers can learn to self-modulate pupil size. We offer new insights into the link between pupil dynamics and LC activity and provide first evidence that volitional pupil modulation may indeed be linked to activity changes in the LC and closely interconnected areas.

237. Microstructural and connectomic fingerprints of inter-individual differences in respiratory interoception

Dr Niia Nikolova1, Dr Olivia Harrison3,4, Dr Nicolas Legrand1, Dr Leah Banellis1, Dr Micah Allen1,2

1Aarhus University, 2University of Cambridge, 3University of Otago, 4University of Zurich and ETH Zurich

237. Objectives The perception of our breathing, respiratory interoception, is related to psychiatric conditions such as anxiety and panic disorder. More generally, the perception, awareness, and control of respiratory sensations is a key component of affective self-regulation and self-consciousness. In order to improve our understanding of the neurobiological underpinnings of respiratory interoception, we used a novel computational psychophysics approach to quantifying individual profiles in respiroceptive perceptual and metacognitive sensitivity, as well as associated affective sensations. We then applied machine learning techniques to derive multimodal cortical fingerprints indexing ability within and across these functional levels. Research questions What cortical features and networks underlie individual profiles in respiratory interoceptive perception, affect, and metacognition? Materials and methods We recently proposed a psychophysical Bayesian approach to quantifying respiratory interoceptive ability across perceptual, metacognitive, and affective axes, the RRST. To interrogate the cortical microstructure and whole-brain connectivity profiles underlying these abilities, we collected multimodal imaging data together with RRST profiles in 300 healthy human participants. Our imaging battery consisted of 12 minutes of multi-band resting state fMRI acquisition, as well as quantitative maps indexing cortical myelination and iron concentration using a multi-parameter mapping technique. Using multivariate, permutation-based canonical correlation analysis, we examined maximally correlated latent dimensions of respiratory interoception, functional connectivity and brain microstructure across perceptual, affective, and metacognitive axes. Results We present results demonstrating the functional and microstructural correlates of respiratory interoception. More specifically, we show how myelination and iron concentration relate to the psychometric threshold, slope, metacognitive and affective measures from the RRST. We also investigate the associations of these variables with patterns of seed-based insular functional connectivity in the anterior, middle, and posterior insula. Finally, we explored whether individual weightings on these connectomic brain variates could be used to predict individual anxiety and depression symptom profiles.

238. Cardiac cycle and respiration phase affect responses to the conditioned stimulus in young adults during trace eyeblink conditioning

Tomi Waselius1,2, Weiyong Xu1,2, Julia Sparre1,2, Markku Penttonen1,2, Miriam Nokia1,2

1Department of Psychology, 2Centre for Interdisciplinary Brain Research

238. OBJECTIVES: Our recent studies suggest that presenting the conditioned stimulus (CS) during expiration or during the diastolic phase of the cardiac cycle facilitates neural processing of that stimulus and improves learning in a trace eyeblink classical conditioning (TEBCC) task in healthy adults. To date, it has not been examined whether utilizing information from both respiration and cardiac cycle phases simultaneously allows even more efficient modulation of learning. RESEARCH QUESTION: We studied whether the timing of the CS to different cardiorespiratory rhythm phase combinations (expiration-diastole, expiration-systole, inspiration-diastole and inspiration-systole) affects learning TEBCC. MATERIALS AND METHODS: Fifty-nine young adult (12 males; ~23 years old) volunteers took part in the study. Participants were conditioned while watching a silent film. The CS was a 200-ms tone, and the unconditioned stimulus was a 100-ms air puff targeted to the right eye. A 600-ms trace interval separated the CS offset from the air puff onset. Five CS-alone trials were followed by 50 paired trials, and the inter-trial interval was random between 20 and 40 s. To time the trials, respiration and electrocardiogram signals were recorded and conveyed to a custom script running in LabVIEW. Electroencephalogram (128 electrodes) and electromyogram from the right eye were recorded to determine brain and behavioral responses to the CS. RESULTS: Consistent with previous reports, timing the CS to diastole during expiration was more beneficial for learning than timing it to systole during inspiration. Cardiac cycle phase seemed to explain most of this variation in learning at the behavioral level. Brain evoked potentials (N1) elicited by the CS were larger when the CS was presented to diastole during expiration than when it was presented to systole during inspiration. Breathing phase explained the variation in the N1 amplitude. CONCLUSION: Our findings suggest that non-invasive monitoring of bodily rhythms combined with closed-loop control of stimulation can be used to promote learning in humans. The next step will be to test if performance can also be improved in humans with compromised cognitive ability, such as in older people with memory impairments.

239. Changes in the external environment are reflected in stable patterns of brain activity that underlie event segmentation

Djamari Oetringer1, Dora Gözükara1, Dr. Umut Güçlü1, Dr. Linda Geerligs1

1Donders Institute

239. Background Our senses receive a continuous stream of complex information. Parsing this information into meaningful events allows us to extract relevant information, remember it and act upon it. Previous research has related these events to so-called ‘neural states’: temporally and regionally specific stable patterns of brain activity, which tend to coincide with events in the stimulus. Neural states show a temporal cortical hierarchy: short states are present in early sensory areas, while longer states can be found in high-order areas. Objectives Here we aimed to find what drives these regional differences in timescales of neural states. Research question We hypothesized that neural states at different levels of the cortical hierarchy are shaped by aspects of the stimulus to which these brain areas are responsive. We therefore examined the following question: are boundaries between neural states associated with changes in the external environment? Materials and Methods To investigate this hypothesis, we analyzed fMRI data of participants watching a 2-hour movie, in which many visual changes and changes in location took place. We defined 3 regions of interest: the parahippocampal place area (PPA), the retrosplenial cortex (RSC), and an early visual area. The PPA and RSC are category-selective regions that respond best to places (rather than e.g. objects), while the early visual area is responsive to low-level visual features. Within each of these regions, we used a data-driven method to identify the neural states. Then we compared the timing of neural state boundaries (i.e., when one neural state ends and another one starts) to the timing of location changes in the movie, as well as the start of new events, and changes in low-level visual features. Results We find support for the aforementioned hypothesis: all investigated visual areas contain neural states that coincide with changes in low-level visual features, while neural states in the PPA and RSC show an additional independent association with changes in location and events. Conclusion These observations suggest that changes in the external environment are reflected in neural states, and that cortical temporal hierarchy partly reflects the temporal scales at which representations of the environment evolve.

240. The importance of considering ongoing brain activity when studying evoked responses in the EEG and pupil signals

Dr Maria Ribeiro1,2, Prof Miguel Castelo-Branco1,2, Nuno Rodrigues1,2

1CIBIT, ICNAS, University of Coimbra, 2Faculty of Medicine, University of Coimbra

240. OBJECTIVE AND RESEARCH QUESTION Evoked neural responses occur on a background of ongoing neural activity that unavoidably adds to the responses measured. Ongoing brain activity has been suggested to reflect variations in brain state that affect cognition. Our study aim was to investigate, in humans, the relation between the dynamics of the ongoing brain activity, evoked neural responses, and task performance. MATERIALS AND METHODS We analysed the electroencephalogram (EEG) and pupillogram of 36 young adults and 39 older adults (mean group ages = 23 and 60 years) acquired while they were engaged in an auditory cued go/no-go task (https://openneuro.org/datasets/ds003690). RESULTS Aperiodic spectral properties of ongoing EEG and pupil data correlated with the variability of the task evoked responses: participants presenting ongoing signals with steeper spectra and with higher spectral offset showed higher trial-by-trial variability in their evoked responses. The correlations were particularly strong between the amplitude of slow (< 2 Hz) ongoing activity fluctuations and the variability of task-related evoked responses. On a trial-by-trial basis, this effect was best modelled by taking into consideration the instantaneous amplitude and phase of slow ongoing fluctuations at stimulus onset, explaining almost 70 % of the trial-by-trial amplitude variability in the evoked responses. Importantly, we found that the variability imposed on the evoked responses by the slow ongoing signal fluctuations did not contribute to the task performance. In fact, adjusting the single trial amplitude values of the evoked responses by taking into consideration these signal fluctuations unmasked brain-behaviour correlations that were not apparent due to the added noise caused by this background brain activity. This adjustment was also crucial to unmask correlations between the evoked responses measured in the EEG and pupil signals. CONCLUSION Our results showed that the effect of the ongoing slow signal fluctuations was not behaviourally relevant and that adjusting for the effect of these ongoing signals in the EEG and the pupil signals drastically reduced the variability of single trial evoked responses and was crucial to reveal brain-behaviour associations as well as associations between event-related potentials and pupil dilation responses.

241. Impaired reward processing in chronic stroke survivors

Minne Schreiber1,2, Franziska Wagner1,2, Annika Volkmer1,2, Alexander Schmidt1,2, Stefan Brodoehl1,2, Carsten M. Klingner1,2

1Department of Neurology, University Hospital Jena, 2Biomagnetic Center, University Hospital Jena

241. Stroke is a main cause of long-term disabilities especially in the elderly population in which stroke incidence is highest. Rehabilitation is essential for stroke patients to try to return to their premorbid functioning. Therefore reward-related learning keeps patients motivated repeating exercises. Based on our previous studies we know that reward sensitivity is reduced in acute state of stroke (Wagner et al. to be published). Accordingly, we need a more detailed understanding of the reward system’s affection in chronic stroke survivors. In our study the hypothesis that patients with chronic ischemic strokes have deficits in reward processing and show altered reward networks was tested. Chronic stroke survivors (n=24, 100 ± 20.8 days post stroke) with a first time ischemia in the supply area of the middle cerebral artery and age-matched healthy controls (n=24) underwent a 3-Tesla functional magnetic resonance imaging (fMRI) scan during which they performed the well-established reward paradigm Monetary Incentive Delay Task (MID). Furthermore, two resting state acquisitions, one before and one after the paradigm, were acquired for connectivity analyses. Behaviorally intact reward processing was established in the stroke and control group. Both required greater monetary reward to decrease their reaction time during the MID. However, fMRI data revealed alterations in neuronal function during reward processing. While activity in regions of positive reward decreased during prediction of reward in stroke survivors, they showed increasing activity during receiving of reward compared to healthy controls. E.g., the middle-frontal-gyrus as a key hub of reward decision making revealed significant differences. More detailed analyses of the fMRI data and connectivity analyses for possible network changes are still in progress. These data suggest that behaviorally chronic stroke survivors seemed to be recovered in functional reward processing, but different activation patterns may be associated with neuronal deficits. Stronger rewarding stimuli may be necessary to improve rehabilitation after stroke. Accordingly, we first need further details about network changes, as these can act as potential compensation for reward processing.

242. Anticipating positive social feedback recruits the ventral and medial human substantia nigra: evidence from high-resolution fMRI

Alexandra Sobczak1, Prof. Dr. Nico Bunzeck1

1Institute of Psychology I, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck

242. Objectives: The human substantia nigra (SN) and nucleus accumbens (NAcc) are central nodes in a network of brain regions that is involved in regulating behaviour by anticipating future outcomes. This appears to include both monetary and, as more recent work suggests, also social incentives. However, it is still under debate whether and which specific parts of the SN and NAcc encode salience or both, salience and valence, of future social outcomes. Research question: The aim of this study is to investigate the regional specificity and functional connectivity of the SN and NAcc with regard to anticipating social reward and punishment. We expected salience coding in the ventral SN (vSN) and lateral SN (lSN) as well as valence coding in the medial SN (mSN) and NAcc. Materials and methods: We used a social incentive delay task (n=36) with neutral, positive, and negative feedback during high-resolution fMRI (1.5x1.5x1.5mm). Neuroimaging data was analyzed using functional connectivity analysis and multivariate-pattern analysis with four decoding models: 1) neutral vs positive vs negative, 2) positive vs neutral, 3) negative vs neutral, and 4) positive vs negative. Results: Behaviorally, participants responded faster when anticipating positive and negative compared to neutral feedback. At the neural level, only model two (positive vs neutral) revealed significant effects, specifically within the vSN and mSN. All other models and brain regions under investigation were not significant. Conclusion: Anticipating social feedback invigorates behavior, but only positive social rewards recruit the ventral and medial SN, which are part of the dopaminergic mesolimbic system. As such, our findings give novel insights into the underlying neural processes underlying social information processing.

243. Bistable critical dynamics in the resting human brain: a MEG source study

Sheng H Wang, Dr Gabriele Arnulfo, Vladislav Myrov, Felix Siebenhühner, Lino Nobili, Michael Breakspear, Satu Palva, J. Matias Palva 1University of Helsinki

243. Population activity across a wide range of spatial scales exhibits power-law dynamics suggesting that the brain and its functional constituents operate near a critical point of a phase transition between order and disorder. Recent research, however, has shown signs of quasi- rather than the classic "bona fide" criticality in neuronal dynamics, i.e., both unimodal and bistable neuronal dynamics can be observed near a critical point. Theoretically, unimodal and bistable dynamics are signatures of underlying second-order (smooth) or first-order (discontinuous) phase transitions, which, in neuronal systems, are thought be associated with low or high demand for limited synaptic resources, respectively. However, observations of bistability in human brain resting-state dynamics in vivo have remained scarce and their relationship to critical-like brain dynamics and human behaviours unclear. With evidence from our model, we first argue that, unimodal and bistable critical-like dynamics in local ensembles can be explained by the canonical Hopf bifurcation: where bistability occurs exclusively within critical regime and is controlled by state-dependent local positive feedback. Next, to examine bistable critical dynamics in vivo, we acquired 10 min of resting-state MEG (BioMag_lab@Helsinki) recording from healthy adults and inspected local critical dynamics in MEG sources (MNE). We not only replicated the well-known visual bistability, but found that bistable critical-like dynamics were a large-scale, robust phenomenon observable from alpha to gamma bands and, importantly, to be correlated with executive functions. Collectively, our results support the proposal that the brain operates in a quasi-critical manner and bistabilty likely an important extension to the classic criticality theory.

244. Reward-context effects on working memory: Insight from an EEG-pupillometry study

Intan K. Wardhani1, Nico Boehler1

1Ghent University

244. Performance has been found to be better when it is rewarded than when not rewarded, leading to a wide use of rewards to increase motivation hence improving performance. However, little is known whether reward-related improvements come at the expense of non-rewarded performance or enhance the proactive control in tasks that are intermittently rewarded. Here, we attempted to conceptually replicate the work of Jimura et al. (2010, PNAS) by combining behavioural-EEG-pupillometry measures in a block-wise design. Participants were asked to perform on a visual working-memory task in blocks containing performance-contingent rewarded trials (R+) and non-rewarded trials (R-) as well as in blocks containing purely non-rewarded trials (NR). With this design, we were able to compare performance in R- and NR trials, thus gaining insight whether performance in the R- trials profited from the reward prospects in the R+ trials (i.e., context effect). Our findings indicated that a context effect was observed in mostly reaction times. Findings from pupillary responses and ERPs further explained the context vs. transient effects especially during the incentive cue, memory task, and performance feedback phases. The implications of the current findings will be discussed.

248. Phasic event-related transcutaneous auricular vagus nerve stimulation modulates pupillary response

Christian Wienke1, Aiden Haghikia1, Tino Zaehle1

1Department of Neurology, Otto-von-Guericke University

248. Objective: Transcutaneous auricular vagus nerve stimulation (taVNS) is a noninvasive stimulation technique aiming to modulate activity in the Locus coeruleus norepinephrine (LC-NE) system (1). Due to its relative novelty, reliable biomarkers that indicate successful LC-NE activation are lacking. Pupil diameter and frontal cortical oscillations in the theta range are considered as promising candidate biomarkers (2). However, results from recent taVNS-studies are heterogeneous in their success to show a modulation by taVNS (3,4). This may be caused by inadequate, continuous or intermittent stimulation paradigms and relying on resting state pupil dilation. Research Question: In a new approach, here we tested the effect of phasic event related-taVNS during light stimulation and response inhibition task, which has been shown to involve LC activity (5), and assessed the time course of the pupillary response and frontal theta oscillations. Materials and Methods: Using a single-blind, within-subject design, 27 participants performed an Emotional Stroop Task (EST) and a passive Pupil Light Reflex Task (PLRT). In each trial of the EST subjects rated the emotional expression of a fearful or happy face while ignoring the simultaneously presented overlaid word (either „Fear“ or „Happy“). During the PLRT, 500ms long flashes of white light induced pupillary light reflexes. Simultaneous to each stimulus onset, either taVNS or sham stimulation was administered as 500ms trains of monophasic pulses (pulse width 200µs) at a frequency of 30Hz. Results: Using cluster based permutation analyses, we show that in contrast to sham stimulation the pupillary response during the EST and PLRT is systematically modulated by taVNS, indicating an increased LC-NE activity during taVNS. Conclusion: These results indicate that event-related taVNS effectively modulates the LC-NE system. Furthermore, we argue that phasic, event-related stimulation paradigms may be more effective in modulating LC-activity on a short-term duration necessary for experimental investigation. References: 1. Ludwig, M. et al., Auton. Neurosci. 236, 102900 (2021). 2. Farmer, A. D. et al., Front. Hum. Neurosci. 14, 568051 (2021). 3. Keute, M. et al., Sci. Rep. 9, 11452 (2019). 4. Sharon, O. et al., J. Neurosci. 41, 320–330 (2021). 5. Grueschow, M. et al., J. Neuroendocrinol. 32, (2020).

247. Human aging influences neural reward processing to maintain robust reward sensitivity

Ms. Annika Volkmer1, Dr. Franziska Wagner1, Ms. Minne Schreiber1, Mrs. Alexander Schmidt1, Dr. Stefan Brodoehl1, Dr. Carsten M. Klingner1

1Department of Neurology, Biomagnetic Center, University Hospital Jena

247. Aging is associated with an overarching process that does not occur equally in all regions and particularly not in all brain regions. Neural processing of reward is considered as an influential factor in controlling individual’s daily behavior. Comparative studies showed age-related neurocognitive changes and it remains unclear whether the aging brain is able to maintain functional integrity of the reward system. To investigate different activation patterns of elderly during prediction and receiving of reward, functional magnetic resonance images (fMRI) were acquired in 23 older (50-80 years) and 35 younger (19-31 years) healthy adults. While undergoing fMRI measurements, participants performed an incentive delay task offering monetary outcome (Monetary Incentive Delay Task). According to our behavioral results, age was associated with slower reaction times. Despite slower reaction times of elderly, reward sensitivity does not differ from that of the younger subsample. Therefore, our results suggest maintaining functional integrity of the aging reward system. Performing region of interest analyses, feedback of monetary reward revealed significant greater activation of reward-related brain structures in older adults compared to the younger control group. These structures included left insula, right middle and inferior frontal gyrus as well as right middle cingulate gyrus. In contrast reward prediction led to enhanced activation of bilateral insula, caudate nucleus, right putamen and anterior cingulate cortex in the younger subsample. Our results suggest the older brain to react more sensitive to the receipt of reward, whereas for younger adults the prospect of potential monetary outcome is sufficient to activate the reward system adequately. The different neural activation patterns suggest a compensation pattern of the aging brain underlying the preserved reward sensitivity.

36. Selective brain response to voices at four months of age

Miss Roberta Pia Calce1, Dr Diane Rekow2, Miss Francesca Barbero1, Miss Anna Kiseleva2, Mr Siddharth Talwar1, Prof Arnaud Leleu2, Prof Olivier Collignon1,3,4,5

1Université Catholique De Louvain, 2Université Bourgogne Franche-Comté, 3Center for Mind/Brain Sciences, University of Trento, 4School of Health Sciences, 5The Sense Innovation and Research Center

36. Human voices are arguably among the most relevant sound in our daily life. Neuroimaging studies have demonstrated the existence of regions in the superior temporal sulcus- the “temporal voice areas” (TVAs)- that respond preferentially to voices vs other sounds in the human adult brain. However, how early in the developing brain such selective categorical response occurs remains poorly understood. In the present study, we investigate voice selective response in the infant's brain, relying on a Fast Periodic Auditory Stimulation (FPAS) paradigm combined with scalp electroencephalography (EEG). This approach provides an objective marker of the brain’s automatic ability to categorize vocal information with a high signal-to-noise ratio within a short testing duration. Twenty-three 4-month-old infants listened to a stream of heterogeneous sounds presented periodically to elicit a brain response at the same frequency in the EEG amplitude spectrum (3.33 Hz). Importantly, sequences were created so that voice stimuli appeared for each third sound (1.11 Hz). This voice presentation rate elicits an additional response in the EEG spectrum only in the case the brain discriminates voices from other sounds and generalizes across heterogeneous voice exemplars. Participants were also presented with a scrambled version of the stimuli with disrupted intelligibility but identical spectral content. We find no amplitude difference at the general rate of sound presentation (3.33 Hz) between the standard and the scrambled conditions. Crucially, we observed a peak in the EEG spectrum over the temporal channels at voice presentation rate (1.11 Hz) that is significantly reduced in the scrambled condition, suggesting that the spectral content associated with voices does not, alone, elicit the voice response. These results suggest that the infant brain successfully discriminates vocal stimuli versus non-vocal stimuli and generalizes them across heterogeneous exemplars, recognizing the voice excerpts as items of the same perceptual category. This study brings forth evidence of high-level voice categorization as early as four months of age.

37. The impact of game elements on cognitive training effectiveness

Annie Desmarais1, Alessandro Pozzi1, François Vachon1

1Université Laval

37. Cognitive training—the repeated practice of mental activities aiming to maintain or enhance one’s cognitive abilities—represents an interesting opportunity to improve quality of life for people of every age. Several researchers recognized that gamification could have the power to contribute in some way to the quality of cognitive training, especially because of its potential in increasing engagement (Baniqued et al., 2014; Bisoglio et al. 2014). Gamification is defined as the application of game elements to a non-game context, in order to increase engagement (Romero et al., 2016). Game elements are conceptualized as a « set of rules, interaction loops (e.g., goals, challenges or rewards) and feedback that aim to enable an engaging and fun gaming experience » (Romero et al., 2016; p.71). They can take different forms, such as leaderboards, points or badges. Game elements aim to promote player interaction with the cognitive training tasks. The present study aims to clarify the contribution of game elements in cognitive training and far transfer effect. A total of 100 participants from 18 to 40 years old were randomly assigned to one of the five training programs: i) active control training, ii) attentional control (AC) training, iii) AC training with point system, iv) AC training with leaderboard, or v) AC training with both game elements. Each training involved performing eight sessions of approximately 30 minutes over 4 to 8 weeks. An assessment of working-memory and attention-control tasks was performed on each group before and after training to assess learning and far transfer. Whereas the addition of game elements failed to affect both the level of engagement and cognitive load in the training program, their presence led to the abolition of the far transfer effect obtained in the non-gamified version of the training. Such a negative impact cannot be attributed to an additional cognitive burden induced by the inclusion of game elements, as proposed by some researchers (Katz et al., 2014). This pattern of results is consistent with the hypothesis that the efficiency of game elements to promote transfer effect relies on their power to successfully engage the trainee into the training program.

38. Neonatal frequency-following response: a new tool in developmental cognitive neuroscience

Prof. Carles Escera1,2, Dr. Teresa Ribas-Prats1,1, Ms. Sonia Arenillas-Alcón1,2, Ms. Marta Puertollano1,2, Dr. Natàlia Gorina-Careta1,2, Dr. Lola Gómez-Roig2,3

1Institute of Neurosciences, University of Barcelona, 2Institut de Recerca Sant Joan de Déu (IRSJD), 3BCNatal – Barcelona Center for Maternal Fetal and Neonatal Medicine (Hospital Sant Joan de Déu and Hospital Clínic)

38. Objectives. The present study aims at discussing the neonatal Frequency-Following Response (FFR) as a potential tool to investigate neural consequences of a compromised intrauterine environment during fetal development, neural plasticity during fetal hearing and the neural basis of early language acquisition. Research question. Specifically, we ask questions related to the effects of abnormal intrauterine nutrition and birth weight, the prenatal exposure to moderate alcohol consumption, the exposure to environmental music during pregnancy and the development of the neural representation of speech sounds in neonates and infants during the first six months of life. Materials and methods. The FFR is a non-invasive scalp-recorded auditory evoked potential that reflects compound phase-locked neural activity elicited to the spectrotemporal components of the acoustic signal, along the entire auditory hierarchy. Compared to other evoked potentials such as mismatch responses, the FFR is unique as it transparently mimics the eliciting stimulus, to that it can be “heard” when played through a speaker. By decomposing the FFR into the temporal and spectral domains, one can read subcortico-cortical neural traces from the human scalp as sounds are transcribed in neuronal aggregates, and how these sound traces are shaped by experience and context. We established the standards for obtaining and analyzing the neonatal FFR (Ribas-Prats et al., 2019; Arenillas-Alcón et al., 2021) and recorded it in a sample of over 200 babies. FFR were analyzed as a function of birth weight (corrected by gestational age), exposure to music (assessed through a questionnaire) and prenatal alcohol (determined by Ethyl Glucuronide in mother’s hair), and development. Results. FFRs were attenuated in babies born both small (Ribas-Prats et al., 2021) and large (Ribas-Prats et al., under review) for gestational age, enhanced when mothers used to sing or listen to music through loudsspeakers on a daily basis (Arenillas-Alcón, in prep.), and enhanced in their higher frequencies (speech formants) at the age of six months. Conclusion. Neonatal FFRs are sensitive to prenatal experience and to auditory system maturation during early language acquisition, and therefore provide a powerful tool in developmental cognitive neuroscience. Funding. PGC2018-094765-B-I00 MCIN/AEI/10.13039/50110001103; Fundación Alicia Koplowitz; 2022AR-IRSJDCdTorres; ICREA Academia.

39. Muscone promotes Abeta clearance and ameliorates cognitive deficiency in APP/PS1 mice through HDAC2 degradation

Yi Liu1, Huijie Bian1, Yun Xu1

1Department Of Neurology, Drum Tower Hospital, Medical School And The State Key Laboratory Of Pharmaceutical Biotechnolog

39. Introduction In the pathology of Alzheimer’s disease (AD), Abeta deposition causes degeneration of synaptic plasticity, leads to memory loss and cognition impairment. Histone deacetylases 2 has been shown to promote the pathologic alterations. Muscone (Mus), one of the simplex ingredients of traditional Chinese medicine, has been discovered neuroprotective effects on cerebral ischemia models. It is aimed to finding a new drug target for AD treatment. Methods Mus was intraperitoneally (i.p.) injected into the 6-month-old APP/PS1 or WT mice every day. 20 days later, Novel object recognition test (NOR) and Morris water maze (MWM) test were performed to evaluate spatial reference and working memory. Enzyme linked immunosorbent assay (ELISA), Immunofluorescence, Golgi staining and long-term potentiation (LTP) were used to measure the Abeta clearance and synaptic morphology. Western blot was conducted to detect the expression of target proteins. Results Behavioral results showed that the APP/PS1 mice with Mus treatment has a longer exploration time for NOR and more crossing platform times for MWM compared with APP/PS1 mice without it. The expression of Abeta was decreased and synaptic plasticity was rescued by administration of Mus in ELISA, Immunofluorescence, Golgi and LTP results. It also decreased the protein levels of HDAC2 in the brain tissues compared with APP/PS1 mice. Conclusions Our results indicated that Mus exhibited a protective effect against Abeta and synaptic plasticity via degradation of HDAC2 in APP/PS1 mice. These results provided evidences for the novel and potential application of Mus for the treatment of AD.

40. Benefits of choir singing on complex auditory encoding in the aging brain: An ERP study

Emmi Pentikäinen1, Dr Lilli Kimppa1, Mr Tommi Makkonen1, Mr Mikko Putkonen2, Ms Anni Pitkäniemi1, Mr Ilja Salakka1, Prof Petri Paavilainen1, Prof Mari Tervaniemi1,3, Assoc Prof Teppo Särkämö1

1Cognitive Brain Research Unit, Department of Psychology and Logopedics, Faculty of Medicine, University Of Helsinki, 2Department of Psychology and Speech-Language Pathology, Faculty of Social Sciences, University of Turku, 3Department of Education, Faculty of Educational Sciences, University of Helsinki

40. Aging is accompanied by difficulties in auditory information processing, especially in more complex sound environments. Choir singing requires efficient processing of multiple sound features and could therefore mitigate the detrimental effects of aging on complex auditory encoding. We recorded auditory event-related potentials during passive listening of sounds in healthy older adult (≥ 60 years) choir singers and non-singer controls. We conducted a complex oddball condition involving encoding of abstract regularities in combinations of pitch and location features, as well as in two simple oddball conditions, in which only either the pitch or spatial location of the sounds were varied. We analyzed change-related mismatch negativity (MMN) and obligatory P1 and N1 responses in each condition. In the complex condition, the choir singers showed a larger MMN than the controls, which also correlated with better performance in a verbal fluency test. In the simple pitch and location conditions, the choir singers had smaller N1 responses compared to the control subjects, whereas the MMN responses did not differ between groups. These results suggest that regular choir singing is associated both with more enhanced encoding of complex auditory regularities and more effective adaptation to simple sound features.

41. Long-term visual deprivation effects selective visual attention, short-term memory and cortical plasticity

Dr. Franziska Wagner1, PD Dr Kathrin Finke1, Dr. Ullrich Voigt2, Dr. Natan Napiorkowski1, Prof Dr. Otto W Witte1, Dr Peter Bublak1, PD Dr. Stefan Brodoehl1, PD Dr Carsten M Klingner1

1Department Of Neurology Universtiy Hospital Jena, 2Department Of ophthalmology University Hospital Jena

41. Little is known about plasticity in the human adult visual cortex. Aim of this study was to better understand the nature of neuroplastic changes in the visual cortex. Studies with up to 150 minutes of monocular deprivation have shown to alter visual perception in adult humans. In this study we used long term monocular deprivation about 7 days with intervals of 1, 3, 5 and 14 days to test for short- and long-term structural and functional changes in brain visual networks by structural and functional MRI. TVA (theory of visual attention)-based assessment was used for sensitive investigation of functional changes in short-term memory and visual attention.

42. Visual ERPs to face onset predict the speech recognition ability after cochlear implantation

Anna Weglage1, Natalie Layer1, Dr. Verena Müller1, Prof. Dr. Martin Walger1, PD Dr. Ruth Lang-Roth1, PD Dr. Pascale Sandmann1

1University Hospital of Cologne

42. Sensorineural hearing loss can cause functional changes not only in the auditory but also in the visual cortex. To better understand the impact of these deprivation-induced effects on auditory recovery after cochlear implantation, we examine postlingually deafened individuals before and after cochlear implantation in the present electroencephalography study. The cochlear implant (CI) candidates and a group of matched normal-hearing (NH) controls performed a visual oddball paradigm with static (targets) and moving faces (non-targets) produced by a computer-based video animation of a talking head. The preliminary results show comparable reaction times in CI candidates and in NH listeners, but significantly higher hit rates for the NH listeners. The analysis of the N1 and P3 event-related potentials (ERPs), including topographic and source analyses, revealed group differences in response to the face onset. Hearing-impaired patients prior to cochlear implantation showed a significantly smaller P1 amplitude and a reduced visual-cortex activation at P1 latency when compared to NH listeners. Moreover, topographic analyses revealed condition-specific ERP topographies at P3 latency and delayed P3 ERPs for the CI candidates compared to the NH listeners. A correlation analysis showed a positive relation between the visual ERP amplitudes (P1, P3) recorded at the time before implantation, and the auditory speech recognition ability after six months of CI usage. Taken together, our CI candidates showed poorer behavioural performance in the visual face categorisation task, reduced recruitment of the visual cortex at sensory processing stages (P1 latency), and a delayed response at cognitive processing stages (P3 latency). These findings confirm previous observations of deprivation-induced alterations in cortical visual functions. Further, they indicate that CI candidates have some difficulties to evaluate and classify the visual face stimuli. The positive correlation between visual ERPs (before implantation) and the auditory speech performance (after implantation) suggests that the pre-implantation level of cortical visual functions (reflected by enhanced ERP amplitudes) can help predicting the CI outcome. We speculate that enhanced cortical visual functions allow the CI recipients to better match the novel auditory input after implantation with the corresponding visual cues.

78. Confirmation behavior in sensorimotor control

Johannes Kasper1, Dr. Christian A. Kell1

1Department of Neurology and Brain Imaging Center, Goethe University

78. Confirmation bias refers to the tendency to conserve prior beliefs by dismissing incompatible evidence. We investigated whether similar mechanisms are at play during sensorimotor control. In an auditory-motor control paradigm, participants kept the randomly drifting pitch of a synthetic sound close to that of a reference sound by compensating the continuous pitch alterations using a trumpet valve-like button. Every few seconds, fast jump-like pitch alterations occurred. Comparing the resulting pitch change to concurrent finger movements yields evidence for a novel auditory-motor mapping. However, if such putative evidence is strongly incompatible with prior knowledge, it should be denied and instead the established law ought to be reconfirmed post-hoc by a motor response compatible with the observed pitch change under this law. Such seemingly counter-productive “catching” responses have previously been described but cannot be explained by standard models of motor control. Here, we analyzed potential behavioral predictors of catching responses and present an explanatory computational model. 21 professional musicians completed 1–2 hours of continuous pitch control. The predictive power of pre-jump behavioral features for response class was assessed by mixed effects additive logistic regression. The model comprises a non-linear auditory and a proprioceptive feedback controller whose coupling strength is dynamically adjusted by a third controller monitoring the ratio of the auditory and proprioceptive change rates. 6% – 40% (median 13%) of all responses to the sudden pitch shifts were quick catching responses. The majority of them occurred when participants were in the course of moving the button in the opposite direction of the pitch shift which would imply a mirrored auditory-motor contingency. The pre-jump quasi-periodic button movements showed a higher inter-trial phase alignment among catching than compensating responses. Our results are compatible with a confirmation bias for the directionality of sensorimotor contingencies and suggest a behavior-dependent modulation of the susceptibility to contingency violations. The computational model could qualitatively account for both response classes while displaying desired characteristics of plasticity leading to implicit anticipation of slow pitch fluctuations. We suppose that catching responses are a means to actively stabilize sensorimotor laws against unlikely evidence for change while remaining sensitive to more consistent evidence.

79. The efficacy of cognitive cues in reducing behavioral interference in complex inhibition tasks

Sarah Kemp1,2, Mr Rohan Puri1, Prof Birte Forstman2, Dr Mark Hinder1

1University of Tasmania, 2University of Amsterdam

79. Objectives A common test of inhibitory control is the stop-signal test, where an initiated action is canceled when an imperative stimulus (e.g., a left-pointing arrow) turns red. However, everyday tasks are often complex and may require only one component of a multi-component action be canceled (response-selective inhibition; Wadsley et al. 2022). Successful inhibition of one component of the initial response is observed in conjunction with a slowing of responses in the non-cancelled component (‘stopping interference’). This finding has led to the assumption that selective stopping in fact occurs as a result of stopping both movement components, followed by initiation of the action not required to stop. We investigated how context cues can affect this selectivity. Research question Can cognitive cues reduce stopping interference? Materials and methods Groups of young (n=25, 18-35 yr) and older (n=20, 60-80 yr) adults responded to left- and right-pointing arrows with simultaneous left and right button presses. On 25% of trials, after a stop signal, one or both arrows turned red, requiring cancellation of that movement component. Each trial began with a simple fixation cross, or a cue that indicated which action may need to be inhibited. Transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability of one effector at various time points in movement preparation when it may be required to inhibit its action. TMS and behavior were modeled using generalized linear mixed modeling with a maximal approach. No effect size is given as they are difficult to estimate for GLMMs using normal methods. Results Both groups exhibited a significant stopping interference (~120 ms; p<.001). Informative cueing enabled a reduction (~40ms), but not elimination, of this interference (p<.001). Interestingly, reaction times in successful selective-stop trials relative to presentation of the stop signal were faster than reaction times of ‘standard’ multicomponent response in Go trials. This effect was greater in cued trials. Conclusion We conceptualize this finding as the cue facilitating the speed of the reprogrammed action. TMS results suggest increases in excitability when a limb will not have to stop, which may underlie the faster selective response following a selective stop signal.

80. Object affordances and action understanding: Do object affordances inform motor action preparation when viewing goal-directed actions?

Charlotte Larkman1, Dr Gethin Hughes1

1University of Essex

80. The present study aims to investigate the way in which object knowledge contributes to our understanding of others' actions. Specifically, we seek to explore the possible involvement of the motor system in the anticipatory representation of action-goals associated with objects (e.g. a mug is for drinking coffee). Participants are seated on an Axilum Robotics TMS-Robot, to which the TMS coil is attached. Motor-evoked potentials (MEPs) will be recorded from the ADM (little finger) and FDI (index finger) muscles of the right hand during the observation of goal-directed action sequences. Each video sequence shows an actor reaching to grasp an object ("the prime") with their left hand before reaching towards two objects with their right hand. One of these objects is functionally related to the prime (“the target,” e.g., cigarette – lighter), while the other is functionally unrelated (“the distractor,” e.g., cigarette – notepad). One object in each object pair requires a precision grip and the other a power grip. We expect that MEPs recorded at the final frame of the action sequence will elicit activation in the hand muscles associated with the functionally-related target object. The experiment will use a within-subjects design with two conditions: Goal condition (with two objects placed on the table - one target and one distractor), and Control condition (with target and distractor objects replaced by two pieces of fruit). A repeated-measures ANOVA will be calculated on the MEP ratios (FDI and ADM), with Condition (Goal, Condition) and Target Grip (Precision, Power) as independent variables. We predict a Condition x Target Grip interaction, such that an effect of target grip is present only in the experimental condition but not in the control condition. This will be verified by pairwise comparisons on FDI and ADM MEP ratios for each Target Grip within each condition. A priori power analysis (https://jakewestfall.shinyapps.io/pangea/) showed that a sample of 27 is required to achieve 90% power with a large effect size (d = 0.8). We will therefore test 30 right-handed participants.

81. Hemispheric differences in the control of visually-guided asymmetric bimanual movements

Christina Nissen1, Diljit Singh Kajal1, Johannes Gehrig1, Christian Kell1

1Brain Imaging Center and Department of Neurology, Goethe University Frankfurt am Main

81. In visuomotor control, the right cerebral hemisphere has been associated with visuospatial, the left with visuotemporal processing (1). Since the hands are controlled by the contralateral hemisphere, this leads to better performance during asymmetric bimanual movements in case hemispheric preferences are respected. We assessed the neuromagnetic signatures of these asymmetries using MEG. 23 right-handed participants controlled two visual cursors by pressing dynamometers. The amount of deflection was instructed via two inward moving lines. One hand performed a ballistic grip which resulted in a cursor jump over a vertical line. The other hand moved the cursor along a diagonal ramp (visuomotor tracking). The ballistic isometric grip only required fine timing, the tracking condition both fine spatial and temporal resolution. Source data based on cortico-muscular coherence was used for time-resolved partial-directed coherence (TPDC) analysis (p<0.05 cluster-corrected). Only 12% correct trials proved that the task was difficult. Expectedly, performance was better when the left hand tracked the ramp and the right hand performed the ballistic grip (optimal condition). Incorrect trials clustered in two types. Either the hand that tracked the ramp mirrored the contralateral ballistic grip or it paused visuomotor tracking during the ballistic grip. Mirror movements occurred more often in the optimal and pauses in the non-optimal condition. The TPDC analysis showed stronger broadband connectivity during preparation in the hemisphere contralateral to the hand performing the ballistic grip. The optimal compared to the non-optimal condition demonstrated stronger intra- and interhemispheric connectivity from left premotor areas and stronger homotopic connectivity between motor and premotor cortices. The non-optimal condition showed stronger intra- and interhemispheric connectivity from right parietal cortex. Our results show that the two cerebral hemispheres solve the dual task problem differently. The left hemisphere integrates both movements via premotor connectivity (2). Better performance in the optimal condition comes at the price of increased risk of mirror movements. In case the right hemisphere is forced to time the ballistic movement in addition to visuospatial processing, task interference results in more sequential task performance and right parietal cortex engagement. 1. Floegel and Kell (2017) PloS one 10.1371/journal.pone.0185152. 2. Debaere et al. (2004) NeuroImage 10.1016/j.neuroimage.2003.12.011.

82. Movement range of elicited finger movements does not affect proprioceptive response strength in magnetoencephalography

Timo Nurmi1,2, Dr Maria Hakonen1,2, Prof Mathieu Bourguignon3, Prof Harri Piitulainen1,2,4

1Faculty of Sport and Health Sciences, University of Jyväskylä, 2Department of Neuroscience and Biomedical Engineering, Aalto University, 3Laboratory of Neurophysiology and Movement Biomechanics, ULB Neuroscience Institute, Université libre de Bruxelles (ULB), 4Aalto NeuroImaging, Aalto University

82. Proprioception is the position and movement sense of the body that relies on afference from the proprioceptors in muscles and joints. Cortical proprioceptive processing can be quantified in the primary sensorimotor (SM1) cortex by stimulating the proprioceptors using evoked (passive) limb movements and recording the movement evoked fields (MEFs) or computing corticokinematic coherence (CKC) between the limb kinematics and cortical activity measured with e.g. magnetoencephalography (MEG). We examined whether cortical proprioceptive processing quantified with MEF and CKC strengths is affected by the movement range of the finger. The MEF and CKC strengths were measured for four different movement-actuator evoked movement ranges of the metacarpophalangeal joint of the right index finger (15, 18, 22 and 26 mm for MEFs every 3000 ± 250 s and 6, 7, 9 and 13 mm for CKC at 3-Hz) from nineteen healthy volunteers (10 females, mean age: 27.8 SD: 4.9) in MEG. CKC was computed between MEG signals and finger acceleration. Peak CKC strength at the 3-Hz-movement frequency and MEF amplitude and latency were compared between the movement ranges both in the sensor- and source-spaces. The MEF and CKC responses peaked at gradiometer pairs above, and were localized to, the contralateral Rolandic SM1 cortex. The response strengths were equivalent for all movement ranges both in MEF and CKC in sensor space. In the source space, the second largest MEF protocol movement range elicited larger responses than the smallest movement range, while all the other movement ranges were equivalent in terms of the response strength. The response strengths of the CKC source space did not differ significantly. The largest movement range produced 14 ms/17% shorter latency of the peak MEF response compared to the smallest movement ranges. Our results indicated that the cortical response strength is mostly independent of the movement range of the index finger within the normal range-of-motion region of the metacarpophalangeal joint of the index finger. However, increasing movement range resulted in shorter peak response latencies which were also affected by the jerk of the movement. These results are relevant when planning and comparing different studies or participants with variable movement ranges.

83. Physical Effort Modulates Urgency and Speed Accuracy Trade-off in Decision Making

Mx Devin Ozbagci1, Prof Ignasi Cos, Prof Ruben Moreno-Bote, Prof Salvador Soto-Faraco 1University Pompeu Fabra

83. To make a decision, one must consider the costs (temporal, physical, cognitive) of gathering information. It is well known that time involves a cost, expressed through the urgency of effecting the decision, as it has been studied intensively through speed accuracy trade-offs (SAT). However, the cost of the physical effort necessary to accumulate evidence and reach a decision has been neglected. Here, we address the hypothesis that physical effort can also alter decision making by modulating urgency. To test this hypothesis, we used a random dot motion discrimination task where stimulus viewing was contingent upon continuous effortful hand press via a dynamometer. By manipulating the amount of physical effort (no, low, or high effort) of the hand press and the response deadline (short = 1.5s & long = 4s), we addressed whether effort induces a change in SAT similar to deadline manipulations, and whether their respective effects can be dissociated. The results showed that physical effort shortened RTs similar to a deadline imposition and impaired accuracy, as well as reducing motion detection performance. Overall, we propose that urgency is influenced by physical effort as well as time costs, and tax the decision maker with costs that accumulate in time.

84. Handedness effects on movement imagery during kinesthetic and visual-motor conditions. An EEG stud

Dr Dariusz Zapała1, MA Paulina Iwanowicz1, Professor Piotr Francuz1, Dr Paweł Augustynowicz1

1The John Paul Ii Catholic University Of Lublin

84. Recent studies show that the power of sensorimotor rhythms during a simple movement imagery task differ according to handedness. However, the effects of motor imagery perspectives on these differences have not been investigated yet. The aim of our study was to check how handedness impacts on the activity of alpha (8-12 Hz) and beta (13-30 Hz) oscillations during creating a kinesthetic (KMI) or visual-motor (VMI) representation of movement. Forty subjects (20. right-handed and 20 left-handed) participated in the experiment and were tasked with imagining sequential finger movement from a visual or kinesthetic perspective. Both the electroencephalographic (EEG) activity and behavioral correctness of the imagery task performance were measured. After the registration, we used independent component analysis (ICA) on EEG data to localize visual- and motor-related EEG sources of activity shared by both motor imagery conditions. It turned out that the activity of alpha and beta oscillations in the motor-related areas (right and left parietal ICs clusters) did not differentiate the subjects during the kinesthetic imagery. However, significant differences were obtained in the visual cortex (the occipital ICs cluster). In comparison to right-handers, who regardless of the task demonstrated the same pattern, left-handers obtained higher power in the alpha waves and lower in beta in the VMI task as well as better performance in this condition. The results may indicate that left-handers imagine movement differently than right-handers, focusing on visual experience. This provides new empirical evidence on the influence of movement preferences on imagery processes and has possible future implications for research in the area of neurorehabilitation and motor imagery-based braincomputer interfaces (MI-BCIs).

377. Data and model considerations for estimating time-varying functional connectivity in fMRI

Christine Ahrends1, Angus Stevner1, Usama Pervaiz2, Morten Kringelbach1,2, Peter Vuust1, Mark Woolrich2, Diego Vidaurre1,2

1Aarhus University, 2University of Oxford

377. Functional connectivity (FC) in the brain has been shown to exhibit subtle but reliable modulations within a session. One way of estimating time-varying FC is by using state-based models that describe fMRI time series as temporal sequences of states, each with an associated, characteristic pattern of FC. However, the estimation of these models from data sometimes fails to capture changes in a meaningful way, such that the model estimation assigns entire sessions (or the largest part of them) to a single state, therefore failing to capture within-session state modulations effectively; we refer to this phenomenon as the model becoming static, or model stasis. It is unclear, what causes this phenomenon of model stasis. Here, we aim to quantify how the nature of the data and the choice of model parameters affect the model’s ability to detect temporal changes in FC. To test the effects of different parameters on model stasis, we use Hidden Markov Models (HMM) on both simulated fMRI time courses and resting state fMRI data. We show that large between-subject FC differences can overwhelm subtler within-session modulations, causing the model to become static. Further, the choice of parcellation can also affect the model’s ability to detect temporal changes. We finally show that the model often becomes static when the number of free parameters per state that need to be estimated is high and the number of observations available for this estimation is low in comparison. Based on these findings, we derive a set of practical recommendations for time-varying FC studies, in terms of preprocessing, parcellation and complexity of the model.

378. Validation of Cortivision PHOTON CAP - a multi-channel wearable fNIRS device

Mr Pawel Augustynowicz1,2, Mr. Michal Kacprzak3, Mr Dariusz Zapała1,2

1The John Paul II Catholic University of Lublin, 2CortiVision Sp. z o.o., 3Nalecz Institute of Biocybernetics and Biomedical Engineering

378. This poster presents the results of validation tests of a new multi-channel wearable functional near-infrared spectroscopy device (fNIRS). The device has 16 emitters and 10 detectors forming up to 37 channels. A continuous-wave principle of operation is used. We evaluated the ability of this device to measure the hemodynamic properties of the human brain utilizing various well-established test procedures. Emission properties of the device's light sources were characterized with the spectrometer measures. During solid phantom measurements, we evaluated such properties as detector stability over time, linearity, and noise profile. Dynamic turbid media phantom was used to evaluate simulated functional response in a laboratory setup. We also conducted three in-vivo tests: breath-hold experiment, motor cortex, and visual cortex stimulation. Results showed the ability of the device to adequately measure properties of hemodynamic response on human subjects. We achieved high stability and linearity measures during phantom measurements and an acceptable signal-to-noise ratio for source-detector separation distances of up to 40 mm. This makes the device suitable for operating in typical conditions for adult human subjects using EEG-like caps with a standard 10-5 optode placement setups. In-vivo tests were in line with these findings. We were able to achieve typical hemodynamic response functions for all three experimental protocols.

379. Creating model brains to make convolutional neural network features more comparable with brain data

Dora Gözükara1, Djamari Oetringer1, Dr. Linda Geerligs1, Dr. Umut Güçlü1

1Radboud University

379. Background Studying the feature maps of artificial neural network (ANN) models and their relation to the brain have led to many insights in computational neuroscience. ANN model features are being used in a variety of ways, from predicting neural activity to understanding neural computation. Nevertheless, making these features comparable with brain data is not a straightforward task. Conventionally, features from an entire layer are group together regardless of their spatial selectivity and are compared with spatially selective brain areas such as the early visual cortex. Free eye movement further complicates the spatial mismatch. Objectives In this work, we aim to create a more valid comparison by demonstrating a new way of comparing fMRI data with convolution neural network (CNN) features that takes the spatial specificity of voxels into account. Research question Does modelling the spatial selectivity and gaze location meaningfully increases the representational similarity between the CNN features and fMRI data? Materials and Methods We use the StudyForrest fMRI dataset, which includes population receptive field (pRF) estimates and eye-tracking data alongside a 2-hour naturalistic movie-viewing session. We get around the spatial selectivity problem by building model ‘brains’, in which for each fMRI voxel we sample only the relevant parts of the features by using pRF estimates. We additionally use eye-tracking data to account for the shifting visual field for each participant and functional volume. We use the features of a pre-trained Alexnet and construct quasi-timeseries by concatenating model responses for every frame of the movie. We then correlate the representational dissimilarity matrices (RDM) of our model brain and fMRI brain, and test our model by comparing the RDM correlations with the correlations of whole-layer CNN RDMs. Results Initial analyses reveal preliminary evidence that our model results in higher RDM correlations with the brain than the conventional approach. The increase is focused on the early visual areas for early layers, and moves along the visual hierarchy for later layers. Conclusion We demonstrate a flexible method to use CNN features that aims to make a more valid comparison between model and brain responses.

77. The effect of data preprocessing by a non-expert on the performance of an Artificial Network supporting stroke detection

Sophia Hemm1,2, Dr. Stefan Brodoehl1,2, Dr. Carsten M. Klingner1,2, Dr. Franziska Wagner1,2

1University Hospital Jena, Department Of Neurology, 2Biomagnetic Center, University Hospital Jena

77. Stroke is the second-leading cause of death worldwide. Diagnosing acute stroke from non-contrast-enhanced CT (NC-CT) images is often a challenge even for experienced physicians. However, there is an opportunity to counteract this problem: Artificial intelligence and in particular neural networks, which can already detect strokes in NC-CT images. Nevertheless, preparing a lot of highly qualitative processed data for network training is time-consuming and only a few experts can provide it. Therefore, we asked to what extent the performance of a network trained with non-expert-generated data (N-EN) differs at all from that of a network trained with expert-generated data (EN) in terms of stroke detection. Furthermore, does training with additional non-expert-generated data improve the performance of the EN? For this purpose, 108 NC-CT images of a total of 50 stroke patients were processed independently according to a defined pipeline by both an expert and a non-expert. The focus was mainly on the following: Stroke yes/no, drawing in the lesion if necessary, defining the location of the lesion. This data was compared and afterward used for training the EN and the N-EN. We finally extended the expert training set with additional previously processed non-expert data. Firstly, we found significant substantial interrater agreement on the recognition of acute stroke. Secondly, the performance of both networks was satisfactory, however, the EN was slightly better. The most important finding of our project, however, was that the EN’s performance could be improved after its training data was additionally augmented with non-expert-generated data. Our results suggest, that using data labeled and preprocessed by non-experts introduces new possibilities to generate training data for stroke imaging as well as further applications.

380. Assessment of MRI Diffusion Parameters and Cerebral Blood Flow on Mild Cognitive Impairment Patients

Doctor Yang Juan1, Doctor Sui Haijing2, Mr Zhang Min3, Professor Liu xueyuan4, Professor Zhao Xiaohui5

1Department of Neurology, Shanghai Pudong New Area People’s Hospital Affiliated to Shanghai University of Medicine&Health, 2Department of Image, Shanghai Pudong New Area People’s Hospital Affiliated to Shanghai University of Medicine&Health Sciences, 3hcit.ai, 4Department of Neurology, Shanghai Tenth People’s Hospital Affiliated to Tongji University School of Medicine, 5Department of Neurology, Shanghai Pudong New Area People’s Hospital Affiliated to Shanghai University of Medicine&Health

380. Objectives: To assess differences between Mild Cognitive Impairment (MCI) and normal patients across different brain regions using diffusion weighted imaging (DWI), diffusion tensor imaging (DTI) and arterial spin labeling imaging (ASL). Research question: MCI has been considered as an early stage of Alzheimer’s Disease (AD). In literature, many researchers were trying to find imaging biomarkers, which are more objective compared to cognitive assessment on MCI diagnosis. This study was trying to employ DTI, DWI and ASL to detect the alternations on MCI compared to normal. Materials and methods: 148 subjects participated in this study in total. Specifically, 67 subjects were MCI patients (average age: 71.73 years, male:27, female:40) and 81 subjects were normal (average age: 72.76 years old, male:42, female:39). All participants were scanned using 1.5T MRI (GE Healthcare, WI, USA) with DWI, DTI and ASL images obtained. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were derived from DTI and DWI respectively, while cerebral blood flow (CBF) were computed from ASL images. All the images were then registered to Montreal Neurological Institute (MNI) space. FA, ADC and CBF median values were extracted from 116 brain regions using automated anatomical labeling parcellation. FA, ADC and CBF values were compared between the two groups and the relationship between diffusion parameters and CBF was tested using ANOVA F-test. Result: No significant CBF differences were observed between MCI and normal group. FA was significant increased/decreased (p-value<0.01) in MCI compared to normal group across four brain regions, like region Cerebelum-3-R increased, region Rolandic-oper-R, Occipital-inf-L and Cerebelum-crusl-R decreased. While ADC value was significant increased/decreased (p-value<0.01) in MCI compared to normal group across nineteen brain regions like region Cerebelum-3-L decreased, region Precentral-R, Frontal-Mid-R, Frontal-inf-oper-R, Olfactory-L, Olfactory-R, Frontal-med-orb-L, Insula-R, Parahippocampal-L, Parahippocampal-R, Lingual-L, Occipital-sup-R, Fusiform-R, Postcentral-L, Postcentral-R, Putamen-R, Temporal-inf-L and Temporal-inf-R. Conclusion: This research showed that DTI is a more sensitive technique than ASL, and was able to detect changes on MCI patient.

158. Meta scientific lessons from the complete Liverpool SPN catalogue

Dr Alexis Makin1

1University of Liverpool

158. Most researchers are now aware of an apparent ‘replication crisis’ in the biomedical sciences. It has been argued that most published research findings are false, and less than half of experiments can be replicated in some fields. The eminent neuroscientist and commentator Dorothy Bishop alleges that the problems have been known for decades, but regrettably, “many researchers still persist in working in ways almost guaranteed not to deliver meaningful results”. Instead, they ‘ride the four horsemen of the irreproducibility apocalypse’. These are 1) Publication bias, 2) Low statistical Power, 3) P-Hacking and 4) HARKing (Bishop, 2019). Such ominous discourses encouraged us to reflect our own data and practices. For the last 10 years, we have been using an Event Related Potential (ERP) signal called the Sustained Posterior Negativity (SPN) to investigate visual symmetry perception. Is our SPN research delivering meaningful results, or is it compromised by Bishops four horsemen? We realized that that seeking objective answer would be an original and provocative meta-scientific research project that could have broad implications. We first compiled all our SPN data into a complete catalogue (40 projects, 6674 ERPs from 2215 participants, https://osf.io/2sncj/). We then analysed the whole data set and identified 1) significant, but largely benign file drawer effect, 2) a substantial problem with statistical power and 3) a minor concern with some kinds of P-Hacking. While other large scale EEG replication studies provide breadth (Pavlov, 2020), this study provides depth. We hope other researchers will be inspired to conduct similar exercises with their own data sets.

381. Improving activation maps and spatial coverage in near-infrared spectroscopy with data-driven physiological noise removal

Anna Padée1, Pascal Missonnier1, Tobias Kober2,3,4, Marco Merlo1, Jonas Richiardi2,3

1Laboratory for Psychiatric Neuroscience and Psychotherapy, University of Fribourg, 2Advanced Clinical Imaging Technology, Siemens Healthcare, 3Center for Biomedical Imaging, 4LTS5, Ecole Polytechnique Fédérale de Lausanne

381. Objectives Near infrared spectroscopy (NIRS) is an emerging technique in functional brain imaging, where neural signal is notoriously mixed with both physiological and instrumental noise. We propose different noise removal methods to improve brain activation recovery. Research question We tested whether data-driven denoising was as effective as using reference (short) channel for denoising. Materials and methods The data was recorded at 7.81Hz using a NIRX NirScout system (16 sources, 16 detectors, 39 channels, 2 short channels) on 4 volunteers. The task was right-hand finger tapping, with 20s blocks tapping followed by approx. 20s of rest, with 20 repetitions. The data were band-pass filtered into 0.01-0.5Hz. A GLM was fitted whose regressor of interest was the block paradigm convolved with a hemodynamic response function. We contrasted two approaches to noise regressors: a) short channels, which require sacrificing a number of data channels. b) Our novel data-driven decomposition method, Stabilised Independent Component Analysis (StabICA), that extracts noise confounds directly from recorded data without short channels or peripheral signals. StabICA combines multiple ICA runs and picks the most stable using clustering criteria, then automatically selects as noise components those with the smallest absolute correlation with the paradigm. A T-test was computed for the obtained beta values, and values were projected and smoothed onto a partially inflated MNI template brain using Vis-Brain. Results For all subjects, the GLM model showed paradigm-related activation in the left premotor cortex and/or M1. Without noise regressors, the average T value across all subjects for channels in the right premotor area were 17.9±8.6 and 2.5±5.9 in the frontal area. Including short channel regressors (approach a) improved the contrast of active and inactive brain areas, with T=19.9±6.1 for the motor area and 0.1±5.0 in the frontal area. Similar effect were observed with the decomposition approach (approach b), with T=19.4±11.4 (motor) and 1.9±8.6 (frontal). Conclusion Using reference channels is effective for NIRS noise removal, but reduces spatial resolution by limiting the available number of channels, and is not available for all manufacturers. Signal decomposition methods such as StabICA provide improved activation maps while preserving spatial resolution.

382. Measuring spectrally-resolved information transfer and information storage

Edoardo Pinzuti1

1Leibniz Institute for Resilience Research, 2Brain Imaging Center

382. Biological systems must process information about their environment and their internal states in order to survive. Many biological systems have evolved specialized where such information processing is particularly evident. Prime examples are the central nervous systems of many animals and the human brain in particular. To understand those systems better and to build a bridge between information processing and their biophysical dynamics, it would be beneficial to link the components of information processing to specific rhythms. We developed an algorithm, to identify separately frequencies sending and receiving information in a network in terms of information transfer (transfer entropy) and to determine frequencies responsible for the internal dynamic of a process (active information storage). Our approach relies on the invertible maximum overlap discrete wavelet transform (MODWT) for the creation of surrogate data in the computation of transfer entropy or active information storage and entirely avoids filtering of the original signals. The approach thereby avoids well-known problems due to phase shifts or the ineffectiveness of filtering in the information theoretic setting. We also show that measuring frequency-resolved information transfer is a partial information decomposition problem that cannot be fully resolved to date. We evaluate the performance of our method in Local Field Potential recordings of a ferret, where show that the prefrontal cortex sends information at low frequencies (4-8 Hz) to early visual cortex (V1), while V1 receives the information at high frequencies (> 125 Hz). Additionally we apply the frequency- esolved active information storage to cortical layers at PFC and V1 in a ferret and show how anesthesia modulates the neural dynamic depending o the nternal information processing across area and layers.

383. Examining valuation decisions for products in the real world using mobile EEG and eye tracking

Miss Hannah Roberts1, Dr John Tyson-Carr1, Dr Vicente Soto1, Dr Katerina Kokmotou1,3, Mr Adam Byrne1,2, Dr Nick Fallon1, Dr Timo Giesbrecht3, Dr Andrej Stancak1,2

1University of Liverpool, 2Institute of Risk and Uncertainty , 3Unilever Research and Development

383. Research question Little is known about the neural temporal dynamics of value-based decisions at the time of choice. Previous electroencephalographic (EEG) studies in humans have shown that valuation decisions can be computed within hundreds of milliseconds (Harris et al., 2011). However, it is not yet well understood how valuation decisions evolve in real-life scenarios as context has been overlooked in valuation research. Objectives The study aimed to examine the spatio-temporal brain dynamics underlying economic decision making to products in realistic environments using mobile EEG and eye tracking. Building on Roberts et al. (2018), the study aimed to develop a method for improving the Signal to Noise Ratio (SNR), extend the price range of products to isolate value and to employ a cluster analysis to improve discrimination of neural responses. Materials and Methods Twenty participants rated 216 product images in a gallery whilst EEG and eye tracking were recorded. A Becker-DeGroot-Marschak (BDM) auction elicited willingness to pay (WTP) for products, creating four subjective value (SV) conditions. Eye Movement Related Potentials (EMRPs) were examined and an Independent Component Analysis (ICA) separated neural activation from grand averaged EEG. A clustering solution was applied to grand averaged EMRPs using the Principle Component Analysis (PCA) method. Each cluster’s mean activation was statistically compared across SV conditions. Results Four clusters were modulated by subjective value. Enhanced amplitude was found for low value products compared to low medium (Cl 5: 50-63ms) high medium/high (Cl6: 56-58 ms; Cl3 116-127ms) and low medium/high (Cl5 132-148 ms) within the lambda component. Enhanced amplitude was found for high medium versus all (Cl 9: 158-185ms), low versus medium (Cl 5: 170-183) medium versus high (Cl3: 193-204), and all versus high medium (Cl 6: 225-230ms), within the P200 latency. Conclusion In accordance with Roberts et al (2018), results suggest that low value products receive neural prioritization of attention in realistic conditions (i.e., lower latency), with multiple clusters isolating and comparing low value products. Medium value products receive attention later as they require more deliberation. Early prioritization of attention towards low value products could represent an aversive mechanism that exists to maximize economic resources.

384. Clock time: a foreign measure to brain dynamics

Sander van Bree1,2, María Melcón3, Luca D. Kolibius1,2, Dr Casper Kerrén4, Prof Maria Wimber1,2, Prof Simon Hanslmayr1,2

1Centre for Cognitive Neuroimaging, School of Neuroscience and Psychology, University of Glasgow, 2Centre for Human Brain Health, School of Psychology, University of Birmingham, 3Department of Biological and Health Psychology, Autónoma University of Madrid, 4Center for Adaptive Rationality, Max Planck Institute for Human Development

384. Human thought is highly flexible and dynamic, achieved by evolving patterns of brain activity across groups of cells. Neuroscience aims to understand cognition in the brain by analysing these intricate patterns. Here, we argue that this goal is impeded by the time format of our data – clock time. The brain is a system with its own dynamics and regime of time, with no intrinsic concern for the human-invented second. A more appropriate time format is cycles of brain oscillations, which coordinate neural firing and are widely implicated in cognition. These brain dynamics do not obey clock time – they start out of tune with clock time and drift apart even further as oscillations unpredictably slow down, speed up, and undergo abrupt changes. Since oscillations clock cognition, their dynamics should critically inform our analysis. We describe brain time warping as a new method to transform data in accordance with brain dynamics, which sets the time axis to cycles of clocking oscillations (a native unit) rather than milliseconds (a foreign unit). We also introduce the Brain Time Toolbox, a software library that implements brain time warping for electrophysiology data and tests whether it reveals information patterns in line with how the brain uses them.

385. Combination of functional, anatomical, and morphological networks in the identification of cognitive impairment in subjects with white matter hypersensitive

Prof. Yun Xu1, Dr. Qing Ye1, Dr. Haifeng Chen1

1Department of Neurology, Affiliated Drum Tower Hospital, Nanjing University Medical School

385. OBJECTIVE: White matter hyperintensity (WMH) is a major cause of cognitive decline in the elderly. Evidence from functional and structural research suggests that abnormal brain connectivity plays an important role in the WMH-related cognitive impairment. However, most previous studies have focused on single modalities only, each of which is associated with its own limitations. Multimodal combinations can more effectively utilize various information. METHODS: We recruited 37 WMH with normal cognition (WMH-NC) and 37 WMH with mild cognitive impairment (WMH-MCI). Functional magnetic resonance imaging, diffusion tensor imaging, and structural magnetic resonance imaging data were used to construct the functional, anatomical, and morphological networks of each participant, respectively. These networks were used in combination with the multiple kernel learning-support vector machine (MKL-SVM) to identify more consistent biomarkers of brain connectivity and explore the relationships between different modalities. RESULTS: We found that although each modality had divergent connectivity biomarkers, the convergent pattern was that all were mostly located within default mode network (DMN) and executive control network (ECN). Furthermore, using the biomarkers of these 3 modalities as a feature yielded the highest classification accuracy (95.95%, relative to a single modality), suggesting that the combination of multiple modalities could be effectively utilized to obtain complementary information regarding different mode networks; furthermore, this information could help distinguish patients. CONCLUSION: Our findings provide direct evidence for the disconnection hypothesis of WMH, suggesting that abnormalities in the DMN and ECN can be used as a biomarker of WMH-related cognitive impairment.

314. HRV biofeedback evokes persisting improvements in attention, short-term memory, and positive self-referential episodic memory

Lukas Bögge1, Dr Itsaso Colás-Blanco1, Prof Pascale Piolino1,2

1Memory, Brain & Cognition Laboratory (MC²Lab), Institute of Psychology, University of Paris, 2Institut Universitaire de France (IUF)

314. Heart rate variability (HRV) biofeedback, an intervention based on the voluntary self-regulation of autonomic parameters, has been shown to improve goal-directed behavior involving cognitive control. These results have been ascribed to parasympathetic activation and physiological coupling which altered brain functioning along the cortical midline and in the prefrontal cortex. However, the persistence of cognitive effects is poorly studied and their association with biofeedback-evoked autonomic changes has not yet been explored. In addition, no study has so far investigated the influence of HRV biofeedback in adults on long-term episodic memory or self-referential encoding processing. In the present study, we sought to answer whether HRV biofeedback based on slow and rhythmic breathing evokes persistent effects on executive functions and self-referential episodic memory and whether these are linked to parasympathetic activation during training. A novel training system was developed integrating HRV and respiratory biofeedback into an immersive virtual reality environment to enhance training efficacy. Twenty-two young healthy adults (25.31 ± 2.87 years, 64% female) were subject to a 5-week blinded randomized placebo-controlled experiment, including six sessions of 25-minute training. Vagally-mediated HRV was assessed before, during, and 5 minutes after each training. Evaluations of executive functions (D2-R, Digit span, SART, Stroop, TMT), episodic memory, and the self-referential encoding effect were performed one week before and after the training program. Linear mixed-effects models showed that HRV biofeedback greatly stimulated vagal afferent outflow and cardio-respiratory synchrony during and after training compared to the placebo control. Moreover, it significantly improved attentional capabilities required for identification and discrimination of stimuli, auditory short-term memory, and self-referential episodic memory recollection of positive stimuli. Episodic memory outcomes indicated that HRV biofeedback reinforced positive self-reference encoding processing. Cognitive changes were strongly dependent on the level of vagally-mediated HRV evoked during training. The present study provides evidence that biofeedback moderates voluntary autonomic control and parasympathetic activation, which in turn mediates improvements in several cognitive processes crucial for everyday functioning including episodic memory, that are maintained beyond the training period. The results highlight the interest in HRV biofeedback as an innovative research tool and medication-free therapeutic approach to affect autonomic and neurocognitive functioning.

315. Modulation of individual gamma frequency: a pilot study of neurofeedback approach

Inga Griskova-Bulanova1, Povilas Tarailis1, Aleksandras Voicikas1

1Vilnius University

315. Objectives The neurofeedback (NFB) is used to improve the aberrant cognitive and perceptual processes in neuropsychiatric disorders. The gamma-activity based neurofeedback procedures showed a potential previously; however, they lack individualized approach. This study is aiming at the development and pilot testing of a neurofeedback system relying 1) on the non-invasive assessment of a unique physiological parameter – an individual gamma peak frequency (IGF) and 2) the application of a unique feedback based on auditory steady-state response (ASSR). Research question Is it possible to modulate individual gamma frequency with neurofeedback? Materials and methods To estimate the IGF, responses to chirp-based auditory stimulation are assessed and phase-locking is used as a target measure. During NFB training (N=22) the phase-locking of gamma response was continuously extracted and converted to the frequency of auditory stimulation and the size of a ball displayed on the screen. Subjects were instructed to increase the diameter of the ball. The control group (N=17) received feedback based on the other person's EEG. Backward digit span task was used as a behavioral control measure. Results An IGF increase was observed in the experimental group (35.7Hz vs 38.1Hz, p=0.035) but not in the control group (36.1Hz vs 36.7Hz, p=0.34) after completion of a single NBF session. This was accompanied by the increase in the working memory capacity in the experimental (5.7 vs 7.3, p=0.002) but not the control group (5.6 vs 6.2, p=0.14). Conclusion In this work we demonstrate a gamma-ASSR/IGF-based neurofeedback system and results of initial evaluation of the capabilities of the proposed NFB system to modulate IGFs. Funding: study was supported by the Research Council of Lithuania (LMTLT agreement No S-LJB-20-1). Authors declare no conflict of interest.

316. Module-level structural and functional alternations in amnestic mild cognitive impairment

Mrs Ying Liu1, Mr ShiJi Deng1, Mrs Yun Xu1

1Drum Tower Hospital, Nanjing, China

316. Background: Mild cognitive impairment (MCI), regarded as the prodromal stage before the clinical phase of Alzheimer's disease (AD), has been considered for early differential diagnosis. Patients with

amnestic mild cognitive impairment (aMCI)，an important subtype of MCI, are more likely to progress to

clinical Alzheimer disease (AD). Objective: To examine the structural and functional connectome in both kinds of MCI and found differences in structural connectivity (SC)-functional connectivity (FC) coupling. Methods: Fifty-nine individuals with aMCI, naMCI and healthy controls (NC) underwent resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI). Brains were parcellated into functional modules according to the FC networks of NC, and individual FC and SC within modules as well as average FC , average SC and average SC-FC correlation values in each module among groups were analyzed, while logistic regression was used to find predictive factors. Results: After controlling for age, sex, and education, the FC values in the temporal-occipital module and the SC-FC correlation values in the temporal-occipital and the default mode module appeared as prediction indicators for aMCI. Conclusion: FC and SC-FC correlation values can be used to differentiate between aMCI and MCI.

317. Development of novel game-based interventions and behavioral and neuronal biomarkers for MDD

Maria Vesterinen1, Lauri Lukka2, Jasmin Elonen1, Antti Apostol2, Joonas Juvonen1,2, Dr. Wenya Liu2, Prof. Matias Palva2, Dr. Satu Palva1

1University of Helsinki, 2Aalto University

317. Background: Major Depressive Disorder (MDD) is a disorder characterized by e.g. depressed mood, loss of interest or pleasure, feelings of worthlessness or excessive guilt, and diminished ability to concentrate or make decisions. MDD is one of the largest contributors to the global burden of disease, yet cognitive deficits; central diagnostic and further impairing symptoms in MDD, have largely been untargeted by treatment. Moreover, entertainment games have been shown to alleviate MDD symptoms and lead to improved cognitive functioning. Neurophysiologically, MDD symptoms are paralleled by hyperactive ventro-medial prefrontal cortex (VMPFC) and the hypoactivity of the lateral prefrontal cortex (LPFC) in fMRI data. MDD biotypes identified from fMRI connectivity patterns transcend conventional clinical classifications and predict treatment responses. Although fMRI is spatially precise, it measures slow blood oxygenation changes and therefore cannot probe cognitive functions in their sub-second timescales. Therefore, treatment of cognitive deficits and restoration of normal brain dynamics in the LPFC could be a useful aim and could support more classical treatments. Objectives: The aim of this project is to investigate the effectiveness of a video-game intervention designed to ameliorate MDD symptoms through cognitive training, to develop game-based mapping of behavioral phenotypes and to develop and discover aberrant oscillatory brain dynamics that identify MDD biotypes. Methods: We will recruit N= 800 MDD patients for the 12-week game-based intervention to treat depression and use these data to map behavioral phenotypes and treatment responses. To identify biotypes based on aberrant oscillatory dynamics, we will collect MEG and MRI data during resting state activity and reward anticipation tasks from N= 200 patients with MDD and 100 healthy controls before and after they complete the game-based intervention. We will then identify oscillatory synchronization and brain criticality dynamics from individual source-reconstructed MEG data. Expected results: We will expect that i) the game-based intervention ameliorates MDD symptoms, ii) aberrant brain dynamics are correlated with symptom-scores in the MDD cohort and iii) the game-based intervention renormalizes neuronal dynamics.

318. Intuitive physical inference of falling objects

Gabrielle Zbären1, Dr. Sarah Meissner1, Dr. Venera Gashaj2, Prof. Manu Kapur2, Prof. Nicole Wenderoth1

1Neural Control of Movement Laboratory, Department of Health Sciences and Technology, ETH Zurich, 2Institute for Learning Sciences and Higher Education, Department of Humanities, Social and Political Sciences, ETH Zurich

318. Despite our ability to successfully interact every day with the physics of the world, our physical inferences are prone to errors. This is illustrated by common misconceptions that arise when solving seemingly simple physics problems. A well-known example is the “straight-down misconception”, which corresponds to the erroneous belief that an object falling from a moving body falls straight-down. Here, we aimed to investigate (i) how common the straight-down misconception is when exposed to a dynamical scene (ii) whether people who do not have a misconception still exhibit biases and (iii) what neural substrates support physical inference. Seventy-nine healthy volunteers (42 females; age = 24.13 +/- 4.17) took part in our study for which we created a computer-based, dynamical 3D physics world. Participants were asked to solve a simple task in which they view a horizontally moving object with a ball attached, coming from either the left or the right side of the screen. At one point, the ball drops and participants indicate via button presses (i) when and (ii) where they think the ball lands. Crucially, once the ball is released, the screen gets occluded such that the trajectory of neither the ball nor the moving object is shown. Additionally, first pilot participants underwent a training session during which they performed the same task while receiving feedback on their performance. This training was followed by a 3T functional MRI experiment to measure BOLD responses during physical inference. We found that 53.16% of the participants exhibited a “straight-down misconception”. Participants who correctly estimated the ball trajectory tended to over-estimate the falling time and mistakenly predict that the ball falls faster at higher velocities of the object. Thus, even when people don’t exhibit a misconception, their inferences are prone to biases. Preliminary training and fMRI data suggest that errors greatly diminish when participants receive feedback. Physical inference of falling objects activates motion-responsive visual (MT/V5), motor and parietal regions. By applying multivariate pattern analysis to our fMRI data, we could successfully decode essential task parameters from visual, parietal and motor regions, suggesting that participants used mental simulation to solve the task.