Biological Psychology - Human Communication
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BİOLOGİCAL PSYCHOLOGY CH.13 HUMAN COMMUNICATION BOur knowledge of the physiology of language has been obtained primarily by observing the effects of brain lesions on people’s verbal behavior. ]Another source of information about the physiology of language comes from studies using functional imaging devices. BLanguage is more than communicating, it is also for thinking. BThe most important category of speech disorders is aphasia, a primary disturbance in the comprehension or production of speech, caused by brain damage. Speech Production and Comprehension: Brain Mechanism 1. Aphasia Difficulty in producing or comprehending speech not caused by deafness or a simple motor deficit; caused by brain damage. BNot all speech disturbances are aphasias; a patient must have difficulty comprehending, repeating, or producing meaningful speech, and this difficulty must not be caused by simple sensory or motor deficits or by lack of motivation. For example, an inability to speak caused by deafness or paralysis of the speech muscles is not considered to be aphasia. In addition, the deficit must be relatively isolated; that is, the patient must appear to be aware of what is happening in his or her environment and to comprehend that others are attempting to communicate. Lateralization BVerbal behavior is a lateralized function; most language disturbances occur after damage to the left side of the brain, whether people are leftBhanded or rightB handed. BThe leftBhemisphere of approximately 90 percent of the total population is dominant for speech. But, if leftBhemisphere is malformed or damaged in early life, then language dominance is very likely to pass to the right hemisphere. BHowever, other hemisphere plays roles in speech. For example, damage to the rightBhemisphere makes it difficult for a person to read maps, perceive spatial relations, and recognize complex geometrical forms of understanding what other people have to say about them. BThe rightBhemisphere also appears to be involved in organizing a narrative – selecting and assembling the elements of what we want to say. The rightBhemisphere is involved in the expression and recognition of emotion in the tone of voice. It is also involved in control of prosody –the normal rhythm and stress found in speech. Therefore, both hemispheres of the brain have contribution to make to our language abilities. Speech Production ]Being able to talk –that is, to produce meaningful speechB requires several abilities. First the person must have something to talk about. For example, we can talk about something that is currently happening or something that happened in the past. In the first case, we are talking about our perceptions: things we are seeing, hearing, feeling, smelling, and so on. In the second case, we are talking about our memories of what happened in the past. 2. Broca’s aphasia A form of aphasia characterized by agrammatism, anomia, and extreme difficulty in speech articulation. BDamage to a region of the inferior left frontal lobe (Broca’s area) disrupts the ability to speak. BBroca’s aphasia is characterized by slow, laborious, and nonfluent speech. BPatients with Broca’s aphasia find it hard to resist supplying the words. BSo, the posterior part of the cerebral hemispheres has something to say, but the damage to the frontal lobe makes it difficult for the patients to express these thoughts. BPeople with Broca’s aphasia can comprehend speech much better than they can produce it. 3. Function word People with Broca’s aphasia find it easier to say some types of words than others. They have great difficulty saying the little words with grammatical meaning, such as a, the, some, in, about, etc., which words are called function words, because they have important grammatical functions. 4. Content word The words that they do manage to say are almost entirely content words (they convey meaning, including nouns, verbs, adjectives, adverbs, such as apple, house, throw, heavy) 5. Broca’s area A region of frontal cortex, located just rostral to the base of the left primary motor cortex, that is necessary for normal speech production. BBroca's area is a functionally defined structure in the left frontal lobe of about 97% of humans (including a large majority of left–handers). BBroca's area is involved mainly in the production of spoken and written language and also in language processing and comprehension. BLesions that produce Broca’s aphasia are certainly centered in the vicinity of Broca’s area. However, damage that is restricted to the cortex of Broca’s area does not appear to produce Broca’s aphasia; the damage must extent to surrounding regions of the frontal lobe and to the underlying subcortical white matter. BIn addition, there is evidence that lesions of the basal ganglia –especially the head of the caudate nucleusB can also produce a BrocaBlike aphasia. BBroca’s area contains motor memories –in particular, memories of the sequences of muscular movements that are needed to articulate words. Talking involves rapid movements of the tongue, lips, and jaw, and these movements must be coordinated with each other and with those of the vocal cords; thus, talking requires some very sophisticated motor control mechanisms. BBecause damage to the inferior caudal left frontal lobe (including Broca’s area) disrupts the ability to articulate words, this region is a likely candidate for the location of these “programs”. BThe fact that this region is directly connected to the part of the primary motor cortex that controls muscles used for speech certainly supports this conclusion. BThree major speech deficits are produced by lesions in and around Broca’s area: Agrammatism, Anomia, and Articulation Difficulties. 6. Agrammatism refers to a patient’s difficulty in using grammatical constructions, without any difficulty in pronouncing words. BOne of the usual symptoms of Broca’s aphasia is agrammatism that is difficulty in comprehending or properly employing grammatical devices, such as verb endings or word order. BPeople with Broca’s aphasia rarely use function words, and they rarely use grammatical makers such as Bed or auxiliaries such as have. They do often –ing, perhaps because this ending converts a verb into a noun. BBroca’s area was activated when people were taught an artificial grammar. BThey cannot understand and use grammar. BThey cannot understand difference between object and subject. So they cannot understand whether horse or cow kick. 7. Anomia The second major speech deficit seen in Broca’s aphasia is anomia (“without name”). BAnomia is actually a primary symptom of all forms of aphasia. BAnomia is difficulty in finding (remembering) the appropriate word to describe an object, action, or attribute. Speech Comprehension BComprehension of speech obviously begins in the auditory system, which detects and analyzes sounds, but recognizing words is one thing; comprehending them –understanding their meaningB is another. BRecognizing a spoken word is a complex perceptual task that relies on memories of sequences of sounds. This task appears to be accomplished by neural circuits in the middle and posterior portion of the superior temporal gyrus of the left hemisphere, a region that has come to be known as Wernicke’s area. 8. Wernicke’s Area A region of the auditory association cortex on the left temporal lobe of humans, which is important in the comprehension of words and the production of meaningful speech. 9. Wernicke’s aphasia A form of aphasia characterized by poor speech comprehension and fluent but meaningless speech.
Transcript of Biological Psychology - Human Communication
!BİOLOGİCAL(PSYCHOLOGY(CH.13(((HUMAN(COMMUNICATION(BOur!knowledge!of!the!physiology!of!language!has!been!obtained!primarily!by!observing!the!effects!of!brain!lesions!on!people’s!verbal!behavior.!((]Another!source!of!information!about!the!physiology!of!language!comes!from!studies!using!functional!imaging!devices.!!BLanguage!is!more!than!communicating,!it!is!also!for!thinking.!!BThe!most!important!category!of!speech!disorders!is!aphasia,!a!primary!disturbance!in!the!comprehension!or!production!of!speech,!caused!by!brain!damage.!!Speech(Production(and(Comprehension:(Brain(Mechanism((1. Aphasia!Difficulty!in!producing!or!comprehending!speech!not!
caused!by!deafness!or!a!simple!motor!deficit;!caused!by!brain!damage.!(BNot!all!speech!disturbances!are!aphasias;!a!patient!must!have!difficulty!comprehending,!repeating,!or!producing!meaningful!speech,!and!this!difficulty!must!not!be!caused!by!simple!sensory!or!motor!deficits!or!by!lack!of!motivation.!For!example,!an!inability!to!speak!caused!by!deafness!or!paralysis!of!the!speech!muscles!is!not!considered!to!be!aphasia.!In!addition,!the!deficit!must!be!relatively!isolated;!that!is,!the!patient!must!appear!to!be!aware!of!what!is!happening!in!his!or!her!environment!and!to!comprehend!that!others!are!attempting!to!communicate.!!(
(Lateralization((BVerbal!behavior!is!a!lateralized!function;!most!language!disturbances!occur!after!damage!to!the!left!side!of!the!brain,!whether!people!are!leftBhanded!or!rightBhanded.!BThe!leftBhemisphere!of!approximately!90!percent!of!the!total!population!is!dominant!for!speech.!But,!if!leftBhemisphere!is!malformed!or!damaged!in!early!life,!then!language!dominance!is!very!likely!to!pass!to!the!right!hemisphere.!!BHowever,!other!hemisphere!plays!roles!in!speech.!For!example,!damage!to!the!rightBhemisphere!makes!it!difficult!for!a!person!to!read!maps,!perceive!spatial!relations,!and!recognize!complex!geometrical!forms!of!understanding!what!other!people!have!to!say!about!them.!!BThe!rightBhemisphere!also!appears!to!be!involved!in!organizing!a!narrative!–selecting!and!assembling!the!elements!of!what!we!want!to!say.!!The!rightBhemisphere!is!involved!in!the!expression!and!recognition!of!emotion!in!the!tone!of!voice.!It!is!also!involved!in!control!of!prosody!–the!normal!rhythm!and!stress!found!in!speech.!Therefore,!both!hemispheres!of!the!brain!have!contribution!to!make!to!our!language!abilities.!! !!Speech(Production((]Being!able!to!talk!–that!is,!to!produce!meaningful!speechB!requires!several!abilities.!First!the!person!must!have!something!to!talk!about.!For!example,!we!can!talk!about!something!that!is!currently!happening!or!something!that!happened!in!the!past.!In!the!first!case,!we!are!talking!about!our!perceptions:!things!we!are!seeing,!hearing,!feeling,!smelling,!and!so!on.!In!the!second!case,!we!are!talking!about!our!memories!of!what!happened!in!the!past.!!!
2. Broca’s(aphasia!A!form!of!aphasia!characterized!by!agrammatism,!anomia,!and!extreme!difficulty!in!speech!articulation.!!BDamage!to!a!region!of!the!inferior!left!frontal!lobe!(Broca’s!area)!disrupts!the!ability!to!speak.!!BBroca’s!aphasia!is!characterized!by!slow,!laborious,!and!nonfluent!speech.!!BPatients!with!Broca’s!aphasia!find!it!hard!to!resist!supplying!the!words.!!BSo,!the!posterior!part!of!the!cerebral!hemispheres!has!something!to!say,!but!the!damage!to!the!frontal!lobe!makes!it!difficult!for!the!patients!to!express!these!thoughts.!!BPeople!with!Broca’s!aphasia!can!comprehend!speech!much!better!than!they!can!produce!it.!(
3. Function(word!People!with!Broca’s!aphasia!find!it!easier!to!say!some!types!of!words!than!others.!They!have!great!difficulty!saying!the!little!words(with(grammatical(meaning,!such!as!a,!the,!some,!in,!about,!etc.,!which!words!are!called!function!words,!because!they!have!important!grammatical!functions.!(
4. Content(word!The!words!that!they!do!manage!to!say!are!almost!entirely!content!words!(they!convey!meaning,!including!nouns,!verbs,!adjectives,!adverbs,!such!as!apple,!house,!throw,!heavy)(
5. Broca’s(area!A!region!of!frontal!cortex,!located!just!rostral!to!the!base!of!the!left!primary!motor!cortex,!that!is!necessary!for!normal!speech!production.!!(
BBroca's!area!is!a!functionally!defined!structure!in!the!left!frontal!lobe!of!about!97%!of!humans!(including!a!large!majority!of!left–handers).!!
BBroca's!area!is!involved!mainly!in!the!production!of!spoken!and!written!language!and!also!in!language!processing!and!comprehension.!!!BLesions!that!produce!Broca’s!aphasia!are!certainly!centered!in!the!vicinity!of!Broca’s!area.!However,!damage!that!is!restricted!to!the!cortex!of!Broca’s!area!does!not!appear!to!produce!Broca’s!aphasia;!the!damage!must!extent!to!surrounding!regions!of!the!frontal!lobe!and!to!the!underlying!subcortical!white!matter.!!BIn!addition,!there!is!evidence!that!lesions!of!the!basal!ganglia!–especially!the!head!of!the!caudate!nucleusB!can!also!produce!a!BrocaBlike!aphasia.!!!BBroca’s!area!contains!motor!memories!–in!particular,!memories'of'the'sequences'of'muscular'movements'that'are'needed'to'articulate'words.!Talking!involves!rapid!movements!of!the!tongue,!lips,!and!jaw,!and!these!movements!must!be!coordinated!with!each!other!and!with!those!of!the!vocal!cords;!thus,!talking!requires!some!very!sophisticated!motor!control!mechanisms.!!BBecause!damage!to!the!inferior!caudal!left!frontal!lobe!(including!Broca’s!area)!disrupts!the!ability!to!articulate!words,!this!region!is!a!likely!candidate!for!the!location!of!these!“programs”.!!BThe!fact!that!this!region!is!directly!connected!to!the!part!of!the!primary!motor!cortex!that!controls!muscles!used!for!speech!certainly!supports!this!conclusion.!BThree!major!speech!deficits!are!produced!by!lesions!in!and!around!Broca’s!area:!Agrammatism,!Anomia,!and!Articulation!Difficulties.!(
(6. Agrammatism!refers!to!a!patient’s!difficulty!in!using!grammatical!
constructions,!without!any!difficulty!in!pronouncing!words.!!BOne!of!the!usual!symptoms!of!Broca’s!aphasia!is!agrammatism!that!is!difficulty!in!comprehending!or!properly!employing!grammatical!devices,!such!as!verb!endings!or!word!order.!BPeople!with!Broca’s!aphasia!rarely!use!function!words,!and!they!rarely!use!grammatical!makers!such!as!Bed!or!auxiliaries!such!as!have.!They!do!often!–ing,!perhaps!because!this!ending!converts!a!verb!into!a!noun.!!BBroca’s!area!was!activated!when!people!were!taught!an!artificial!grammar.!!BThey!cannot!understand!and!use!grammar.!!BThey!cannot!understand!difference!between!object!and!subject.!So!they!cannot!understand!whether!horse!or!cow!kick.!(
(7. Anomia(The!second!major!speech!deficit!seen!in!Broca’s!aphasia!is!
anomia!(“without!name”).!!BAnomia!is!actually!a!primary!symptom!of!all!forms!of!aphasia.!!BAnomia!is!difficulty!in!finding!(remembering)!the!appropriate!word!to!describe!an!object,!action,!or!attribute.!!(
!Speech(Comprehension(!BComprehension!of!speech!obviously!begins!in!the!auditory!system,!which!detects!and!analyzes!sounds,!but!recognizing!words!is!one!thing;!comprehending!them!–understanding!their!meaningB!is!another.!!BRecognizing!a!spoken!word!is!a!complex!perceptual!task!that!relies!on!memories!of!sequences!of!sounds.!This!task!appears!to!be!accomplished!by!neural!circuits!in!the!middle!and!posterior!portion!of!the!superior!temporal!gyrus!of!the!left!hemisphere,!a!region!that!has!come!to!be!known!as!Wernicke’s(area.!!!
8. Wernicke’s(Area!A!region!of!the!auditory!association!cortex!on!the!left!temporal!lobe!of!humans,!which!is!important!in!the!comprehension!of!words!and!the!production!of!meaningful!speech.(
9. Wernicke’s(aphasia!A!form!of!aphasia!characterized!by!poor!speech!comprehension!and!fluent!but!meaningless!speech.!!!
Wernicke’s(Aphasia:(Description!BThe!primary!characteristics!of!Wernicke’s!aphasia!are!poor!speech!comprehension!and!production!of!meaningless!speech.!!BUnlike!Broca’s!aphasia,!Wernicke’s!aphasia!is!fluent!and!unlabored;!this!person!does!not!strain!to!articulate!words!and!does!not!appear!to!be!searching!for!them.!!BWhen!you!listen!to!the!speech!of!a!person!with!Wernicke’s!aphasia,!it!appears!to!be!grammatical.!!BHowever,!the!person!uses!few!content!words,!and!the!words!that!he!or!she!strings!together!just!do!not!make!sense.!!Wernicke’s(Aphasia:(Analysis((BBecause!the!superior!temporal!gyrus!is!a!region!of!the!auditory!association!cortex!and!because!a!comprehension!deficit!is!so!prominent!in!Wernicke’s!aphasia,!this!disorder!has!been!characterized!as!a!receptive!aphasia.!!BWernicke!claimed!that!the!Wernicke’s!area!is!the'location'of'memories'of'the'sequences'of'sounds'that'constitute'words.!!BThe!auditory!association!cortex!of!the!superior!temporal!gyrus!recognize!the!sounds!of!words,!just!as!the!visual!association!cortex!of!the!inferior!temporal!gyrus!recognize!the!sight!of!objects.!!BBut!why!should!damage!to!an!area!that!is!responsible!for!the!ability!to!recognize!spoken!words!disrupt!people’s!ability!to!speak?!In!fact!it!does!not;!Wernicke’s!aphasia,!like!Broca’s!aphasia,!actually!appears!to!consist!of!several!deficits.!The!abilities!that!are!disrupted!include!recognition'of'spoken'words,'comprehension'of'the'meaning'of'the'words,'and'the'ability'to'convert'thoughts'into'words.!'Recognition:(1.(Pure(Word(Deafness(BRecognizing!a!word!in!not!the!same!as!comprehending!it.!If!you!hear!a!foreign!word!several!times,!you!will!learn!to!recognize!it,!but!unless!someone!tells!you!what!it!means,!you!will!not!comprehend!it.!!BRecognition!is!a!perceptual!task;!comprehension!involves!retrieval!of!additional!information!from!memory.!!BDamage!to!the!left!temporal!lobe!can!produce!a!disorder!of!auditory!word!recognition,!uncontaminated!by!other!problems.!This!syndrome!called!pure(word(deafness.!!10. Pure(word(deafness!The!ability!to!hear,!to!speak,!and!(usually)!to!
read!and!write!without!being!able!to!comprehend!the!meaning!of!speech;!caused!by!damage!to!Wernicke’s!area!or!disruption!of!auditory!input!to!this!region.!!BAlthough,!people!with!pure!word!deafness!are!not!deaf,!they!cannot!understand!speech.!As!one!patient!expressed!that,!“I!can!hear!you!talking,!I!just!can’t!understand!speech.”!BThese!patients!can!recognize!nonspeech!sounds!such!as!the!barking!of!a!dog,!the!sound!of!a!doorbell,!and!the!honking!of!a!horn.!!BOften,!they!can!recognize!the!emotion!expressed!by!the!intonation!of!speech!even!though!they!cannot!understand!what!is!being!said.!!BMore!significantly,!their!own!speech!is!unimpaired.!!BThey!can!often!understand!what!other!people!are!saying!by!reading!their!lips.!!BThey!can!also!read!and!write,!and!they!sometimes!ask!people!to!communicate!with!them!in!writing.!!BClearly,!pure!word!deafness!is!not!an!inability!to!comprehend!the!meaning!of!words.!!BThey!know!what!car!is,!but!they!just!cannot!understand!difference!between!the!linguistic!sounds!of!car!and!cat.!!BTwo!types!of!brain!injury!can!cause!pure!word!deafness:!disruption!of!auditory!input!to!Wernicke’s!area!or!damage!to!Wernicke’s!area!itself.!Either!type!of!damage!disrupts!the!analysis!of!the!sounds!of!words!and!hence!prevents!people!from!recognizing!other!people’s!speech.!(
]Primary(auditory(cortex(or(connection(between(primary(auditory(cortex(and(Wernicke’s(area(lesions(cause(pure(word(deafness.((
BOur!brains!contain!circuits!of!mirror!neurons!–neurons!activated!either!when!we!perform!an!action!or!see!another!person!performing!particular!grasping,!holding,!or!manipulating!movements!or!when!we!perform!these!movements!ourselves.!!BFeedback!from!these!neurons!may!help!us!to!understand!the!intent!of!the!actions!of!others.!!BAlthough!speech!recognition!is!clearly!an!auditory!event,!research!indicates!that!hearing!words!automatically!engages!brain!mechanisms!that!control!speech.!In!other!words,!these!mechanisms!appear!also!to!contain!mirror!neurons!that!are!activated!by!the!sounds!of!words.!!BThe!investigators!found!that!the!excitability!of!the!subjects’!tongue!muscles!was!increased!only!when!they!heard!words!that!involved!tongue!movements.!Such!as,!the!word!beer!requires!tongue!movements,!but!the!word!buffo!does!not.!!BA!functional!imaging!study!found!that!the!auditory!cortex!is!strongly!activated!when!people!speak!out!loud!but!not!when!they!whisper.!The!investigators!suggest!that!this!region!is!involved!in!selfBmonitoring!of!speech.!Presumably,!auditory!feedback!from!our!own!voices!helps!to!regulate!our!speech.!!Extra!Notes:!BJapanese!children!until!4!years!old,!they!can!differentiate!r!and!l,!but!after!that!time,!they!get!used!to!Japanese!rules!that!there!is!no!difference!r!and!l.!!!Comprehension:(2.(Transcortical(Sensory(Aphasia((BThe!other!symptoms!of!Wernicke’s!aphasia!–failure!to!comprehend!the!meaning!of!words!and!inability!to!express!thoughts!in!meaningful!speechB!appear!to!be!produced!by!damage!that!extends!beyond!Wernicke’s!area!into!the!region!that!surrounds!the!posterior!part!of!the!lateral!fissure,!near!the!junction!of!the!temporal,!occipital!and!parietal!lobes.!For!want!of!better!term,!this!region!is!the!posterior'language'area.!!!BThe!posterior!language!area!appears!to!serve!as!a!place!for!interchanging!information!between!the!auditory!representation!of!words!and!the!meanings!of!these!words,!stored!as!memories!in!the!rest!of!the!sensory!association!cortex.!!BDamage!to!the!posterior!language!area,!which!isolates!Wernicke’s!area!from!the!rest!of!the!posterior!language!area,!produces!a!disorder!known!as!transcortical(sensory(aphasia.!!
11. Transcortical(sensory(aphasia!A!speech!disorder!in!which!person!has!difficulty!comprehending!speech!and!producing!meaningful!spontaneous!speech!but!can!repeat!speech;!caused!by!damage!to!the!region!of!the!brain!posterior!to!Wernicke’s!area.!!BThe!difference!between!transcortical!sensory!aphasia!and!Wernicke’s!aphasia!is!that!patients!with!transcortical!sensory!aphasia!can!repeat!what!other!people!say!to!them;!therefore,!they!can!recognize!words.!However,!they!cannot!comprehend!the!meaning!of!what!they!hear!and!repeat,!nor!can!they!produce!meaningful!speech!of!their!own.!!BHow!can!these!people!repeat!what!they!hear?!–Because!the!posterior!language!area!is!damaged,!repetition!does!not!involve!this!part!of!the!brain.!Obviously,!there!must!be!a!direct!connection!between!Wernicke’s!area!and!Broca’s!area!that!bypasses!the!posterior!language!area.!!BTranscortical!sensory!aphasia!can!be!seen!as!Wernicke’s!aphasia!without!a!repetition!deficit.!!BThe!symptoms!of!Wernicke’s!aphasia!consist!of!those!of!pure!word!deafness!plus!those!of!transcortical!sensory!aphasia.!!WA!=!TSA!+!PWD!,!TSA!=!WA!–!PWD.!(BAnother!most!important!function!of!linguistic!is!that!referring!the!things.!!Transcortical!sensory!aphasia!don’t!know!what!refers!what.!They!don’t!know!meaning,!so!they!cannot!produce!meaningful!speech.!!
(
What(is(Meaning?(BWernicke’s!area!is!involved!in!the!analysis!of!speech!sounds!and!thus!in!the!recognition!of!words.!BDamage!to!the!posterior!language!area!does!not!disrupt!people’s!ability!to!recognize!words,!but!it!does!not!disrupt!their!ability!to!understand!words!or!to!produce!meaningful!speech!of!their!own.!!BBut!what,!exactly,!do!we!mean!by!the!word!meaning?!And!what!types!of!mechanism!are!involved?!!BWords!refer!to!objects,!actions,!or!relationships!in!the!world.!Thus!the!meaning!of!a!word!is!defined!by!particular!memories!associated!with!it.!!BFor!example,!knowing!the!meaning!of!the!word!tree!means!being!able!to!imagine!the!physical!characteristics!of!trees:!what!they!look!like,!what!the!wind!sound!likes!blowing!through!their!leaves,!what!the!bark!feels!like,!and!so!on.!It!also!means!knowing!facts!about!trees:!about!their!roots,!buds,!flowers,!nuts,!and!wood!and!the!chlorophyll!in!their!leaves.!These!memories!are!stored!not!in!the!primary!speech!areas!but!in!other!parts!of!the!brain,!especially!regions!of!the!association!cortex.!Different!categories!of!memories!may!be!stored!in!particular!regions!of!the!brain,!but!they!are!somehow!tied!together,!so!hearing!the!word!tree!activates!all!of!them.!!First,!we!must!recognize!the!sequence!of!sounds!that!constitute!the!word;!we!find!the!auditory!entry!for!the!word!in!our!“dictionary”.!This!entry!appears!in!Wernicke’s!area.!!Next,!the!memories!that!constitute!the!meaning!of!the!word!must!be!activated.!Presumably,!Wernicke’s!area!is!connected!–through!the!posterior!language!areaB!with!the!neural!circuits!that!contain!these!memories.!!Damage!to!particular!regions!of!the!sensory!association!cortex!can!damage!particular!kinds!of!information!and!thus!abolish!particular!kinds!of!meaning.!!Damage!to!part!of!the!association!cortex!of!the!left!parietal!lobe!can!produce!an!inability!to!name!the!body!parts.!This!disorder!is!called!autotopagnosia,!or!poor!knowledge!of!one’s!own!topography.!(autotopanomia,!poor!naming!of!one’s!own!topography)!!
!!?Speech'conveys'abstract'concepts,'some'of'them'quite'subtle.'Comprehension'of'the'more'subtle,'figurative'aspects'of'speech'involves'the'right'hemisphere.'Judging'the'moral'of'Aesop’s'fables'activated'regions'of'the'right'hemisphere.'Comprehension'of'metaphors'such'as'green'lung'of'the'city'(that'is,'a'park)'activated'the'right'superior'temporal'cortex.''
12. Autotopagnosia!Inability!to!name!body!parts!or!to!identify!body!parts!that!another!person!names.!!BThis!disorder!is!called!autotopagnosia!or!poor!knowledge!of!one’s!own!topography.!(poor!naming!of!one’s!own!topography)!BDamage!to!part!of!the!association!cortex!of!the!left!parietal!lobe!can!produce!an!inability!to!name!body!parts.!!BPeople!who!can!otherwise!converse!normally!cannot!reliably!point!to!their!elbow,!knee,!or!cheek!when!asked!to!do!so!and!cannot!name!body!parts!when!the!examiner!points!to!them.!!BHowever,!they!have!no!difficulty!understanding!the!meaning!of!other!words.!BThis!is!about!memory.(
!Repetition:(Conduction(Aphasia((People!with!transcortical!sensory!aphasia!can!repeat!what!they!hear!suggests!that!there!is!a!direct!connection!between!Wernicke’s!area!and!Broca’s!area!–and!there!is:!the!arcuate(fasciculus.!(
13. Arcuate(fasciculus!A!bundle!of!axons!that!connects!Wernicke’s!area!with!Broca’s!area;!damage!causes!conduction!aphasia.!!BThis!bundle!of!axons!appears!to!convey!information!about!the!sounds!of!words!but!not!their!meanings.!(
(14. Conduction(aphasia!An!aphasia!characterized!by!an!inability!to!
repeat!words!that!are!heard!but!the!ability!to!speak!normally!and!comprehend!the!speech!of!others.!!BPeople!with!conduction!aphasia!can!repeat!speech!sounds!that!they!hear!only!if!these!sounds!have!meaning.!They!are!unable!to!repeat!nonwords!such!as!blayngge.!They!could!repeat!a!meaningful!threeBword!phrase!but!not!three!unrelated!words.!!BOpposite!transcortical!sensory!aphasia.!!BWhen!you!say!car,!they!cannot!repeat,!but!they!know!what!car!is,!so!they!can!say!it!is!machine!that!people!drive!it!to!go!somewhere.!(
!!BSpeech!and!meaning!is!different!things.!!BThe!symptoms!of!transcortical'sensory'aphasia!and!conduction'aphasia!lead!to!the!conclusion!that!there!are!pathways!connecting!the!speech!mechanisms!of!the!temporal!lobe!with!those!of!the!frontal!lobe.!The!direct!pathway!though!the!arcuate!fasciculus!simply!conveys'speech'sounds!from!Wernicke’s!area!to!Broca’s!area.!We!use!this!pathway!to!repeat!unfamiliar!words!–for!example,!when!we!are!learning!a!foreign!language!or!a!new!word!in!our!own!language!or!when!we!are!trying!to!repeat!a!nonwords!such!as!blaynge.!!The!second!pathway,!between!the!posterior!language!area!and!Broca’s!area,!is!indirect!and!is!based'on'the'meaning'of'words,!not!on!the!sounds!they!make.!When!patients!with!conduction!aphasia!hear!a!word!or!a!sentence,!the!meaning!of!what!they!hear!evokes!some!sort!of!image!related!to!that!meaning.!They!are!then!able!to!describe!that!image,!just!as!they!would!put!their!own!thoughts!into!words.!Of!course,!the!words!they!choose!might!not!be!the!same!as!the!ones!used!by!the!person!who!spoke!to!them.!!!BThe!symptoms!of!conduction!aphasia!indicate!that!the!connection!between!Wernicke’s!area!and!Broca’s!area!appears!to!play!an!important!ole!in!shortBterm!memory!of!words!and!speech!sounds!that!have!just!been!heard.!Presumably,!rehearsal!of!such!information!can!be!accomplished!by!“talking!to!ourselves”!inside!our!head!without!actually!having!to!say!anything!aloud.!Imaging!ourselves!saying!the!word!activates!the!region!of!Broca’s!area,!whereas!imaging!that!we!are!hearing!it!activates!the!auditory!association!area!of!the!temporal!lobe.!These!two!regions,!connected!by!means!of!the!arcuate!fasciculus!circulate!information!back!and!forth,!keeping!the!shortBterm!memory!alive.!Baddeley!(1993)!refers!to!this!circuit!as!the!phonological!loop.!BWe!do!use!Borca’s!area!when!we!talk!to!ourselves.!!!
!
Memory(of(Words:(Anomic(Aphasia!BAnomia,!in!one!form!or!other,!is!a!hallmark!of!aphasia.!!BHowever,!one!category!of!aphasia!consists!of!almost!pure!anomia,!the!other!symptoms!being!inconsequential.!!BSpeech!of!patients!with!anomic!aphasia!is!fluent!and!grammatical,!and!their!comprehension!is!excellent,!but!they!have!difficulty!finding!the!appropriate!words.!!BThey!often!employ!circumlocutions!to!get!around!missing!words.!!BAnomic!aphasia!is!different!from!Wernicke’s!aphasia.!People!with!anomic!aphasia!can!understand!what!other!people!say,!and!what!those!with!anomic!aphasia!say!makes!perfect!sense,!even!if!they!often!choose!roundabout!ways!to!say!it.!!BAnomia!has!been!described!as!partial!amnesia!for!words.!It!can!be!produced!by!lesions!in!either!the!anterior!or!posterior!regions!of!the!brain,!but!only!posterior!lesions!produce!a!fluent!anomia.!!BThe!most!likely!location!of!lesions!that!produce!anomia!without!the!other!symptoms!of!aphasia,!such!as!comprehension!of!!!
15. Circumlocution!A!strategy!by!which!people!with!anomia!find!alternative!ways!to!say!something!when!they!are!unable!to!think!of!the!most!appropriate!word.!(literally,!“speaking!in!a!roundabout!way”)(
!BThe!patient!with!anomic!aphasia!seemed!to!have!more!difficulty!finding!nouns!than!other!types!of!words.!While!she!is!telling!something,!she!made!almost!no!errors!in!finding!verbs.!!BSeveral!studies!have!found!that!anomia!for!verbs!(averbia)!is!caused!by!damage!to!the!frontal!cortex,!in!and!around!Broca’s!area.!The!frontal!lobe!are!devoted!to!planning,!organizing,!and!executing!actions,!so!it!should!not!surprise!us!that!they!are!involved!in!the!task!of!remembering!the!names!of!action.!!BSeveral!functional!imaging!studies!have!confirmed!the!importance!of!Broca’s!area!and!the!region!surrounding!it!in!the!production!of!verbs.!!In!a!study,!subjects!read!verbs!that!related!to!movements!of!different!parts!of!the!body.!For!example,!bite,!slap,!kick!involve!movements!of!the!face,!arm,!leg.!The!investigators!found!that!when!the!subjects!read!a!verb,!they!saw!activation!in!the!regions!of!the!motor!cortex!that!controlled!the!relevant!part!of!the!body.!!BAnother!study!found!that!hearing!sentences!that!involved!hand!movements!(such!as!turning!the!key)!activated!the!hand!region!of!the!motor!cortex,!and!that!hearing!sentences!that!involved!foot!movements!(such!as!stepping!on!the!grass)!activated!the!foot!region.!Presumably,!thinking!about!particular!actions!activated!regions!that!control!these!actions.!!!Aphasia(in(Deaf(People!BSeveral!studies!have!found!a!linkage!between!speech!ad!hand!movements,!which!supports!the!suggestion!that!the!spoken!language!of!presentBday!humans!evolved!from!hand!gestures.!!(BDeaf!community!involves!another!medium:!sign!language.!Sign!language!is!expressed!manually,!by!movements!of!the!hands.!!BBroca’s!area!was!activated!when!people!observed!and!imitated!finger!movements.!!BDeaf!people!use!Broca’s!area!while!using!their!sign!language!(hand!movements!etc).!!BBut!in!normal!people!body!movements!or!hand!movements!is!controlled!by!motor!cortex.!!BAs!it!mentioned!earlier,!mirror!neurons!become!active!when!we!see!or!perform!particular!grasping,!holding,!or!manipulating!movements.!Some!of!these!neurons!are!found!in!Broca’s!area.!Presumably,!these!neurons!plan!an!important!role!in!learning!to!mimic!another!people’s!hand!movement.!!BWhen!the!experimenter!grasped!a!large!object,!the!subjects!opened!their!mouths!more!and!said!the!syllable!more!loudly!than!when!he!grasped!small!one.!These!results!suggest!that!the!region!of!the!brain!that!control!grasping!is!also!involved!in!controlling!speech!movements.!!BBecause!Broca’s!area!is!also!responsible!meaningful!movements!of!body!parts,!when!we!see!a!person!grasping!large!object,!our!mouth!will!open!largely,!and!if!we!see!a!person!grasping!small!object,!our!mouth!will!open!small.!!BDeaf!signers!produced!meaningful!signs;!increased!activity!was!seen!in!the!left!inferior!frontal!cortex!–the!region!of!Broca’s!area.!When!these!subjects!viewed!signs!made!by!others,!they!showed!increased!activity!in!the!left!superior!temporal!cortex.!Therefore,!sign!language,!like!auditory!and!written!language,!appears!to!rely!primarily!on!the!left!hemisphere!for!comprehension!and!expression.!A!study!had!both!deaf!and!hearing!subjects!sign!or!say!the!names!of!objects!they!were!shown.!Activation!was!seen!in!the!primary!visual!cortex!and!visual!association!cortex!(inferior!temporal!cortex)!and!in!Broca’s!area!in!both!deaf!and!hearing!subjects.!In!addition,!two!regions!of!the!parietal!cortex!were!specifically!activated!in!deaf!signers,!presumably!because!of!the!spatiallyBoriented!movements!these!subjects!made.!!
Prosody:(Rhythm,(Tone,(and(Emphasis(in(Speech((BWhen!we!speak,!we!do!not!merely!utter!words.!Our!speech!has!a!regular!rhythm!and!cadence;!we!give!some!words!stress,!and!we!vary!the!pitch!of!our!voice!to!indicate!phrasing!and!to!distinguish!between!assertions!and!questions.!!BIn!addition!we!can!impart!information!about!our!emotional!state!through!the!rhythm,!emphasis,!and!the!tone!of!our!speech.!These!rhythmic,!emphatic,!and!melodic!aspects!of!speech!are!referred!to!as!prosody.!!
16. Prosody!The!use!of!changes!in!intonation!and!emphasis!to!convey!meaning!in!speech!besides!that!specified!by!the!particular!words;!an!important!means!of!communication!of!emotion.!(
BJust!as!the!lesions!that!produce!Broca’s!aphasia!destroy!grammar,!they!also!severely!disrupt!prosody.!In!patients!with!Broca’s!aphasia,!articulation!is!so!labored!and!words!are!uttered!so!slowly!that!there!is!little!opportunity!for!the!patient!to!demonstrate!and!rhythmic!elements;!and!because!of!the!relative!lack!of!function!words,!there!is!little!variation!in!stress!or!pitch!of!voice.!!BProsody!is!a!special!function!of!the!right!hemisphere.!This!function!is!undoubtedly!related!to!the!more!general!role!of!this!hemisphere!in!musical!skills!and!the!expression!and!recognition!of!emotions:!Production!of!prosody!is!rather!like!singing,!and!prosody!often!serves!as!a!vehicle!for!conveying!emotion.!!BThe!meaningful!components!of!speech!primarily!activated!the!left!hemisphere.!The!prosodic!components!primarily!activated!the!right!hemisphere.!!(Stuttering((Kekeleme)!BStuttering!is!a!speech!disorder!characterized!by!frequent!pauses,!prolongations!of!sounds,!or!repetitions!of!sounds,!syllables,!or!words!that!disrupt!the!normal!flow!of!speech.!!BStuttering!which!appears!to!be!influenced!by!genetic!factors,!affects!approximately!1!percent!of!the!population!and!is!three!times!more!prevalent!in!men!than!women.!!BPeople!usually!start!stuttering!at!the!beginning!of!the!word/sentence.!The!reason!might!be!they!are!grammatically!planning,!it!is!about!planning.!!This!fact!suggests!that!stuttering!in!a!disorder!of!“selection,!initiation,!and!execution!of!motor!sequences!necessary!for!fluent!speech!production”.!BStuttering!is!not!a!result!of!abnormalities!in!the!neural!circuits!that!contain!the!motor!programs!for!speech.!!BFor!example,!stuttering!is!reduced!or!eliminated!when!a!person!reads!aloud!with!another!speaker,!signs,!or!reads!in!cadence!with!a!rhythmic!stimulus!!BThe!source!of!problem!may!be!faulty!auditory!feedback!from!sounds!of!the!stutterers’!own!speech.!Disruptions!in!the!normal!timing!of!activation!of!brain!regions!involved!in!speech!production.!!BDelayed!auditory!feedback!interferes!with!the!speech!of!most!fluent!speakers!but!actually!facilitates!the!speech!of!many!people!who!stutter.!!BDelayed!auditory!feedback!is!a!procedure!in!which!person!wearing!headphones!tries!to!speak!normally!while!hearing!his!or!her!own!voice,!which!has!been!electronically!delayed,!usually!by!50B200msec.!!!Effects!of!Therapy!for!Stuttering!!!
Disorder( Ares(of(Lesion((Spontaneous(
Speech(Comprehension( Repetition(Naming(
Broca’s!Aphasia!
Frontal!cortex!rostral!to!base!of!primary!motor!cortex!(Broca’s!are)!
Non!Bfluent!
Good! Poor! Poor!
Wernicke’s!Aphasia!
Posterior!portion!of!superior!temporal!gyrus!(Wernicke’s!area)!and!posterior!language!area!
Fluent! Poor! Poor! Poor!
Transcortical!Sensory!Aphasia!!
Posterior!language!area!Fluent! Poor! Good! Poor!
Pure!Word!Deafness!
Wernicke’s!area!or!its!connection!with!primary!auditory!cortex!
Fluent! Poor! Poor! Good!
Conduction!Aphasia!!
White!matter!beneath!parietal!lobe!superior!to!lateral!fissure!(arcuate!fasciculus)!
Fluent! Good! Poor! Good!
Anomic!Aphasia!
Various!parts!of!parietal!and!temporal!lobes!
Fluent! Good! Good! Poor!
Summary(! Two!regions!of!the!brain!are!especially!important!in!understanding!and!producing!speech.!Broca’s!area,!in!the!left!frontal!lobe!just!rostral!to!the!region!of!the!primary!motor!cortex!that!controls!the!muscles!of!speech,!is!involved!with!speech!production.!This!region!contains!memories!of!the!sequences!of!muscular!movements!that!produce!words,!each!of!which!is!connected!with!its!auditory!counterpart!in!the!posterior!part!of!the!brain.!Broca’s!aphasia!–which!is!caused!by!damage!to!Broca’s!area,!adjacent!regions!of!the!frontal!cortex,!and!underlying!white!matterB!consists!of!varying!degrees!of!agrammatism,!anomia,!and!articulation!difficulties.!! Wernicke’s!area,!in!the!posterior!superior!temporal!lobe,!is!involved!with!speech!perception.!The!region!just!adjacent!to!Wernicke’s!area,!which!I!have!called!the!posterior!language!area,!is!necessary!for!speech!comprehension!and!the!translation!of!thoughts!into!words.!Presumably,!Wernicke’s!area!contains!memories!of!the!sounds!of!words,!each!of!which!is!connected!through!the!posterior!language!area!with!circuits!that!contain!memories!about!the!properties!of!the!things!the!words!denote!and!with!circuits!that!are!responsible!for!pronouncing!the!words.!!! Damage!restricted!to!Wernicke’s!area!causes!pure!word!deafness!–loss!of!the!ability!to!understand!speech!without!loss!of!the!ability!to!talk,!read,!and!write.!Wernicke’s!aphasia,!caused!by!damage!to!Wernicke’s!area!and!the!posterior!language!area,!consists!of!poor!speech!comprehension,!poor!repetition,!and!production!of!fluent,!meaningless!speech.!!! Transcortical!sensory!aphasia,!caused!by!damage!to!the!posterior!speech!area,!consists!of!poor!speech!comprehension!and!production,!but!the!patients!can!repeat!what!they!hear.!Thus,!the!symptoms!of!Wernicke’s!aphasia!consist!of!those!of!transcortical!sensory!aphasia!plus!those!of!pure!word!deafness!(WA!=!TSA!+!PWD).!!! Feedback!from!mirror!neurons!that!are!activated!when!people!hear!the!speech!of!other!people!may!facilitate!speech!recognition.!The!right!hemisphere!plays!a!role!in!the!more!subtle,!figurative!aspects!of!speech.!!! The!fact!that!people!with!transcortical!sensory!aphasia!can!repeat!words!that!they!cannot!understand!suggests!that!there!s!a!direct!connection!between!Wernicke’s!area!and!Broca’s!area.!!Indeed,!there!is:!the!arcuate!fasciculus.!Damage!to!this!bundle!of!axons!produces!conduction!aphasia:!disruption!of!the!ability!to!repeat!exactly!what!was!heard!without!disruption!of!the!ability!to!comprehend!or!produce!meaningful!speech.!A!parallel!pathway,!consisting!of!an!anterior!and!a!posterior!bundle!that!connect!in!the!inferior!parietal!cortex,!may!be!responsible!for!the!ability!of!people!with!pure!conduction!aphasia!to!understand!and!paraphrase!what!they!hear.!!! The!meanings!of!words!are!our!memories!of!objects,!actions,!and!other!concepts!associated!with!them.!These!meanings!are!memories!and!are!stored!in!the!association!cortex,!not!in!the!speech!areas!themselves.!Anomic!aphasia,!caused!by!damage!to!the!temporal!or!parietal!lobes,!consists!of!difficulty!in!word!finding,!particularly!in!naming!objects.!Brain!damage!can!also!disrupt!the!“definitions”!as!well!as!the!“entries”!in!the!mental!dictionary;!damage!to!specific!regions!of!the!association!cortex!effectively!erases!some!categories!of!the!meanings!of!words.!Damage!to!Broca’s!area!and!surrounding!regions!disrupts!the!ability!to!name!actions!–to!think!of!appropriate!verbs.!The!right!hemisphere!plays!a!role!in!the!more!subtle,!figurative!aspects!of!speech.!!! The!left!hemisphere!plays!the!more!important!role!in!the!language!abilities!of!deaf!people!who!use!sign!language,!just!as!it!does!in!people!who!communicate!acoustically.!Gestural!language!may!have!been!the!precursor!to!vocal!speech;!mirror!neurons!in!Broca’s!area!are!activated!by!hand!movements.!!! Prosody!includes!changes!in!intonation,!rhythm,!and!stress!that!add!meaning,!especially!emotional!meaning,!to!the!sentences!that!we!speak.!The!neural!mechanisms!that!control!the!prosodic!elements!of!speech!appear!to!be!in!the!right!hemisphere.!!! Stuttering!appears!to!be!cause!by!abnormalities!in!neural!circuits!that!are!involved!in!feedback!and!planning!and!initiating!speech,!not!in!the!circuits!that!contain!the!motor!programs!for!articulation.!Functional!imaging!indicates!deficient!auditory!feedback!produced!by!the!stutterers’!own!voice.!Delayed!auditory!feedback,!which!impairs!the!speech!of!most!fluent!speakers,!often!facilitates!the!speech!of!stutterers.!!
DISRODERS(OF(READING(AND(WRITING!BReading!and!writing!are!closely!related!to!listening!and!talking;!thus,!oral!and!written!language!abilities!have!many!brain!mechanisms!in!common.!!
17. Pure(alexia!Loss!the!ability!to!read!without!loss!of!the!ability!to!write;!produced!by!brain!damage.!!BPure!alexia,!pure!word!blindness,!or!alexia!without!agraphia.!!BDejerine!(1892)!described!this!syndrome,!and!his!patient!had!lesion!in!the!visual!cortex!of!the!left!occipital!lobe!and!the!posterior!end!of!the!corpus!collosum.!!BThe!patient!could!still!write,!although!he!had!lost!the!ability!to!read.!!BIn!fact,!if!he!was!shown!some!of!his!own!writing,!he!could!not!read!it.!!BPatients!with!pure!alexia!cannot!read,!but!they!can!recognize!words!that!are!spelled!aloud!to!them,!so!they!have!not!lost!their!memories!of!the!spellings!of!words.!!BPure!alexia!is!obviously!a!perceptual!disorder;!it!is!similar!to!pure!word!deafness,!except!that!the!patient!has!difficulty!with!visual!input,!not!auditory!input.!!BThis!disorder!is!caused!by!lesions!that!prevent!visual!information!from!reaching!extrastriate!cortex!of!the!left!hemisphere.!!BFlow!of!visual!information!for!a!person!with!this!brain!damage:!Information!from!the!left!side!of!the!visual!field!is!transmitted!to!the!right!striate!cortex!(primary!visual!cortex)!and!then!to!regions!of!the!right!visual!association!cortex.!!From!there,!the!information!crosses!the!posterior!corpus!collosum!and!is!transmitted!to!the!left!visual!association!cortex,!where!it!is!analyzed!further.!!The!information!is!then!transmitted!to!speech!mechanisms!located!in!the!left!frontal!lobe.!Thus,!the!person!can!read!the!words!aloud.!!BBut,!lesion!of!the!corpus!collosum!prevents!visual!information!concerning!written!text!from!reaching!the!posterior!left!hemisphere.!Without!this!information,!the!patient!cannot!read.!!BFace!area!is!used!for!reading.!Recognizing!words.!(
((Toward(an(Understanding(of(Reading((Reading!involves!at!least!two!different!processes:!!
18. Whole]word(reading!Reading!by!recognizing!a!word!as!a!whole;!“sight!reading”.!Direct!recognition!of!the!word!as!a!whole!and!sounding!it!out!letter!by!letter.!!BWhen!we!see!a!familiar!word,!we!normally!recognize!and!pronounce!it.!This!process!is!known!as!wholeBword!reading.!(With!very!long!words,!we!might!instead!perceive!segments!of!several!letters!each).!(
19. Phonetic(reading!Reading!by!decoding!the!phonetic!significance!of!letter!strings;!“sound!reading”.!!BThe!second!method!of!reading,!which!we!use!for!unfamiliar!words,!requires!recognition!of!individual!letters!and!knowledge!of!the!sounds!they!make.!!BIf!you!did!not!recognize!the!words,!because!you!never!saw!before,!so!you!had!to!figure!out!how!to!pronounce!the!words.!!BWhen!we!see!familiar!word,!we!normally!recognize!it!as!a!whole!and!pronounce!it.!!If!we!see!unfamiliar!word!or!a!pronounceable!nonword,!we!must!try!to!read!it!phonetically.!!BGenerally!in!Turkish!and!Italian!we!commonly!use!phonetic!language,!we!spell!them!out.!!BWhen!we!read!unknown!words!we!use!phonetic!reading.!(
((
BDyslexia!means!“faulty!reading”.!Acquired!dyslexias!are!those!caused!by!damage!to!the!brains!of!people!who!already!know!how!to!read.!In!contrast,!developmental!dyslexias!refer!to!reading!difficulties!that!become!apparent!when!children!are!learning!to!read.!!!Investigators!have!reported!several!types!of!acquired!dyslexias:!Surface(dyslexia,(phonological(dyslexia,(and(direct(dyslexia.((
20. Surface(dyslexia!A!reading!disorder!in!which!a!person!can!read!words!phonetically!but!has!difficulty!reading!irregularly!spelled!words!by!the!wholeBword!method.!!BSurface!dyslexia!is!a!deficit!in!wholeBword!reading.!!BThe!term!surface!reflects!the!fact!that!people!with!this!disorder!make!errors!related!to!the!visual!appearance!of!the!words!and!to!pronunciation!rules,!not!to!the!meaning!of!the!words,!which!is!metaphorically!“deeper”!than!the!appearance.!!BBecause!patients!with!surface!dyslexia!have!difficulty!recognizing!words!as!a!whole,!they!are!obliged!to!sound!them!out.!!BThus,!they!can!easily!reads!words!with!regular!spelling!such!as!hand,!table!or!chin.!!BBut!they!have!difficulty!reading!words!with!irregular!spelling,!such!as!sew,!pint,!yacht.!–!They!read!them!yatchet!(not!as!yaat),!because!they!don’t!read!effectively,!so!they!don’t!understand!their!meanings.!!In!fact,!they!may!read!these!words!such!as!sue,!pint,!yatchet.!!BThey!have!no!difficulty!reading!pronounceable!nonwords!such!as!glab,!trisk,!and!chint.!!BBecause!people!with!surface!dyslexia!cannot!recognize!whole!words!by!their!appearance,!they!must,!in!effect,!listen!to!their!own!pronunciation!to!understand!what!they!are!reading.!!BAlso,!if!the!word!is!one!member!of!a!homophone!(eşsesli),!it!will!be!impossible!to!understand!it!unless!it!is!read!in!the!context!of!a!sentence.!For!example,!if!you!hear!the!single!word!“pair”!without!additional!information,!you!cannot!know!whether!the!speaker!is!referring!to!pair,!pear,!or!pare.!It!could!be!for!example!pair!of!apple!to!be!understood!by!people!who!with!surface!dyslexia.!!BIf!they!read!the!word!pint!and!pronounce!it!pint,!they!will!say!that!is!not!an!English!word!(which!it!is!not,!pronounced!that!way)!BEx:!Hakim.!We!use!phonological!reading!mostly!in!Turkish!because!we!not!simply!say!hakim,!we!say!actually!haaakim.!!(
(
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21. Phonological(dyslexia(A!reading!disorder!in!which!a!person!can!read!familiar!words!but!has!difficulty!reading!unfamiliar!words!or!pronounceable!nonwords.!!BThe!symptoms!of!phonological!dyslexia!are!opposite!those!of!surface!dyslexia:!People!with!this!disorder!can!read!by!the!wholeBword!method!but!cannot!sound!words!out.!!!BThus,!they!can!read!words!that!they!are!familiar!with!but!have!great!difficulty!figuring!out!how!to!read!unfamiliar!words!or!pronounceable!nonwords.!!BPeople!with!phonological!dyslexia!may!be!excellent!readers!if!they!had!already!acquired!a!good!reading!vocabulary!before!that!brain!damage!occurred.!!BAntiestamblishmentarianism!–!the!only!way!to!read!this!word,!we!have!to!use!phonological!reading.!!!BGrab,!trisk!–!the!only!way!to!read!these!nonwords,!meaningless!words,!we!have!to!use!phonological!reading!because!we!have!never!seen!them!before,!we!are!not!familiar!to!them.!But!phonological!dyslexia!cannot!read!unfamiliar!words.!(
BWholeBword!reading!and!phonological!reading!involve!different!brain!mechanisms.!!BThe!process!of!whole!word!reading!follows!the!ventral!stream!of!the!visual!system!to!the!fusiform!gyrus,!located!on!the!base!of!the!temporal!lobe.!!(
22. Visual(word]form(area((VWFA)!A!region!of!the!fusiform!gyrus!on!the!base!of!the!temporal!lobe!that!plays!a!critical!role!in!wholeBword!recognition.!!BThis!region!is!also!involved!in!the!perception!of!faces!and!other!shapes!that!require!expertise!to!distinguish,!and!certainly!recognizing!whole!words!or!kanji!symbols!requires!expertise.!!BVWFA!quickly!recognize!words!written!in!different!typestyles,!fonts!or!CASES.!This!means!that!the!VWFA!can!recognize!whole!words!with!different!shapes;!certainly!chair!and!CHAIR!do!not!look!same.!!BDamage!to!the!VWFA!produces!surface!dyslexia;!that!is,!impairment!of!wholeBword!reading.!!BFusiform!Face!Area!is!responsible!for!recognizing!faces,!but!left!side!of!this!area!most!responsible!recognizing!letters.!!BWhen!VWFA!is!damaged,!it!is!surface!dyslexia.!(
(BPhonological!reading!appears!to!follow!the!dorsal!stream!to!the!region!around!the!junction!of!the!inferior!parietal!lobe!and!the!superior!temporal!lobe!(temporoparietal!cortex)!and!then!follows!a!fiber!bundle!from!this!region!to!the!inferior!frontal!cortex!–which!includes!Broca’s!area.!!BPhonological!reading!activates!the!left!temporoparietal!cortex!and!Broca’s!area.!!BSome!parts!of!the!visual!association!cortex!must!be!involved!in!perceiving!written!words.!For!instance,!visual!agnosia!is!a!perceptual!deficit!in!which!people!with!bilateral!damage!to!the!visual!association!cortex!cannot!recognize!objects!by!sight.!However,!people!with!visual!agnosia!can!still!read,!which!means!that!the!perceptual!analysis!of!objects!and!words!involves!at!least!some!different!brain!mechanisms.!!BCertainly,!the!ability!to!read!cannot!have!shaped!the!evolution!of!human!brain,!because!the!invention!of!writing!is!only!a!few!thousand!years!old.!Thus,!reading!and!object!recognition!use!brain!mechanisms!that!undoubtedly!existed!long!before!the!invention!of!writing.!!!!!
23. Direct(dyslexia(A!language!disorder!caused!by!brain!damage!in!which!the!person!can!read!words!aloud!without!understanding!them.!!BRecognizing!a!spoken!word!is!different!from!understanding!it.!!BFor!example,!patients!with!transcortical!sensory!aphasia!can!repeat!what!is!said!to!them!even!though!they!show!no!signs!of!understanding!what!they!hear!or!say.!!BThe!same!is!true!for!reading.!Direct!dyslexia!resembles!transcortical!sensory!aphasia,!except!that!the!words!in!question!are!written,!not!spoken.!!BPatients!with!direct!dyslexia!are!able!to!read!aloud!even!though!they!cannot!understand!the!words!they!are!saying.!(
BDyslexia!is!more!common!in!English.!!BFor!example,!a!bilingual!person!know!English!and!Japanese,!he!might!have!dyslexia!in!English!but!not!in!Japanese.!!!Subtle(Differences(in(written(words:!Unless!you!can!read!Arabic,!Hindi,!or!Mandarin,!you!will!probably!have!to!examine!these!words!carefully!to!find!the!small!differences.!However,!as!a!reader!of!English,!you!will!immediately!recognize!the!words!“car”!and!“ear”.!!Stimuli(Used(in(a(Test(of(Word(Recognition:!These!examples!of!stimuli!were!used!in!the!experiment!by!Vinckier!et!al.!Mouton!is!the!French!word!for!“sheep”.!If!we!don’t!know!Arabic,!Hindi!and!mandarin!we!cannot!differ!these!words!from!each!other,!but!if!we!are!expert!we!can!differ!them.!!If!you!cannot!differentiate!the!word!with!wholeBword!reading,!you!have!to!use!phonological!reading.!We!use!wholeBword!reading!when!we!are!expert!on!that!language.!!!BThese!words!activates!different!brain!areas.!!!BThese!findings!indicate!that!the!brain!regions!responsible!for!phonetic!reading!and!wholeBword!reading!are!each!independently!connected!with!brain!regions!responsible!for!speech.!!!Toward(an(Understanding(of(Writing((BWriting!depends!on!knowledge!of!the!words!that!are!to!be!written,!along!with!the!proper!grammatical!structure!of!the!sentences!they!are!to!form.!!BTherefore,!if!a!patient!is!unable!to!express!himB!or!herself!by!speech,!we!should!not!be!surprised!to!see!a!writing!disturbance!(dysgraphia)!as!well.!!BIn!addition,!most!cases!of!dyslexia!are!accompanied!by!dysgraphia.!!BOne!type!of!writing!disorder!involves!difficulties!in!motor!control—in!directing!the!movements!of!a!pen!or!pencil!to!form!letters!and!words.!Investigators!have!reported!surprisingly!specific!types!of!writing!disorders!that!fall!into!this!category.!!BOrganization!of!the!motor!aspects!of!writing!involved!the!dorsal!parietal!lobe!and!the!premotor!cortex.!BFor!example,!some!patients!can!write!numbers!but!not!letters,!some!can!write!uppercase!letters!but!not!lowercase!letters,!some!can!write!consonants!but!not!vowels,!some!can!write!cursively!but!cannot!print!uppercase!letters,!and!others!can!write!letters!normally!but!have!difficulty!placing!them!in!an!orderly!fashion!on!the!page.!BMany!regions!of!the!brain!are!involved!in!writing.!For!example,!damage!that!produces!various!forms!of!aphasia!will!produce!impairments!in!!writing!that!are!similar!to!those!seen!in!speech.!!BOrganization!of!the!motor!aspects!of!writing!involves!the!dorsal!parietal!lobe!and!the!premotor!cortex.!These!regions!(and!the!primary!motor!cortex,!of!course)!become!activated!when!people!engage!in!writing,!and!damage!to!these!regions!impairs!writing.!!BA!functionalBimaging!study!by!Rijntjes!et!al.!(1999)!had!people!sign!their!names!with!either!their!index!finger!or!their!big!toe.!!BIn!both!cases,!doing!so!activated!the!premotor!cortex!that!controlled!movements!of!the!hand.!!BThis!finding!suggests!that!when!we!learn!to!make!a!complex!series!of!movements,!the!relevant!information!is!stored!in!regions!of!the!motor!association!cortex!that!control!the!part!of!the!body!that!is!being!used!but!that!this!information!can!be!used!to!control!similar!movements!in!other!parts!of!the!body.!!
BLongcamp!et!al.!(2005)!found!that!simply!looking!at!alphabetical!characters!activated!the!premotor!cortex:!on!the!left!side!in!rightBhanded!people!and!on!the!right!side!in!leftB!handed!people.!!
!BA!more!basic!type!of!writing!disorder!involves!problems!in!the!ability!to!spell!words,!as!opposed!to!problems!with!making!accurate!movements!of!the!fingers.!!BLike!reading,!writing!(or,!more!specifically,!spelling)!involves!more!than!one!method.!The!first!method!is!related!to!audition.!!BWhen!children!acquire!language!skills,!they!first!learn!to!recognize!the!sounds!of!words,!then!learn!to!say!them,!then!learn!to!read,!and!then!learn!to!write!Undoubtedly,!reading!and!writing!depend!heavily!on!the!skills!that!are!learned!earlier.!!BFor!example,!to!write!most!words,!we!must!be!able!to!“sound!them!out!in!our!heads,”!!that!is,!to!hear!them!and!to!articulate!them!subvocally.!!BA!second!way!of!writing!involves!transcribing!an!image!of!what!a!particular!word!looks!like—copying!a!visual!mental!image.!!BHave!you!ever!looked!off!into!the!distance!to!picture!a!word!so!that!you!could!remember!how!to!spell!it?!!BSome!people!are!not!very!good!at!phonological!spelling!and!have!to!write!some!words!down!to!see!whether!they!look!correct.!!BThis!method!obviously!involves!visual!memories,!not!acoustical!ones.!!!BNeurological!evidence!supports!at!least!the!first!three!of!these!speculations.!Brain!damage!can!impair!the!first!of!these!methods:!phonetic!writing.!This!deficit!is!called!phonological(dysgraphia.!!
24. Phonological(dysgraphia(A!writing!disorder!in!which!the!person!cannot!sound!out!words!and!write!them!phonetically.!BPeople!with!this!disorder!are!unable!to!sound!out!words!and!write!them!phonetically.!!BThus,!they!cannot!write!unfamiliar!words!or!pronounceable!nonwords,!such!as!antiestablishmentaniarism,!trisk.!!BThey!can,!however,!visually!imagine!familiar!words!and!then!write!them.!!BPhonological!dysgraphia!appears!to!be!caused!by!damage!to!regions!of!the!brain!involved!in!phonological!processing!and!articulation.!!BDamage!to!Broca’s!area,!the!ventral!precentral!gyrus,!and!the!insula!cause!this!disorder,!and!phonological!spelling!tasks!activate!these!regions.!?Dysgraphia'refers'to'a'writing'deficit,'just'as'dyslexia'refers'to'a'reading'deficit.'!(
25. Orthographic(dysgraphia!A!writing!disorder!in!which!the!person!can!spell!regularly!spelled!words!but!not!irregularly!spelled!ones.!!BOrthographic!dysgraphia!is!just!the!opposite!of!phonological!dysgraphia:!It!is!a!disorder!of!visually!based!writing.!!BPeople!with!orthographic!dysgraphia!can!only!sound!words!out;!thus,!they!can!spell!regular!words!such!as!care!or!tree,!and!they!can!write!pronounceable!nonsense!words.!BHowever,!they!have!difficulty!spelling!irregular!words!such!as!half!or!busy;!they!may!write!haff!or!bizzy.!!BOrthographic!dysgraphia!(impaired!phonological!writing),!like!surface!dyslexia,!is!caused!by!damage!to!the!VWFA!on!the!base!of!the!temporal!lobe.!!
!26. Developmental(dyslexia(A!reading!difficulty!in!a!person!of!normal!
intelligence!and!perceptual!ability;!of!genetic!origin!or!caused!by!prenatal!or!perinatal!factors.!!BSome!children!have!great!difficulty!learning!to!read!and!never!become!fluent!readers,!even!though!they!are!otherwise!intelligent.!Specific!language!learning!disorders,!called!developmental!dyslexias,!tend!to!occur!in!families,!a!finding!that!suggests!a!genetic!(and!hence!biological)!component.!!BThe!concordance!rate!of!monozygotic!twins!ranges!from!84!percent!to!100!percent,!and!that!of!dizygotic!twins!ranges!from!20!percent!to!35!percent.!!BLinkage!studies!suggest!that!the!chromosomes!1,2,6,15!and!18!may!contain!genes!responsible!for!different!components!of!this!disorder.(
BOne!common!deficit!is!deficient!phonological!awareness.!That!is,!people!with!developmental!dyslexia!have!difficulty!blending!or!rearranging!the!!sounds!of!words!that!they!hear.!Problems!such!as!these!might!be!expected!to!impair!the!ability!to!read!phonetically.!(!BDyslexic!children!also!tend!to!have!great!difficulty!in!writing:!They!make!spelling!errors,!they!show!poor!spatial!arrangements!of!letters,!they!omit!letters,!and!their!writing!tends!to!have!weak!grammatical!development.!BFor!example,!Shaywitz!et!al.!(2002)!had!seventy!dyslexic!children!and!seventyBfour!nondyslexic!children!read!words!and!pronounceable!nonwords.!The!researchers!found!significantly!different!patterns!of!brain!activation!in!the!two!groups.!A!child’s!reading!skill!was!positively!correlated!with!activation!of!the!left!VWFA.!!Hoeft!et!al.!(2007)!found!that!dyslexics!showed!decreased!activation!in!the!left!temporoparietal!cortex!(dorsal!to!the!region!identified!by!Shaywitz!et!al.)!and!in!the!VWFA.!They!also!saw!hyperactivation!of!the!left!inferior!frontal!cortex,!including!Broca’s!area.!!BPresumably,!the!activation!of!Broca’s!area!reflected!an!effort!to!decode!the!phonology!of!the!incomplete!information!being!received!from!the!poorly!functioning!regions!of!the!more!posterior!brain!regions!involved!in!reading.!((
SUMMARY(! Brain!damage!can!produce!reading!and!writing!disorders.!Pure!alexia!is!caused!by!lesions!that!produce!blindness!in!the!right!visual!field!and!that!destroy!fibers!of!the!posterior!corpus!collosum.!!! Research!in!the!past!few!decades!has!discovered!that!acquired!reading!disorders!(dyslexias)!can!fall!into!one!of!several!categories,!and!the!study!of!these!disorders!has!provided!neuropsychologist!and!cognitive!psychologists!with!thoughtBprovoking!information!that!has!helped!them!to!understand!the!brain!mechanisms!involved!in!reading.!!! Analysis!of!written!words!appears!to!begin!in!the!left!posterior!inferior!temporal!cortex.!Phonological!information!is!then!analyzed!by!the!temporoparietal!cortex!and!Broca’s!area,!whereas!wordBform!information!is!analyzed!by!the!visual!word!form!area,!located!in!the!fusiform!cortex.!Surface!dyslexia!is!a!loss!of!wholeBword!reading!ability.!Phonological!dyslexia!is!a!loss!of!the!ability!to!read!phonetically.!Reading!of!kana!(phonetic)!and!kanji!(pictographic)!symbols!by!Japanese!people!is!equivalent!to!phonetic!and!wholeBword!reading,!and!damage!to!different!parts!of!the!brain!interfere!with!these!two!forms!of!reading.!!! Direct!dyslexia!is!analogous!to!transcortical!sensory!aphasia;!the!patients!can!read!words!aloud!but!cannot!understand!what!they!are!reading.!Some!can!read!both!real!words!and!pronounceable!nonwords,!so!both!phonetic!and!wholeBwords!reading!can!be!preserved.!!! Brain!damage!can!disrupt!writing!ability!by!impairing!people’s!ability!to!form!letters!–or!even!specific!types!of!letters,!such!as!uppercase!or!lowercase!letters!or!vowels.!!! The!dorsal!parietal!cortex!appears!to!be!the!most!critical!region!for!knowledge!of!the!movements!that!produce!letters.!Other!deficits!involve!the!ability!to!spell!words.!!!! We!normally!use!two!different!strategies!to!spell!words:!phonetic!(sounding!the!word!out),!visual!(remembering!how!it!looks!on!paper).!!! Two!types!of!dysgraphia—phonological!and!orthographic—represent!difficulties!in!implementing!phonetic!and!visual!strategies,!respectively.!The!existence!of!these!two!disorders!indicates!that!several!different!brain!mechanisms!are!involved!in!the!process!of!writing.!In!addition,!some!patients!have!a!deficit!parallel!to!direct!dyslexia:!They!can!write!words!they!can!no!longer!understand.!!!! Developmental!dyslexia!is!a!hereditary!condition!that!may!involve!abnormal!development!!of!parts!of!the!brain!that!play!a!role!in!language.!Most!developmental!dyslexics!have!difficulty!with!phonological!processing—of!spoken!words!as!well!as!written!ones.!!!! FunctionalBimaging!studies!report!decreased!activation!of!a!region!of!the!left!occipitotemporal!and!temporoparietal!cortex!and!hyperactivation!of!Broca’s!area!may!be!involved!in!developmental!dyslexia.!!!!!!!!
!! Children!who!learn!to!read!languages!that!have!writing!with!regular!correspondence!between!spelling!and!pronunciation!(such!as!Italian)!are!much!less!likely!to!become!dyslexic!than!are!those!who!learn!to!read!languages!with!irregular!spelling!(such!as!English!or!French).!A!better!understanding!of!the!components!of!reading!and!writing!may!help!us!to!develop!effective!teaching!methods!that!will!permit!people!with!dyslexia!to!take!advantage!of!the!abilities!that!they!do!have.!!!!!
Reading(Disorder(Whole]word(Reading(
Phonetic(Reading(
Remarks(
Pure!Alexia! Poor! Poor! Can!write!
Surface!Dyslexia!! Poor! Good! !
Phonological!Dyslexia!! Good!Poor! !
Direct!Dyslexia!! Good!Good! Cannot!comprehend!words!
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Writing(Disorder(Whole]word(
Writing(
Phonetic(Writing(
Remarks(
Phonological!Dysgraphia! Good! Poor! !
Orthographic!Dysgraphia!! Poor! Good!! !
Semantic!Agraphia!!(direct!dysgraphia)! Good!
Good! Cannot!comprehend!words!
!By:!
Sbselman [email protected]
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