BASAL GANGLIA ATAUBASAL NUCLEI

Bagian dari Telensefalon Cerebrum Ensefalon

• Basal ganglia mrpkn bagian dari nuclei di Brain yang dihubungkan dgn cerebral cortex, thalamus dan brainstem.

• Pada mamalia, basal ganglia dihubungkan dgn berbagai fungsi: motor control, cognition, emotions, and learning

• Basal ganglia mengarah pada konsentrasi neural nuclei hanyahanya di perifer, ex: Autonomic Nervous System

Basal Ganglia         

sebagai pusat koordinasi yang penting terutama untuk mengontrol gerakan-gerakan yang ada kaitannya dengan gerakan otomatis.

Pengaturan tonus motorik tubuh dan gerakan-gerakan bertujuan kasar

The basal ganglia and cerebellum are large collections of nuclei that modify movement on a minute-to-minute basis. Motor cortex sends information to both, and both structures send information right back to cortex via the thalamus.

The output of the cerebellum is excitatory, while the basal ganglia are inhibitory.

The balance between these two systems allows for smooth, coordinated movement, and a disturbance in either system will show up as movement disorders.

Ganglia Basalis

• Ganglia basalis adalah massa yang terdiri dari sekumpulan inti-inti di substansia abu-abu pada bagian hemisfer otak, terdiri dari: nukleus caudatus, putamen, globus pallidus dan area bau-abu lain.

• Ganglia basalis menerima serabut-serabut nervus dari semua area di cerebral korteks, penting dalam gerakan motorik yang terampil dan prosesnya dalam jarak luas pada informasi kortikal.

• Ganglia basalis adalah kumpulan nukleus pada massa putih di cerebral korteks, terdiri dari: caudate, putamen, nucleus accumbens, globus pallidus, substantia nigra, subthalamic nucleus, and historically the claustrum and the amygdala.

• Note:

the claustrum and the amygdala do not really deal with movement, nor are they interconnected with the rest of the basal ganglia, so they have been dropped from this section.

Lesi pada ganglia basalis:

a. CORPUS STRIATUM KONTRALATERAL

HIPERKINESIA – HIPOTONIA HIPO / BRADIKINESIA

Korea (Hemikorea kontralateral)Korea (Hemikorea kontralateral), yaitu hipokinesiahipokinesia, yaitu tidak mampu Gerakan involunter mirip gerakan bergerak namun tonus otot masih adaTangan menari.

AtetosisAtetosis yaitu keadaan motorik dimana BradikinesiaBradikinesia, yaitu kelambatan berge-Jari tangan, lidah, kaki atau otot wajah gerak namun tonus otot masih adaTidak bisa diam sejenak

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b. NUKLEUS SUBTALAMIKUS KONTRALATERAL & KORPUS STRIATUM KONTRALATERAL

SINDROMA BALISTIK

BallismusBallismus, mirip gerakan DistoniaDistonia, sikap menetap hipertoni/ rigiditashipertoni/ rigiditas, tonus

Chorea tapi lebih kasar dari salah satu atetotik otot yang meningkat hebat, berupa hiperflexi melawan gerakan flexi-ex- tangan/ hiperextensi, tensi scr pasif hiperinversi kaki

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c. SUBSTANSIA NIGRA PARS KOMPAKTA &KORPUS STRIATUM KONTRALATERAL

SINDROMA HYPOKINESIA – HIPERTONIA (PARKINSON)

akinesiaakinesia, gerak lambat rigorrigor, otot tak dapat tremortremor, gerakan ritmik Meliputi pro/ retro/ relaksasi dan terjadi tanganLateropulsi Coghweel rigidity

tanpa parase

The five individual nuclei that make up the primate basal ganglia, along with their major subdivisions, are:

rostral • the striatum, which consists of

– putamen – caudate nucleus

• external segment of the globus pallidus (GPe) • internal segment of the globus pallidus (GPi)caudal • subthalamic nucleus (STN) • substantia nigra (SN)

– substantia nigra pars compacta (SNc) – substantia nigra pars reticulata (SNr) – substantia nigra pars lateralis (SNl)

Rostral section Middle section

Caudal section

Connectivity Diagram showing glutamatergic pathways as red, dopaminergic as magenta and GABA pathways as blue.

1. Striatum/ Corpus Striatum

• Striatum adl bagian subcortical telesephalon. Striatum adl input utama pada sistem ganglia basalis. Secara anatomis, striatum terdiri dari nukleus kaudatus dan putamen.

• the caudate, the putamen and the fundus striati, that ventral part linking the two precedings together ventrally to the inferior part of the internal capsule.

• caudate nucleus and putamen essentially induced by the internal capsule do not completely overlap with now accepted anatomo-functional subdivisions

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Corpus Striatum, meliputi:

Neostriatum : Nukleus kaudatus dan putamen

Paleostriatum: Globus pallidusatau palidum

Nukleus lentiformis/ lentikularis: putamen dan globus pallidus

http://en.wikipedia.org/wiki/Image:Telencephalon-Horiconatal.jpg

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Nukleus caudatus dan putamen bertang-gungjawab atas pengaturan pencetusan dan penghambatan gerakan-gerakan tubuh yang bertujuan kasar, tetapi yang dilakukan tanpa disadari oleh orang normal.

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Anatomy• The caudate nuclei are located near the center of the brain, sitting astride

the thalamus. There is a caudate nucleus within each hemisphere of the brain. Individually, they resemble a C-shape structure with a wider head at the front, tapering to a body and a tail. (Sometimes a part of the caudate nucleus is referred to as genu

• The head and body of the caudate nucleus form the part of the floor of the anterior horn of the lateral ventricle. After the body travels briefly towards the back of the head, the tail curves back toward the anterior, forming the roof of the inferior horn of the lateral ventricle. This means that a coronal (on the same plane as the face) section that cuts through the tail will also cross the body (or head) of the caudate nucleus.

• The caudate nucleus is related anatomically to a number of other structures. It is separated from the lenticular nucleus (made up of the globus pallidus and the putamen) by the anterior limb of the internal capsule. Together the caudate and putamen form the dorsal striatum

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• The caudate and putamen receive most of the input from cerebral cortex; in this sense they are the doorway into the basal ganglia. There are some regional differences: for example, medial caudate and nucleus accumbens receive their input from frontal cortex and limbic areas, and are implicated more in thinking and schizophrenia than in moving and motion disorders. The caudate and putamen are reciprocally interconnected with the substantia nigra, but send most of their output to the globus pallidus (see diagram below).

2. Globus pallidus

• Globus pallidus terbagi menjadi dua: globus pallidus externa (GPe) and globus pallidus interna (GPi). Keduanya menerima input dari kaudatus dan putamen, dan keduanya berkomunikasi atau berhubungan dengan Nukleus subthalamic.

• Jalurnya adalah GPi, akan tetapi yang mengirim penghambat utama output dari ganglia basalis kembali ke thalamus. GPi mengirimkan sedikit projection ke area midbrain (PPPa), dan agaknya untuk membantu di postural cintrol.

3. Nucleus accumbens(NAcc)

also known as the accumbens nucleus or as the nucleus accumbens septi is a collection of neurons within the forebrain. It is thought to play an important role in reward, laughter, pleasure, addiction, fear, and the placebo effect

the nucleus accumbens core and the nucleus accumbens shell

4. Substantia nigra

• Substansia nigra terbagi menjadi dua: substantia nigra pars compacta (SNpc) and substantia nigra pars reticulata (SNpr). SNpc menerima input dari kaudatus dan putamen, dan mengirim kembali informasi.

• SNpr menerima input dari kaudatus dan putamen tetapi mengirim informasinya diluar ganglia basalis untuk mengontrol kepala dan pergerakan mata.

• SNpc lebih terkenal, memproduksi dopamine, yang mana gerakan mendadak pada pergerakan normal. Bila terjadi degenerasi SNpc akan mengalami syndrom Parkinson, tetapi masih bisa dilakukan perawatan dengan pemberian dopamine peroral sebagai prekursor.

5. Subthalamic nucleus

Lokasi nukleus subthalamic di ventral thalamus, dorsal substansia nigra dan medial internal capsule. StructureThe principal type of neuron found in the subthalamic nucleus has rather long dendrites devoid of spines. The dendritic arborizations are ellipsoid, replicating in smaller dimension the shape of the nucleus. However, the number of neurons increases across evolution as well as the external dimensions of the nucleus. Due to the bending of dendrites at the border, the subthalamic nucleus is a close nucleus, able to receive information only in its space. The principal neurons are glutamatergic, which give them a particular functional position in the basal ganglia system. FunctionFungsinya tidak diketahui, tetapi menurut teori zaman sekarang adalah sebagai komponen pengontrol sistem ganglia basalis yang mana bisa melakukan pilihan pergerakan. Bila terjadi disfungsi STN akan menunjukkan penurunan impulsiviti pada individu yang dikenal dengan “two equally rewarding stimuli”.

6. Amygdala

Function:- Emotional learning - Memory modulation

Anatomical subdivisionsThe regions described as amygdalae encompass several nuclei with distinct functional traits. Among these nuclei are the basolateral complex, the centromedial nucleus and the cortical nucleus. The basolateral complex can be further subdivided into the lateral, the basal and the accessory basal nuclei

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Connections

The amygdalae send impulses to the hypothalamus for important activation of the sympathetic nervous system, to the thalamic reticular nucleus for increased reflexes, to the nuclei of the trigeminal nerve and facial nerve for facial expressions of fear, and to the ventral tegmental area, locus coeruleus, and laterodorsal tegmental nucleus for activation of dopamine, norepinephrine and epinephrine.[4]

http://en.wikipedia.org/wiki/Image:Constudoverbrain.gif