Anatomy of the basal ganglia By Dr. Mohammed Ahamed Abuelnor Department Of Anatomy

3. Describe the important connections of corpus striatum. Objectives 1. Describe the subdivisions of basal ganglia and state the function of each of them. 2. Understand the important relations of corpus striatum (caudate & lentiform nuclei). 3. Describe the important connections of corpus striatum. 4. Describe briefly the main effects in cases of lesion of basal ganglia. اسم ورقم المقرر – Course Name and No. 7/6/2019

Basal ganglia The basal ganglia is a collection of gray matter in the cerebrum including the: corpus striatum, Amygdala and claustrum. Has importantconnections with other regions of the brain, particularly: Thalamus, Subthalamic nuclei, Red nucleus and Substantia nigra Important in coordinating movement. اسم ورقم المقرر – Course Name and No. 7/6/2019

Components of Basal Ganglia Corpus Striatum Striatum ----- Caudate Nucleus & Putamen Pallidum ----- Globus Pallidus (GP) Substantia Nigra اسم ورقم المقرر – Course Name and No. 7/6/2019

Basal ganglia

TERMINOLOGIES Neurological structure Basal nuclei Corpus striatum Caudate nucleus + lentiform nucleus Amygdala Amygdaloid nucleus Claustrum Claustrum Neostriatum Caudate nucleus + putamen Paleostriatum Globus pallidus Lentiform nucleus Globus pallidus + putamen

Basal ganglia ANTERIOR Caudate nucleus Globus pallidus Insula HORIZONTAL SECTION ANTERIOR Caudate nucleus Globus pallidus Insula Lentiform nucleus Putamen Claustrum POSTERIOR اسم ورقم المقرر – Course Name and No. 7/6/2019

Basal ganglia CORONAL SECTION SUPERIOR Caudate nucleus Thalamus Lentiform nucleus Claustrum Amygdala INFERIOR اسم ورقم المقرر – Course Name and No. 7/6/2019

Caudate nucleus C-shaped Head, body,tail Large head,tapering curved tail Head-frontal lobe Tail-occipital lobe End of tail-temporal lobe -terminates in amygdaloid nucleus (roof of inf horn of lateral ventricle) thalamus Caudate Lentiform Putamen Globus pallidus Amygdaloid

Lentiform nucleus Wedge-shaped Internal capsule External capsule Horizontal section ANT Wedge-shaped Lateral Internal capsule Caudate n ventricle- Ant horn Putamen External capsule Third ventricle Globus pallidus Thalamus Extreme capsule Claustrum Lateral ventricle- Post horn Lateral and medial medullary lamina اسم ورقم المقرر – Course Name and No. 7/6/2019 POST

Lentiform nucleus Putamen – lateral medullary lamina – Globus Pallidus Lat GP – medial medullary lamina – Med GP thalamus Caudate Lentiform Putamen Globus pallidus Amygdaloid

Amygdaloid nucleus Caudate thalamus Lentiform Putamen Globus pallidus Temporal lobe - Roof of inf horn of lateral ventricle اسم ورقم المقرر – Course Name and No. 7/6/2019

Substantia nigra Subthalamic nuclei Caudate n Putamen Globus pallidus Thalamus Subthalamic nuclei Substantia nigra Coronal section اسم ورقم المقرر – Course Name and No. 7/6/2019

Function motor activity muscle tone organisation of movement Cerebral cortex, basal ganglia, cerebellum and thalamus motor activity muscle tone organisation of movement What type ? How to perform? -cerebral cortex -basal ganglia+cerebellum Assist in regulation-thalamus

Cerebral cortex Corticospinal Corticobulbar Corticostriatal excitatory Direct Indirect inhibitory Striatonigral Striatopallidal Lat pallidal inhibitory Subthalamic N inhibitory Med pallidal Activate neurone Disinhibit neurone thalamus Facilitate movement Inhibit unwanted movement

Connections Caudate nucleus Putamen receive input Globus pallidus – output leaves اسم ورقم المقرر – Course Name and No. 7/6/2019

Connections of striatum Connections of globus pallidus Caudate nucleus & putamen – input Receive afferent - cerebral cortex, thalamic nuclei, subs nigra Efferent – globus pallidus, subs nigra 2 segments – med & lat Med & subs nigra – output Receive afferent – striatum, subthalamic nucleus Efferent Lat – subthalamic N Med – thalamus– motor areas

اسم ورقم المقرر – Course Name and No. 7/6/2019

Basal Ganglia (Prefronatal Complex Loop) Connections Primary (M I) STRIATUM Nucleus) Prefrontal Motor Area Association (Caudate Cortex pyramidal tract SNr THALAMUS (Substantia Nigra, (VLm, VAmc, MD) pars reticulata) LMN

Orbitofrontal Cortex Anterior Cingulate Gyrus Hippocampal Formation Basal Ganglia (Limbic Loop) Connections Ventral Striatum Orbitofrontal Cortex Anterior Cingulate Gyrus Hippocampal Formation Caudate Nucleus Ventral Pallidum GPi, SNr THALAMUS (VAmc, MD) اسم ورقم المقرر – Course Name and No. 7/6/2019

اسم ورقم المقرر – Course Name and No. 7/6/2019

Disease of basal ganglia Change in muscle tone Abnormal involuntary movement Parkinsonism Effect on the opposite side Degeneration of dopamine-producing cells in substantia nigra-depletion of dopamine in striatum Resting tremor Rigidity – simultaneous contraction of flexors and extensors Hypokinesia = Slowness of movement – brake cannot be released No paralysis, ataxia

Disease of basal ganglia Huntington’s disease – hereditary disease of unwanted movements. It results from degeneration of the caudate and putamen, and produces continuous dance-like movements of the face and limbs -choreoathetosis Hemiballism - flailing movements of one arm and leg (one-sided), which is caused by damage (i.e., stroke) of the subthalamic nucleus.

References: Clinical Neuroanatomy by Richard S. Snell, 7th ed. Neuroanatomy by A.R. Crossman & D. Neary 3rd ed.