Basal ganglia Caudate nucleus Lentiform nucleus Putamen Globus palidus Internal External Claustram Amygdaloid body CORPUS STRIATUM

Basal Ganglia (traditional concept) Corpus striatum lenticular nucleus putamen globus pallidus caudate nucleus Amygdaloid body

Basal Ganglia 3 2 1 3 2 1 4

Basal Ganglia 2 1 1 2 3 3

Neostriatum or striatum Paleostriatum or pallidum CORPOUS STRIATUM Neostriatum or striatum Dorsal Caudate nucleus putamen Ventral Nucleus accumbance Paleostriatum or pallidum Globus pallidus Substantia nigra inominate

Basal Ganglia Introduction Traditional Concepts of Basal Ganglia Corpus Striatum Caudate Nucleus Lenticular Nucleus Putamen Globus Pallidus Paleostriatum Pallidum Corpus Amygdaloideum Archistriatum Neostriatum Striatum

Lateral surface of basal ganglia 1. Putamen 2. Tail of caudate nucleus 3. Caudatolenticular gray bridge 4. Amygdaloid body 5. thalamus

Basal Ganglia Connections Input Portion STRIATUM (Caudate Nucleus and Putamen) Output Portion 1. PALLIDUM (Globus Pallidus) 2. SNr (Substantia Nigra, Pars Reticulata)

Basal Ganglia Connections STRIATUM Afferents from 1. Cerebral Cortex [Corticostriatal Projection] 2. Thalamus (CM-PF complex) [Thalamostriatal Projection] 3. SNc (Substantia Nigra, pars compacta), Ventral Tegmental Area (VTA, A10) and A8(Retrorubral Area) [Nigrostriatal Projection] 4. Dorsal Raphe Nucleus (B6, B8) [Raphestriatal Projection] 5. Amygdaloid Nuclear Complex [Amygdalostriatal Projection] Efferents to 1. Pallidum (GPi & GPe) [Striopallidal Projection] 2. SNr [Strionigral Projection] 3. SNc from striosome

An oblique section through the diencephalon and basal ganglia An oblique section through the diencephalon and basal ganglia. Abbreviations: A8, 9, 10, dopaminergic cell groups; AL, ansa lenticularis; CL, centrolateral nucleus of thalamus; cm, centromedian nucleus of thalamus; EX, external pallidal segment; FS, fasciculus subthalamicus; H, H1, H2, subthalamic fields of Forel; ICV, internal cerebral veins in the transverse fissure; INT, internal pallidal segment; ITA, interthalamic adhesion; MFB, median forebrain bundle; SLIC, sublentiform internal capsule; 3, 3rd ventricle.

Connections of the striatum Connections of the striatum. The major afferent projections to the striatum are shown on the left and major efferent projections from the striatum on the righ

Major interconnections of the basal ganglia.

Input-Output Relationship of Basal Ganglia 1. striopallidal fiber 2. strionigral fiber 3. strionigral fiber from striosome to SNc 4. ventrostrio- ventro-pallidal fiber

Basal Ganglia Connections PALLIDUM (Globus Pallidus) Afferents from 1. Striatum [Striatopallidal Projection] 2. STN <GPi & GPe> [Subthalamopallidal Projection] Efferents to 1. Thalamus (VLo, VApc, CM) <GPi> [Pallidothalamic Projection] 2. STN <GPe> [Pallidosubthalamic Projection] SNr (Substantia Nigra, Pars Reticulata) Afferents from Striatum [Striatonigral Projection] 1. Thalamus (VLm, VAmc, MD) [Nigrothalamic Projection] 2. Brain Stem Nucleus: Tectum (Superior Colliculus) & Pedunculopontine Nucleus (PPN)

Basal Ganglia Connections Pallidothalamic Fibers from GPi to VLo, VApc, CM Ansa Lenticularis from outer (lateral) portion of GPi fibers sweep ventromedially and rostrally around the posterior limb of the internal capsule enters Forel’s field H Lenticular Fasciculus from inner (medial) portion of GPi perforate internal capsule enters Forel’s field H2 Thalamic fasciculus ansa lenticularis, lenticular fasciculus and cerebellothalamic fibers Forel’s field H1

Basal Ganglia syndromes Hyperkinetic Chorea Athetosis Ballism Dystonia tourrette Hypokinetic Parkinsonism پارکينسون : رفت R: Rigidity A: Akinasia F: Flex Posture, falling-freezing T: Tremor

Basal Ganglia Functional Consideration 1. Selection of “Preprogramed (learned) motor plans” Basal Gangla Circuit ---- Selection Mechanism Selection Inability -------- Akinesia and Hypokinesia Faulty Selection ----------- Hyperkinesia 2. Generation (learning) of motor programs Programming of several motor fragments into complex motor routines Cerebral Palsy ------------- Disordered motor program

SYDENHAM’S CHOREA Clinical Feature - Complication of Rheumatic Fever - Fine, disorganized , and random movements of extremities, face and tongue - Accompanied by Muscular Hypotonia - Typical exaggeration of associated movements during voluntary activity - Usually recovers spontaneously in 1 to 4 months Principal Pathologic Lesion: Corpus Striatum

Principal Pathologic Lesion: HUNTINGTON’S CHOREA Clinical Feature - Predominantly autosomal dominantly inherited chronic fatal disease (Gene: chromosome 4) - Insidious onset: Usually 40-50 - Choreic movements in onset - Frequently associated with emotional disturbances - Ultimately, grotesque gait and sever dysarthria, progressive dementia ensues. Principal Pathologic Lesion: Corpus Striatum (esp. caudate nucleus) and Cerebral Cortex

HEMIBALLISM Clinical Feature - Usually results from CVA (Cerebrovascular Accident) involving subthalamic nucleus - sudden onset - Violent, writhing, involuntary movements of wide excursion confined to one half of the body - The movements are continuous and often exhausting but cease during sleep - Sometimes fatal due to exhaustion - Could be controlled by phenothiazines and stereotaxic surgery Lesion: Subthalamic Nucleus

Disease of mesostriatal Parkinson’s Disease PD Disease of mesostriatal dopaminergic system normal Muhammad Ali in Alanta Olympic

Parkinson’s Disease - Paralysis Agitans Substantia Nigra, Pars Compacta (SNc) DOPAminergic Neuron Clinical Feature (1) Slowness of Movement - Difficulty in Initiation and Cessation of Movement

Parkinson’s Disease Paralysis Agitans Clinical Feature (2) Resting Tremor Parkinsonian Posture Rigidity-Cogwheel Rigidity