BASAL GANGLIA

Caudate Nucleus

•           C shaped structure

•           Lateral wall of lateral ventricle

•           Head, body and tail of caudate are parallel to anterior horn, body and inferior horn of the lateral ventricle

NUCLEI OF BASAL GANGLIA

Caudate nucleus

Lentiform nucleus

.Globus pallidus

.Putamen

Clastridium

( Striatum – caudate + Globus pallidus)

NEURAL PATHWAYS

PUTAMEN PATHWAY

CAUDATE PATHWAY

Functions of Basal Ganglia

1. Primitive cortex for voluntary muscular activity
2. Planning of movements
3. Control of complex & reflexive movements
4. Timing of movements
5. Speed of movements
6. Scale the intensity of movements
7. Sequencing of multiple successive movements
8. Sequencing of multiple parellel movements
9. Help cortex to execute subconscious but learned patterns
10. Inhibition of motor tone
11. Control the group movements for emotional  expression
12. Checks abnormal involuntary movements

GLOBUS PALLIDUS

–        Helps girdle movements

–        Locks the movements

PUTAMEN CIRCUIT

–           Controls subconscious execution of learned patterns of movement

CAUDATE CIRCUIT

–           Controls cognitive planning of sequential and parallel motor patterns to achieve specific conscious goals

Basal Ganglia Dysfunction

Rigidity – lead pipe or cog wheel

Akinesia or bradykinesia

Tremors at rest

Loss of associated movements

Loss of postural reflexes

Autonomic dysfunction

Involuntary movements

chorea – putamen dysfunction

hemiballismus – subthalamic

athetosis – globus pallidus

•         Dementia

•         CHOREA

•         Random uncontrolled flickering type movements occur one after the other

•         Huntingtons chorea (hereditary)

•         Lesion – caudate + putamen (GABA Neurons)

•         ATHETOSIS

•         Worms like movements of hand, neck and face

•         Lesion – lateral protion of globus pallidus

•         HEMIBALLISMS

•         Uncontrolled succession of violent movements of large area of the body.

•         Lesion – In the opposite hypothalamus

•         PARKINSNONS – (paralysis agitrans)

•         widespread destruction of substantial nigra

. Rigidity

. Tremors

. Akinesia

Lesion at  Substantia Nigra

Dopamine deficiency

Features

Rigidity – cog wheel

Rolling tremors- at rest

Akinesia or dyskinesia

Staccato speech

Shuffling gait