The basal ganglia consist of several nuclei found deep in the forebrain that are involved in movement. Dysfunction of specific regions can lead to different movement disorders. Parkinson's disease results from loss of dopamine-producing cells in the substantia nigra and causes hypokinetic movements. Huntington's chorea is associated with damage to the caudate and putamen and causes hyperkinetic chorea. Lesions of the subthalamic nucleus can cause hyperkinetic movements like hemi-ballismus due to overactivity of the direct pathway.

1. BASAL GANGLIA:
In correlation with
MOVEMENT DISORDERS
Dr. Pavithra Arunachaleeswaran
JR, Department of Psychiatry
SSIMS RC

2. BASAL GANGLIA: ganglia ?
• Ganglion – collection of neuronal cell bodies
outside the CNS
• Nuclei – collection of cell bodies within the CNS
surrounded by white matter.
• Basal ganglia is a misnomer  Basal Nuclei
• Basal Ganglia – collection of nuclei that are
found deep in the base of the forebrain.
• DEVELOPED – telencephalon  relate to the
functions of the cerebral cortex. Parts developed
from diencephalon and mesencephalon as well.

6. CAUDATE:
• C shaped structure divided
into
• HEAD
• BODY
• TAIL
• The caudate nucleus is
associated with the contour
of the lateral ventricles:
• HEAD – frontal horn
• TAIL – temporal horn
• Head continuous with
PUTAMEN
• TAIL terminates in
AMYGDALA

7. PUTAMEN
• Putamen in relation to the
brain:
• Medial to INSULA
• Bounded laterally by
EXTERNAL CAPSULE
• Medially by the GLOBUS
PALLIDUS separated by
lateral medullary lamina
• Continuous with the head of
the caudate nucleus
• Though continuity of
neurons with the caudate
nucleus, the 2 structures are
separated by fibers of
ANTERIOR LIMB OF
INTERNAL CAPSULE

8. GLOBUS PALLIDUS
• Derived from the
DIENCEPHALON
• Lentiform nucleus
• Medial to the PUTAMEN,
separated by the LATERAL
MEDULLARY LAMINA
• DIVISIONS:
• GLOBUS PALLIDUS INERNA
• GLOBUS PALLIDUS
EXTERNA
• Separated by the MEDIAL
MEDULLARY LAMINA

9. SUBTHALAMIC NUCLEUS
• Subthalamic nucleus (of
LUYS)
• Derived fron
DIENCEPHALON
• Inputs to Gpi. Important
sources of modulation of
basal ganglia
• Large celled nucleus –
• Dorsomedial to posterior
limb of internal capsule
• Dorsal to substantia nigra
• Ventral to thalamus
• Lateral and caudal to
hypothalamus

10. SUBSTANTIA NIGRA
• Substantia nigra
• In the midbrain
• Between tegmentum & basis
pedunculi
• MESENNCHEPHALIC origin
• COMPONENTS:
• Pars compacta
• dorsal cell-rich portion
• Pigmented (neuromelanin )
neurons = DOPAMINE
• Principal source of striatal
dopamine
• Pars Reticularis
• Ventral cell – sparse portion
• GABA Neurotransmitter

11. FUNCTION & CIRCUITARY
INITIATION OF
BEHAVIOR
SUPPRESSION OF
UNWANTED
BEHAVIOR

14. OCCULOMOTOR LOOP
PREFRONTAL LOOP

15. LIMBIC LOOP

16. DIRECT PATHWAY
INDIRECT PATHWAY
BODY MOVEMENT LOOP

17. INDIRECT
PATHWAY
DIRECT
PATHWAY

19. DOPAMINERGIC EFFECT

20. CHOLINERGIC EFFECT

22. CLINICAL IMPLICATION:
MOVEMENT
DISORDERS
HYPOKINETIC HYPERKINETIC

23. HYPOKINETIC
PARKINSONS DISEASE

25. HYPOKINETIC
PARKINSONS
DISEASE

26. BALLISMUS
CHOREA
ATHETOSIS
HYPERKINETIC

30. HYPERKINETIC
HUNTINGTON CHOREA

32. HYPERKINETIC
HEMIBALLISMUS
SUBTHALAMIC NUCLEUS LESION
Direct pathway still UP
Indirect pathway DOWN
MORE MOTOR ACTIVITY

34. SUMMARY: BASAL GANGLIA – MOVEMENT DISORDERS
DISORDER REGION
PARKINSON C/L SUBSTANTIA NIGRA
CHOREA
HUNTINGTON CHOREA
CAUDATE / PUTAMEN
STIATO-PALLIDAL CELLS
ATHETOSIS C/L PUTAMEN / THALAMUS
HEMIBALLISMUS C/L SUBTHALAMIC NUCLEUS

35. THANK YOU!