The basal ganglia are a group of nuclei located at the base of the forebrain that include the caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. They are involved in motor control and receive input from motor, association, and limbic areas of the cortex. The basal ganglia have direct and indirect pathways that use inhibitory neurotransmitters like dopamine and GABA to regulate movement. Disorders of the basal ganglia can cause either hyperkinetic or hypokinetic movement abnormalities and include Parkinson's disease, chorea, athetosis, Huntington's disease, and hemiballism.

1. Basal ganglia’s
connections
Presented by Irma
Suntoo
ROLL NUMBER 102

2. Table of content:
 Introduction.
 Components of Basal Ganglia.
 Connections.
 Functions.
 Disorders of Basal Ganglia.
 References.

3. Basal Ganglia
 Group of nuclei (masses of grey matter).
 Located at the base of forebrain and upper part
of brain stem, in the telencephalon area.

4. Components:
 (1) Caudate nucleus
 (2) Putamen
 (3)Globus pallidus
 (4) Subthalamic nucleus
 (5)Substantia Nigra
o The caudate nucleus and putamen are
together known as Corpus striatum.
o The putamen and globus pallidus are
together known as Lenticular Nucleus.

5.  Substantia nigra is divided into :
(1) dorsomedial pars compacta.
(2)ventrolateral pars reticulata.
 Globus pallidus is divided into:
(1) globus pallidus internal.
(2) gobus pallidus external.

7. Neurotransmitters:
 Inhibitory :
(1) Dopamine.
(2) GABA.
 Excitatory :
(1) Acetylcholine
(2) Glutamic acid
The direct pathway is excitatory.
The indirect pathway is inhibitory.

8. Connections:

9. Functions:
 Subthalamic nucleus is responsible for
planning and programming of movements.
 Caudate nucleus plays an important role in
cognitive processes.
 Globus pallidus provides appropriate muscle
tone for performance of skilled movements.
 Subs. Nigra is centre of coordination of those
impulses which are essential for skilled
movements.
 Basal ganglia is responsible for control of
normal auto. and associated movements
such as swinging of arms while walking.

10. Disorders:
Two types :
(1) Hyperkinetic
 Excessive and abnormal movements.
(2) Hypokinetic
 Difficulty in initiating movement. (Akinesia)
 Slowness of movement. (Bradykinesia)

11. Disorders of Basal ganglia
 (1) Parkinson’s disease:
 Both hypokinetic and hyperkinetic.
 Degeneration of D1 fibres of Subs. Nigra.
 Tremor,rigidity,festinant gait, mask-like face.

13.  (2) Chorea.
 Hypokinetic.
 Interruption of inhibitory pathway via caudate to
thalamus.
 Rapid, irregular involuntary movements of short
duration.
 Decreased muscle tone& muscular weakness.
 (3)Athetosis
 Hypokinetic.
 Lesion of lenticular nucleus.
 Continuous slow twisting movement.

14.  (4) Huntington’s Disease
 Damage to GABA-ergic and cholinergic
neurons that project to the putamen.
 Damage to this inhibitory pathway results in
hyperkinetic features such as slurred speech
& dementia.
(5) Hemiballism
 Hyperkinetic.
 Damage to subthalamic nucleus.
 Haemorrhage within the nucleus.

15. References:
 Class notes
 Ganong
 AK Jain
 Internet