QS Study

Basal ganglia:

These are the collection of masses of gray matter situated within each cerebral hemisphere. They are a group of subcortical nuclei, of varied origin, in the brains of vertebrates, including humans, which are situated at the base of the forebrain and top of the midbrain. They are located deep within the cerebral hemispheres of the brain.

Formation: Its input structure, the striatum, receives a dense dopaminergic input that is critical for reinforcement learning and whose dysfunction contributes to the motor and cognitive pathologies.

(1) Corpus striatum, which consists of –

  1. Caudate nucleus &
  2. Lentiform nucleus, which has 2 parts: Putamen and Globus pallidus.

(2) Amygdaloid nucleus

(3) Claustrum.

basal ganglia 1

Fig: Basal Ganglia formation

The function of basal nuclei: Basal ganglia are important parts of the extrapyramidal system. Basal ganglia dysfunction is associated with a number of disorders that influence movement including Parkinson’s disease, Huntington disease, and uncontrolled or slow movement (dystonia). They have the following functions –

  • Control reflex and voluntary muscular activity.
  • Control abnormal involuntary movements.
  • Control emotional expression movements.
  • Control skilled & manipulative movements of the body, e.g., – threading a needle.
  • Control automatic associated movements as coordinated movements of legs or swinging of arms during walking.
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