Basal Ganglia and their functions*

Question 1

What is the basal ganglia?

Answer 1

A system of nuclei located deep in each cerebral hemisphere and the midbrain.

Question 2

What are the basal ganglia in the cerebral hemispheres called?

Answer 2

Corpus striatum.

Question 3

What are the basal ganglia involved in controlling?

Answer 3

Posture/movement, inhibiting unwanted movements.

Question 4

What does the basal ganglia comprise?

Answer 4

• Caudate nucleus
• Lentiform nucleus
• Substantia nigra

Question 5

where do the 3 sources which input into the basal ganglia arise from?

Answer 5

• Cerebral cortex
• Thalamus
• Substantia nigra

Question 6

Explain the connections in the basal ganglia simply?

Answer 6

The motor and association cortices project to the caudate nuclei and putamen.

The caudate and putamen project to the globus pallidus and substantia nigra.

The globus pallidus projects to the thalamus and then back to the motor cortex.

The substantia nigra projects back to the globus pallidus then to the thalamus and motor cortex.

Question 7

Explain the loop system of the connections of the basal ganglia?

Answer 7

When a movement is initiated in the motor areas impulses pass through motor pathways to the cranial and spinal nerves (see tutorial 12) but excitatory axons also stimulate the basal ganglia.

There are two routes that influence what the basal ganglia do and this, in turn, influences the motor cortex.

Question 8

How does dyskinesia show?

Answer 8

• Tremors:
• Chorea: rapid dance like movements of the limbs.
• Athetosis: Slow writhing movements

Question 9

What is parkinson’s disease?

Answer 9

It is a disease of the basal ganglia. The substantia nigra degenerates and stops producing the neurotransmitter dopamine.