13 BASAL GANGLIA

Question 1

What are the specific functions of the basal ganglia

Answer 1

Mood of movement
Initiation of movement
Execution of movement
Muscle tone

Question 2

Name the major nuclei in the basal ganglia

Answer 2

Caudate nucleus
Putamen
Globus pallidius
Subthalamus nucleus
Substantia nigra

Question 3

What do disorders of the basal ganglia result in

Answer 3

Mood and cognitive changes, difficulty in initiating movement, involuntary movements, muscle tone defects.

Question 4

Describe functions of the caudate nucleus

Answer 4

Control of movement (nigrostriatal pathway affected in Parkinsons).
Procedural learning
Inhibition of movements
Associative learning 
Reward loop

Question 5

Describe functions of the putamen

Answer 5

Regulate movement and in learning.

Question 6

Describe the amygdalda

Answer 6

Part of the limbic system. Involved in memory, decision making and emotional reactions.

Question 7

Describe the sub thalamic nucleus

Answer 7

Deep brain stimulation to SUT occurs in Parkinson’s treatment. Has afferent neurons to the GPi which when stimulated cause the Gp to be hyper excitable more firing of pallidial-thalamic pathway which causes increased inhibition of the thalamus-motor cortex pathway causing hypokinesia. DBS stuns the SUT resulting in less GP excitation.
Also thought to be involved in obsessive compulsive disorders.

Question 8

Describe the substantial nigra

Answer 8

Dopamine sink. Communicates with the striatum. Striatal nigral pathway affected in Parkinsons whereby dopamine mediated inhibition of GABA into the GPe does not occur. More GABA in GPe causes more inhibition of transmission to SUT, less GABA in SUT means afferent in SUT less inhibited more excitation of GPi. More firing of inhibitory GABA to thalamus, more inhibition of thalamus more inhibition of motor cortex- hypokinesia.

Question 9

Describe the pathology in Huntington’s.

Answer 9

Loss of GABAergic projection cells affecting the striatopallidial pathway. Less firing. Less inhibition of GPe, more inhibition of SUT, less excitation of GPi. Less inhibition of thalamus. More excitation of motor cortex. Hyperkinesia, rigidity.

Question 10

Describe the symptoms of Huntington’s

Answer 10

Early cognitive and behavioural changes, mood swings, depression, hyperkinesia, involuntary movements.

Question 11

Treatment of Huntington’s

Answer 11

No treatment.
Treat symptoms
Gene therapy
Neuron transplants