Basal Ganglia

Question 1

What are the primary roles of the Basal Ganglia?

Answer 1

Controlling movement, cognition, and planning complex motor sequences

Basal Ganglia indirectly influence movement through subcortical control loops involving the motor areas of the cerebral cortex.

Question 2

What structures make up the Basal Ganglia?

Answer 2

Five pairs of nuclei:
* caudate
* putamen
* subthalamic nucleus
* globus pallidus (GP)
* substantia nigra (SN)

These nuclei are interconnected and located subcortically.

Question 3

What is the pathway through which the Basal Ganglia influences movement?

Answer 3

Indirectly influences movement via subcortical control loops involving motor areas of the cerebral cortex

The output from the Basal Ganglia is primarily inhibitory.

Question 4

What are the two main pathways through the Basal Ganglia?

Answer 4

Direct and Indirect pathways

The direct pathway facilitates movement, while the indirect pathway inhibits movement.

Question 5

What is the function of the direct pathway in the Basal Ganglia?

Answer 5

Facilitation of movement leading to excitation of premotor areas

This pathway involves inhibition of GP and SN, resulting in disinhibition of thalamus.

Question 6

What is the function of the indirect pathway in the Basal Ganglia?

Answer 6

Inhibition of movement leading to inhibition of premotor areas

This pathway involves activation of GP and inhibition of thalamus.

Question 7

What is the main neurotransmitter involved in the direct pathway of the Basal Ganglia?

Answer 7

GABA and Substance P

These neurotransmitters play a role in inhibitory transmission within the Basal Ganglia.

Question 8

What is a key symptom of Parkinson’s Disease?

Answer 8

Rigidity

This includes increased resistance to passive stretch and is sometimes referred to as ‘cogwheel’ rigidity.

Question 9

What is the primary cause of Parkinson’s Disease?

Answer 9

Loss of dopamine in cells in substantia nigra

This can be up to 90% loss and typically occurs around the age of 60-65.

Question 10

What are common symptoms of Parkinson’s Disease?

Answer 10

• Tremor
• Bradykinesia
• Gait disorders
• Postural deficits

Symptoms vary and can include resting tremors and slowness of movement.

Question 11

What is a treatment option for Parkinson’s Disease?

Answer 11

L-Dopa

L-Dopa is a precursor of dopamine and can have side effects like dyskinesia.

Question 12

What distinguishes Huntington’s Disease from Parkinson’s Disease?

Answer 12

Huntington’s involves uncontrolled movements (chorea) due to selective loss of neurotransmitters

In contrast, Parkinson’s is characterized by a ‘poverty’ of movement.

Question 13

What is the role of the Striatum in the Basal Ganglia?

Answer 13

It consists of the caudate and putamen, involved in cognitive/behavioral and motor planning

The Striatum receives organized input from the cerebral cortex and thalamus.

Question 14

What happens when there is an imbalance between the direct and indirect pathways in the Basal Ganglia?

Answer 14

Results in involuntary movements or poverty of movement

An imbalance leads to conditions such as Huntington’s disease (excessive movement) or Parkinson’s disease (insufficient movement).

Question 15

Fill in the blank: The primary function of the _______ pathway is to facilitate movement.

Answer 15

direct

Question 16

True or False: The output of the Basal Ganglia is primarily excitatory.

Answer 16

False

The output is primarily inhibitory.

Question 17

What are the effects of insufficient output from the Basal Ganglia?

Answer 17

Hyperkinesia

This condition is seen in Huntington’s disease.

Question 18

What is ‘bradykinesia’?

Answer 18

Slowness of movement not under voluntary control

It can lead to an increase in reaction time and movement time.