Week 12 - The Basal Nuclei

Question 1

What are the components of the basal nuclei?

Answer 1

The components of the basal nuclei include:
- Caudate nucleus
- Putamen
- Globus pallidus
- Subthalamic nucleus
- Substantia nigra

Each component has distinct roles in motor control and connectivity.

Question 2

What role do the basal nuclei play in movement?

Answer 2

The basal nuclei encode for:
- The decision to move
- The direction of movement
- The amplitude of movement
- The motor expression of emotions

They integrate information from different cortical and subcortical regions.

Question 3

What is the overall output of the globus pallidus?

Answer 3

Inhibitory

The globus pallidus sends inhibitory signals to the thalamus.

Question 4

What type of neurons are found in the subthalamic nucleus?

Answer 4

Glutaminergic neurons

These neurons provide excitatory output to the globus pallidus and substantia nigra.

Question 5

What is the primary role of the substantia nigra in the basal nuclei?

Answer 5

The substantia nigra contains dopaminergic neurons that project to the putamen, caudate nucleus, and subthalamic nucleus, influencing motor pathways

It plays a crucial role in both the direct and indirect pathways.

Question 6

Fill in the blank: The overall output from the striatum is ______.

Answer 6

Inhibitory

This applies to both the caudate nucleus and putamen.

Question 7

What is the function of the direct pathway in the basal nuclei?

Answer 7

The direct pathway releases the thalamus from tonic inhibition, leading to more excitation of the cortex

This pathway facilitates movement.

Question 8

How does the indirect pathway affect thalamic excitation?

Answer 8

The indirect pathway increases inhibition going to the thalamus, leading to less excitation of the cortex

This pathway counterbalances the direct pathway.

Question 9

True or False: The caudate nucleus is primarily involved in motor function.

Answer 9

False

The caudate nucleus is more likely involved with cognitive aspects of movement.

Question 10

What is hypokinesia and how is it related to Parkinson’s Disease?

Answer 10

Hypokinesia is a decrease in movement, associated with the loss of dopaminergic neurons in the substantia nigra in Parkinson’s Disease

This leads to reduced excitatory input to the direct pathway.

Question 11

What are the effects of Huntington’s Disease on the basal nuclei?

Answer 11

Huntington’s Disease leads to degeneration of the striatum, resulting in a loss of inhibitory signals to the GPe and excessive movement due to decreased inhibition of the thalamus

This results in increased stimulation of the cortex.

Question 12

What neurotransmitter is primarily involved in the excitatory input from the subthalamic nucleus?

Answer 12

Glutamate

Glutamate is used to excite the globus pallidus interna.