Motor control 2

Question 1

Nuclei in Basal Ganglia Circuitry

Answer 1

• Putamen
• Lateral Globus Pallidus (GPI)
• Substantia Nigra (SNc)
• Medial Globus Pallidus (GPm)
• Subthalamic Nucleus (STN)

Question 2

Basal Ganglia Circuitry - Input

Answer 2

The Putamen receives excitatory input from the cortical eareas (e.g. motor cortex).

Question 3

Basal Ganglia Circuitry - Output

Answer 3

The GPm projects back to the cortex. Output from the GPm up to the Thalamus, which is inhibitory.

Question 4

Direct Pathway

Answer 4

Excitatory: can allow a movement to happen

Question 5

Direct Pathway - Detail

Answer 5

1. Excitatory signal from the cortex (e.g. motor cortex)
2. Increases inhibitory signal from the Putamen to the GPm
3. Reduces activity in the GPm
4. Increased excitatory output to cortex (signal from the thalamus to the motor cortex)

Question 6

Indirect Pathway

Answer 6

Inhibitory: stops movements

Question 7

Indirect Pathway - Detail

Answer 7

1. Excitatory signal from the cortex
2. Increased inhibitory signal from Putamen to GPI
3. Reduced inhibitory signal from GPI to STN
4. Increased excitatory input to GPm
5. Increased inhibitory output to thalamus
6. Reduced excitatory output to cortex (signal from the thalamus to the motor cortex)

Question 8

Parkinson’s - Basal Ganglia Circuitry

Answer 8

• Under-active Direct Pathway.
• Overactive Indirect Pathway.

Question 9

Huntingtons - Basal Ganglia Circuitry

Answer 9

Under-active Indirect Pathway.

Question 10

Tourettes - Basal Ganglia Circuitry

Answer 10

Overactive Direct Pathway/