Basal Ganglia

Question 1

What makes up the striatum?

Answer 1

Caudate and the Putamen

Question 2

Where do the efferent fibers of the basal ganglia generally arise from?

Answer 2

Internal Globus Pallidus (GPi)

Question 3

Does the basal ganglia have any major output to LMNs?

Answer 3

NO

Question 4

What is the normal effect of the Direct Pathway?

Answer 4

Increases motor activity via increased inhibition of the GPi which will lead to decreased VA/VL inhibition and increase input to the premotor cortex.

Question 5

What is the effect of DOPA addition to the Direct Pathway with D1 receptors?

Answer 5

Motor activity will be increased even further with interaction of DOPA on the D1 receptors increased Caudate/Putamen activity leading to further GPi inhibition.

Question 6

What is the normal effect of the Idirect Pathway?

Answer 6

Inhibition of motor activity with Striatum inhibition of GPe which then cannot act on the STN leading to the STN increasing inhibition of the GPi and inhibiting the VA/VL and therefore decreasing motor activity.

Question 7

What is the effect of DOPA addition to the Indirect Pathway with D2 receptors?

Answer 7

D2 receptors decrease the activity of the Striatum which then allows increased GPe activity to inhibit GPi and STN which leads to increased VA/VL activity and increased motor action.

Question 8

What is the net effect of Parkinson’s?

Answer 8

Decreased movement due to increased activity of GPi leading to more tonic inhibition

Question 9

What is the net effect of Huntington’s?

Answer 9

Increased movement due to decreased activity of GPi from increased inhibition leading to leass tonic inhibition.