Basal Ganglia

Question 1

Components of the basal ganglia

Answer 1

Striatum: caudate (lateral to ventricles) and putamen (lateral to internal capsule)

Lentiform: Globus pallidus (medial to the putamen), Putamen

Subthalamic nucleus

Substantia Nigra in the midbrain

Question 2

Direct and Indirect pathways both have pathways to the striatum, then they diverge and have separate ways of synapsing in the globus pallidus internus. What is the diffrence in these to pathways in getting to the GPi

Answer 2

Direct: glutamate to striatum then synapse with GABA from striatum to GPi which then synapses with the GABA from GPi to the thalamus

Indirect: glutamate to striatum synapses on GABA to the GPexternus which synapses with a GABA to the subthalamic nucleus which synapses with a glutamate back to the GPi which synapses on the GABA to the thalamus. So one extra glutamate that activates the GPi GABA inhibition.

Question 3

Hemiballismus is a finding when what part of the basal ganglia is a affected?

Answer 3

Subthalamic nuclei, affecting the inhibitory indirect pathway

Question 4

Huntington’s disease affects what part of the basal ganglia?

Answer 4

Striatum (caudate and putamen)

affects both indirect and direct pathways

Question 5

Unilateral lesions will affect the ______lateral side

Answer 5

contralateral side because of the projection and input from motor tracts that decussate lower down (medulla)

Question 6

D1 stimulates which pathway promoting movement?

Answer 6

Direct pathway promoting movement

Question 7

D2 receptors act on which pathway promoting movement?

Answer 7

Indirect pathway because D2 receptors are inhibitory