Basal Ganglia

Question 1

What are the major constituents of the basal ganglia?

Answer 1

Caudate, Putamen, Nucleus Accumbens, Globus Pallidus, Subthalamic Nucleus, Substantia Nigra, Ventral Tegmentum (they are masses of gray matter (nuclei) in the cerebral hemispheres that surround the thalamus)

Question 2

What is meant by the term striatum?

Answer 2

Corpus striatum = caudate + putamen.

Question 3

Describe the sources of dopamine neuromodulation for the striatum.

Answer 3

Substantia Nigra, pars compacta, (SNpc) contains pigmented cells and projects to striatum. Ventral tegmentum projects to ventral striatum (nucleus accumbens) and prefrontal cortex.

Question 4

What is a corticostriate (CS) loop?

Answer 4

Basal ganglia form a feedback loop. Motor/cognitive cortical programs are funneled through the striatum through the striatum and globus pallidus. GP projects to thalamus which in turn conveys information back to frontal cortex to refine motor and cognitive programs. SN and subthalamus modulate loop activity to select or reinforce certain motor/cognitive outputs.