Basal Ganglia.2 part question. Are the divisions of it in seperate areas or are they clumped together?

Question

2nd part is each section a nucleus? or ?

Answer 1

Good question.  They are separate, identifiable areas anatomically, although some of them are "clumped together."  The basal ganglia consist of the putamen, the caudate nucleus, the globus pallidus, the claustrum and the amygdaloid body--the last two being much less significant than the first three.  However, there are different ways of defining them--the caudate and putamen with the anterior limb of the internal capsule that runs between them are collectively called the corpus striatum and the putamen and globus pallidus together are often called the 'lenticular nucleus'.  The functionally related subthalamic nucleus and substantia nigra are also often included on the list.

They are nuclei and in fact there is a push to change the terminology so they are referred to as basal nuclei.  However, people are used to the old term, so it's probably going to take a while.  "Ganglia" is really an inappropriate term because that usually refers to a cluster of nerves in the peripheral nervous system, not within the CNS, so it's confusing.  (As if they weren't confusing enough on their own.)

The basal nuclei, or ganglia, or whatever you want to call them, are involved with the modulation of movement mostly via inhibition of the motor pathways.  They seem to project their influence mostly back to the cerebral cortex, rather than directly to the descending motor pathways, and they are directly involved in the pathology of such disorders as Huntington's disease, WIlson's disease and Parkinson's.