Basal Ganglia - Primary Functions

Professor Trevor Robbins discusses the function of a set of structures called the basal ganglia, which seem to be involved in response selection.

The basal ganglia are a very mysterious set of structures. They comprise the striatum, which we commonly call the caudate nucleus and putamen, and also this set of structures also called the ventral striatum, including the nucleus accumbens and their outflow through the globus pallidus. I think it has been difficult to suss out [investigate] the basal ganglia because, in a sense, they're an entire brain in their own right, a bit like the cerebellum or the hippocampus itself. And they do tend to ape or mimic what the neocortex does, so the cortex projects in a very orderly way to the basal ganglia and one of the functions of the basal ganglia is to send streams of information off to the motor system for performance. Another main function is to reroute that information back, through loops, to the frontal cortex in particular. So, it is acting on this information and adding something to it. What is it adding? One possibility is it is adding motivational activational salience via the activity of the dopamine system, which projects to the striatum. We think that the striatum in general is very importantly involved in the elementary or first stages of selecting a response. The details of that selection are then filled in by the cortex. So, that is as far as we have got with the basal ganglia, but it's something we're going to continue to strive at.