Basal Ganglia

What are the basal ganglia?

The basal ganglia are interconnected groups of neurons, or nuclei, involved in regulating movement and other functions. Core structures include the caudate, putamen, and globus pallidus. The substantia nigra and subthalamic nucleus are closely related components of the functional circuit, although they are not both located within the cerebral hemispheres.

Basal ganglia function: movement control

The Neuroscience textbook describes loops connecting these structures with the cortex and other motor regions. Their influence on movement is indirect: they regulate motor circuits rather than projecting directly to the lower motor neurons that activate muscles.

Damage to a component of these circuits can disrupt the smooth initiation and termination of movement.

Procedural learning and habits

The basal ganglia also take part in learning how to perform actions. Research on habit formation distinguishes networks involved in goal-directed action from those involved in habitual responding. It does not identify one structure that stores every skill or habit.

Example: Parkinson’s disease

In Parkinson’s disease, loss of dopamine-producing neurons in the substantia nigra disrupts basal ganglia circuits. The description of these circuits explains how this disruption can make movements difficult to initiate and terminate. It gives a concrete example of why normal movement depends on regulation across a network.