Network-level neuroplasticity in cortico-basal ganglia pathways.

The striatum, the largest input nucleus of the basal ganglia, receives massive inputs from the neocortex and thalamus, and gives rise to the direct, indirect and striosomal pathways of the basal ganglia. Here, the view is developed that the striatum is a major site for adaptive plasticity in cortico-basal ganglia circuits, affecting in the normal state a broad range of behaviours. This plasticity can become a major source of maladaptive responses in disease states affecting the basal ganglia.