The basal ganglia

The basal ganglia include the striatum (caudate, putamen, and ventral striatum) which receive from all cortical areas, and which project via the globus pallidus and substantia nigra back to the neocortex. The basal ganglia are implicated in stimulus-response habit learning, which may be provided by a reinforcement learning signal received by dopamine neurons responding to reward prediction error. The dopamine neurons may receive reward-related information from the orbitofrontal cortex, via the ventral striatum and habenula. The network mechanisms in the basal ganglia implement selection of a single output for behaviour, which is highly adaptive, by mutual direct inhibition between neurons.