 The disinhibition of the thalamus leads to activation of the prefrontal cortex and ventral striatum, selective for increased D1 activity leading to reward.There is also evidence from non-human primate and human electrophysiology studies that other basal ganglia structures including the globus pallidus internus and subthalamic nucleus are involved in reward processing.Two models have been proposed for the basal ganglia, one being that actions are generated by a "critic" in the ventral striatum and estimates value, and the actions are carried out by an "actor" in the dorsal striatum.