Defining circuits of the basal ganglia circuits for human action selection and instrumental learning. (360G-Wellcome-092859_Z_10_Z)

An unanswered question in human cognition is the precise role of the basal ganglia (BG) will much recent emphasis on reward processing and reward learning. In recent work we have shown that a disposition to act is strongly encoded in BG. Given these findings it is opportune to re examine the precise role of the basal ganglia in action selection and instrumental learning. 1. Effective connectivity in the direct and indirect pathway is enhanced and reduced, respectively, when an action is required compared to when there is no requirement for action. 2. Increased reward enhances activity the direct pathway for Go trials, and enhances activity in the indirect pathway for NoGo trials. 3. Instrumental reinforcement learning involves changes in effective connectivity in these pathways.