The C-BG-C circuitry influences a wide variety of behaviors. Most notable among these behaviors is movement, as evidenced by the severe movement impairments in neurological disorders involving the BG (e.g. Huntington’s and Parkinson’s diseases). The role the BG in movement has been strongly debated, with ideas including control of movement initiation and cessation, control of movement velocity and/or acceleration, movement sequencing, and generation of diverse movements (Kim, Barter et al. 2014, Jin and Costa 2015, Rueda-Orozco and Robbe 2015). All of these ideas have relatively strong experimental support, and thus it is possible that BG has diverse roles in movement control, or that there is a unifying role that is not easily fit into our heuristic categories. The hypotheses about diverse roles may also reflect variability in the BG subcircuit examined. Now that new approaches allow for more easily identification of different subcircuits, we can expect that, some of the issues will be clarified. Another important function of the BG is in the control of reward and reinforcement-based learning. This function overlaps to some extent with its role in movement
