Figure 3.

Two cycles of two-phase operation of action selection interaction with motor control. The figure illustrates two-phase control of basal ganglia function and how this might interact with the discontinuous (10 Hz) function of the motor system. The relative duration of the two phases is illustrated here as equal but might well be unequal. In this figure, a cycle of BG involvement occurs every 100 ms, illustrating an upper limit. Many tasks may not require BG involvement on each cycle of the motor system. DA, dopamine. (Online version in colour.)