Figure 3.

Feedback-loop speed control system possibly involved in MOT activity. The closed-loop would reduce the slip speed between the target motion (v_o) and the angular speed of the visual axes (v_e). In this model, the periodic response of the muscle is seen to be triggered by an external signal acting as an input disturbance on the visual feedback loop. K_vu and K_m are two pure gains, whereas the clock block can be regarded as a periodic signal generator. Reproduced with permission from Northrop (2001).