PREDICTIVE SMOOTH-PURSUIT OF COMPLEX 2-DIMENSIONAL TRAJECTORIES DEMONSTRATED BY PERTURBATION RESPONSES IN MONKEYS

Two-dimensional sum-of-sines waveforms were pursued by the eye with ve ry small phase delays compared with visual feedback delays estimated i n the same monkeys. Processing delays in making smooth corrections ave raged 90 msec after infrequent right-angle perturbations from a circul ar trajectory. These feedback delays were much larger than component p hase delays during pursuit that averaged: 10 msec for sinusoids, 3 mse c for circles, 20 msec for sum-of-two-sines trajectories, and 19 msec for sum-of-three-sines trajectories. This suggests that predictive con trol can play a strong role during tracking for a variety of simple an d complex target trajectories. (C) 1997 Elsevier Science Ltd.