Fig. 2.

Pursuit eye movements. a Horizontal pursuit eye position traces of squirrel monkey 087 for target velocities of 10, 20, and 30 deg/s. b Histogram showing the distributions of pursuit latencies for the three squirrel monkeys used in this study (solid curves) and the rhesus macaque (dashed curves). c–f Curves showing maximum eye velocities achieved at different target velocities during three phases of pursuit averaged across all squirrel monkeys (c, e) and the macaque (d, f) for horizontal (c, d) and vertical (e, f) pursuit: early open loop (40 ms), late open loop (80 ms), and closed loop (240 ms). g–h Bode plots showing pursuit gain at different frequencies for ±8 deg sinusoidal target motion averaged across all squirrel monkeys (g) and the macaque (h). All error bars are SD.