The conjugacy of human saccadic eye movements.

Binocular measurements of instantaneous velocity vectors in normal human subjects during saccades showed: (1) considerable trial to trial variation in peak velocity, saccade duration, and saccade curvature despite saccade accuracy; (2) variations in one eye were mirrored by similar variations in the other eye, with a high positive correlation. The high correlation between the peak velocities suggest that saccades in the two eyes are driven by a common saccade generator. Assuming that a local feedback loop guides saccades, the high correlation between saccade durations and between saccade curvatures suggests that both eyes are guided by common feedback. If so, monocular adaptation must occur downstream from the saccade generator.