Influences of Existence of a Fixation Point and Target upon Dynamics of Voluntary Saccades and a Comparison with Visually Guided Reflexive Saccades

Abstract

It was investigated whether the existence of a fixation point and saccade target influences the dynamics (peak velocity and duration) of voluntary saccades. In addition, the difference in dynamics between visually guided reflexive saccades, which reflexively occur oriented forward a suddenly appearing target, and visually guided voluntary saccades, which were voluntarily elicited toward the target, was investigated. Five experiments were conducted on young subjects in darkness. The results gave new findings as follows. (1) Independent of the fixation point the existence of the saccade target increases the peak velocity and reduces the duration of the voluntary saccades. (2) Independent of the existence of the saccade target the existence of the fixation point does not influence the dynamics of the voluntary saccades. (3) The visually guided reflexive saccade is larger in peak velocity and shorter in duration than the visually guided voluntary saccade.