On-line modification of saccadic eye movements by retinal signals.

A saccade is a rapid shift of the position of the eyes (< 100 ms). Saccades are generally considered too quick to be influenced by retinal signals. To address this idea, we displaced the visual target of a rightward horizontal saccade at eye movement onset (when there is suppression of conscious perception). To prevent adaptive and learning effects to occur, jump saccades were always followed by a random series of 10 no-jump saccades. Results indicated that the target jump influenced significantly the amplitude and the peak velocity of the ongoing saccade (opposite effects were found for rightward and leftward jumps). Changes in saccade kinematics occurred as early as 50 ms after the target jump. These results show that retinal information is processed quickly during eye movements, presumably through sub-cortical pathways.