Time Course of Visual Inhibition during Voluntary Saccades*†

Abstract

Partial inhibition of vision occurs during voluntary saccadic eye movements. This paper reports its time course, measured by detection of a target flashed at various times in relation to the saccade. One value of stimulus luminance was chosen which was nearly always detected by the fixating eye, but hardly ever by the moving eye. A dot pattern was presented to the fovea in 6-μsec flashes of this luminance under photopic viewing conditions. Photographic records of each saccade made by the subject and each stimulus flash permitted analysis of the precise time of occurrence of the flash in relation to the saccade. Under these conditions, curves from three subjects showed that detection decreases to 50% for a flash occurring about 20 msec before the onset of the saccade and reaches a minimum such that vision of the flash is almost completely absent when it occurs during the saccade. Detection then begins to improve, reaching the 50% point again for a flash occurring about 75 msec after the onset of the eye movement. Results are compared with other studies which employed different viewing conditions, and the use of the data to support a notion of partial central inhibition is evaluated.