Abstract
Saccadic suppression is the perceptual suppression of visual stimuli during or just before rapid eye movements. How, or even where in the brain this perceptual suppression takes place is not clear. One common viewpoint, however, is that that saccadic suppression originates in the Lateral Geniculate Nucleus (LGN). This study uses behavioral methods to show that at least part of the mechanism must be of cortical origin. We flashed sinusoidal gratings just before an eye movement and compared their 80% detection thresholds to those obtained during fixation. The critical manipulation was to change the background luminance in the visual hemifield opposite to that where the stimulus appeared. It has been shown before that background luminance affects the amount of saccadic suppression. Our data, however, showed that increasing the background luminance in the left hemifield increased the suppression of the target in the right hemifield. Since each LGN receives information exclusively from one of the visual fields, this change in suppression can only be due to cortical processing. We conclude that at least part of the processing that takes place to suppress peri-saccadic stimuli must take place in the cortex.
Supported by the Pew Charitable Trusts.