Interocular Transfer of Suppressive Effects of Retinal Image Displacement

Abstract

WHEN the retinal image of the visual field is suddenly displaced by a saccadic eye movement, perceptual sensitivity to a weak test flash at the time of displacement is reduced. Flashes presented from 40 ms before until at least 100 ms after the displacement may be affected. I have discovered¹ that visibility is similarly reduced when the visual field is displaced as a whole before a stationary (fixating) eye. This throws doubt on the idea that either oculomotor activity² or mechanical acceleration of the eyeball³ is required to account for such effects. It suggests rather that the surge of neural activity caused by the rapid displacement of the retinal image has side-effects that interfere with processing of the signals generated by the test flash, and so raise the perceptual threshold¹.