Suppressive effects of a peripheral grating displacement during saccadic eye movement and during fixation

Summary Rapid displacement of a peripheral grating reduced sensitivity to test flashes presented at the center of gaze equally well, whether the displacement was produced by mirror movement during fixation or by saccadic eye movement with the grating stationary. Small 0.5 ° flashes in the retinal periphery were not affected by distant grating displacements, but large (5.0 °) flashes were suppressed. Thus there is a size-selective suppressive mechanism which does not affect small stimuli except at the fovea.This research was supported by NIH (NEI) grant No. 5R01 EY01497 to Dr. Brooks and by NIH (NEI) Postdoctoral Fellowship No. 5F32 EY05 191-03 to Dr. Impelman     

Influence of background luminance on visual sensitivity during saccadic eye movements

Summary Detection thresholds were measured for a brief test flash projected on a uniform background before, during, and after saccadic eye movement. The amount and duration of threshold elevation during saccades was directly dependent on background illumination; no significant elevations occurred at backgrounds of ¯2.0 log fl or less. Similar results were obtained during fixation when the backgrounds were saccadically displaced.An occipital evoked potential was recorded in association with both eye movements and background displacements at higher background luminances (no test flash). These results may indicate an activation of a selected population of neural elements — probably the Y channels — which occurs during saccades in illuminated environments and which renders the channels less responsive to additional, simultaneous, and appropriately structured stimuli.