Influence of background luminance on visual sensitivity during saccadic eye movements.

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 back-ground 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.