Influence of background luminance on visual sensitivity during saccadic eye movements

Abstract

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.

Backward and forward masking associated with saccadic eye movement

“…A lack of significant difference between thresholds associated with eye movements and fixation on dim scotopic backgrounds had also been reported by Brooks and Fuchs (1975), Brooks, Impelman, and Lum (1980), Mitrani (1971), and Richards (1969). These results are in disagreement with the results of Abscissa: Conventions as in the last figure, except that the mask affects the center gaze at the termination of movement ("mask on," downward pointing arrow).…”

“…This suggests that activation of movement detecting (Y) channels is not affected by simultaneous of near-simultaneous activity in pattern detecting (X) channels. Supporting this conclusion is the report of Brooks, Impelman, and Lum (1980) that light flash threshold during saccades are unaffected by high-frequency gratings continuously present in the visual background across which the saccades are made. Our data do not permit the conclusion that pattern-detecting channels are unaffected by activity in the "Y" channels; on the contrary, it has been speculated that X channels may register the clear images of fixation and that Y channels may inhibit the X channels during saccadic movement, so as to cut off potential forward masking effects from the presaccadic scene and "clear" the X channels for the new postsaccadic images (e.g., see review by Breitmeyer & Ganz, 1976).…”

“…In our conditions, the subject perceived the target at the postsaccadic fixation area, and not in its actual position on the lens screen. This is probably due to the latency of neural elements affected by the target (see also Brooks, Impelman, & Lum, 1980). It requires 20-40 msec for retinal processing alone and more time before the neural correlate of the stimulus reaches the cortex.…”

Postsaccadic processing of the retinal image during picture scanning

“…It has been suggested that each successive image that falls on the retina is subsequently discarded during the next saccade because of saccadic suppression (see reviews by E. Matin, 1974, andVolkmann, 1986) and the masking effects of images seen following saccades (Brooks & Fuchs, 1975;Brooks, Impelman, & Lum, 1980;Campbell & Wurtz, 1978;MacKay, 1970;E. Matin, Clymer, & L. Matin, 1972).…”

“…Matin, Clymer, & L. Matin, 1972). Saccadic suppression is found not only during a saccade, but also, in some cases, until about 100 msec after the beginning of a saccade (50 msec or more after the saccade terminates; e.g., Brooks et al, 1980;Ishida & Ikeda, 1989;Volkmann, 1986). In other cases, however, rather quick recovery from the suppression has been reported (e.g., Riggs, Volkmann, Moore, & Ellicot, 1982).…”