TEMPORAL IMPULSE-RESPONSE FUNCTIONS FOR LUMINANCE AND COLOR DURING SACCADES

Previous work has shown that during saccadic eye movements, contrast s ensitivity for low spatial frequency patterns modulated in luminance i s selectively reduced by up to one logarithmic unit, while high spatia l frequency patterns, and equiluminant patterns of all spatial frequen cies are not suppressed at all: [Burr et al. (1994). Nature, 371, 511- 513]. Here we study the temporal characteristics for sensitivity to lu minance and chromatic patterns during saccades, using the two-pulse su mmation technique. Sensitivity was measured for detecting two successi ve pulses as a function of stimulus-onset asynchrony, during normal vi ewing and during saccades, Impulse response functions were estimated f rom the summation data, for all conditions. For equiluminance, the fun ctions were monophasic during normal viewing and saccades. For luminan ce modulation, the impulse response functions were di-phasic in both n ormal viewing and saccades. However, during saccades the impulse respo nses were faster in normal viewing. This result is consistent with the suggestion that saccadic suppression is mediated by contrast gain con trol mechanisms, known to occur in M-cells but not P-cells. Copyright (C) 1996, Published by Elsevier Science Ltd.