Alina Neverodska¹, Y. Howard Li¹, Eli Brenner², Jonathan D. Victor³, Michele Rucci¹; ¹University of Rochester, ²Vrije Universiteit Amsterdam, ³Weill Cornell Medical College

Previous research with achromatic stimuli has shown that eye movements contribute to a coarse-to-fine progression in visual processing during post-saccadic fixation (Boi et al., 2017): saccade-induced transients preferentially enhance low spatial frequency information, whereas improvements at high spatial frequencies emerge with prolonged post-saccadic exposure supported by fixational drift. Recent work with chromatic stimuli, however, revealed perceptual improvements at both low and high spatial frequencies as exposure increases, suggesting that color may follow different temporal dynamics than luminance. It is unknown whether these differences reflect distinct influences of eye movements on chromatic and achromatic processing. Here we examined whether eye movements contribute to the dynamics of color perception. Observers (N=6) judged the orientation (±45°) of an isoluminant red–green grating (1 or 10 cpd) embedded in a 1/k² chromatic noise field following a 6° saccade. Retinal stimulation was controlled with a high-resolution digital DPI eye-tracker coupled to a system for real-time gaze-contingent display. Trials interleaved three conditions. Normal: the stimulus appeared immediately upon saccade detection and remained visible for 500 ms, followed by a new noise field. Stabilized: after the saccade, the stimulus moved on the display to remain immobile on the retina, eliminating drift-related modulations. No-Transient: the stimulus was presented at saccade end but slowly ramped on over 1 s, eliminating the saccadic transient, before remaining visible for 500 ms. The three conditions yielded complementary outcomes, consistent with previous luminance findings: low spatial frequency performance was selectively impaired in the No-Transient condition, whereas high spatial frequency performance declined in the Stabilized condition. These results indicate that both saccade-induced transients and fixational drift support chromatic perception, as they do for luminance. Thus, the distinct post-saccadic dynamics observed for chromatic and luminance stimuli are unlikely to originate from different contributions of eye movements.

Acknowledgements: NIH EY18363