Human flicker sensitivity: how well our visual system utilizes the information supplied by retina photoreceptors

Dawei Dong

It is natural to hypothesize that under the evolution pressure, nerve systems should be optimized to process sensory information. Thus, for a given sensitivity of photoreceptors, the rest of the visual system should be compatible with it to fully utilize the information supplied by those photoreceptors. At high temporal frequency, the flicker sensitivity of photoreceptors decreases for increasing temporal frequencies. It is not surprising that flicker sensitivity of human visual system also decreases for increasing temporal frequencies, as revealed in psychophysical experiments. But a puzzle exists: the psychophysical flicker sensitivity decreases much more than the flicker sensitivity of retinal photoreceptors. Based on measurements of the statistics of natural time-varying images, I will show that the difference can be explained by the need of suppressing noise under various light intensities. In fact, the information supplied by retina photoreceptors is utilized by our visual system optimumly under natural conditions. The result is in quantitative agreement with physiological and psychophysical experiments on visual temporal response and adaptation.
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