Sequential processing in vision: The interaction of sensitivity regulation and temporal dynamics

The goal of this work was to describe the interaction of sensitivity regulation and temporal dynamics through the primate retina. A linear systems model was used to describe the temporal amplitude sensitivity at different retinal illuminances. Predictions for the primate H1 horizontal cell were taken as the starting point. The H1 model incorporated an early time-dependent stage of sensitivity regulation by the cones. It was adjusted to reduce the effects of gap junction input and then applied as input to a model describing temporal amplitude sensitivity of Parvocellular and Magnocellular pathway retinal ganglion cells. The ganglion cell model incorporated center–surround subtraction. The H1 based model required little modification to describe the Parvocellular data. The Magnocellular data required a further time-dependent stage of sensitivity regulation that resulted in Weber’s Law. Psychophysical data reflect the sensitivity regulation of the retinal ganglion cell pathways but show a decline in temporal resolution that is most pronounced for the post-retinal processing of Parvocellular signals.