A retino-cortical model of anticipation

Description

When processing a moving object, the visual system uses several anticipation mechanisms to compensate the delay induced by the photo-transduction. On one hand, retinal gain control advances the peak in sensory cells response. On the other hand, due to the lateral connectivity, the activity begins to raise before the moving stimulus enters in the receptive field of the sensory cells. This last effect, a "latency shift", is observed both in the cortex and in the retina. We present a model assembling a realistic retinal input fed by a video stimulus to a cortical model of V1. We address the respective role of retinal and cortical anticipation mechanisms. Our study unravels the role of retinal amacrine cells in the latency shift. We shows simulation of the V1 cortical activity, in response to a moving bar, obtained with amacrine cells and gain control activated or not (control conditions). In both conditions, with amacrine or gain control, the peak response arrive well before the peak in control condition. This is a transfer of retinal anticipation by adaptation in the cortex. This retinal anticipation also reduces the strength of latent anticipation. We also reproduce another form of retinal anticipation, known as prediction, and observe its effect on the cortical response.

Abstract

International audience

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