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User Pierre Baudot
title Eye movement dynamic constrain V1 code precision and sparsening through adapted non-linearities
Authors Baudot P., Levy M., Marre O., and Frégnac, Y.
Type Working paper
Type of publication ISC-PIF scholar

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Abstract The stereotyped dynamics imposed on the retinal flow by eye-movements are a prerequisite for visual perception. However, their impact on the processing of visual information in primary visual cortex (V1) remains largely unknown. By intracellularly recording the visual responses of V1 neurons to various simplifications of the natural optic flow, we show that saccadic and fixation eye-movements recruit intracortical non-linearities which increase the reliability of membrane potential dynamics and the temporal precision of spiking responses. Our data suggest that the Receptive fields process visual input at different spatio-temporal scales and directional axis during fixational and saccadic eye movements.. In particular, a switch of direction preference is observed during saccadic-like motion for the collinear axis of the receptive field. At the mechanistic level, the cortical effects of natural visuo-motor statistics during full field stimulation are best explained by the sequential recruitment of facilitatory and suppressive processes. This biphasic spike-timing dependent non-linearity promotes β−γ frequency fast subliminal events further converted into sparse and precise spiking activity, suggesting a generic neo-cortical filtering mechanism. As a result of this dynamic modulation by eye-movements, most of the simple cells responses has to be credited to nonlinear process even at the synaptic input level. We conclude that cortical nonlinearities and eye-movements cooperate during the viewing of natural scenes to achieve a temporal, selective and motor-invariant encoding of high order spatial input statistics.
Link http://www.iscpif.fr/%7Ebaudot
Created Thursday 23 April, 2009 15:48:26

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