Sensory Processing as a Function of Stimulus Statistics in the Rat Barrel Cortex

Abstract:

Rats sweep their whiskers on textured objects, triggering decorrelated whisker deflections. Nonetheless, when contacting large scale objets, they produce synchronous deflections of their whiskers. The impact of such sensory context (the interwhisker correlation level) on the encoding of whisker deflections by barrel cortex neurons is unknown. Using a multi-whisker stimulator (Jacob et al., 2010, JNM 189: 65-74) allowing the independent deflection of 24 caudal whiskers, we applied white noise approach and reverse correlation analysis to study the impact of interwhisker correlation on neuronal coding. In particular, Spike-Triggered Analysis (STC) allowed us to identify a phase encoding space for barrel cortex neurons and to single out simple-like and complex-like response characteristics. It also provided and efficient framework to demonstrate the massive impact of interwhisker correlation on neurons functional selectivity. A large subset of neurons displayed responses only at the highest levels of interwhisker correlation whereas other cells were specifically sensitive to center-surround antagonism. This new functional description appear more suited to describe barrel cortex neuron responses to a large variety of sensory statistics.

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