Network-selectivity and stimulus-discrimination in the primary visual cortex : cell-assembly dynamics

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Publication date
2015Author(s)
Bharmauria, Vishal; Bachatene, Lyes; Cattan, Sarah; Brodeur, Simon; Chanauria, Nayan; Rouat, Jean; Molotchnikoff, Stéphane
Subject
Functional connectionAbstract
Abstract : Visual neurons coordinate their responses in relation to the stimulus; however, the complex
interplay between a stimulus and the functional dynamics of an assembly still eludes
neuroscientists. To this aim, we recorded cell assemblies from multi-electrodes in the primary
visual cortex of anaesthetized cats in response to randomly presented sine-wave drifting gratings
whose orientation tilted in 22.5° steps. Cross-correlograms divulged the functional connections
at all the tested orientations. We show that a cell-assembly discriminates between orientations by
recruiting a ‘salient’ functional network at every presented orientation, wherein, the connections
and their strengths (peak-probabilities in the cross-correlogram) change from one orientation to
another. Within these assemblies, closely tuned neurons exhibited increased connectivity and
connection-strengths than differently tuned neurons. Minimal connectivity between untuned
neurons suggests the significance of neuronal selectivity in assemblies. This study reflects upon
the dynamics of functional connectivity, and brings to the fore the importance of a ‘signature’
functional network in an assembly that is strictly related to a specific stimulus. Apparently, it
points to the fact that an assembly is the major ‘functional unit’ of information processing in
cortical circuits, rather than the individual neurons.
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