title: Network-selectivity and stimulus-discrimination in the primary visual cortex: cell-assembly dynamics.
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 revealed 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 compared with 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. It appears that an assembly is the major 'functional unit' of information processing in cortical circuits, rather than the individual neurons.
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.
authors.forename: Vishal
authors.initials: V
authors.lastname: Bharmauria
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.
authors.forename: Lyes
authors.initials: L
authors.lastname: Bachatene
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Cattan
authors.affiliation: Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.|Département de Génie Électrique et Génie Informatique, Université de Sherbrooke, Sherbrooke, QC, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Brodeur
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.
authors.forename: Nayan
authors.initials: N
authors.lastname: Chanauria
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.|Département de Génie Électrique et Génie Informatique, Université de Sherbrooke, Sherbrooke, QC, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Rouat
authors.affiliation: Neurophysiology of Visual System, Département de Sciences Biologiques, Université de Montréal, CP 6128 Succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7.|Neurosciences Computationnelles et Traitement Intelligent des Signaux (NECOTIS), Sherbrooke, QC, Canada.|Département de Génie Électrique et Génie Informatique, Université de Sherbrooke, Sherbrooke, QC, Canada.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Molotchnikoff
mesh_terms: D000200:Action Potentials; D000818:Animals; D002415:Cats; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: assembly-dynamics; cat; functional connection; network-selectivity; primary visual cortex; stimulus-discrimination