title: Shifts of Gamma Phase across Primary Visual Cortical Sites Reflect Dynamic Stimulus-Modulated Information Transfer.
abstract: Distributed neural processing likely entails the capability of networks to reconfigure dynamically the directionality and strength of their functional connections. Yet, the neural mechanisms that may allow such dynamic routing of the information flow are not yet fully understood. We investigated the role of gamma band (50-80 Hz) oscillations in transient modulations of communication among neural populations by using measures of direction-specific causal information transfer. We found that the local phase of gamma-band rhythmic activity exerted a stimulus-modulated and spatially-asymmetric directed effect on the firing rate of spatially separated populations within the primary visual cortex. The relationships between gamma phases at different sites (phase shifts) could be described as a stimulus-modulated gamma-band wave propagating along the spatial directions with the largest information transfer. We observed transient stimulus-related changes in the spatial configuration of phases (compatible with changes in direction of gamma wave propagation) accompanied by a relative increase of the amount of information flowing along the instantaneous direction of the gamma wave. These effects were specific to the gamma-band and suggest that the time-varying relationships between gamma phases at different locations mark, and possibly causally mediate, the dynamic reconfiguration of functional connections.
authors.affiliation: Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Max Planck Institute for Intelligent Systems, Tübingen, Germany.
authors.forename: Michel
authors.initials: M
authors.lastname: Besserve
authors.affiliation: Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Lowe
authors.affiliation: Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom.
authors.forename: Nikos K
authors.initials: NK
authors.lastname: Logothetis
authors.affiliation: Max Planck Institute for Intelligent Systems, Tübingen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schölkopf
authors.affiliation: Laboratory of Neural Computation, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Panzeri
mesh_terms: D000818:Animals; D008253:Macaca mulatta; D014793:Visual Cortex / Q000502:physiology*