Cognisciences: Synaptic integration and functional plasticity in primary visual cortex
Dir. Yves Frégnac

An issue central to the theme of complexity in the dynamics and function of biological networks concerns the inferences that can be made from multiscale measurements ranging from microscopic to macroscopic levels of integration. Our research is based on interdisciplinary approaches ranging from electrophysiology (intracellular sharp and patch recordings, in vivo), network imaging (voltage sensitive dye), psychophysical measurements to functional databasing and phenomenological and computational modeling. The long-term aim is to relate elementary processes of integration (conductance activation) to the emergence of collective « high-order » network properties expressed during low-level (non-attentive) perception.

The various research axes are centered on the study of complexity in the dynamics of neocortical networks during sensory processing and percept formation, as well as during functional adaptation and plasticity:
- At the experimental level, reverse engineering techniques will be developed to extrapolate, from the synaptic echoes recorded intracellularly in a single cell, the dynamics of the effective cortical network in which this recorded cell is functionally embedded. Dynamic clamp techniques will be developed with Thierry Bal’s team to connect biological and artificial neurons, in real time in vivo. Multiscale space-frequency-time analyses will be performed on simultaneously recorded microscopic (single cell Vm, synaptic conductances) and macroscopic (VSD imaging, EEG) signals during various levels of anesthesia. A collaboration is under way with Shulz’s team to explore neuroprosthetic applications.
– At the theoretical level, computer-based simulations will be used in two ways : i) neuroinformatics : an integrated database pooling a ten-year period of electrophysiological exploration is developed in collaboration with Andrew Davison’s team, and will serve to generate structural and functional models obtained through international collaborations (Ad Aertsen, Anders Lansner, Wolfgang Maass, Guillaume Masson, all partners in a European integrated project (Facets)); ii) computational neuroscience : large-scale numerical simulations are used to test general algorithms of associative plasticity and predict the dynamic behaviour of constrained recurrent networks, working near the edge of a deterministic chaos.

Our work should open new perspectives on the concept of « ongoing activity » in neural networks, and more specifically « coding efficiency » in sensory neocortex.

An issue central to the theme of complexity in the dynamics and function of biological networks concerns the inferences that can be made from multiscale measurements ranging rom microscopic to macroscopic levels of integration. Our research is based on interdisciplinary approaches ranging from electrophysiology (intracellular sharp and patch recordings, in vivo), network imaging (voltage sensitive dye), psychophysical measurements to functional databasing and phenomenological and computational modeling. The long-term aim is to relate elementary processes of integration (conductance activation) to the emergence of collective « high-order » network properties expressed during low-level (non-attentive) perception. The various research axes are centered on the study of complexity in the dynamics of neocortical networks during sensory processing and percept formation, as well as during functional adaptation and plasticity: - At the experimental level, reverse engineering techniques will be developed to extrapolate, from he synaptic echoes recorded intracellularly in a single cell, the dynamics of the effective cortical network in which this recorded cell is functionally embedded. Dynamic clamp techniques will be developed with Thierry Bal’s team to connect biological and artificial neurons, in real time in vivo. Multiscale space-frequency-time analyses will be performed on simultaneously recorded microscopic (single cell Vm, synaptic conductances) and macroscopic (VSD imaging, EEG) signals during various levels of anesthesia. A collaboration is under way with Shulz’s team to explore neuroprosthetic applications. – At the theoretical level, computer-based simulations will be used in two ways : i) neuroinformatics : an integrated database pooling a ten-year period of electrophysiological exploration is developed in collaboration with Andrew Davison’s team, and will serve to generate structural and functional models obtained through international collaborations (Ad Aertsen, Anders Lansner, Wolfgang Maass, Guillaume Masson, all partners in a European integrated project (Facets)); ii) computational neuroscience : large-scale numerical simulations are used to test general algorithms of associative plasticity and predict the dynamic behaviour of constrained recurrent networks, working near the edge of a deterministic chaos. Our work should open new perspectives on the concept of « ongoing activity » in neural networks, and more specifically « coding efficiency » in sensory neocortex.

Selected Publications

Yves Frégnac and Brice Bathellier, Cortical Correlates of Low-Level Perception: From Neural Circuits to Percepts, Neuron 88(1): 110-126, (2015) [PubMed]

Xoana Troncoso, Michael McCamy, Ali Najafian, Jie Cui, Jorge Otero-Millan, Stephen Macknik, Francisco Costela and Susana Martinez-Conde, V1 neurons respond differently to object motion versus motion from eye movements, Nature Communications 6: 8114, (2015) [pdf] [PubMed]

Andrew Davison, Daniel Brüderle, Jochen Eppler, Jens Kremkow, Eilif Muller, Dejan Pecevski, Laurent Perrinet and Pierre Yger, PyNN: a common interface for neuronal network simulators, Frontiers in NeuroInformatics 2: doi:10.3389/neuro.11.011.2008, (2009) [pdf] [abstract]

Vincent Bringuier, Frédéric Chavane, Larry Glaeser and Yves Frégnac, Horizontal propagation of visual activity in the synaptic integration field of area 17 neurons, Science 283: 695-9, (1999) [pdf] [abstract]

Lyle J. Borg-Graham, Cyril Monier and Yves Frégnac, Visual input evokes transient and strong shunting inhibition in visual cortical neurons, Nature 393: 369-73, (1998) [pdf] [abstract]