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  • Neuroscience Seminar Series

    Friday, November 22, 2019, 11:30, R229 (2e étage), Centre Universitaire des Saints Pères, 45 rue des Saints Pères, 75006 Paris

    Fritjof Helmchen, Professor , Brain Research Institute, University of Zurich, Switzerland

    Neocortical dynamics during sensory discrimination behavior


    Through the combination of in vivo optical imaging and chronic expression of genetically encoded
    calcium indicators it is now feasible to directly ‘watch’ neuronal population dynamics in the
    neocortex of awake, head-restrained mice during specific behaviors. Here, I will present results

    from calcium imaging experiments in mouse neocortex while the animals perform whisker-
    based or auditory sensory discrimination tasks. We used wide-field calcium imaging to resolve
    spatiotemporal activation patterns across large parts of the neocortex during individual trials. We
    also chronically monitored cortical dynamics over weeks and across task learning. We observed
    wide-spread, coordinated activation of multiple cortical areas, which correlated with various
    behavioral aspects such as whisking, body movements, and licking. In particular, we identified
    highly distinct patterns of persistent cortical activity during a short-term memory phase, which
    were contingent of the animal’s behavior (active versus passive). We also found that posterior
    parietal cortex (PPC) presumably acts as a routing hub, with distinct subdivisions being activated
    for tactile versus auditory discriminations. During learning we identified two salient phases
    framing the effective learning period, which in particular reorganized the signal flow through
    posterior association areas, including PPC. Our results contribute to the understanding of the
    principles of large-scale activation patterns supporting sensory discrimination and of how these
    patterns emerge during learning.

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