Seminar June 11 by Demian Battaglia



Tuesday June 11, 2013, 10:00, Faculty Club, Panum, there will be a seminar "Function follows dynamics: brain state-dependency of inter-areal information flow" given by Demian Battaglia.

Title: Function follows dynamics: brain state-dependency of inter-areal information flow
Demian Battaglia (MPIDS-BCCN, Göttingen, on move to Institute for Systems Neuroscience, University of Aix-Marseilles) in collaboration with Christoph Kirst, Erik Martens, Olav Stetter, Theo Geisel

Abstract: Brain functions, from vision or motor preparation up to memory, selective attention or awareness, require the control of inter-areal interactions on time-scales faster than synaptic changes. In particular, the way in which information conveyed by neuronal activity is routed through the complex multiscale circuits of the brain must be reconfigurable even when the underlying structural (i.e. anatomic) connectivity is fixed. The ability to quickly reshape such "effective connectivity" ---measured from neural recordings with tools like Granger Causality or Transfer Entropy--- is a chief requirement for performance in a changing environment. Yet it is an open problem to understand which circuit mechanisms allow for achieving this ability. How can manifold effective connectivities ---corresponding to different patterns of inter-areal interactions, or brain states--- result from a fixed structural connectivity? And how can effective connectivity be controlled without resorting to structural plasticity, leading to a
flexible ‘‘on demand’’ selection of function?

Such a general question is explored through computational studies of systems at different scales, including "in silico" models of in vitro cultures of dissociated neurons or of meso-scale motifs of a few interacting cortical areas. Profiting of the advantages provided by a computational framework, in which the ground-truth structure of the
analyzed systems is known and in which their dynamics can be characterized with full precision, we show that "function follows dynamics", rather than structure. Different dynamic states of a same structural network, characterized by different synchronization
properties, are indeed associated to different directed functional networks, corresponding to alternative information flow patterns, with a different balance between bottom-up and top-down functional influences. Switching between multiple dynamical states (either spontaneous, or induced through ad hoc local manipulations or perturbations) leads therefore to a self-reconfiguration of network-wide functional
interactions without need of parallel structural changes.