"Spatiotemporal firing patterns and chaotic attractors: two faces of the
same coin? Experimental and theoretical hints."

               Alessandro Villa

Laboratory of Neurobiophysics
Faculty of Medicine
University Joseph Fourier, Grenoble 1 (France)
&
Neuroheuristic Research Group
Institute of Physiology
University of Lausanne (Switzerland)


Abstract:


The brain is a highly interconnected network of neurons, in which the
activity in any neuron is necessarily related to the combined activity
in the neurons that are afferent to it.  Due to the widespread presence
of reciprocal connections between brain areas, re-entrant activity
through chains of neurons is likely to occur and some ordered sequences
of intervals within spike trains of individual neurons, and across spike
trains recorded from different neurons, are observed experimentally in
several conditions. On the other hand we know that the detection of a
deterministic dynamics necessarily requires the stability of the
generating processes over a relatively long period of time.  Significant
deterministic dynamics across spike trains might reveal neuronal
interactions involved in long-term processes (e.g., memory traces,
learned motor programs), whereas synchronous activities might reveal
short-term operational processes at attentional or feature-binding
level. Although little or few reasons are generally considered for these
frameworks as complementary approaches to the same biological system,
several observations, either from experimental or simulated data, and
theoretical assumptions have lead us to analyze the relationships
between spatiotemporal firing patterns and chaotic processes in neural
networks.