Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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BCCN/BFNT AG-Seminar

Tuesday, 23.04.2013 17 c.t.

The idling brain: the formation and maintenance of spontaneous cortical dynamics

by Prof. Brent Doiron
from Department of Mathematics, University of Pittsburgh, USA

Contact person: Fred Wolf

Location

big lecture hall (L01), Von-Siebold-Str. 6, side entrance, 37075 Göttingen

Abstract

Neuronal networks in cortex exhibit complex and variable patterns of activity even in the absence of a stimulus. However, it is unclear what network mechanisms give rise to these fluctuations. One possibility is so-called attractor dynamics, which endows a neural system with a multitude of stable states that are sampled stochastically during spontaneous activity. Recently, we proposed that clustered synaptic connections among members of neuronal assemblies give rise to attractor dynamics in balanced excitatory/inhibitory networks. We investigate how synaptic plasticity rules promote biophysically plausible formation and maintenance of neural assemblies with clustered connections. We show how activity dependent plasticity between excitatory neurons allow for the selective growth of neural assemblies. In balanced networks these assemblies produce spontaneous activity that reflects features of the training set, consistent with experiments in sensory cortex. Inhibitory synaptic plasticity ensures that large neuronal assemblies with many recurrent excitatory synapses do not suppress other assemblies through inhibition, effectively preventing winner-take-all behavior. In total, the combination of excitatory and inhibitory plasticity create rich spontaneous cortical dynamics that are reflective of recent sensory experiences.

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