Yoram Burak: Shaping neural circuits by high order synaptic interactions

Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem

How do plasticity rules, acting locally at the level of single synapses, shape the global structure of recurrent neural circuits? We recently developed a theoretical framework for addressing this question. The theoretical formalism allows us to evaluate precisely how synaptic weights evolve under spike-timing dependent plasticity (STDP) in recurrent networks with linear-Poisson dynamics, and arbitrary topology. We show that STDP induces non-local interactions between synapses of different neurons, whose influence on the synaptic dynamics can be described as a sum over contributions from structural motifs. These high-order synaptic interactions, which were often neglected in previous theoretical treatments of the plasticity dynamics, can have a pivotal influence on the global structure of a neural network in steady state. As an example,I will consider the spontaneous formation of two simple structures: wide synfire chains, in which groups of neurons project to each other sequentially, and self connected assemblies - both of which are important models for generation of structured neural dynamics. With appropriate choice of the biophysical parameters, predicted by the theory, these ordered structures can emerge autonomously under the influence of STDP, without exposing the neural network to any structured external inputs during learning. I will also discuss how the framework can be extended to situations in which the network receives structured, time-dependent feed-forward inputs.

 

Organized by

Henning Sprekeler, Laura Naumann & Loreen Hertäg

Location

BCCN Berlin, lecture hall, Philippstr. 13 Haus 6, 10115 Berlin