Talk by Prof. Alessandro Torcini

We hereby announce the next talk in the 'CSN Virtual Seminar':

A robust balancing mechanism for spiking neural networks in absence of strong external currents

by Prof. Alessandro Torcini, CY Cergy Paris University

Abstract

Neurons in the cortex fire irregularly and with a low firing rate despite being subject to a continuous stimulation (bombardment) from thousands of presynaptic neurons. This seemingly counter-intuitive evolution has been explained in terms of the theory of dynamical balance of excitation and inhibition [1]. However, this theory has been recently criticized, because it requires unphysically large external currents, experimentally unjustified. Here, we propose a nonlinear balancing mechanism based on a biologically plausible form of synaptic plasticity which works also with weak external currents. Biologically, the mechanism exploits the plasticity of excitatory-excitatory synapses induced by short-term depression. Mathematically, the nonlinear response of the synaptic activity is the key ingredient responsible for the emergence of a stable balanced regime. Our claim is supported by a simple self-consistent analysis accompanied by extensive simulations of current driven Leaky Integrate-and-Fire neurons and other models, performed for increasing network sizes. The observed regime is essentially fluctuation driven and characterized by highly irregular spiking dynamics of all neurons [2].

References

[1] C. van Vreeswijk and H. Sompolinsky, Science 274, 1724 (1996)

[2] A. Politi, and A. Torcini, (2024). A robust balancing mechanism for spiking neural networks. Chaos (in press as Fast Track) arXiv preprint arXiv:2401.12559