Phase transition for infinite systems of spiking neurons
(joint work with P. Ferrari, A. Galves and I. Grigorescu)

Abstract : We prove the existence of a phase transition for a stochastic model of interacting neurons. The spiking activity of each neuron is represented by a point process having rate 1 whenever its membrane potential is larger than a threshold value. This membrane potential evolves in time and integrates the spikes of all presynaptic neurons since the last spiking time of the neuron. When a neuron spikes, its membrane potential is reset to 0 and simultaneously, a constant value is added to the membrane potentials of its postsynaptic neurons. Moreover, each neuron is exposed to a leakage effect leading to an abrupt loss of potential occurring at random times driven by an independent Poisson point process of rate γ > 0. For this process we prove the existence of a value γc such that the system has one or two extremal invariant measures according to whether γ > γc or not.