Scale-free avalanches in arrays of FitzHugh-Nagumo oscillators

TL;DR

This paper demonstrates that simple arrays of coupled FitzHugh-Nagumo oscillators near a canard transition can produce neuronal avalanche patterns coexisting with synchronous oscillations, revealing mechanisms behind brain activity phenomena.

Contribution

It introduces a minimal model showing how avalanches and synchrony coexist, driven by inhibitory interactions near a canard transition, highlighting a potential mechanism for brain activity patterns.

Findings

Avalanche patterns emerge in coupled oscillators near a canard transition.

Avalanches coexist with synchronous oscillations in the model.

The system exhibits criticality indicators like scale-invariant event distributions.

Abstract

The activity in the brain cortex remarkably shows a simultaneous presence of robust collective oscillations and neuronal avalanches, where intermittent bursts of pseudo-synchronous spiking are interspersed with long periods of quiescence. The mechanisms allowing for such a coexistence are still a matter of an intensive debate. Here, we demonstrate that avalanche activity patterns can emerge in a rather simple model of an array of diffusively coupled neural oscillators with multiple timescale local dynamics in vicinity of a canard transition. The avalanches coexist with the fully synchronous state where the units perform relaxation oscillations. We show that the mechanism behind the avalanches is based on an inhibitory effect of interactions, which may quench the spiking of units due to an interplay with the maximal canard. The avalanche activity bears certain heralds of criticality, including scale-invariant distributions of event sizes. Furthermore, the system shows an increased sensitivity to perturbations, manifested as critical slowing down and a reduced resilience.