Collective dynamics in the presence of finite-width pulses

TL;DR

This paper examines how finite pulse-widths influence the collective dynamics of neuronal networks, revealing a transition from irregular to synchronous activity and smoothing out phase transitions seen with idealized delta spikes.

Contribution

It provides a detailed analysis of finite pulse-width effects on neuronal network dynamics, including stability, hysteresis, and phase transition behaviors, which were not addressed in models with idealized spikes.

Findings

Finite pulse-widths induce a transition from irregular to synchronous dynamics.

Wider inhibitory pulses promote synchronization over excitatory pulses.

Finite-width pulses smooth out the phase transition observed with delta spikes.

Abstract

The idealisation of neuronal pulses as $\delta$-spikes is a convenient approach in neuroscience but can sometimes lead to erroneous conclusions. We investigate the effect of a finite pulse-width on the dynamics of balanced neuronal networks. In particular, we study two populations of identical excitatory and inhibitory neurons in a random network of phase oscillators coupled through exponential pulses with different widths. We consider three coupling functions, inspired by leaky integrate-and-fire neurons with delay and type-I phase-response curves. By exploring the role of the pulse-widths for different coupling strengths we find a robust collective irregular dynamics, which collapses onto a fully synchronous regime if the inhibitory pulses are sufficiently wider than the excitatory ones. The transition to synchrony is accompanied by hysteretic phenomena (i.e. the co-existence of collective irregular and synchronous dynamics). Our numerical results are supported by a detailed scaling and stability analysis of the fully synchronous solution. A conjectured first-order phase transition emerging for $\delta$-spikes is smoothed out for finite-width pulses.