Delay-induced chimera transitions via mode selection in a multiplex FitzHugh Nagumo network

TL;DR

This paper demonstrates that inter-layer delay in a multiplex FitzHugh Nagumo network can control pattern transitions, from incoherence to chimera states and full coherence, by mode selection mechanisms.

Contribution

It reveals how deterministic delays serve as a control parameter for pattern formation and synchronization in multiplex neural networks, with a detailed stability analysis of modes.

Findings

Delay induces transitions from incoherence to chimera states and coherence.

Mode-dependent exponential factors explain delay-induced stability changes.

Inter-layer delay acts as a robust control mechanism for pattern formation.

Abstract

We investigate delay-induced collective dynamics in a two-layer multiplex FitzHugh Nagumo network with nonlocal intra layer coupling and delayed inter layer interactions. While delay effects are often treated as secondary, we show that deterministic inter-layer delay alone can act as a control mechanism for spatial coherence. Through systematic numerical simulations, we observe a clear transition as the delay parameter increases: fragmented incoherence evolves into chimera-like partial coherence, and eventually into a coherent traveling-wave state. This transition is consistently captured by spatial snapshots, space-time plots, and mean phase velocity profiles. To explain this behavior, we analyze the stability of spatial Fourier modes and show that the delay term introduces a mode-dependent exponential factor in the characteristic equation. This term induces non-monotonic changes in modal stability, effectively acting as a mode-selection mechanism: intermediate delays selectively destabilize a subset of modes, producing chimera-like coexistence, while larger delays suppress incoherent modes and restore global coherence. Our results demonstrate that inter-layer delay provides a simple and robust mechanism for controlling pattern formation in multiplex excitable networks, offering new insight into delay driven synchronization phenomena.