Chimera states in uncoupled neurons induced by a multilayer structure

TL;DR

This paper investigates how chimera states can emerge in a multilayer neuronal network where the upper layer consists of uncoupled neurons influenced by a lower layer acting as a medium, revealing density-dependent thresholds and delay effects.

Contribution

It introduces a novel multilayer neuronal model demonstrating chimera states in uncoupled neurons mediated by a lower layer with mixed synaptic interactions.

Findings

Chimera states can occur in uncoupled neurons via a multilayer structure.

A density-dependent threshold for chimera emergence was identified.

Inter-layer delays significantly affect chimera dynamics.

Abstract

Spatial coexistence of coherent and incoherent dynamics in network of coupled oscillators is called a chimera state. We study such chimera states in a network of neurons without any direct interactions but connected through another medium of neurons, forming a multilayer structure. The upper layer is thus made up of uncoupled neurons and the lower layer plays the role of a medium through which the neurons in the upper layer share information among each other. Hindmarsh-Rose neurons with square wave bursting dynamics are considered as nodes in both layers. In addition, we also discuss the existence of chimera states in presence of inter layer heterogeneity. The neurons in the bottom layer are globally connected through electrical synapses, while across the two layers chemical synapses are formed. According to our research, the competing effects of these two types of synapses can lead to chimera states in the upper layer of uncoupled neurons. Remarkably, we find a density-dependent threshold for the emergence of chimera states in uncoupled neurons, similar to the quorum sensing transition to a synchronized state. Finally, we examine the impact of both homogeneous and heterogeneous inter-layer information transmission delays on the observed chimera states over a wide parameter space.