Rapidly forming, slowly evolving, spatial patterns from quasi-cycle Mexican Hat coupling

TL;DR

This paper investigates how stochastic quasi-cycle oscillations coupled with Mexican Hat interactions produce rapidly forming, slowly evolving spatial patterns and phase synchronization in neural systems, with distinct behaviors in one and two dimensions.

Contribution

It introduces a novel analysis of quasi-cycle oscillations with Mexican Hat coupling, revealing their role in neural pattern formation and phase synchronization.

Findings

Phase synchronization occurs rapidly at weak coupling in 1D.

Amplitude patterns form more quickly in 2D, sometimes without phase patterns.

Higher coupling strengths lead to both phase and amplitude pattern formation.

Abstract

A lattice-indexed family of stochastic processes has quasi-cycle oscillations if its otherwise-damped oscillations are sustained by noise. Such a family performs the reaction part of a discrete stochastic reaction-diffusion system when we insert a local Mexican Hat-type, difference of Gaussians, coupling on a one-dimensional and on a two-dimensional lattice. Quasi-cycles are a proposed mechanism for the production of neural oscillations, and Mexican Hat coupling is ubiquitous in the brain. Thus this combination might provide insight into the function of neural oscillations in the brain. Importantly, we study this system only in the transient case, on time intervals before saturation occurs. In one dimension, for weak coupling, we find that the phases of the coupled quasi-cycles synchronize (establish a relatively constant relationship, or phase lock) rapidly at coupling strengths lower than those required to produce spatial patterns of their amplitudes. In two dimensions the amplitude patterns form more quickly, but there remain parameter regimes in which phase synchronization patterns form without being accompanied by clear amplitude patterns. At higher coupling strengths we find patterns both of phase synchronization and of amplitude (resembling Turing patterns) corresponding to the patterns of phase synchronization. Specific properties of these patterns are controlled by the parameters of the reaction and of the Mexican Hat coupling.