Excitable chaos in diffusively coupled FitzHugh-Nagumo equations

Abstract

A prototypic model of three coupled FitzHugh-Nagumo oscillators is shown to exhibit spatio-temporal hyperchaos. With increasing the number of coupled units the number of positive Lyapunov exponents increases. A system in two spatial dimensions shows two types of excitable spatio-temporal (hyper-)chaos depending on which variable is chosen for the coupling. Some implications for excitable cardiac tissue are discussed.