Varieties of spiral wave behavior: An experimentalist’s approach to the theory of excitable media

TLDR

Spiral waves in excitable media display diverse behaviors, yet models are rarely rejected because parameter tuning can make different media behave similarly. The study seeks to identify generic features of excitable media by distinguishing them from model‑specific idiosyncrasies. The authors varied two parameters of the FitzHugh‑Nagumo model and compared the resulting spiral wave behaviors with other media to identify generic parameter‑dependence patterns. The study reveals a wide range of rotor behaviors within a single model and supplies a database for testing mathematical generalizations.

Abstract

Spiral waves in diverse excitable media exhibit strikingly variegated behavior. Mechanistic interpretations of excitability in laboratory systems are commonly tested by comparing the wavelength, period, and meander patterns of the model's spiral waves with laboratory observations, but models seem seldom to be rejected by such tests. The reason may be that almost any excitable medium behaves in many respects like almost any other, if its parameters are properly adjusted within a reasonable range. What generalizations can be made about "excitable media" in the absence of more specifications? It would be useful to distinguish such generic features from idiosyncrasies of specific models. The range of behavioral flexibility of the FitzHugh-Nagumo excitable medium is explored by varying two of its parameters and comparing the results with other excitable media to suggest a generic pattern of parameter dependence. The results exhibit the remarkable diversity of rotor behavior in a single model and provide a database for quantitative testing of mathematical generalizations.