Pulse Dynamics in a Model of Coupled Excitable Fibers: A Variety of Patterns and Spatio-temporal Chaos

摘要

It has been identified that there is a rich variety of interactions among spatially localized patterns such as pulses and spots in a reaction-diffusion medium. In addition, interactions among patterns in different reaction-diffusion media should be also of interests from practical viewpoints. In fact, in several nerve systems, it is observed that huge nerve axons are arranged in a densely packed bundle so that pulses traveling in adjacent axons electronically communicate each other. In this paper, we investigate what kinds of pulse dynamics can be emerged when two excitable reaction-diffusion media are coupled with each other, especially focusing on a situation in which parameters of two excitable fibers are not equal. Such a situation is not uncommon because the diameters of fibers are not equivalent in the real nerve systems in general, leading to a difference of diffusion coefficients in mathematical models.