Soliton-like regimes, echo and concave spiral waves in mathematical modelsof biological excitable media

On the basis of numerical simulations with partial reaction-diffusion equat ions describing the dynamics of electrical processes in biological excitabl e tissues, such as a nerve axons and cardiac Purkinje fibers, we have revea led unusual - soliton-like - regimes of interaction of propagating nonlinea r excitation waves: reflection of the colliding waves instead of their anni hilation. The specific nature of wave dynamics due to the reflection effect s in two-dimensional excitable media is considered.