Excitable calcium wave propagation in the presence of localized stores.

We study the propagation of calcium waves in the presence of a discrete distribution of calcium stores. Calcium-induced calcium release coupled to diffusion can be used to produce a criterion for wave propagation across connected clusters of stores. The velocity of the resulting wave and its relationship to the frequency of the excitatory stimulus can then be described using percolation theory. Simulations show a homogeneous and a fractal regime and are in agreement with both experiments and theory.