Collective dynamics of excitable system in heterogeneous media

The collective behaviors of excitable system in heterogeneous media are discussed. Due to the heterogeneity on diffusion and other properties of media, the spiral wave will drift over the media and its stability will also be affected. The drift behaviors are different for dense and sparse waves because their different core properties. Moreover we have found that spatial inhomogeneities on diffusion could destabilize the spiral wave. It will cause stable spiral wave meandering or even breakup. Several cases have been investigated including the effects of heterogeneity caused by fiber rotation in cardiac tissue. The meaning of these results for neuro-dynamics in brain and cognitive behavior is discussed.