The effect of spatiotemporal fluctuations on the pulse propagation

We have studied the influence of uncorrelated Gaussian fluctuations on the propagation of pulses in an excitable medium modeled by the FitzHugh-Nagumo system under an external point action. Depending on the properties of this medium, one of the two possible scenarios is realized in the noise-induced suppression of propagating pulses. The first scenario can be classified as the noise-induced incoherence (breakage of the links) between adjacent elements of the medium. The second scenario is related to a spontaneous generation of pulses in the medium under the action of fluctuations. These models are applied to analysis of some recent biological experiments devoted to the dynamics of calcium waves.