| Motivated by recent experiments on intracellular calcium release we study the effects of different types of coupling on the dynamics of arrays of excitable elements. We aim to identify a coupling mechanism, which produces a sustained activity of each single element after the initiation of the spike. The first candidate, instantaneous, diffusive coupling, does not exhibit this property. We show that, on the other hand, for a coupling term with time delay the signals from adjacent elements can serve as mutual excitations and thus prolong the duration of the signal. We propose that time delayed coupling is generated by diffusion between isolated clusters of calcium channels. Our model could thus provide an explanation for the two different release modes observed in the calcium system. |
|