An explanation of the distribution of inter-seizure intervals

Recently Osorio et al [1] reported that probability distribution of epileptic seizure energies and inter-seizure intervals follow a power law with exponents 1.67 and 1.5 respectively. Earlier Beggs and Plenz [2] had observed spontaneous neuronal avalanches in neocortical tissues. The distribution of sizes of these avalanches, computed by summing local field potentials, followed a power law with exponent 1.5 as in critical branching process. The relevance of the branching process to explanation of seizure energies distribution is thus obvious. Here we show that in addition the distribution of inter-seizure intervals is also consistent with the branching process.