Analysis of Variability of Complex Stochastic Oscillations in a Tristable Calcium Model

Motivated by important biophysical applications, we study the stochastic version of a mathematical model of calcium oscillations. For the deterministic model proposed by Li and Rinzel, a parametric zone of tristability, where two stable equilibria and a limit cycle coexist, is found for the first time. In this zone, and also in adjacent bi- and monostability zones, different scenarios of noise-induced generation and suppression of complex calcium oscillations are studied in detail. In these studies, along with the traditional direct numerical simulation and statistical processing, a new analytical apparatus of the stochastic sensitivity technique and confidence domains is effectively used.