Dynamics of Coupled Oscillator Systems - Abstract
We consider slow stochastic fluctuations in a system of two adaptively coupled active rotators with excitable intrinsic dynamics. Depending on the adaptation rate, the interplay of plasticity and noise is demonstrated to give rise to two qualitatively different types of switching behavior. For slower adaptation, one finds alternation between the two modes of noise-induced oscillations, distinguished by the different order of successive spiking of the two units. For intermediate adaptation rates, the deterministic dynamics involves multistability between the stationary and oscillatory regimes. In presence of noise, the phases then exhibit a bursting-like behavior, mediated by switching between the metastable states associated to coexisting attractors of the deterministic system. Once the switching dynamics for intermediate adaptation rates becomes strongly biased toward the stationary states, one observes the effect of inverse stochastic resonance, where the oscillation frequency displays a non-linear dependence on noise, characterized by a minimum at a preferred noise level. Applying the fast-slow analysis and the averaging approach, we analyze the mechanisms behind the two types of switching dynamics and explain the scenario by which plasticity enhances the effect of inverse stochastic resonance.