Author: Svetlana Postnova, Institute of Physiology, Philipps University of Marburg.
Names and affiliation of other authors:
Karlheinz Voigt and Hans Braun, Institute of Physiology, Philipps University of Marburg.
Oral or poster: Poster
We examine phase synchronization effects in a system of two electrically coupled Hodgkin-Huxley like neurons in different dynamical states: tonic, chaos and bursting with different types of transitions between them. We use applied current as a control parameter to tune each neuron. Different types of synchronization: out of phase, chaotic and in-phase, can be observed in dependence on coupling strength, regime of spike generation and initial conditions. Out of phase and chaotic regimes always coexist with in-phase. As a remarkable result, in bursting regime out of phase and chaotic activity can only be observed close to the one side of period-adding transition from n to n+1 spikes per burst.
To bring our model closer to physiology we have added white Gaussian noise. In the areas where two or more synchronous regimes coexist noise induces switching between them. In the same time out of phase regime is very sensitive to noise, while chaotic and in-phase looks resistant. As a conclusion we can say that neurons (mostly in bursting regimes) can be driven from out of phase or chaotic synchronization to in-phase not only with changing of coupling strength but also with tuning of applied current. And in the presence of noise they can be easily driven back: from in-phase to chaos, using the same parameters, what is not possible in deterministic case.