Noise-induced synchronous stochastic oscillations in small scale cultured heart-cell networks

This paper reports that the synchronous integer multiple oscillations of heart-cell networks or clusters are observed in the biology experiment. The behaviour of the integer multiple rhythm is a transition between super-and subt hreshold oscillations, the stochastic mechanism of the transition is identified. The similar synchronized oscillations are theoretically reproduced in the stochastic network composed of heterogeneous cells whose behaviours are chosen as excitable or oscillatory states near a Hopf bifurcation point. The parameter regions of coupling strength and noise density that the complex oscillatory rhythms can be simulated are identified.There sults show that the rhythm results from a simple stochastic alternating process between super- and sub-thresholdoscillations.Studies on single heart cells forming these clusters reveal excitable or oscillatory state near by a Hopf bifurcation point under pinning the stochastic alternation. In discussion, the results are related to some abnormal heart beat rhythms such as the sinus arrest.