System-Size Effects on the Collective Dynamics of Cell Populations with Global Coupling(Condensed Matter and Statistical Physics)

概要

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Phase-transition-like behavior is found to occur in globally coupled systems consisting of finite numbers of elements, and a theoretical explanation of this behavior is given. The system studied is a population of globally pulse-coupled integrate-and-fire cells subject to a small additive noise. As the population size is changed, the system exhibits phase-transition-like behavior, that is, there exists a well-defined critical system size above which the system remains in a monostable state with high-frequency activity and below which a new phase characterized by the alternation of high- and low-frequency types of activity appears. The mean field motion obeys a stochastic process with a state-dependent noise, and the above described phenomenon can be interpreted as a noise-induced transition characteristic of such processes. The coexistence of high- and low-frequency activity observed in finite size systems was reported by Cohen, Soen and Braun [Physica A 249 (1998), 600] in experiments on cultivated heart cells. The present report gives the first qualitative interpretation of their experimental results.
理論物理学刊行会の論文
2003-01-25