EFFECT OF SYNCYTIUM STRUCTURE OF RECEPTOR SYSTEMS ON STOCHASTIC RESONANCE INDUCED BY CHAOTIC POTENTIAL FLUCTUATION

To study a role of syncytium structure of sensory receptor systems in the detection of weak signals through stochastic resonance, we present a model of a receptor system with syncytium structure in which recept or cells are interconnected by gap junctions. The apical membrane of e ach cell includes two kinds of ion channels whose gating processes are described by the deterministic model. The membrane potential of each cell fluctuates chaotically or periodically, depending on the dynamica l state of collective channel gating. The chaotic fluctuation of membr ane potential acts as internal noise for the stochastic resonance. The detection ability of the system increases as the electric conductance between adjacent cells generated by the gap junction increases. This effect of gap junctions arises mainly from the fact that the synchroni zation of chaotic fluctuation of membrane potential between the recept or cells is strengthened as the density of gap junctions is increased.