A Stochastic Neural Firing Generated at a Hopf Bifurcation and Its Biological Relevance

摘要

The integer multiple firing patterns, generated in the rabbit depressor baroreceptors under the different static blood pressure, were observed between the resting state and the periodic firing and were characterized to be stochastic but not chaotic by a series of nonlinear time series estimations. These patterns exhibited very similar characteristics to those observed in the experimental neural pacemaker. Using I_(nap)+ I_K models with dynamics of a supercritical Hopf bifurcation, we successfully simulated the bifurcation process of firing patterns and observed the induction of the integer multiple firing patterns by adding noise. The results strongly suggest that the integer multiple firing rhythms generated by rabbit baroreceptors result from the interplay between noise and the system's dynamics. Because of the important normal physiological function of baroreceptors, the biological significance of noise and the noise-induced firing rhythms at a Hopf bifurcation is interesting to be addressed.