可兴奋性细胞混沌放电区间的识别机理

在神经起步点记录到加周期分岔过程的生理实验数据，在对此分岔过程中位于周期n爆发 和周期(n+1)爆发之间的混沌的峰峰间期数据检测不稳定的周期轨道时，发现从靠近周期 n爆发的混沌的峰峰间期数据中，可以检测出不稳定的周期n轨道；而从靠近周期(n+1)爆 发的混沌的峰峰间期数据中，不仅可以检测出不稳定的周期(n+1)轨道，还可以检测出不稳 定的周期n轨道.针对该现象，借助于Sherman建议的胰腺β细胞模型，从非线性动力 学角度给出了理论解释.指明了由鞍结分岔和倍周期分岔分别产生第一类阵发和第三类阵发 为出现该 关键词： 峰峰间期 不稳定的周期轨道 鞍结分岔 倍周期分岔

Mechanism for identification of chaotic firing interval in excitable cells

The experimental data of interspike intervals were recorded in a neural pacemaker,and the presence of period-adding bifurcation cascade was demonstrated.By detecting unstable periodic orbits from the chaotic interspike intervals located in between period-n bursting and period-(n+1) bursting,it is found that the unstable period-n orbit can be detected from the chaotic interspike intervals near the period-n bursting,and the unstable period-(n+1) orbit exists in the chaotic interspike intervals near period-(n+1) bursting.Moreover,the unstable period-n orbit also can be detected.For such a phenomenon the theoretical analyses are presented from the point of view of the nonlinear dynamics by way of the pancreatic β-cell model suggested by Sherman.The direct causes of emergence of the phenomenon are shown to be the intermittency of type Ⅰ and that of type Ⅲ,and they are induced by the saddle-node bifurcation and period-doubling bifurcation,respectively.Consequently,the mechanism for identification of chaotic firing interval is revealed.At the same time,the universality of the phenomenon is elucidated to a certain extent.Furthermore,a novel method is put forward for identifying the chaotic firing interval.