含快慢子系统的神经元数学模型仿真预期,神经放电节律经历加周期分岔序列,可以进一步表现激变,并通过逆倍周期分岔级联进入周期1峰放电。实验调节胞外钙离子浓度,观察到从周期1簇放电开始的带有随机节律的加周期分岔到簇内有多个峰的簇放电,再经激变转迁到峰放电节律的分岔序列,提供了这种分岔序列模式实验证据。实验所见之激变表现为簇放电节律的休止期消失,放电节律变为混沌峰放电和周期峰放电。作者利用随机Chay模型更加逼真地仿真再现了实验所见的分岔序列。该实验结果验证了以前的确定性数学模型的理论预期,并利用随机理论模型仿真了其在现实神经系统的表现;揭示了一类完整的神经放电节律的转换规律。
The bifurcation scenario of period adding bifurcation scenarios with stochastic bursting from period 1 bursting to high order bursting firstly, and then to spiking pattern via crisis was discovered in the experimental neural pacemaker when extracellular [Ca^2+] was decreased gradually. The quiescence of the bursting pattern disappeared and the firing pattern was changed into chaotic and periodic spiking patterns when crisis was generated. The bifurcation scenario was simulated by adjusting the relevant parameters in stochastic Chay model. The experimental results not only verified the previous theoretical anticipation in the deterministic mathematic model and were simulated by the stochastic theoretical model, but also revealed a kind of firing pattern transition regularity.