神经放电节律的不同复杂分岔序列的实验研究

神经放电节律在参数空间的分岔结构不仅是重要的动力学问题，对于揭示神经信息编码也具有重要的意义．在大鼠损伤坐骨神经模型，研究了不同K^＋通道阻断剂的浓度下神经自发放电随Ca^2＋浓度变化的分岔序列规律．结果发现，包含节律模式种类较少的简单分岔序列可以与包含多类周期和混沌的复杂分岔序列相互转换，复杂分岔序列之间也可以转换．分岔点附近的混沌节律的不同是识别分岔序列不同的主要标志．研究结果不仅丰富了神经放电的非线性动力学现象，也会为建立神经放电在参数空间的分岔序列结构进而揭示神经编码机制提供帮助．

Experimental researches on different complex bifurcation procedures of neural firing patterns

The bifurcation structures of neural firing patterns in parameter space are important in nonlinear dynamics, playing important roles in identifying neural information coding mechanism. The bifurcation structures of neural firing with respect to the changes of concentration of calcium ion are observed in the experiment on an injured sciatic nerve model when concentration of voltage dependent potassium channel blockers is fixed at different values. The simple bifurcation procedure composed of a few kinds of firing patterns and the complex one composed of multiple kinds of periodic and chaotic firing patterns can be transited each other. Two different kinds of complex bifurcation structures can also be transited each other. The difference between chaotic firing patterns near bifurcation points is the key indicator to distinguish the kinds of bifurcation procedures. The results not only enrich the nonlinear phenomenon of neural firing patterns, but also are helpful to identify neural coding mechanism based on the construction of the bifurcation structure of neural firing patterns in parameter space.