Channell Paul, Cymbalyuk Gennady, Shilnikov Andrey
Department of Mathematics and Statistics, Georgia State University, Atlanta, GA 30303, USA.
Phys Rev Lett. 2007 Mar 30;98(13):134101. doi: 10.1103/PhysRevLett.98.134101.
The origin of spike adding in bursting activity is studied in a reduced model of the leech heart interneuron. We show that, as the activation kinetics of the slow potassium current are shifted towards depolarized membrane potential values, the bursting phase accommodates incrementally more spikes into the train. This phenomenon is attested to be caused by the homoclinic bifurcations of a saddle periodic orbit setting the threshold between the tonic spiking and quiescent phases of the bursting. The fundamentals of the mechanism are revealed through the analysis of a family of the onto Poincaré return mappings.
我们在水蛭心脏中间神经元的简化模型中研究了爆发活动中尖峰添加的起源。我们发现，随着慢钾电流的激活动力学向去极化膜电位值偏移，爆发阶段在序列中容纳的尖峰逐渐增多。这种现象被证明是由鞍周期轨道的同宿分岔引起的，该分岔设定了爆发的强直尖峰和静息阶段之间的阈值。通过对一族到庞加莱返回映射的分析揭示了该机制的基本原理。
