神经元阵发放电序列的非稳定周期轨道分析

Identification of unstable periodic orbits in the sequence of neuronal burst firing

大鼠背根节 (dorsal root ganglion,DRG)神经元在慢性压迫损伤后可自发产生大量不规则的阵发放电。为探讨此类放电序列的动力学机制 ,我们以单纤维引导的方法记录了受损神经元阵发放电的动作电位间期 (interspike interval,ISI)序列 ,并计算得到放电的事件间期 (interevent interval,IEI)序列。然后 ,运用一种从时间序列中识别非稳定周期轨道 (unstable periodic orbits,UPOs)的新方法对阵发放电 IEI序列进行分析。从得到的 1 0例数据中无一例外地检测到了具有高度统计显著性的非稳定周期 1轨道。在此基础上 ,进一步对阵发放电的非稳定周期轨道分级进行了初步研究 ,检测到了显著的周期 2与周期 3轨道。结果表明 :受损 DRG神经元的不规则阵发放电节律具有显著地确定性动力学机制。

Irregular spontaneous burst firing is abundantly generated by the rat's DRG neurons after injured with chronic compression. To investigate the dynamics underlying the burst firing, we experimentally recorded the interspike interval (ISI) sequence of single unit burst firing from the injured neurons. The original ISI sequence was processed to obtain the interevent interval(IEI) sequence of burst firing. Then, a newly developed unstable periodic orbit (UPO) identification method was used to analyze the IEI sequence. Unstable period 1 orbits with high statistical significance were identified in all 10 data sets. We also detected the orbits with higher periods, and highly significant unstable period 2 and period 3 orbits were identified. The results indicate that the irregular burst firing from the injured DRG neuron possesses significantly deterministic dynamics.[