热敏神经元网络中螺旋波死亡和破裂的数值模拟

Numerical study of the death and breakup of spiral wave in the networks of thermosensitive neurons

实验发现大脑皮层内出现螺旋波且螺旋波对神经元电信号传递有积极作用.利用细胞网络方法从对大脑皮层观察到的螺旋波进行数值模拟.以包含温度因子的热敏神经元模型在二维空间构造规则网络,研究了神经元膜片温度参数对神经元网络中螺旋波演化影响;定义了一类统计同步因子来刻画温度因子引起螺旋波相变(破裂和死亡)的临界条件.发现在规则网络下,当温度超过一定值后螺旋波会死亡和消失而导致整个网络达到均匀同步;在考虑了弱通道噪声情况下,螺旋波温度超越一定临界值则引起螺旋波的破裂.进一步分析了暂时性发烧昏迷的可能机制在于神经系统某些功能区螺旋波传播电信号的中断.

The experimential evidences confirm that spiral waves are observed in the disinhibited mammalian neocortex.The scheme of cellular networks is used to simulate the formation and the evolution of spiral wave in the neocortical slices.The regular networks of neurons are constructed in the two-dimensional space,the dynamical properties of thermosensitive neurons is described by temperature factor,and the effect of membrane temperature on the evolution of spiral wave is investigated in detail.A statistical factor of synchronization is defined to measure the critical condition inducing phase transition of spiral wave（death or breakup） by the factor of temperature of membrane.It is confirmed that spiral wave is removed and the whole networks become homogeneous and synchronous completely when the membrane temperature exceeds a certain threshold;the breakup of spiral wave is induced in the presence of weak channel noise being considered.Furthermore,it is suggested that the mechanism of temporary heat stupor could be the blocking of spiral wave propagation in some functional domain.