Wang Junjie, Xu Jieqiong, Wu Jianmei, Xu Qixiang
School of Mathematics and Information Science, Guangxi University, Nanning, 530004 China.
Scientific Research Center of Engineering Mechanics, Guangxi University, Nanning, 530004 China.
Cogn Neurodyn. 2022 Dec;16(6):1505-1524. doi: 10.1007/s11571-022-09799-x. Epub 2022 Apr 1.
In general, inhibitory stimuli are thought to inhibit neuronal firing, but they may actually enhance firing sometimes, such as post-inhibitory rebound spike (PIR spike) and post-inhibitory facilitation (PIF) phenomena, which play an important role in human neuronal activities. We study responses to inhibitory pulse in a classical neuron model (Quartic adaptive Integrate-and-fire model) well known to reproduce a number of biologically realistic behaviors. The three phenomena that we study are PIR, in which a neuron fires after an inhibitory pulse, and PIF, in which a subthreshold excitatory input can induce a spike if it is applied with proper timing after an inhibitory pulse, as well as period firing after inhibitory pulse. When the system features focus and saddle two equilibriums, the three phenomena will be occurred under the inhibitory pulse, while all three phenomena will not be induced when the system features node and saddle two equilibriums. Using dynamical systems theory, we explain the threshold mechanism of enhancement of neural firing response induced by inhibitory pulse and analyze the origin of these phenomena from several factors. We also describe the geometric characterization of dynamical structures of these three phenomena. This study therefore enrich the paradoxical phenomena that induced by inhibitory input and advance our understanding of its role.
一般来说，抑制性刺激被认为会抑制神经元放电，但它们有时实际上可能会增强放电，比如抑制后反弹峰电位（PIR峰电位）和抑制后易化（PIF）现象，这些现象在人类神经元活动中起着重要作用。我们在一个以能重现多种生物学现实行为而闻名的经典神经元模型（四次自适应积分发放模型）中研究对抑制性脉冲的反应。我们研究的三种现象是：抑制性脉冲后神经元放电的PIR现象；如果在抑制性脉冲后以适当的时间施加阈下兴奋性输入就能诱导产生峰电位的PIF现象；以及抑制性脉冲后的周期性放电。当系统具有焦点和鞍点两种平衡点时，在抑制性脉冲作用下会出现这三种现象，而当系统具有节点和鞍点两种平衡点时，则不会诱导出所有这三种现象。我们运用动力系统理论解释了抑制性脉冲诱导神经放电反应增强的阈值机制，并从几个因素分析了这些现象的起源。我们还描述了这三种现象的动力学结构的几何特征。因此，本研究丰富了由抑制性输入诱导的矛盾现象，并增进了我们对其作用的理解。
