Clay J R, Shrier A
Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
J Theor Biol. 1999 Mar 21;197(2):207-16. doi: 10.1006/jtbi.1998.0867.
The role of subthreshold dynamics in neuronal signaling is examined using periodic pulse train stimulation of the Fitzhugh-Nagumo (FN) model of nerve membrane excitability and results from the squid giant axon as an experimental data base. For a broad range of stimulus conditions the first pulse in a pulse train elicited an action potential, whereas all subsequent pulses elicited subthreshold responses, both in the axon and in the FN model. These results are not well described by the Hodgkin and Huxley 1952 model. Various different patterns of subthreshold responses, including chaotic dynamics, can be observed in both systems-the FN model and the axon-depending upon stimulus conditions. For some conditions action potentials are occasionally interspersed among the subthreshold events with randomly occurring interspike intervals. The randomness is directly attributable to the underlying subthreshold chaos-deterministic chaos-rather than to a stochastic noise source. We conclude that this mechanism may contribute to multimodal interspike interval histograms which have been observed from individual neurons throughout the nervous system.
利用神经膜兴奋性的Fitzhugh-Nagumo（FN）模型的周期性脉冲串刺激，并以鱿鱼巨轴突的实验数据为基础，研究了阈下动力学在神经元信号传导中的作用。在广泛的刺激条件下，脉冲串中的第一个脉冲引发动作电位，而所有后续脉冲在轴突和FN模型中均引发阈下反应。霍奇金和赫胥黎1952年的模型无法很好地描述这些结果。根据刺激条件，在FN模型和轴突这两个系统中都可以观察到各种不同的阈下反应模式，包括混沌动力学。在某些条件下，动作电位偶尔会穿插在阈下事件中，且峰间间隔随机出现。这种随机性直接归因于潜在的阈下混沌——确定性混沌——而非随机噪声源。我们得出结论，这种机制可能有助于解释在整个神经系统中从单个神经元观察到的多峰峰间间隔直方图。
