Sinha Nirvik, Heckman C J, Yang Yuan
Northwestern Interdepartmental Neuroscience Program, Feinberg School of Medicine, Northwestern University, 320 E Superior Street, Morton 1-645, Chicago, IL 60611-3010, USA; Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Ave., Suite 1100, Chicago, IL 60611, USA.
Northwestern Interdepartmental Neuroscience Program, Feinberg School of Medicine, Northwestern University, 320 E Superior Street, Morton 1-645, Chicago, IL 60611-3010, USA; Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Ave., Suite 1100, Chicago, IL 60611, USA; Department of Physiology, Feinberg School of Medicine, Northwestern University, 310 E. Superior Street Morton 5-660, Chicago, IL 60611, USA.
J Theor Biol. 2021 Jan 21;509:110509. doi: 10.1016/j.jtbi.2020.110509. Epub 2020 Oct 3.
A major challenge in understanding spike-time dependent information encoding in the neural system is the non-linear firing response to inputs of the individual neurons. Hence, quantitative exploration of the putative mechanisms of this non-linear behavior is fundamental to formulating the theory of information transfer in the neural system. The objective of this simulation study was to evaluate and quantify the effect of slowly activating outward membrane current, on the non-linearity in the output of a one-compartment Hodgkin-Huxley styled neuron. To evaluate this effect, the peak conductance of the slow potassium channel (g) was varied from 0% to 200% of its normal value in steps of 33%. Both cross- and iso-frequency coupling between the input and the output of the simulated neuron was computed using a generalized coherence measure, i.e., n:m coherence. With increasing g, the amount of sub-harmonic cross-frequency coupling, where the output frequencies (1-8 Hz) are lower than the input frequencies (15-35 Hz), increased progressively whereas no change in iso-frequency coupling was observed. Power spectral and phase-space analysis of the neuronal membrane voltage vs. slow potassium channel activation variable showed that the interaction of the slow channel dynamics with the fast membrane voltage dynamics generates the observed sub-harmonic coupling. This study provides quantitative insights into the role of an important membrane mechanism i.e. the slowly activating outward current in generating non-linearities in the output of a neuron.
理解神经系统中与尖峰时间相关的信息编码的一个主要挑战是单个神经元对输入的非线性放电反应。因此，对这种非线性行为的假定机制进行定量探索是构建神经系统信息传递理论的基础。本模拟研究的目的是评估和量化缓慢激活的外向膜电流对单室霍奇金-赫胥黎式神经元输出非线性的影响。为了评估这种影响，慢钾通道的峰值电导（g）以33%的步长从其正常值的0%变化到200%。使用广义相干度量（即n:m相干）计算模拟神经元输入和输出之间的交叉频率耦合和同频耦合。随着g的增加，输出频率（1 - 8赫兹）低于输入频率（15 - 35赫兹）的次谐波交叉频率耦合量逐渐增加，而同频耦合没有变化。神经元膜电压与慢钾通道激活变量的功率谱和相空间分析表明，慢通道动力学与快速膜电压动力学的相互作用产生了观察到的次谐波耦合。本研究为一种重要的膜机制，即缓慢激活的外向电流在产生神经元输出非线性方面的作用提供了定量见解。
