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arXiv 2005.10598q-bio.NCcs.NAmath.NA
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随机Hodgkin-Huxley动力学的快速精确Langevin模拟

Fast and Accurate Langevin Simulations of Stochastic Hodgkin-Huxley Dynamics

Shusen Pu, Peter J. Thomas

摘要:

Fox和Lu为随机门控离子通道的离散时间随机模型(如Hodgkin-Huxley(HH)系统)引入了朗之万框架。他们导出了具有状态相关扩散张量$D$的福克-普朗克方程,并提出了具有噪声系数矩阵$S$的朗之万公式,使得$SS^\intercal=D$。随后,几位作者介绍了HH系统的各种朗之万方程。在本文中,我们提出了一个自然的14维动力学的HH系统中,每个\emph{directed}边缘的离子通道状态转换图作为一个独立的噪声源,导致$14\times 28$噪声系数矩阵$S$。我们证明了(i)相应的14维常微分系统\rev{equations}与HH系统的经典4维表示是一致的:(ii)14维表示导致噪声系数矩阵$S$,它可以在每个时间步上廉价地获得,而不需要矩阵分解;(iii)14 D表示的样本轨迹在路径上等同于Fox和Lu系统的轨迹,以及几个现有Langevin模型的轨迹;(iv)我们的14 D表示(以及与之等效的表示)给出了最准确的尖峰间期分布,不仅在矩方面,而且在$L_1$和$L_\infty$度量空间规范下;以及(v)14 D表示给出了与所有等效模型一样快速和有效的精确马尔可夫链模拟的近似。我们的方法超越了现有的模型,因为它支持一个随机屏蔽分解,大大简化了$S$与电压和电流钳条件下的精度损失最小。

英文摘要:

Fox and Lu introduced a Langevin framework for discrete-time stochastic models of randomly gated ion channels such as the Hodgkin-Huxley (HH) system. They derived a Fokker-Planck equation with state-dependent diffusion tensor $D$ and suggested a Langevin formulation with noise coefficient matrix $S$ such that $SS^\intercal=D$. Subsequently, several authors introduced a variety of Langevin equations for the HH system. In this paper, we present a natural 14-dimensional dynamics for the HH system in which each \emph{directed} edge in the ion channel state transition graph acts as an independent noise source, leading to a $14\times 28$ noise coefficient matrix $S$. We show that (i) the corresponding 14D system of ordinary differential \rev{equations} is consistent with the classical 4D representation of the HH system; (ii) the 14D representation leads to a noise coefficient matrix $S$ that can be obtained cheaply on each timestep, without requiring a matrix decomposition; (iii) sample trajectories of the 14D representation are pathwise equivalent to trajectories of Fox and Lu's system, as well as trajectories of several existing Langevin models; (iv) our 14D representation (and those equivalent to it) give the most accurate interspike-interval distribution, not only with respect to moments but under both the $L_1$ and $L_\infty$ metric-space norms; and (v) the 14D representation gives an approximation to exact Markov chain simulations that are as fast and as efficient as all equivalent models. Our approach goes beyond existing models, in that it supports a stochastic shielding decomposition that dramatically simplifies $S$ with minimal loss of accuracy under both voltage- and current-clamp conditions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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