Investigation of Electro-mechanical Coupling in Neuronal Membrane - Towards an Electro-mechanical Model of Nerve Pulse Propagation

该项目与神经退行性疾病的基础研究以及涉及植入物和电极的相应治疗相关。这一结果将更有利于更好地理解神经元的功能。随着人类神经系统并发症的增加，电刺激植入物的使用也越来越多。然而，神经脉冲传递下的基本现象尚不清楚。除了关于神经脉冲产生和传播的霍奇金-赫胥黎假说和模型外，2005年Heimburg和Jackson还提出了基于热力学的假说和模型。其中脂质相变和脂质基质中相关的机电变化被认为是神经信号传递的原因。脂质基质在神经信号产生和传播中的作用不容忽视，需要从理论和实验两方面进行研究。20世纪60年代有许多实验发现，显著地表明了脂质膜的机电耦合特性。然而，脂-脂链转换的固有特性影响了电-机械特性，并可能负责神经脉冲的产生和传播。从理论上和实验上研究这种多参数依赖性确实很重要。因此，本项目的目的是通过理论程序研究脂质膜的机电耦合，为神经脉冲的产生和传播提供机电模型。为此，建立了具有空间变介电常数的生理条件下脂质双分子层的静电模型。因此，神经信号传递的多物理场模型可用于耳蜗和深部脑刺激模型等神经植入研究。主要目标是：1。模拟神经脉冲传播的多物理现象，包括热力学、力学和电学现象。为了在数值上解决这个耦合问题3。为了更好地理解神经元的功能

The proposed project is connected to the basic research of neurodegenerative disorders and respective treatments involving implants and electrodes. The results would be more beneficial for a better understanding of neuronal function. With growing number of neurological complications in human population, the usage of electrically stimulating implants is growing. However, the basic phenomena under the nerve pulse transmission are not clearly understood. Besides the Hodgkin-Huxley hypothesis and model about nerve pulse generation and propagation, in 2005 Heimburg and Jackson have proposed a thermodynamics-based hypothesis and model. Therein the lipid phase transition and the associated electro-mechanical changes in the lipid matrix are attributed for the nerve signal transmission. The role of the lipid matrix in the nerve signal generation and propagation cannot be ignored and needs to be investigated both theoretically and experimentally. There are number of experimental findings in 1960s that have significantly shown the coupling of electro-mechanical properties of lipid membranes. However, the intrinsic property of lipid-lipid chain transition affects the electro-mechanical properties and can be responsible for nerve pulse generation and propagation. It is indeed important to investigate this multi-parametric dependence both theoretically and experimentally. Therefore, the aim of this project is to investigate the electro-mechanical coupling of lipid membranes through theoretical procedures and to provide an electro-mechanical model for nerve pulse generation and propagation. To this end, electrostatic models for lipid bilayers in physiological conditions, with space varying permittivity have been developed. Thus the multi-physics model for nerve signal transmission can be used in neurological implant studies like Cochlea and Deep Brain Stimulation models. The key objectives are 1. to model the multi-physics phenomena of nerve pulse propagation including thermodynamics, mechanical and electrical phenomena 2. to solve this coupled problem numerically 3. for gaining better understanding of neuronal function