动作电位编码光学二次谐波快速检测神经纤维膜电位动力学

神经纤维膜电位动力学特性与神经信息的传导和编码密切关联。目前,传统电生理测量方法无法同时对膜上多个部位的动作电位进行快速检测。利用非线性光学二次谐波方法,通过数学建模,研究了髓鞘神经纤维动作电位编码的二次谐波信号特征及其检测灵敏性,并将其用于分析由压力引起的神经纤维形态改变,包括轴突直径和髓鞘厚度的改变,实现神经传导信息变化的快速检测。发现神经纤维膜电位的变化可以通过光学二次谐波信号的特征来表征。当神经纤维严重脱鞘时,其上的动作电位会产生明显的传输阻滞。结果表明光学二次谐波技术有望成为神经纤维损伤状态快速检测的一种有力手段。

Membrane Potential Dynamics of Nerve Fibers Fast Probed by Action-Potential-Encoded Second Harmonic Generation

Action potential dynamics of nerve fibers is related to the information conduction and code among neurons. Nowadays, traditional electrophysiologic approach still could not fast probe the action potential dynamics simultaneously at multiple positions on nerve fibers. Nonlinear optical second harmonic generation combined with mathematical modeling is used to study the characteristics of myelinated nerve fibers. The detected sensitivity of the method is analyzed at first, and then, the information changes induced by the changes in morphology including axonal diameter and myelin thickness on a myelinated nerve fiber under a compression are investigated. The results demonstrate that changes in membrane potential induced by a compression may be fast probed via second harmonic generation. Furthermore, the action potential conduction is blocked when severe demyelination happens on the nerve fiber. It is shown that optical second harmonic generation is a potential tool to evaluate the injured states of nerve fibers.