高频双向电刺激下无髓神经模型传导阻断的仿真研究

Simulation study of unmyelinated nerve model blocked by high frequency biphasic electrical stimulation

目的：神经纤维异常兴奋会造成许多功能障碍疾病，因此，研究无髓神经纤维受到电刺激时动作电位的传播规律及传导阻断情况有重要的科研意义和临床价值。方法本文基于 Hodgkin-Huxley模型，在高频双向电刺激下研究无髓神经纤维的阻断阈和阻断机制，并提出一种电刺激结束后轴突恢复初始状态的时间测量方法。结果电刺激下直径大的神经纤维先被阻断，直径小的神经纤维后被阻断，并随着刺激频率的增加，阻断阈在12~16 kHz时达到峰值。阻断电极处钠离子和钾离子通道的持续开放造成神经纤维的传导阻断。电刺激结束后，神经纤维恢复初始状态的时间随着频率的增加而增加。结论本研究揭示了无髓神经纤维的阻断机制以及电刺激结束后神经纤维恢复初始状态的时间与电刺激频率的关系，这些结果将为相关动物实验和功能电刺激的临床应用提供更多的信息。

Objective Abnormal nerve fiber activation can cause many disorder diseases. Therefore, the study on action potential propagation and conduction block of unmyelinated nerve with electrical stimulation has great values for science research and clinical application. Methods Based on Hodgkin-Huxley model,we research on fiber blocking threshold and blocking mechanism of unmyelinated nerve under high frequency biphasic electrical stimulation. A measurement method for the recovery time of axon to the initial state after electrical stimulation is proposed in this paper. Results Larger diameter fibers tend to be blocked early than smaller nerve fibers under electrical stimulation. With the increase of frequency,the biggest block threshold is 12 kHz to 16 kHz. The high frequency stimulation produces constant activation of both sodium and potassium channels at the nerve fiber node under the block electrode,which causes the conduction block of nerve fiber. After the electrical stimulation,the recovery time of nerve fiber to the initial state increases with the increase of frequency. Conclusions This study reveals the blocking mechanism of unmyelinated nerve fiber,and the relationship between recovery time of axon to the initial state and the frequency of electrical stimulation after electrical stimulation. The results can provide more information for animal experiments and clinical applications.