Tai C, Jiang D
Biomedical Engineering Institute, Xi'an Jiaotong University, Shaanxi, China.
IEEE Trans Biomed Eng. 1994 Mar;41(3):286-91. doi: 10.1109/10.284949.
Electrical stimulation of unmyelinated nerve fibers is analyzed, using point sources in a simple volume conductor model and a dynamic Hodgkin-Huxley model of nerve fiber. The excitation and blocking threshold of single cathode stimulation with an indifference anode at infinity are calculated by solving difference equations with axons of different diameters. The relation between the blocking threshold and the pulsewidth of single cathode stimulation is also calculated. The results suggest a method of selectively stimulating the smaller fibers in a compound nerve trunk. Two kinds of stimulation electrodes are designed to test this method. Both of them are proven to yield results in accordance with our model by the animal experiments on a toad's sciatic nerve trunk. It is possible to excite the smaller fibers without exciting the larger ones in a compound nerve trunk by properly controlling the stimulus intensity. The method is likely to be used in both physiological experiments and neural prostheses.
利用简单容积导体模型中的点源和神经纤维的动态霍奇金-赫胥黎模型，对无髓神经纤维的电刺激进行了分析。通过求解不同直径轴突的差分方程，计算了在无穷远处设置无关阳极时单阴极刺激的兴奋阈值和阻断阈值。还计算了单阴极刺激的阻断阈值与脉冲宽度之间的关系。结果提出了一种选择性刺激复合神经干中较细纤维的方法。设计了两种刺激电极来测试该方法。通过对蟾蜍坐骨神经干的动物实验，证明这两种电极都能产生与我们模型相符的结果。通过适当控制刺激强度，有可能在复合神经干中兴奋较细纤维而不兴奋较粗纤维。该方法可能会用于生理实验和神经假体。
