Rubinstein J T, Spelman F A
Regional Primate Research Center, University of Washington, Seattle, Washington 98195.
Biophys J. 1988 Dec;54(6):975-81. doi: 10.1016/S0006-3495(88)83035-2.
The cable model of a passive, unmyelinated fiber in an applied extracellular field is derived. The solution is valid for an arbitrary, time-varying, applied field, which may be determined analytically or numerically. Simple analytical computations are presented. They explain a variety of known phenomena and predict some previously undescribed properties of extracellular electrical stimulation. The polarization of a fiber in an applied field behaves like the output of a spatial high-pass and temporal low-pass filter of the stimulus. High-frequency stimulation results in a more spatially restricted region of fiber excitation, effectively reducing current spread relative to that produced by low-frequency stimulation. Chronaxie measured extracellularly is a function of electrode position relative to the stimulated fiber, and its value may differ substantially from that obtained intracellularly. Frequency dependence of psychophysical threshold obtained by electrical stimulation of the macaque cochlea closely follows the frequency dependence of single-fiber passive response.
推导了处于外加细胞外电场中的无源无髓鞘纤维的电缆模型。该解对于任意随时间变化的外加电场均有效，可通过解析法或数值法确定该电场。给出了简单的解析计算。它们解释了各种已知现象，并预测了细胞外电刺激一些先前未描述的特性。纤维在外加电场中的极化表现类似于刺激的空间高通和时间低通滤波器的输出。高频刺激导致纤维兴奋的空间限制区域更窄，相对于低频刺激产生的电流扩散，有效地减少了电流扩散。细胞外测量的时值是电极相对于受刺激纤维位置的函数，其值可能与细胞内测量的值有很大差异。通过电刺激猕猴耳蜗获得的心理物理阈值的频率依赖性与单纤维被动反应的频率依赖性密切相关。
