Ushida T, Tani T
Department of Orthopaedic Surgery, Kochi Medical School, Japan.
Nihon Seikeigeka Gakkai Zasshi. 1994 Apr;68(4):207-20.
Single nerve fiber action potential (single-NAP) was computer simulated using solid angle approximation theory. The simulated spinal cord evoked potential (Simulated-SCEP) was then produced by summing the simulated single-NAPs according to the data of the fiber diameter spectrum of the human spino-cerebellar tract. To model the conduction block phenomenon in the spinal cord, it was assumed that each fiber impulse which reached the conduction block point could not go through the point and gradually became smaller. When the largest 10% of the constituent fibers had become blocked, there was augmentation of the negative peak at just before the conduction block point and at every point after the block. As the percentage of the blocked fibers increased, the amplitude of the simulated-SCEP decreased at every point except at just before the block. When 50% or more of the largest fibers were blocked, then augmentation of the negative peak still remained at just before the conduction block. However at the points just after the conduction block there was a monophasic positive waveform which is known as the killed-end potential. Phase cancellation normally dictates the wave forms of compound action potential. However, the killed-end potential and the augmentation of the amplitude associated with the conduction block can be explained by the loss of the phase cancellation.
利用立体角近似理论对单神经纤维动作电位（single-NAP）进行了计算机模拟。然后根据人类脊髓小脑束纤维直径谱的数据，将模拟的单神经纤维动作电位进行叠加，从而产生模拟脊髓诱发电位（Simulated-SCEP）。为了模拟脊髓中的传导阻滞现象，假设每个到达传导阻滞点的纤维冲动都无法通过该点，并逐渐变小。当最大的10%的组成纤维发生阻滞时，在传导阻滞点之前以及阻滞点之后的每个点，负峰都会增大。随着阻滞纤维百分比的增加，除了阻滞点之前的点外，模拟脊髓诱发电位在每个点的幅度都会降低。当最大纤维的50%或更多发生阻滞时，在传导阻滞点之前仍会出现负峰增大的情况。然而，在传导阻滞点之后的点会出现一种单相正波形，即所谓的终末失活电位。通常情况下，相位抵消决定复合动作电位的波形。然而，终末失活电位以及与传导阻滞相关的幅度增大可以通过相位抵消的丧失来解释。
