Age-related decreases in the conduction velocity (CV) of action potentials along myelinated axons have been linked to morphological changes in the myelin sheath. In particular, evidence suggests the presence of segmental demyelination and remyelination of axons. In remyelinated segments, the distance between adjacent nodes of Ranvier is typically shorter, and myelin sheaths are thinner. Both experimental and computational evidence indicates that shortened internodes slows CV. In this computational study, we determine the impact of progressive segmental demyelination and remyelination, modeled by shorter internodes with thinner myelin sheaths interspersed with normal ones, upon the CV. We find that CV progressively decreases as the number of remyelinated segments increases, but this decrease is greater than one would expect from an estimate of the CV based merely upon the number of short and long internodes. We trace the additional suppression of the CV to transitions between long and short internodes. Our study presents an important consideration for the precise modeling of neural circuits with remyelinated neurons.

与年龄相关的髓鞘轴突动作电位传导速度（CV）的下降与髓鞘的形态变化有关。特别是，证据表明存在轴突节段性脱髓鞘和再髓鞘化。在髓鞘节段中，Ranvier相邻节之间的距离通常较短，而髓鞘则较薄。实验和计算证据均表明，节间缩短会降低CV。在这项计算研究中，我们确定了渐进节段性脱髓鞘和再髓鞘化对较短的节间，较薄的髓鞘和正常的髓鞘的影响。我们发现CV随着髓鞘片段数量的增加而逐渐降低，但是这种减少大于仅根据短节和长节之间的数量对CV进行估计所得出的结果。我们跟踪对CV的额外抑制，以发现长节间和短节间之间的过渡。我们的研究提出了具有髓鞘神经元的神经回路的精确建模的重要考虑。