Fig. 8.5. A bundle of nerve fibers in layer 5 of the primary visual cortex of a 25 year old monkey. One of the nerve fibers is surrounded by a sheath that is only one lamella thick. The internode of myelin is only 5 microns long and the nodes of Ranvier (nodes) are apparent at each end of the internodal length. The short internodal length and the thin sheath suggest that this nerve fiber is undergoing remyelination.
