Qualitative Investigation of the Postnatal Development of Axon and Nerve Fiber Calibers in the Ventral Roots of Rats

Abstract

The postnatal development of the ventral spinal roots of rats was studied with optical microscopic and morphometric methods. Adult rats show a craniocaudal decrease of axon and nerve fiber diameters which cannot be detected in younger animals. The bimodal differentiation of the nerve fiber populations occurs between the 15th and 20th day. Myelinated nerve fibers show a g ratio of 0.6 for all examined age groups.