Effects of spinal cord stimulation on the differentiation of posterior latissimus dorsi nerve in the chick embryo

Abstract Spinal cord stimulation was carried out during embryonic development of the chick from the 10th day until 13.5, 14.5, or 15.5 days of embryonic life. The effects of this superimposed neuronal activity upon the cytodifferentiation of the nerve entering the posterior latissimus dorsi (PLD) muscle were studied by comparative analysis of electron micrographs of PLD nerves from control and spinal cord-stimulated embryos. For each embryonic stage studied, electrical stimulation of the spinal cord appeared to accelerate the growth of axons, to enhance Schwann cell mitosis, and the enclosure of a single axon in a Schwann cell, i.e., the process of myelination. These results underline the role of neuronal activity in the maturation of a developing nerve.