The Distribution And The Origin Of Unmyelinated Fibers In The Central Nervous System

Background: The distribution and the origin of unmyelinated fibers in the central nervous system(CNS) are not well known. This is because the positive markers of unmyelinated fibers have not been known or electron micrograph(EM) studies were used for the identification of unmyelinated fibers. Well-known unmyelinated fibers in CNS are hippocampal mossy fibers and cerebellar parallel fibers. Recently we have reported the striatal projection fibers are unmyelinated based on the diffuse staining pattern of antibodies to sodium channel beta4 subunit, which stain Ranvier nodes on myelinated fibers as dot pattern(Miyazaki et al. Nat Commun 2014). We also found anti-Nav1.2 antibodies stain diffusely striatal unmyelinated fibers.