The fine structure of the node of Ranvier in the rat cerebellar cortex.

The transitional zone between the myelinated and the terminal portions of nerve fibers was electron microscopically investigated in the cerebellar cortex of normal rats. A noteworthy finding in the present study is the existence of a "heminode" consisting of the myelinated and non-myelinated portions, as demonstrated within a single section. The heminode seems to be a characteristic structure in the granular layer of the rat cerebellar cortex.