Myelination kinetics of spiral ganglion cells in kitten.

A study of the regions of myelination of spiral ganglion cell bodies at birth in the kitten revealed that the first myelination occurred before birth. A quantitative analysis of myelinated versus unmyelinated cells, and the distribution of myelin lamellae of the ganglion cell sheath reflect the kinetics of the later stages of cochlear maturation. The onset of the final maturation process begins in the basal region of the first turn, which is 20% of the length of the spiral lamina measured from the basal extremity of the cochlea. This maturation proceeds in an orderly manner from the lower half of the first turn to the apex, but also develops to a smaller degree toward the hook region. Results are compared with previous findings.