Postnatal maturation in the cochlea of the cat

Abstract At birth, the cochlea of the cat, though generally developed, is still immature. Maturation of the organ of Corti begins at the base and gradually reaches the apex. In two weeks the process is complete. The most significant morphological criteria of the epithelial maturation are the formation of the tunnel of Corti and of the space of Nuel, the lengthening of the outer hair cells and the freeing of the internal spiral sulcus. On the third day after birth, the appearance of these criteria at the level of the first coil of the lamina spiralis coincides with the general physiological awakening of the auditory systems, as testified by the recording of evoked potentials from the cerebral cortex. Since such responses can be provoked by electrical stimulation of the nerve from birth onwards, the maturation of the organ of Corti appears to be the final stage in the development of the auditory system.