Shift of tonotopic organization in brain stem auditory nuclei of the chicken during late embryonic development.

The tonotopic organization of nucleus magnocellularis and nucleus laminaris, second and third order nuclei in the avian auditory system, was mapped in 19-20-day old chick embryos (E19-20). The characteristic frequency recorded at any given location in each nucleus was intermediate between the frequencies observed previously at E17 and one day after hatching. This indicates that tonotopic organization changes during the embryonic as well as the postnatal development of hearing in birds.