Mouse brainstem auditory nuclei development.

The cross-sectional areas of brainstem auditory neurons were measured in a potential developmental series of mice. There is no demonstrable neuronal growth between days 1 and 3. Between days 3 and 12 the neuronal somas grow rapidly to their adult size. Most of this growth occurs prior to any cochlear physiological activity and all of it occurs before cochlear maturation. Most brainstem auditory neurons of 45-day-old mice postnatally deprived of sound or with conductive losses are of a size comparable to normal nine-day-old mice.