The effects of auditory deprivation on morphological maturation of the ventral cochlear nucleus

The volumes of the auditory brainstem nuclei and age-related auditory brainstem response (ABR) thresholds were analyzed in homozygote (je/je) and heterozygote (je/+) jerker mutant mice. Altogether 97 mice were used in the study. Je/je mice never develop any hearing. The dorsal (DCN) and ventral (VCN) cochlear nuclei were found to have stopped their growth at 56 days after birth. In je/+ mutants, ABR thresholds remained normal or near-normal for 3-6 months, whereas VCN and DCN volumes remained unchanged at least after 56 days after birth. There is no significant difference in DCN volume in je/je and je/+ mice. However, the VCN volume and the cross-sectional area of globular cells were both significantly larger in je/+ than in je/je mice (P less than 0.01). These findings show that auditory deprivation during the maturation of hearing in je/je mutants causes an incomplete maturation of only the ventral cochlear nucleus.