Incomplete maturation of brainstem auditory nuclei in genetically induced early postnatal cochlear degeneration.
In the Shaker-2 mouse mutant, a cochleo-saccular type of genetically induced inner ear degeneration occurs. Morphological signs of degeneration are evident in the 3rd postnatal week and a severe and almost total degeneration has occurred by the age of 6-9 weeks. There are no qualitative differences between the brain of the normal CBA/J mouse and that of the Shaker-2 mouse. The growth of the auditory brainstem nuclei (dorsal cochlear nucleus and ventral cochlear nucleus) in the mutant Sh-2 mouse has stopped by 14 days of age--but not in the normal CBA/J mouse. The brainstem as a whole continues to grow between 14 and 140 days of age in both strains. The early cochlear degeneration coincides with the critical period when a normal input from the peripheral receptor organ is necessary for the maturation of the central auditory pathway.
D000818:Animals; D001933:Brain Stem / Q000254:growth & development*; D003051:Cochlea / Q000473:pathology; D003056:Cochlear Nerve / Q000254:growth & development*; D007759:Labyrinth Diseases / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008808:Mice, Inbred CBA; D008817:Mice, Mutant Strains; D009925:Organ of Corti / Q000254:growth & development; D014726:Vestibular Nuclei / Q000254:growth & development