近年、先天聾小児の人工内耳手術が増加し、手術時期も低年齢化が進んでいる。先天聾における聴覚中枢の発生が正常と比べてどのように変化するかについて検討した。我々の開発した薬剤性先天聾モデルを用いて、脳幹部聴覚中枢から下丘への神経投射を検討したところ、交叉性/非交叉性投射路の比率が、正常発達ラットとは異なっており、外側網帯核から下丘への投射に比べて、蝸牛神経核から下丘への投射が、先天聾の影響をより強く受けることが明らかとなった。
The purpose of this study was to investigate the effects of early hearing loss on the anatomy of the central auditory system, specifically, the ascending projections to the inferior colliculus (IC). We compared normal animals with animals deafened during early development by administration of amikacin, an ototoxic antibiotic that is known to destroy the hair cells in the inner ear. Neonatal deafness reduces the number of labeled neurons projecting from the CN to the IC with the effect being more evident during later stages of deafness. In contrast, there are no significant changes in the projections from DNLL to IC.