Department of Otolaryngology-Head and Neck Surgery, Kanazawa University, Kanazawa, 920-8640, Ishikawa, Japan.
Department of Neuroscience, Carleton University, Ottawa, Ontario, K1S 5B6, Canada.
Sci Rep. 2019 Apr 4;9(1):5643. doi: 10.1038/s41598-019-41955-y.
To understand brain changes caused by auditory sensory deprivation, we recorded local-field potentials in the inferior colliculus of young adult rats with neonatal cochlear damage produced by systemic injections of amikacin. The responses were elicited by electrical stimulation of the entire cochlea and recorded at various locations along a dorsolateral-ventromedial axis of the inferior colliculus. We found that hair cells were completely destroyed and spiral ganglion neurons were severely damaged in the basal cochleae of amikacin-treated animals. Hair cells as well as spiral ganglion neurons were damaged also in the middle and apical areas of the cochlea, with the damage being greater in the middle than the apical area. Amplitudes of local-field potentials were reduced in the ventromedial inferior colliculus, but enhanced in the dorsolateral inferior colliculus. Latencies of responses were increased over the entire structure. The enhancement of responses in the dorsolateral inferior colliculus was in contrast with the damage of hair cells and spiral ganglion cells in the apical part of the cochlea. This contrast along with the overall increase of latencies suggests that early cochlear damage can alter neural mechanisms within the inferior colliculus and/or the inputs to this midbrain structure.
为了理解听觉感觉剥夺引起的大脑变化，我们记录了氨基糖苷类抗生素全身注射致新生大鼠耳蜗损伤后，下丘脑中的局部场电位。通过对整个耳蜗的电刺激来诱发反应，并在下丘脑中沿背外侧-腹内侧轴的不同位置进行记录。我们发现，氨基糖苷类抗生素处理的动物的耳蜗底部毛细胞完全破坏，螺旋神经节神经元严重受损。耳蜗中部和顶部也有毛细胞和螺旋神经节神经元受损，中部的损伤比顶部更严重。腹侧下丘脑中的局部场电位幅度降低，但背外侧下丘脑中的局部场电位幅度增强。反应的潜伏期在整个结构中增加。背外侧下丘脑中反应的增强与耳蜗顶部毛细胞和螺旋神经节细胞的损伤形成对比。这种对比以及潜伏期的整体增加表明，早期耳蜗损伤可以改变下丘脑中的神经机制和/或传入该中脑结构的输入。
