Type II Cochlear Ganglion Neurons Do Not Drive the Olivocochlear Reflex: Re-Examination of the Cochlear Phenotype in Peripherin Knock-Out Mice.
Type II Cochlear Ganglion Neurons Do Not Drive the Olivocochlear Reflex: Re-Examination of the Cochlear Phenotype in Peripherin Knock-Out Mice.
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DOI：
10.1523/eneuro.0207-16.2016
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发表时间：
2016-07
期刊：
影响因子：
3.4
通讯作者：
Liberman MC
中科院分区：
文献类型：
--
作者：
Maison S;Liberman LD;Liberman MC
耳蜗神经包括一小部分无髓感觉纤维，将外毛细胞连接到大脑。这些II型传入神经元的功能作用是有争议的，因为神经生理学数据很少。最近的一项研究报道，靶向删除外周蛋白，一种神经细丝，消除了II型传入并灭活了对外部毛细胞的传出反馈，从而表明II型传入是这种声音诱发的负反馈反射--橄榄耳蜗路的感觉驱动力。在这里，我们从外周基因敲除线重新评估了小鼠的耳蜗表型，结果表明：(1)II型传入终末在正常数量中存在；(2)即使当这一传出通路被电击直接激活时，也不存在对耳蜗反应的橄榄耳抑制。我们的结论是，II型神经元不是传出反射的感觉驱动力，外周蛋白缺失可能导致橄榄耳蜗末梢与其外周靶点之间的突触传递功能障碍。
The cochlear nerve includes a small population of unmyelinated sensory fibers connecting outer hair cells to the brain. The functional role of these type II afferent neurons is controversial, because neurophysiological data are sparse. A recent study reported that targeted deletion of peripherin, a type of neurofilament, eliminated type II afferents and inactivated efferent feedback to the outer hair cells, thereby suggesting that type II afferents were the sensory drive to this sound-evoked, negative-feedback reflex, the olivocochlear pathway. Here, we re-evaluated the cochlear phenotype in mice from the peripherin knock-out line and show that (1) type II afferent terminals are present in normal number and (2) olivocochlear suppression of cochlear responses is absent even when this efferent pathway is directly activated by shocks. We conclude that type II neurons are not the sensory drive for the efferent reflex and that peripherin deletion likely causes dysfunction of synaptic transmission between olivocochlear terminals and their peripheral targets.