Department of Chemosensation, Institute for Biology 2, RWTH Aachen University, Worringer Weg 3, D-52074, Aachen, Germany.
Hear Res. 2019 Dec;384:107824. doi: 10.1016/j.heares.2019.107824. Epub 2019 Oct 17.
Bushy cells of the ventral cochlear nucleus are time-coding neurons. They receive axosomatic synaptic terminals from the auditory nerve, the so-called endbulb of Held synapses and project to sound localization centers in the superior olivary complex. Bushy cells are specialized to maintain and even improve the temporal code contained in the auditory nerve activity. In the present review an overview is given of the dynamic features and convergent inputs that modulate the response of bushy cells to auditory stimuli. The biophysics and synaptic specializations and dynamics of these neurons were studied extensively. These studies will be reviewed briefly in the initial part of this paper. In addition to auditory nerve input, powerful but slow inhibitory inputs act on bushy cells. Studies on these inhibitory inputs to bushy cells are discussed as part of this review. Furthermore, evidence for four classes of additional or secondary inputs that also impinge on the bushy cells will be reviewed: 1) small auditory nerve boutons, 2) commissural connections that are either inhibitory or excitatory, 3) multimodal inputs from somatosensory nuclei and 4) descending modulatory axons employing monoaminergic transmitters all interact with the main auditory nerve input in the bushy cells. The present article aims at reviewing how complex the influences on neuronal processing are, already in this early stage of the auditory pathway. It is concluded that the various modulatory influences help to better adapt bushy cell coding functions to dynamics of the sensory world.
腹侧耳蜗核的毛细胞是时间编码神经元。它们接收来自听神经的轴突体突触末端，即所谓的 Held 终球突触，并投射到上橄榄复合体中的声音定位中心。毛细胞专门用于维持甚至改善听神经活动中包含的时间编码。在本综述中，概述了调节毛细胞对听觉刺激反应的动态特征和会聚输入。这些神经元的生物物理学和突触特化和动力学已被广泛研究。本文的初始部分将简要回顾这些研究。除了听神经输入外，强大但缓慢的抑制性输入也作用于毛细胞。本文将讨论这些对毛细胞的抑制性输入研究。此外，还将回顾对毛细胞的四类其他或次要输入的证据：1）小听神经末梢，2）兴奋性或抑制性的连合连接，3）来自躯体感觉核的多模态输入，以及 4）使用单胺递质的下行调制轴突，它们都与毛细胞中的主要听神经输入相互作用。本文旨在综述在听觉通路的早期阶段，对神经元处理的影响是多么复杂。结论是，各种调制影响有助于更好地适应毛细胞编码功能对感觉世界动态的变化。
