In vivo Whole-Cell Recordings Combined with Electron Microscopy Reveal Unexpected Morphological and Physiological Properties in the Lateral Nucleus of the Trapezoid Body in the Auditory Brainstem.
In vivo Whole-Cell Recordings Combined with Electron Microscopy Reveal Unexpected Morphological and Physiological Properties in the Lateral Nucleus of the Trapezoid Body in the Auditory Brainstem.
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DOI：
10.3389/fncir.2016.00069
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发表时间：
2016
影响因子：
3.5
通讯作者：
Joris PX
中科院分区：
文献类型：
--
作者：
Franken TP;Smith PH;Joris PX
梯形体外侧核（LNTB）是包括人类在内的哺乳动物上橄榄复合体中的一个突出核。由于缺乏记录，对其体内的生理学知之甚少。它被认为可以向内侧上橄榄（MSO）提供甘氨酸投射，在双耳处理和声音定位中发挥重要作用。我们将体内膜片钳记录与蒙古沙鼠个体神经元的标记结合起来。对记录的神经元进行标记使我们能够在光和电子显微镜水平上将生理特性与解剖学联系起来。我们发现了一群位于背侧的神经元，它们具有令人惊讶的大树突树，大部分突触输入都撞击到树突树上。在大多数神经元中，一个或多个树突穿过 MSO，然后位于 MSO 的内侧。这些神经元通常是双耳的，甚至可以表现出对刺激精细结构或包络的耳间时间差（ITD）的敏感性。此外，一个亚群表现出对调谐曲线尾部传递的音调的锁相增强。我们认为这些神经元构成了沙鼠主要 LNTB (mLNTB)。相比之下，我们发现了一个较小的神经元样本，其位置更靠腹侧，我们将其指定为位于后腹侧 LNTB (pvLNTB)。这些细胞从球状浓密细胞接收大的体细胞兴奋末梢。我们还发现了先前未描述的来自外侧上橄榄的突触输入。 pvLNTB 神经元通常是单耳的，对 CF 处的同侧短音表现出类似初级的带缺口响应，并且可以锁相到低频音。我们得出的结论是，mLNTB 包含一群具有扩展树突树的神经元，其中发现了大部分突触输入，这可以显示出增强的锁相和对 ITD 的敏感性。 pvLNTB 细胞被认为向 MSO 提供甘氨酸能输入，获得大量体细胞球状浓密突触输入，并且通常是单耳的，具有类似于其来自耳蜗核的主要输入的短音响应。
The lateral nucleus of the trapezoid body (LNTB) is a prominent nucleus in the superior olivary complex in mammals including humans. Its physiology in vivo is poorly understood due to a paucity of recordings. It is thought to provide a glycinergic projection to the medial superior olive (MSO) with an important role in binaural processing and sound localization. We combined in vivo patch clamp recordings with labeling of individual neurons in the Mongolian gerbil. Labeling of the recorded neurons allowed us to relate physiological properties to anatomy at the light and electron microscopic level. We identified a population of quite dorsally located neurons with surprisingly large dendritic trees on which most of the synaptic input impinges. In most neurons, one or more of these dendrites run through and are then medial to the MSO. These neurons were often binaural and could even show sensitivity to interaural time differences (ITDs) of stimulus fine structure or envelope. Moreover, a subpopulation showed enhanced phase-locking to tones delivered in the tuning curve tail. We propose that these neurons constitute the gerbil main LNTB (mLNTB). In contrast, a smaller sample of neurons was identified that was located more ventrally and that we designate to be in posteroventral LNTB (pvLNTB). These cells receive large somatic excitatory terminals from globular bushy cells. We also identified previously undescribed synaptic inputs from the lateral superior olive. pvLNTB neurons are usually monaural, display a primary-like-with-notch response to ipsilateral short tones at CF and can phase-lock to low frequency tones. We conclude that mLNTB contains a population of neurons with extended dendritic trees where most of the synaptic input is found, that can show enhanced phase-locking and sensitivity to ITD. pvLNTB cells, presumed to provide glycinergic input to the MSO, get large somatic globular bushy synaptic inputs and are typically monaural with short tone responses similar to their primary input from the cochlear nucleus.