MEDIAL SUPERIOR OLIVARY CIRCUITRY

内侧上橄榄(MSO)被认为在发音中起主要作用 本地化。这是听觉中枢神经系统中的最初位置 来自双耳的声音诱发活动会聚在个体身上并使其兴奋 神经元。有人提出，位于这里的细胞可以通过比较 这些双耳输入，提取并响应重要的时间线索 在此输入信号中可用。这些时间线索会以声音的形式变化 改变方位空间中的位置，也有人提出 MSO细胞群体的不同成员仅对 这些双耳线索产生于这个空间中的一个特定点(S)。 因此，提取了外部空间“地图”的重要方面 在一群选择性敏感的神经元中进行神经编码。 不幸的是，从正面录音的巨大困难 鉴定MSO细胞，使用体内标准细胞外和 细胞内方法阻碍了对这些假说的验证。 我们打算从MSO细胞进行两种体外细胞内记录 (以及从橄榄周核中的细胞输入到MSO)和体内 高阻抗记录MSO轴突的轴突内记录 神经生物素填充的玻璃电极。在体外，我们将描述 MSO细胞的固有膜特征和突触输入 区分可能对实现以下目标非常重要的方面 上述本地化任务。然后我们将学习解剖学 以确定本地电路，并且如果确定 细胞亚型表现出独特的生理学特征。在活体中，我们将记录 当MSO细胞接近下部时，它们从轴突内发出 丘脑外侧丘系，并描述它们对 单耳和双耳刺激。我们随后将分析1) 标记轴突，在光镜和电子显微镜水平上，以确定 MSO细胞对其他听觉核团的影响 回填的MSO胞体的类型以确定1)胞体类型2)其 突触输入3)不同细胞类型是否编码不同的听觉 要素和4)如果它们基于任何一种顺序(地图)进行排列 这些特征(例如，用于编码空间位置的那些特征)。

The medial superior olive (MSO) is presumed to play a major role in sound localization. It is the initial site in the auditory CNS where sound-evoked activity from both ears converges on and excites individual neurons. It has been proposed that cells located here can, by comparing these binaural inputs, extract and respond to important temporal cues available in this incoming signal. These temporal cues change as a sound changes location in azimuthal space and it has also been proposed that different members of the MSO cell population respond optimally to only those binaural cues generated from a particular point(s) in this space. Thus, important aspects of the "map" of external space are extracted and neurally encoded in a population of selectively sensitive neurons. Unfortunately, the great difficulty in recording from positively identified MSO cells, using standard in vivo extracellular and intracellular methods, has hindered verification of such hypotheses. We intend to do both in vitro intracellular recordings from MSO cells (and from cells in periolivary nuclei inputting to MSO) and in vivo intraaxonal recordings from MSO axons using high impedance Neurobiotin-filled glass electrodes. In vitro, we will characterize intrinsic membrane features of - and synaptic inputs to - MSO cells to distinguish aspects that could be important in accomplishing the localization tasks described above. We will then study the anatomical aspects of the labeled cell to determine local circuitry and if certain cell subtypes show unique physiology. In vivo, we will record intraaxonally from axons of MSO cells, as they approach inferior colliculus in lateral lemniscus, and characterize their responses to monaural and binaural stimuli. We will subsequently analyze 1) the labeled axon, at light and electron microscopic levels, to determine the influence of MSO cells on other auditory nuclei and 2) the location and type of the backfilled MSO cell body to determine 1) cell type 2) its synaptic input 3) whether different cell types encode different auditory features and 4) if they are arranged in any sort of order (map) based on such features (e.g. those features used to encode location in space).