Projections of Characterized Trapezoid Body Axons

听觉信息首先在脑干中被处理， 耳蜗核复合体中的神经元，包含数个细胞 类型 许多这些细胞的输出轴突向前投射， 形成称为梯形体的结构的主要途径（从 其形状）。 这些轴突然后终止于下一个神经元。 更高级的称为上级橄榄复合体。 我们还不 了解耳蜗核的信号是如何相互关联的 到听觉功能的更高方面，例如声音 定位或惊吓反应，由神经元处理 在上级橄榄中。 该项目将确定信号和目标 这些梯形体轴突的目的地 细胞内 记录将用于生理学表征 延伸到大脑中的单个轴突的反应特性 梯形体，然后将使用细胞内染料填充 追踪从原始细胞到靶细胞的路径， 在猫的脑干里 光学和电子显微镜将 提供每个小区终端位置的详细信息， 突触末梢的详细形态， 表征细胞类型。 这一分类将是 与观察到的这些细胞的功能反应相关。 这项工作将提供一个独特的信息整合， 中枢听觉通路;它将阐明什么样的信号 处理发生在连接耳蜗的重要水平 核的上级橄榄复合体，并将澄清 形态细胞分类的功能意义 耳蜗核

Auditory information is first processed in the brainstem by neurons in the cochlear nuclear complex, containing several cell types. Output axons of many of these cells project forward in a major pathway forming a structure called the trapezoid body (from its shape). These axons then terminate on neurons at the next higher level called the superior olivary complex. We do not yet understand how the signals from the cochlear nuclei are related to higher aspects of auditory function, such as sound localization or startle responses, which are handled by neurons in the superior olive. This project will determine the signalling and target destinations of the these trapezoid body axons. Intracellular recordings will be used to physiologically characterize the response properties of single axons that extend into the trapezoid body, and intracellular dye filling then will be used to trace the pathways, from cells of origin to target cells, within the cat brainstem. Light and electron microscopy will provide details of location of terminals for each cell, and of detailed morphology of the synaptic endings, to morphologically characterize cell types. This classification then will be correlated to the observed functional responses of these cells. This work will provide a unique integration of information in the central auditory pathway; it will clarify what kinds of signal processing occur at the important level connecting the cochlear nuclei to the superior olivary complex, and will clarify the functional significance of morphological cell classification in the cochlear nucleus.