CYTOCHEMISTRY OF CENTRAL AUDITORY PATHWAYS

该项目的长期目标是了解结构和 听觉脑干的神经化学回路足够详细 我们可以进行智能结构/功能的关联和预测 每个部分如何对听觉信号处理做出贡献。在现在 建议，我们将集中在外侧丘系的核。 (NLL)。NLL为听觉提供单耳和双耳输入 中脑，即下丘中央核(ICC)。他们 是国际商会的第二大投入来源(仅次于 来自耳蜗核的投射)，是其最大的单一来源 抑制性输入。新出现的证据表明，抑制可能对 在形成ICC神经元反应中的许多作用，包括频率 调谐、时间响应模式和速率-强度函数。 来自NLL背核的抑制被认为与 国际刑事法院的双耳抑制。除了他们的主要预测外， 国际刑事法院，NLL也对大脑外预测做出贡献 听觉丘脑和上丘，下行投射至 耳蜗核和上橄榄复合体。然而，在所有地区中， 中枢听觉系统NLL在以下方面最不为人所知 它们的细胞组成和细胞连通性。在现在 建议，我们将描述NLL的蜂窝架构和 将这些发现与细胞递质类型的差异和 突触目标。我们还将检查交叉连接的传入输入 以及NLL背侧核的非交叉投射，这样我们就可以 推断由以下人员提供给国际刑事法院的信息类型 它的投影的每一个组成部分。这些实验旨在 弥合纯粹的形态和纯粹的神经化学之间的差距 形态定位神经元的细胞化学研究 在NLL中。此外，通过检查传入和传出 这些在形态和细胞化学上定义的神经元的连接， 我们希望了解每种类型的信息 传输到它的突触目标。这应该更好地使我们能够联系到 我们对神经生理学和神经药理学的观察 调查，并预测NLL的每个组成部分如何预测 对单声道和双声道信号处理做出贡献。

The long term goal of this project is to understand the structural and neurochemical circuitry of the auditory brainstem in sufficient detail that we can make intelligent structure/function correlations and predict how each part contributes to auditory signal processing. In the present proposal, we will concentrate on the nuclei of the lateral lemniscus (NLL). The NLL provide both monaural and binaural inputs to the auditory midbrain, i.e., the central nucleus of the inferior colliculus (ICc). They are the second largest source of inputs to the ICc (surpassed only by projections from the cochlear nucleus) and are its single largest source of inhibitory inputs. Emerging evidence suggests that inhibition may have many roles in shaping the responses of ICc neurons, including frequency tuning, temporal response patterns, and rate-intensity functions. Inhibition from the dorsal nucleus of the NLL has been implicated in binaural suppression in the ICc. In addition to their main projections to the ICc, the NLL also contribute extralemniscal projections to the auditory thalamus and superior colliculus, and descending projections to the cochlear nucleus and superior olivary complex. Yet, of all regions of the central auditory system, the NLL are the least understood in terms of their cellular composition and cellular connectivity. In the present proposal, we will characterize the cellular architecture of the NLL and correlate these findings with cellular differences in transmitter type and synaptic target. We will also examine the afferent inputs to the crossed and uncrossed projections of the dorsal nucleus of the NLL, so that we can infer something about the types of information being carried to the ICc by each component of its projections. These experiments are designed to bridge the gap between purely morphological and purely neurochemical studies by examining the cytochemistry of morphologically defined neurons in the NLL. In addition, by examining the afferent and efferent connections of these morphologically and cytochemically defined neurons, we hope to learn something about the types of information that each transmits to its synaptic targets. This should better enable us to relate our observations to neurophysiological and neuropharmacological investigations, and to predict how each component of the NLL projections contributes to monaural and binaural signal processing.