DEVELOPMENT AND REGENERATION IN THE AUDITORY SYSTEM

这项建议考察了两个主题：(1)自发动作电位 发育中的听觉系统中的放电。(2)再生 耳蜗毛细胞。 1.大细胞(NM)神经元的自发放电 雏鸡的板层状(NL)核以同步节律的方式出现 在听力胚胎发育过程中的模式，而不是在之后 孵化。这种同步节奏的模式的特征 将在单个单元和多个单元的记录中检查放电 NM在胚胎中的活性。中的相对同步量 NM不同可调区之间的自发放电将被 以定量的方式测量。总体目标是了解 自发活动对听觉发育的贡献 系统结构和功能。 2.鸟耳损伤后丢失的毛细胞有 取而代之的是新毛细胞的再生。实验将检验 毛细胞后生理功能的恢复 再生。注射阿司匹林可导致鸟类毛细胞丢失 庆大霉素，一种氨基糖苷类抗生素。在第一个实验中， 听觉阈值和复合动作电位调谐曲线将 在不同注射后存活间隔的禽类中进行测量。 耳蜗毛细胞和神经节神经元数量的测量 会使这些鸟类的生理功能丧失和恢复 与结构性变化相关。在第二个实验中， NM和NL的正位组织将在 庆大霉素治疗后的不同间隔。这些项目的目标是 研究旨在了解毛细胞再生和毛细胞再生的机制 恢复听力和正常生理功能的潜力 功能。

This proposal examines two topics: (1) Spontaneous action potential discharge in the developing auditory system. (2) Regeneration of cochlear hair cells. 1. The spontaneous discharge of neurons in the magnocellular (NM) and laminar (NL) nuclei of the chick occurs in a synchronously rhythmic pattern during the embryonic development of hearing but not after hatching. The characteristics of this synchronously rhythmic pattern of discharge will be examined in recordings of single and multiple unit activity from NM in embryos. The relative amount of synchrony in spontaneous discharge between different tonotopic regions of NM will be measured quantitatively. The overall objective is to understand the contribution of spontaneous activity to the development of auditory system structure and function. 2. Hair cells in the avian cochlea which are lost following injury are replaced by the regeneration of new hair cells. Experiments will examine the restoration of physiological function following hair cell regeneration. Hair cell loss will be induced in birds by injections of gentamicin, an aminoglycoside antibiotic. In the first experiment, auditory thresholds and compound action potential tuning curves will be measured in birds at various post-injection survival intervals. Measurements of the number of cochlear hair cells and ganglion neurons in these birds will allow loss and recovery of physiological function to be related to structural changes. In the second experiment, the tonotopic organization of NM and NL will be measured physiologically at different intervals following gentamicin treatment. The goal of these studies is to understand the mechanisms of hair cell regeneration and the potential for restoration of hearing and normal physiological function.