MORPHOLOGY AND CONNECTIONS OF THE SPIRAL GANGLION

螺旋神经节的形态和连接

• 批准号: 3215929
• 负责人: Patricia A. Leake
• 金额: $ 11.26万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-07-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3215929
• 关键词: acoustic nerve; afferent nerve; aminoglycoside antibiotics; auditory discrimination; auditory nuclei; auditory threshold; cats; cochlea; cochlear implants; deafness; developmental neurobiology; ear hair cell; electrophysiology; ganglions; horseradish peroxidase; neural degeneration; neural plasticity; neuroanatomy; neurons; newborn animals; organ of Corti; ototoxin; scanning electron microscopy; sensory deprivation; transmission electron microscopy

The experiments proposed in this application address specific questions relating to the postnatal maturation of the auditory periphery in the cat. These studies will provide fundamental new information about the morphology of the developing organ of Corti and about anatomical details of the development of cochlear spiral ganglion cell projections to the cochlear nuclei (CN) in normal and deafened animals. Cytochemical labeling (BRP) techniques for neuronal tract tracing and single fiber labeling combined with physiological recording and extensive light and electron microscopic analyses will be employed in these studies. Among the objectives are the following: 1) To map the postnatal development of spiral ganglion projections to the CN utilizing HRP microinjections into the spiral ganglion, and to determine if refined isofrequency laminae are present at birth and/or prior to the development of adult auditory thresholds. 2) To determine if cochlear nucleus projection patterns remain static, or undergo topographic remodeling following profound sensory deprivation from ototoxic drug-induced deafness. 3) To examine the consequences of chronic electrical stimulation upon the organization of CN projections, and thus to determine if anatomical remodeling of projections underlies the striking loss of frequency selectivity in the auditory midbrain produced by electrical stimulation in neonatally deafened cats. 4) To determine the nature of spontaneous activity in the auditory nerve of neonatally deafened cats, and thus to assess how it might contribute to the establishment of the normal tonotopic organization of the CN. 5) To explore mechanisms underlying the striking disparity between patterns of ganglion cell and organ of Corti degeneration observed following neonatal deafening by ototoxic drugs. 6) To characterize specific ultrastructural features of postnatal development of the cat cochlea at locations defined by the adult frequency map of the basilar membrane. 7) To correlate the functional development of individual, physiologically-characterized auditory nerve fibers with the morphologic features of organ of Corti development at cochlear locations innervated by individual labeled neurons. This proposed work will increase our understanding of the anatomical framework for information processing mechanisms in the developing peripheral auditory system and should be of critical interest to many investigators. Studies in deafened animals address important questions regarding sensitive periods and plasticity in the auditory system, and have practical implications regarding the efficacy and optimization of cochlear implants in children.

本申请中提出的实验解决了特定问题 与出生后听觉外围的成熟有关 猫。 这些研究将提供有关 发育中的柯蒂氏器官的形态和解剖细节 耳蜗螺旋神经节细胞投射到的发育 正常和聋动物的耳蜗核（CN）。 细胞化学 用于神经元束追踪和单纤维的标记 (BRP) 技术 标记结合生理记录和广泛的光和 这些研究将采用电子显微镜分析。 之中 目标如下： 1) 绘制出生后发育图 利用 HRP 显微注射将螺旋神经节投射到 CN 螺旋神经节，并确定精细的等频层是否 出生时和/或成人听觉发育之前存在 阈值。 2) 确定耳蜗核投射模式是否 保持静止，或在深刻的影响后进行地形重塑 耳毒性药物引起的感觉剥夺。 3）检查 慢性电刺激对组织的影响 CN 投影，从而确定是否进行解剖重塑 预测是频率选择性显着损失的基础 新生儿电刺激产生的听觉中脑 聋哑的猫。 4) 确定自发活动的性质 新生耳聋猫的听觉神经，从而评估它如何 可能有助于建立正常的主题 CN 的组织。 5）探索惊人的机制 神经节细胞和柯蒂氏器模式之间的差异 新生儿耳毒性药物导致耳聋后观察到的退化。 6） 表征产后特定的超微结构特征 猫耳蜗在成人定义的位置发育 基底膜的频率图。 7）关联功能 个体生理特征听觉神经的发育 具有柯蒂氏器发育形态特征的纤维 由单个标记神经元支配的耳蜗位置。 这项拟议的工作将增加我们对解剖学的理解 发展中国家的信息处理机制框架 外周听觉系统，应该引起许多人的兴趣 调查人员。 对聋动物的研究解决了重要问题 关于听觉系统的敏感期和可塑性，以及 对于功效和优化具有实际意义 儿童人工耳蜗。