PHYSIOLOGICAL STUDIES OF AGE RELATED HEARING LOSS

年龄相关听力损失的生理学研究

• 批准号: 2769435
• 负责人: RICHARD A SCHMIEDT
• 金额: $ 15.31万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2769435
• 关键词: acoustic nerve; aging; audiometry; cochlear microphonic potentials; disease /disorder model; ear pharmacology; furosemide; gerbil /jird; model design /development; neural information processing; presbycusis

DESCRIPTION: The overall aim is to examine the mechanisms underlying pathophysiologic changes in neural coding in the auditory nerves of animals aged in quiet. Over the past 10 years they have successfully developed the Mongolian gerbil as a model of human presbyacusis. In this proposal we focus on one cochlear potential in the gerbil model known to be affected by age: the endocochlear potential (EP) produced by the lateral wall system. We examine the relationship between the EP and neural coding in young and aged animals. Specific focus is on the effects of EP on the processing of temporal information in auditory nerve fibers, an aspect not yet addressed in the literature in the normal cochlea, much less in the presbyacusic cochlea. There are three specific aims. Specific aim 1 examines neural coding of timing information in the auditory nerves of young and quite-aged gerbils. Experiments include single fiber studies and population studies using the compound action potential (CAP). The hypothesis to be tested is that temporal coding in quiet-aged animals becomes deficient with age. Specific Aim 2 acutely manipulates the EP in old and young gerbils to test the hypothesis that the EP plays a fundamental role in the coding of temporal information in auditory-nerve activity. Specific Aim 3 examines neural coding under conditions of a chronically low EP in young gerbils. The lowered EP will be maintained by infusing furosemide into the cochlea with an implanted cannula and osmotic pump over periods ranging from weeks to months. Previous work supports the hypothesis that ;the quiet-aged gerbil cochlea can be modeled as an intact hair cell system operating under conditions of a low EP. The last aim will establish a model of presbyacusic cochlea in a young animal, thereby greatly enhancing the efficiency of studies of presbyacusis in animal models.

描述：总体目的是检查基础机制 动物听觉神经中神经编码的病理生理学变化 安静地老化。 在过去的十年中，他们成功地开发了 蒙古的沙鼠是人类长老会的典范。 在这个建议中，我们 专注于已知会影响的Gerbil模型中的一个人工耳蜗潜力 年龄：外侧壁系统产生的内凝性（EP）。 我们研究了年轻的EP和神经编码之间的关系 老年动物。 具体重点是EP对处理的影响 听觉神经纤维中的时间信息，尚未解决的方面 在正常耳蜗的文献中，在长老会中少得多 耳蜗。 有三个特定的目标。 特定目标1检查神经 年轻人和年龄分子的听觉神经中的定时信息编码 沙鼠。 实验包括单纤维研究和人群研究 使用复合动作电位（CAP）。 要检验的假设是 安静的动物中的时间编码随着年龄的增长而缺乏。 特定的目标2急性操纵EP和年轻的沙鼠测试 EP在编码中起着基本作用的假设 听觉障碍活动中的时间信息。 特定目标3检查 在年轻的沙鼠中，慢性EP的条件下的神经编码。 通过将速尿中注入耳蜗来维持降低的EP 植入的套管和渗透泵在几周的时间内 到几个月。 以前的工作支持以下假设。 沙鼠耳蜗可以建模为完整的毛细胞系统 低EP的条件。 最后一个目标将建立一个老年人的模型 一只年轻动物的耳蜗，从而大大提高了 在动物模型中对长老会的研究。