PHYSIOLOGICAL STUDIES OF AGE RELATED HEARING LOSS

描述：总体目标是研究潜在的机制 动物听神经编码的病理生理变化 在安静中成长 在过去的10年里，他们成功地开发了 蒙古沙鼠作为人类老年性聋模型的研究。 在本提案中，我们 专注于沙鼠模型中的一个耳蜗电位，已知受 年龄：由外侧壁系统产生的耳蜗内电位（EP）。 我们研究了年轻人和老年人EP和神经编码之间的关系， 老年动物 具体重点是EP对加工的影响， 听觉神经纤维中的时间信息，这是一个尚未解决的问题 在正常耳蜗的文献中， 耳蜗 有三个具体目标。 具体目标1检查神经 青年和老年人听神经的时间信息编码 沙鼠 实验包括单纤维研究和群体研究 复合动作电位（CAP）。 待检验的假设是 安静年龄动物的时间编码随着年龄的增长而变得不足。 特异性目标2急性操纵老年和年轻沙鼠的EP， 假设EP在编码中起着重要作用， 神经活动中的时间信息。 具体目标3检查 长期低EP条件下的神经编码在年轻沙鼠。 降低的EP将通过将呋塞米注入耳蜗来维持 用植入的套管和渗透泵， 几个月 先前的研究支持了这一假设，即： 沙鼠耳蜗可以被模拟为一个完整的毛细胞系统， 低EP的条件。 最后一个目的是建立老年性耳聋的动物模型 耳蜗在一个年轻的动物，从而大大提高效率， 在动物模型中的老年性耳聋研究。

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.