THE PHYSIOLOGICAL BASES OF OTOTRAUMATIC INSULT

拟议的实验是早期和正在进行的研究的延续 噪声性听力损失的生理基础， 清醒和清醒时耳蜗核水平的单细胞模型 敏锐的灵长类动物 基本的实验策略继续利用 神经元内设计，以研究短暂的相对持久的影响， 传统上被称为临时阈值的事件 生理活动的TTS。 迄今为止， 研究结果表明，显著和持久的变化可能是 记录单个电池的放电响应， 反映在同时测量，但不太敏感，纯音 听力功能 此外，已经证明，标准 TTS样暴露刺激（100 dB SPL，3 min）能够影响 应用时耳蜗导管元件的永久性组织学改变 在许多蛾的周期内定期进行，从而证明了 单单位分析对理解生物学的相关性 现代社会中最常见的听力障碍之一的基础，即， 听力损失是由于经常暴露在中等程度的 声音的水平。 暴露于标准方案后，中枢听觉系统 耳蜗核的所有部分的神经元显示出许多 明显的变化表明外周和 引发复杂效应的中枢机制。 本 实验旨在区分周边和中央 听觉神经系统对中等强度声音的反应 第八神经纤维与耳蜗核细胞联合发声 记录技术，以确定更集中的改变输入 定位神经元。 这些研究将确定早期的生理 改变潜在的TTS和提供有用的洞察改变的感觉 编码过程，可能伴随着知觉的变化， 噪音=耳朵受损。

The proposed experiments are a continuation of earlier and ongoing studies of the physiological bases of noise-induced hearing loss carried out in a single-cell model at the level of the cochlear nucleus in both awake and acute primates. The basic experimental strategy continues to make use of a within-neuron design to study the relatively long-lasting effects of brief episodes of what has traditionally been referred to as temporary threshold shift (TTS) on physiological activity. To date, one of the principal findings has revealed that significant and long-lasting alterations can be documented for the discharge responses of the single cell which are not reflected in simultaneously measured, but less sensitive, pure-tone audiometric functions. Further, it has been demonstrated that the standard TTS-like exposure stimuli (100 dB SPL, 3 min) are capable of effecting permanent histological alterations to cochlear duct elements when applied at regular intervals over a period of many moths thus demonstrating the relevance of single-unit analyses towards understanding the biological bases of one of the most common hearing disorders in modern society, i.e., slowly developing hearing loss caused by regular exposure to moderate levels of sound. Following exposure to the standard protocol, central auditory system neurons of all divisions of the cochlear nucleus demonstrate a number of distinct changes that suggest the contribution of both peripheral and central mechanisms towards eliciting the complex effects. The present experiments are designed to distinguish the peripheral from central components of the auditory nervous system's response to moderately intense sound by employing both single eighth nerve fiber and cochlear nucleus cell recording techniques to identify altered inputs to the more centrally located neurons. Such studies will determine the early physiological changes underlying TTS and provide useful insight into the altered sensory encoding processes that probably accompany perceptual changes in the noise=damaged ear.