INTENSITY CODING AND DYNAMIC PROCESSES IN HEARING

声音的动态方面--振幅和频率的变化， 是听觉感知和交流的关键。 听觉系统跟踪和解决这种变化的能力 这是这个提案的主题。 具体而言，拟议项目 是一项全面的行为研究，使用正常听力的成年人， 能够从振幅的变化中提取信息 声音的频谱。该提案包括三个相关项目， 研究动态听觉处理的日益复杂的方面。 第一个项目解决了强度编码的基本问题， 一般关注正常人的听觉如何在巨大的 强度范围（120 dB）。 拟议的实验解决假设 与这个动态范围问题相关，并研究 诸如抑制、耳蜗传出、中耳肌肉 以及激励的非线性扩展。 第二个项目检查听觉系统提取的能力 来自产生的振幅和频率的动态变化的信息 调制（AM和FM）。该项目的总体目标是开发 AM和FM处理的全面说明，包括划界 这些方面的振幅包络是重要的 检测和识别。 第三个项目是关于阈上振幅处理 因此，它代表了先前研究的重要延伸。 驱动具体研究问题的假设是基于 阈值现象的理论和数据。这件事的总体目标是 项目是为了扩展我们对动态处理的理解， 逼真的听觉刺激。 总的来说，这些项目将提供基本的信息， 了解正常人某些基本特性的重要性 并最终理解听力的后果 损伤从健康的角度来看，特别重要的是 建议的强度编码-动态范围限制的工作是 这可能是耳蜗缺失最重要的后果。此外，工作 关于超阈值处理的研究应该能直接导致 的影响，响度招聘，另一个潜在的重要 耳蜗损伤的后果。

The dynamic aspects of sound--the amplitude and frequency changes that occur over time--are crucial for auditory perception and communication. The ability of the auditory system to follow and to resolve such changes is the topic of this proposal. More specifically, the proposed project is a comprehensive behavioral study, using normal-hearing adults, of the ability to extract information from changes in the amplitude and the spectrum of sound. The proposal consists of three related projects that investigate increasingly complex aspects of dynamic auditory processing. The first project addresses basic issues of intensity coding and is generally concerned with how normal human hearing can operate over a huge intensity range (120 dB). The proposed experiments address hypotheses that are relevant to this dynamic range problem and examine the role of such processes as suppression, cochlear efferents, middle ear muscles, and nonlinear spread of excitation. The second project examines the ability of the auditory system to extract information from dynamic changes in the amplitude and frequency produced by modulation (AM and FM). The general aim of this project is to develop a comprehensive account of AM and FM processing, including delineation of those aspects of the amplitude envelope that are important for detection and discrimination. The third project is concerned with supra-threshold amplitude processing and, as such, represents a significant extension of previous research. The hypotheses driving the specific research questions are based upon theory and data from threshold phenomenon. The general aim of this project is to extend our understanding of dynamic processing to more realistic auditory stimuli. Overall, these projects will provide information of fundamental importance for understanding certain basic properties of normal human hearing and, eventually, for understanding the consequences of hearing impairment. Of particular importance from the standpoint of health, is the proposed work on intensity coding--dynamic range limitation is perhaps the most important consequence of cochlear loss. Also, the work on supra-threshold processing should lead directly to an understanding of the effects of loudness recruitment, another potential important consequence of cochlear impairment.