INTENSITY CODING AND DYNAMIC PROCESSES IN HEARING

声音的动态方面--幅度和频率的变化 随着时间的推移而发生--对听觉感知和交流至关重要。 听觉系统跟踪和解决这种变化的能力 是这项提案的主题。更具体地说，拟议的项目 是一项全面的行为研究，使用的是听力正常的成年人， 能够从幅度和频率的变化中提取信息 声音的频谱。该提案由三个相关项目组成， 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，并 普遍关注正常的人类听力是如何在巨大的 强度范围(120分贝)。拟议的实验解决了假设问题。 与此动态范围问题相关，并检查 如抑制、耳蜗神经传出、中耳肌、 以及激励的非线性传播。 第二个项目检查听觉系统提取 来自所产生的幅度和频率的动态变化的信息 通过调制(AM和FM)。这个项目的总体目标是开发 AM和FM处理的综合说明，包括描绘 幅度包络的那些方面对 侦测和辨别。 第三个项目涉及超阈值幅度处理 因此，这代表了先前研究的重大扩展。 驱动具体研究问题的假设是基于 来自阈值现象的理论和数据。这样做的总体目的是 项目的目的是将我们对动态处理的理解扩展到更多 逼真的听觉刺激。 总体而言，这些项目将提供基本信息 理解正常人某些基本属性的重要性 听证，并最终理解听证的后果 减损。从健康的角度来看，特别重要的是 关于强度编码--动态范围限制的建议工作是 也许是耳蜗术后最重要的后果。还有，这项工作 关于超过阈值的加工应该直接导致理解 在响度招募的影响中，另一个潜在的重要因素 耳蜗性损伤的后果。

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.