Intensity Coding and Dynamic Processes in Hearing

声音的动态方面--随时间发生的幅度和频率变化--是听觉感知和交流的关键信息承载要素。听觉系统跟踪和解决这种变化的能力是这项提议的主题。建议的项目是一项全面的行为研究，使用听力正常的成年人，从声音的幅度和频谱的变化中提取信息的能力。该提案由三个相关项目组成，这些项目研究动态听觉处理的日益复杂的方面。第一个项目解决了听觉编码的基本问题。其中一个焦点是正常的人类听力是如何在巨大的强度范围内运作的。建议的实验解决了基于生理数据的假说，这些假说表明抑制、耳蜗传出和兴奋的非线性传播可能起到作用。另一个焦点是精细结构信息在单耳听力中的作用。关于这个基本的、长期存在的问题的拟议实验将阐明精细结构和包络信息在检测和识别中的相对重要性。第二个项目检查听觉系统从幅度的动态变化中提取信息的能力，例如由幅度和频率调制产生的信息。该项目的总体目标是对这类处理进行全面的经验和理论说明，包括描绘对检测和区分很重要的幅度包络的那些方面。第三个项目是关于阈值以上的动态处理，涉及对高度可检测的幅度变化的处理，因此，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数据和理论。这个项目的总体目标是将我们对动态加工的理解扩展到更现实的听觉刺激。总体而言，这些项目将为理解正常人类听力的基本特性以及最终理解听力损伤的知觉后果提供至关重要的信息。它将有助于在听觉生理学和现实世界听力之间架起一座桥梁。这对于充分理解听力以及开发和评估减轻听力损失的策略是必不可少的。

The dynamic aspects of sound-- the amplitude and frequency changes that occur over time- are crucial information- bearing elements of auditory perception and communication. The ability of the auditory system to follow and to resolve such changes is the topic of this proposal. 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 in auditory coding. One focus is on how normal human hearing can operate over a huge intensity range. The proposed experiments address hypotheses based on physiological data that suggest a possible role for suppression, cochlear efferents, and nonlinear spread of excitation. The other focus is on the role of fine-structure information in monaural hearing. The proposed experiments on this basic, long-standing issue will delineate the relative importance of fine-structure and envelope information in detection and discrimination. The second project examines the ability of the auditory system to extract information from dynamic changes in amplitude such as produced by amplitude and frequency modulation. The general aim of this project is to develop a comprehensive empirical and theoretical account of such processing, including delineation of those aspects of the amplitude envelope that are important for detection and discrimination. The third project, on supra-threshold dynamic processing, is concerned with the processing of amplitude changes that are highly detectable and, as such, represents a significant extension of previous research. The hypotheses driving the specific research questions are based upon data and theory 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 the basic properties of normal human hearing and, eventually, for understanding the perceptual consequences of hearing impairment. It will help provide a bridge between auditory physiology and real-world hearing. This is essential for a full understanding of hearing and for the development and evaluation of strategies for alleviating hearing loss.