Binaural and top-down mechanisms in auditory scene analysis

描述（由申请人提供）：在我们正常的忙碌生活中，我们很少听到孤立的声音。在大多数情况下，例如鸡尾酒会，许多声源都存在，并且它们的波形在听者的耳朵处简单地加在一起;所有听者听到的都是单个复杂的波形。值得注意的是，听众能够分解这种复杂的波形，通过频率和其他线索分离成分，并将它们组合在一起以形成对单独来源的连贯感知;这个过程通常被称为“听觉场景分析”。助听器和人工耳蜗使用者在这个过程中有特别的困难，许多人避免在存在多个声源的环境中使用。更好地理解听觉场景分析的机制可能会解决这些困难。听觉场景分析是利用声音的特征（自下而上的处理）和听者的期望（自上而下的处理）的过程。拟议研究的长期目标是了解自下而上处理的机制以及它如何与自上而下处理相互作用。拟议的研究旨在了解用于从具有多个声源的环境中提取单个声音的双耳机制的生理学。听觉系统可以比较和对比两只耳朵的输入，并使用这些双耳线索来分离声音。当有多个声音时，人们对比较双耳输入的生理过程知之甚少。这种知识的缺乏已经成为进一步提高双耳助听器或人工耳蜗植入者听力的障碍。所提出的研究的一个目的是确定用于提取单个声音时，存在多个声源的双耳机制。目前的建议将使用多个复杂的声音（谐波复合），以确定双耳神经机制，用于分离的声音。拟议的研究的第二个目的是确定自上而下的过程如何影响用于分离声音的双耳机制。这项研究将联合收割机结合下丘电生理学和听觉皮层失活技术，以确定双耳机制和自上而下处理之间的相互作用。研究结果将为复杂环境中的双耳优势提供一个框架，这可能有助于最大限度地发挥双侧助听器和双侧人工耳蜗植入的益处。

DESCRIPTION (provided by applicant): In our normal busy lives we rarely hear isolated sounds. In most situations, such as a cocktail party, many sound sources are present and their waveforms simply add together at the listener's ears; all that listeners hear is a single complex waveform. Remarkably, listeners are able to break down this complex waveform, segregate the components by frequency and other cues, and group them together to form a coherent percept of the separate sources; this process is commonly referred to as "auditory scene analysis". Hearing aid and cochlear implant users have particular difficulty with this process and many avoid environments where multiple sound sources are present. A better understanding of the mechanisms underlying auditory scene analysis may solve some of these difficulties. Auditory scene analysis is a process that utilizes the features of the sound (bottom-up processing) and the expectations of the listener (top-down processing). The long-term objective of the proposed research is to understand the mechanisms of the bottom-up processing and how it interacts with the top-down processing. The proposed research aims to understand the physiology of the binaural mechanisms used to extract a single sound from an environment with multiple sound sources. The auditory system can compare and contrast the input of the two ears and use these binaural cues to segregate sounds. Little is understood about the physiological processes that compare the input of the two ears when multiple sounds are present. This lack of knowledge has become a barrier to further improving the hearing of people with hearing aids or cochlear implants in both ears. One aim of the proposed research is to determine the binaural mechanisms used in extracting a single sound when multiple sound sources are present. The present proposal will use multiple complex sounds (harmonic complexes) to identify the binaural neural mechanisms used to segregate sounds. The second aim of the proposed research is to determine how top-down processes affect the binaural mechanisms used to segregate sounds. The proposed research will combine electrophysiology in the inferior colliculus with auditory cortical inactivation techniques to determine the interaction between binaural mechanisms and top-down processing. The results will provide a framework for binaural advantages in complex environments that may help with maximizing the benefit from bilateral hearing aids and bilateral cochlear implants.