Collaborative Research: Studies of Binaural Processing

Ibn 98-15056约翰逊。与单耳聆听相比，双耳聆听在安静和嘈杂的房间中提供了显着的优势。一只耳朵聋的人在定位声源和识别噪音中出现的话语等任务上的表现明显比正常听者差。实验表明，我们的大脑利用两只耳朵发出的声音之间的差异（即耳际差异）来提供这种“双耳”优势。两个重要的脑中心参与比较这些耳际差异是外侧上橄榄核（LSO）和梯形体内侧核（MNTB）。MNTB神经元向LSO提供来自一只耳朵的声音信息，而耳蜗核神经元提供来自另一只耳朵的声音信息。Tsuchitani博士和她的合作者的研究表明，LSO神经元利用这些信息来计算响度差异（ILD）和由头部和耳朵的声音阴影效应产生的随时间变化的ILD。约翰逊博士和合作者开发了一种LSO神经元的计算模型，可以模拟LSO反应，以及统计模型，可以描述和预测LSO系统对不同类型的双耳刺激的反应。将要进行的研究将探索LSO和MNTB在复杂信号的神经处理中的作用，类似于使用虚拟声学开发的方法自然遇到的那些信号。将使用瞬态复杂刺激，单独呈现和在背景噪声中。信号源的明显位置将由威斯康星大学的约瑟夫·欣德博士和约翰·布鲁日博士提供的与猫头相关的传递函数来控制。听觉神经生理学家Tsuchitani博士将进行操纵刺激的实验，并记录LSO和MNTB中单个和多个神经元对这些刺激的电反应。约翰逊博士是一位通信/信号处理理论家，他将对记录的数据应用先进的信号分析技术，以确定LSO神经元对复杂刺激的反应是如何处理双耳信息的。该技术将用于确定LSO集合响应提供的感知线索、ILD、时变ILD、耳间时间差和耳间光谱差异。这个项目的结果将揭示大脑是如何利用耳际差异在安静和嘈杂的房间里产生双耳优势的。

IBN 98-15056 JOHNSON. Compared to listening with one ear, listening with two ears provides significant advantages to hearing in quiet and noisy rooms. Individuals who are deaf in one ear perform significantly more poorly than normal listeners on tasks such as locating sound sources and identifying spoken words presented in noise. Experiments have shown that differences between the sounds at the two ears (i.e., interaural differences) are used by our brains to provide this "binaural" advantage. Two important brain centers involved in comparing these interaural differences are the lateral superior olive (LSO) and the medial nucleus of the trapezoid body (MNTB). MNTB neurons provide the LSO with information about sounds coming from one ear, while cochlear nuclear neurons provide information about sounds coming from the opposite ear. The studies of Dr. Tsuchitani and her collaborators have shown that LSO neurons use this information to compute interaural differences in loudness (ILD) and time-varying ILDs produced by the sound-shadowing effect of the head and ear. Dr. Johnson and collaborators developed a computational model of LSO neurons that permits simulation of LSO responses, and statistical models that provide descriptions and predictions of how the LSO system responds to different types of binaural stimuli. The studies to be undertaken will explore the role of the LSO and MNTB in the neural processing of complex signals akin to those encountered naturally by employing methods developed for virtual acoustics. Transient complex stimuli will be used, presented alone and in background noise. The apparent location of the signal source will be manipulated by applying cat head-related transfer functions supplied by Dr. Joseph Hind and Dr. John Brugge of the University of Wisconsin. Dr. Tsuchitani, an auditory neurophysiologist, will conduct the experiments manipulating the stimuli and recording the electrical responses of single and multiple neurons in the LSO and MNTB to these stimuli. Dr. Johnson, a communication/signal processing theorist, will be applying advanced signal analysis techniques to the recorded data to determine how the ensemble of LSO neurons responding to complex stimuli processes binaural information. This technique will be used to determine what perceptual cues, ILD, time varying ILDs, interaural time differences, and interaural spectral differences, the LSO ensemble response provides. The results of this project will reveal how the brain uses interaural differences to produce the binaural advantage in hearing in quiet and noisy rooms.