NOISE AND THE NEURAL REPRESENTATION OF PURE TONES IN THE AUDITORY SYSTEM

噪声与听觉系统中纯音的神经表征

• 批准号: 6104389
• 负责人: BRADFORD J MAY
• 金额: $ 10.15万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6104389
• 关键词: audiometry; auditory cortex; auditory discrimination; auditory nuclei; behavioral /social science research tag; behavioral habituation /sensitization; binaural hearing; brain mapping; cats; electrophysiology; environmental adaptation; inferior colliculus; microelectrodes; neural information processing; noise; single cell analysis; stereotaxic techniques

This project will use extracellular electrophysiological recording to study the effects of background noise on the neural representation of pure tone stimuli. Neural responses will be measured in terms of average discharge rates for single units. Dynamic range properties of single-unit responses will be derived from measures of rate-level functions that are obtained in quiet and in the presence of continuous background noise. Dynamic range measures will be sampled in the dorsal cochlear nucleus, inferior colliculus and primary auditory cortex of behaving cats. Inhibitory mechanisms that shape the neural representation of tones in noise at each of these three levels of auditory processing will be described by frequency response maps, responses to bandpass noise, and responses to broad band noise with notched spectra. This research is based on independent observations that inhibitory influences increasingly reduce auditory responses to continuous noise at higher levels of the auditory system. A reduction in noise-driven activity potentially enhances the rate representation of signals that occur in the presence of background noise by decreasing the negative effects of noise adaptation The primary objectives of this proposal are to demonstrate changes in noise adaptation across three levels of auditory processing, to reveal neural inhibitory mechanisms that contribute to changes in noise-driven activity, and to measure the functional consequences of these changes in terms of the quality of neural representations for signals in noise. Although some of these objectives have been addressed in the nervous system of anesthetized and decerebrate cats, a comprehensive analysis of the neural encoding of pure tones in noisy environments has not been performed in behaving cats. Data obtained in behaving cats are critical to our understanding of noise adaptation because anesthesia substantially alters activity of descending efferent projections to the auditory periphery and inhibitory mechanisms at each subsequent level of auditory processing.

该项目将利用细胞外电生理记录来 研究背景噪声对纯神经表征的影响 音刺激。神经反应将以平均值来衡量 单个装置的排放率。单个单元的动态范围特性 响应将来自于速率水平函数的测量，这些函数是 在安静且存在连续背景噪音的情况下获得。 动态范围测量将在耳蜗背核中采样， 行为猫的下丘和初级听觉皮层。 塑造音调神经表征的抑制机制 这三个听觉处理级别中的每一个级别的噪声都将是 由频率响应图、带通噪声响应描述，以及 对带缺口光谱的宽带噪声的响应。这项研究基于 根据独立观察，抑制影响逐渐减少 听觉水平较高时对连续噪声的听觉反应 系统。噪音驱动活动的减少可能会提高比率 存在背景噪声时出现的信号的表示 通过减少噪声适应的负面影响 该提案的目标是展示噪声适应方面的变化 跨越听觉处理的三个层次，揭示神经抑制 有助于噪声驱动活动变化的机制，以及 衡量这些变化的功能后果 噪声中信号的神经表征的质量。虽然有些 这些目标已在麻醉的神经系统中得到解决 和去大脑猫，对神经编码的全面分析 吵杂环境中的纯音尚未在行为猫身上表现出来。 从行为猫身上获得的数据对于我们理解噪音至关重要 适应，因为麻醉大大改变了下行的活动 听觉周边的传出投射和抑制机制 在听觉处理的每个后续级别。