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.

该项目将使用细胞外电生理记录到 研究背景噪声对纯神经表示的影响 音调刺激。神经反应将以平均值来衡量 单个单位的放电率。单单元的动态范围属性 响应将来自速率级函数的度量 在安静的情况下获得，并在存在连续的背景噪声的情况下获得。 动态范围度量将在背部耳蜗核中采样， 行为猫的下丘和主要听觉皮层。 抑制性机制，这些机制塑造了色调的神经表示 这三个级别的听觉处理中的噪声将是 通过频率响应图，对带通噪声的响应以及 对宽带光谱对宽带噪声的响应。这项研究是基于 关于抑制性影响的独立观察结果越来越减少 听觉响应对较高听觉水平的连续噪声的响应 系统。降低噪声驱动的活动可能会提高速率 在背景噪声存在下发生的信号的表示 通过减少噪声适应的负面影响 该提案的目标是证明噪声适应的变化 在三个级别的听觉处理中，以揭示神经抑制 导致噪声驱动活动变化的机制以及 衡量这些变化的功能后果 噪声信号的神经表示质量。虽然有些 这些目标已在麻醉的神经系统中解决 和脑猫，对神经编码的综合分析 在嘈杂的环境中，纯音调尚未在行为猫中进行。 在行为猫中获得的数据对于我们对噪声的理解至关重要 适应，因为麻醉基本上改变了下降的活性 对听觉外围和抑制机制的传出预测 在随后的每个听觉处理中。