CORTICAL REPRESENTATION OF AUDITORY SPACE

描述（由申请人提供）：本地化是听证会的一项基本任务。在高等哺乳动物中，听觉皮层的正常功能对于正常的声音定位是必不可少的。尽管有积极的研究，大脑皮层空间表征的基本原理仍然未知。提议的实验将扩展PI实验室的观察结果，该观察结果表明单个皮层神经元的时间放电模式可以以神经学的方式发出声音的位置，这意味着任何声源的位置都由广泛分布的神经群体表示。具体目标1将评价听觉皮层场之间空间编码的专业化。以前的研究在猫，集中在A1，A2和AES领域，没有发现任何定性的专业化。其他尚未探索的领域显示双耳和频率特异性，似乎特别有利于空间选择性，我们的初步结果显示，增强的空间选择性，在PAF区。我们将测试的假设，即皮层区PAF和背侧部分的Al区专门为空间表示。具体目标2将对比猫皮层神经元在麻醉，空闲，视觉检测和听觉辨别条件下的听觉空间选择性。我们将测试的假设，神经尖峰模式的位置特异性增强清醒的动物，特别是当动物从事听觉任务。具体目标3将探索人类听众从声音频谱中提取位置线索的规则。我们将采用一种新的程序，其特点是近端刺激光谱，导致特别海拔的判断。我们将区分假设的宽带和单一功能的机制，并将确定频谱定位线索的频率分辨率的水平。具体目标4将皮层神经元的高度敏感性与其频率响应区域的特征联系起来。我们将测试的假设，兴奋和抑制域的具体配置的基础检测光谱定位线索。这项研究将提供对颞叶病理学评估和设计对损伤和疾病的治疗反应所需的听觉皮层机制的基本理解。

DESCRIPTION (provided by applicant): Localization is a fundamental task of hearing. In higher mammals, normal function of the auditory cortex is essential for normal sound localization. Despite active research, basic principles of spatial representation in the cortex remain unknown. Proposed experiments will extend observations from the PI's laboratory that indicate that the temporal firing patterns of single cortical neurons can signal the locations of sounds panoramically, implying that the location of any sound source is represented by widely distributed neural populations. Specific Aim 1 will evaluate specialization for spatial coding among auditory cortical fields. Previous studies in cats, focusing on areas Al, A2, and AES, have not discovered any qualitative specialization. Other as yet unexplored areas show binaural and frequency specificity that seem particularly conducive to spatial selectivity, and our preliminary results show enhanced spatial selectivity in area PAF. We will test the hypothesis that cortical areas PAF and the dorsal part of area Al are specialized for spatial representation. Specific Aim 2 will contrast auditory spatial selectivity in cat cortical neurons during anesthetized, idle, visual-detection, and auditory-discrimination conditions. We will test the hypothesis that location specificity of neural spike patterns is enhanced in awake animals, particularly when the animal is engaged in an auditory task. Specific Aim 3 will explore the rules by which human listeners extract location cues from sound spectra. We will employ a new procedure that characterizes the proximal stimulus spectra that result in particular elevation judgments. We will discriminate between hypothetical broadband and single-feature mechanisms and will determine the level of frequency resolution by which spectral localization cues are recognized. Specific Aim 4 will relate elevation sensitivity of cortical neurons to characteristics of their frequency response areas. We will test the hypothesis that specific configurations of excitatory and inhibition domains underlie detection of spectral localization cues. This research will provide basic understanding of auditory cortical mechanisms that is needed for evaluation of temporal lobe pathology and for the design of therapeutic responses to injury and disease.