CODING COMPLEX BIOLOGICAL SIGNALS BY THE COORDINATED ACTIVITY OF CORTICAL NEURONS

空间听觉提供了一种强大的辨别声音的机制 嘈杂的背景。项目1将探索空间运动的大脑皮层机制 听觉，先在安静中，然后在环境噪音中。一个可听到的声音必须 导致整个大脑皮层活动的时变分布，这 将在这里被称为该声音的“皮质图像”。发送到 特定的皮质图像对于特定的声音是唯一的程度， 声源可以通过它们的皮质图像来识别。这个项目 将使用多通道记录技术对单个单位的活动进行采样 同时在多达32个位置的皮质图像中。在…的背景下 这种应用，大脑皮层的图像可以被认为是神经元级的 与磁共振、正电子发射计算机断层扫描和磁共振成像观察到的功能图像的相关性 功能光学成像，在这种情况下使用单细胞空间成像和1毫秒成像 时间分辨率。 具体目标1的目标是识别皮质图像的特征 它可以携带与刺激相关的信息。人工神经网络 将用于识别声源位置的基础上的皮质 反应，识别的准确性将揭示相对的 对象的特定元素可以承载的信息量 单个神经元和多达32个神经元的集合的响应。 将对相对幅度和时序进行特别研究 多个单位之间的活动。《特定目标2》的设计与 项目2研究环境噪声中的空间听觉。在多大程度上 皮质反应的特定元素跟踪行为敏感性 掩码级别将揭示这些功能在以下方面的相对重要性 环境噪声中的信号检测和识别。 听觉皮质是颞叶的一个关键部分。建议数 该项目解决了刺激如何在大脑中编码的问题 大脑皮层由神经元群体的协调活动决定。这些研究 声音的皮质图像将补充诊断功能 单个神经元水平的成像技术。这项工作应该是 有助于我们理解感知的神经编码， 颞叶病理评价及其对治疗方案设计的影响 对伤害和疾病的反应。

Spatial hearing provides a powerful mechanism for discriminating sounds in noisy backgrounds. Project 1 will explore cortical mechanisms of spatial hearing, first in quiet, then in ambient noise. An audible sound must result in a time-varying distribution of activity across the cortex, which will be referred to here as the "cortical image" of that sound. To the extent that specific cortical images are unique to particular sounds, sound sources can be identified by their cortical images. This project will use multi-channel recording techniques to sample single-unit activity within cortical images at up to 32 sites simultaneously. In the context of this application, a cortical image may be regarded as the neuron-level correlate of the functional images that are observed with MRI, PET, and functional optical imaging, in this case with single-cell spatial and 1-ms temporal resolution. The goal of Specific Aim 1 is to identify the features of cortical images that can carry stimulus-related information. Artificial neural networks will be used to identify sound-source locations on the basis of cortical responses, and the accuracy of identification will reveal the relative amount of information that can be carried by particular elements of the responses of single neurons and of ensembles of up to 32 neurons. Particular study will be given to the relative amplitude and timing of activity among multiple units. Specific Aim 2 is designed in parallel with Project 2 to study spatial hearing in ambient noise. The degree to which specific elements of cortical responses track behavioral sensitivity to masker levels will reveal the relative significance of those features for signal detection and discrimination in ambient noise. The auditory cortex is a key element of the temporal lobe. The proposed project addresses the issue of how stimuli might be coded in the cerebral cortex by the coordinated activity of populations of neurons. The studies of the cortical image of a sound will complement diagnostic functional imaging techniques at the level of single neurons. This work should contribute to our understanding of the neural coding of perception, the evaluation of temporal lobe pathology and to the design of therapeutic responses to injury and disease.