FMRI OF AUDITORY ATTENTION TO COMPLEX ENVIRONMENTAL SOUNDS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。这项研究的总体目标是更好地理解人类皮层系统的组织和机制，这些系统涉及将我们的注意力引导到日常复杂环境声音的不同方面。为了实现这一目标，将使用功能性磁共振成像（fMRI）来区分，绘制和功能表征大脑区域（包括正常人和盲人），这些区域涉及将注意力引导到三维（3D）可定位的自然声音，当参与者躺在MRI扫描仪中时，通过高保真耳机系统呈现。重点将放在(1)映射皮层通路，优先处理空间位置（“在哪里”），而不是识别复杂自然声音的内容（“什么”）。我们期望在对声音的空间注意期间激活一个特定的“额顶叶”网络，在对相同声音刺激内容的注意期间激活几个高层次的听觉关联区域。由于我们最近发现了处理动物发声与手操作工具声音（两种截然不同的声音概念类别）的部分分离通路，我们还将确定(2)沿着这些不同通路的活动是否可以通过注意力来调节。这将通过同时提供声源来评估，要求参与者忽略分散注意力的声音。我们还将能够确定额顶叶皮层网络的某些部分（如上所述）是否也参与“听觉流”，其中注意力被引导到处理一个声源，不得不过滤掉其他声源。志愿者将执行听觉行为任务，同时使用3T GE LX研究扫描仪获取功能图像，使用回声平面和/或螺旋成像序列获取T2*加权功能图像。我们会用无声的？集群采集fMRI范式（事件相关），其设计允许高保真的声音直接传递到耳朵（在耳罩下）在扫描过程的静默期间，从而最大限度地减少或消除与扫描仪噪声相关的干扰。总之，这个项目中的实验试图识别负责听觉注意的皮层系统，提供了负责我们感知复杂自然声音中不同类型信息的不同和重叠皮层通路的详细地图。这些结果将显著地推进与人类听觉处理有关的知识体系。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this study is to provide a better understanding of the organization and mechanism of human cortical systems involved in directing our attention to different aspects of every day, complex environmental sounds. To achieve this goal, functional magnetic resonance imaging (fMRI) will be used to differentiate, map and functionally characterize brain regions (in both sighted and blind people) involved in directing attention to three-dimensionally (3D) localizable natural sounds, presented over a high fidelity headphone system while participants are lying in the MRI scanner. Emphasis will be placed on (1) mapping cortical pathways preferential for processing the spatial location ("where") versus recognizing the content of the complex natural sounds ("what"). We expect to activate a specific "fronto-parietal" network during spatial attention to sound, and several high-level, auditory-association regions during attention to the content of that same sound stimulus. Due to our recent discovery of partially separate pathways in cortex for processing animal vocalizations relative to hand-manipulated tool sounds (two distinct conceptual categories of sound), we will also determine (2) if activity along these distinct pathways can be modulated by attention. This will be assessed by presenting simultaneous sound-sources, requiring the participant to ignore the distracting sound(s). We will additionally be able to determine if portions of the fronto-parietal cortical network (mentioned above), are also involved in "auditory streaming", wherein attention is directed to processing one sound-source, having to filter out the other(s). Volunteer participants will perform auditory behavioral tasks while functional images are acquired with a 3T GE LX research scanner, using echo-planar and/or spiral imaging sequences for T2* weighted functional images. We will use a ?silent? clustered acquisition fMRI paradigm (event-related), which is designed to allow high fidelity sound to be delivered directly to the ears (under ear muffs) during silent periods of the scanning process, thereby minimizing or eliminating interference associated with scanner noise. Together, the experiments in this project seek to identify cortical systems responsible for auditory attention, providing detailed maps of both distinct and overlapping cortical pathways responsible for our perception of different types of information contained in complex natural sounds. The results will significantly advance the body of knowledge pertaining to human auditory processing.