Attention and stimulus-driven processes in auditory object perception

描述(申请人提供)：在自然情况下，声环境是动态和快速变化的，多个来源在时间上重叠，争夺注意力。当你走在嘈杂的城市街道上时，要想听你的朋友说话，需要大脑机制来分离声音混合，将你朋友的声音与汽车和其他过往对话的声音分开。听觉场景分析，即分析和组织声音输入的混合的能力，是一个基本的听觉过程。然而，帮助知觉健全组织的神经机制仍然知之甚少，而且往往依赖于主要用于描述视觉系统机制的理论。当有多个相互竞争的声源时，选择相关信息的能力不足是老年人和听力损失患者的常见症状，并可能极大地阻碍沟通能力。没有计算机算法或假肢设备可以模仿大脑在存在竞争性背景噪音时所做的事情。这项建议的总体目标是表征听觉系统如何适应动态变化的多流环境，允许快速和灵活地切换到周围环境中的不同声音事件。特定目标1确定如何在生理上存储模糊的输入。具体目标2描述了注意力如何改变神经活动，以支持模棱两可的情况下的行为。具体目标3确定听觉输入的神经表征如何适应不断变化的多流环境。这些目标将通过获得输入感知模糊时的声音组织的行为和多个电生理指数来实现，从而为描述大脑如何在噪声环境中保持稳定的声音事件提供了一个新的模型。当前项目的一个关键优势是能够从神经生理学的角度评估听觉皮质中的声音组织，包括有人听和无人听的声音。拟议的实验结果将阐明大脑系统如何维持动态变化的环境；表征场景分析的自动和专心机制如何在感知众多数据流中的一个时相互作用。这将填补我们在理解复杂和动态变化的声音环境中感知稳定听觉事件的神经机制方面的深刻空白。

DESCRIPTION (provided by applicant): In natural situations, the sound environment is dynamically and rapidly changing, with multiple sources overlapping in time and competing for attention. The ability to listen to your friend talking while walking down a noisy city street requires brain mechanisms that disentangle the sound mixture, separating your friend's voice from the sounds of the cars and other passing conversations. Auditory scene analysis, the ability to parse and organize the mixture of sound input, is a fundamental auditory process. Yet, the neural mechanisms that subserve perceptual sound organization are still poorly understood, and often rely on theories developed primarily to describe mechanisms of the visual system. Deficits in the ability to select relevant information when there are multiple competing sound sources is a common complaint in aging and in individuals with hearing loss, and can greatly hinder communication ability. There is no computer algorithm or prosthetic device that can mimic what the brain does when there is competing background noise. The overall goal of this proposal is to characterize how the auditory system adapts to dynamically changing multi-stream environments, allowing rapid and flexible shifting to different sound events in one's surroundings. Specific Aim 1 determines how ambiguous input is physiologically stored. Specific Aim 2 characterizes how attention modifies neural activity to support behavior in ambiguous situations. Specific Aim 3 identifies how neural representations of auditory input accommodate to changing multi-stream environments. The aims will be accomplished by obtaining behavioral and multiple electrophysiological indices of sound organization when the input is perceptually ambiguous, thus providing a novel model in normal hearing adults for characterizing how the brain maintains stable sound events in noisy environments. A key strength of the current project is the ability to neurophysiologically assess sound organization in auditory cortex for both attended and unattended sounds. The results of the proposed experiments will elucidate how dynamically changing environments are maintained by brain systems; characterizing how automatic and attentive mechanisms of scene analysis interact in the perception of one among many streams. This will fill a profound gap in our understanding of the neural mechanisms contributing to the perception of stable auditory events in complex and dynamically changing sound environments.