Attention and stimulus-driven processes in auditory object perception

描述（由申请人提供）：在自然情况下，声音环境是动态和快速变化的，多个声源在时间上重叠并争夺注意力。当你走在嘈杂的城市街道上时，听你的朋友说话的能力需要大脑的机制来解开声音的混合，将你朋友的声音与汽车的声音和其他经过的谈话分开。听觉场景分析，即分析和组织混合声音输入的能力，是一种基本的听觉过程。然而，支持感知声音组织的神经机制仍然知之甚少，并且通常依赖于主要用于描述视觉系统机制的理论。当存在多个竞争声源时，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抱怨，并且会极大地阻碍沟通能力。没有计算机算法或假体设备可以模仿大脑在竞争背景噪音时的行为。该提案的总体目标是描述听觉系统如何适应动态变化的多流环境，允许快速灵活地转换到周围环境中的不同声音事件。Specific Aim 1决定了歧义输入在生理上是如何储存的。具体目标2描述了在模棱两可的情况下，注意力如何改变神经活动来支持行为。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。当输入感知模糊时，将获得声音组织的行为和多种电生理指标，从而为正常听力成人提供一个新的模型，以表征大脑如何在嘈杂环境中保持稳定的声音事件。当前项目的一个关键优势是能够从神经生理学上评估听觉皮层中有参与和无参与声音的声音组织。提出的实验结果将阐明大脑系统如何维持动态变化的环境；描述场景分析的自动和细心机制如何在许多流中的一个感知中相互作用。这将填补我们对在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的理解的深刻空白。

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.