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，要想听朋友说话，需要大脑的机制来理清声音的混合，把朋友的声音从汽车的声音和其他经过的谈话中分离出来。听觉场景分析是一种基本的听觉过程，是对输入声音进行分析和组织的能力。然而，有助于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衰老和听力损失个体的常见问题，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存在竞争背景噪音时的行为。该提案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，允许快速灵活地切换到周围环境中的不同声音事件。具体目标1确定模糊输入在生理上如何存储。具体目标2描述了注意力如何修改神经活动，以支持在模糊情况下的行为。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声音组织的行为和多个电生理指标来实现，当输入在感知上是模糊的，从而提供了一个新的模型，在正常听力的成年人，用于表征大脑如何在嘈杂的环境中保持稳定的声音事件。目前的项目的一个关键优势是神经生理学评估的听觉皮层的声音组织的能力，无论是有人值守和无人值守的声音。拟议的实验的结果将阐明如何动态变化的环境是由大脑系统维护;表征场景分析的自动和专注的机制如何在许多流中的一个的感知中相互作用。这将填补我们对复杂和动态变化的声音环境中稳定听觉事件感知的神经机制的理解中的一个深刻空白。

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.