Neural Mechanisms of Auditory Attention

描述（由申请人提供）：感官信息不断淹没我们的感知系统。成功地选择性地关注特定的环境刺激需要我们忽略竞争性刺激。这个项目研究了竞争性听觉干扰的感知处理的大脑机制。长期以来，认知科学一直在争论不相关刺激被处理的程度，自20世纪50年代以来，理论家们主张早期选择（在感官水平上进行门控，导致对干扰物的有限处理）或晚期选择（在对干扰物进行完全感官处理后，在意识水平上进行门控）。这两种观点在最近的模型中得到了调和（Lavie，1995，2000; Lavie等人，2004），根据负荷水平（高，低）和注意力任务所需的心理处理（知觉，认知控制）来确定选择的轨迹。根据这一“负荷”模型，在高知觉负荷或低认知控制负荷的条件下，成功的选择性注意是最好的。相当多的行为证据和一些神经影像学数据支持负荷模型，至少在视觉模态。在听觉通道的相应研究是罕见的，主要涉及行为和电生理措施。我们建议使用ERPs和fMRI的同步记录来研究知觉负荷和认知控制负荷（即，工作记忆）各自影响沿着听觉通路的与任务无关的语音的感知处理。语音是作为干扰物的理想选择，因为它们与人类高度相关，并且它们的处理相对较好地定位在大脑中。此外，将采用复杂的声学匹配的非语音声音来测试选择性注意效应对音素感知的特异性。我们建议提供直接的神经证据轴承之间的辩论早期和晚期选择意见的听觉模态。具体目标1是研究在何种程度上不相关的语音在皮层听觉系统的处理调制的感知需求的主要任务。根据负荷模型，我们假设在高感知负荷的条件下，语音相关区域的大脑活动减少，干扰相关ERP反应较小。具体目标2是研究在何种程度上不相关的语音在皮层听觉系统的处理调制的认知控制所要求的主要任务。根据负荷模型，我们假设在低工作记忆负荷的条件下，语音相关区域的脑活动减少，并且与分心物相关的ERP反应较小。这个项目将提供一些关于健康人类听觉系统中选择性注意的皮层机制的第一个神经影像学证据。结果应该提供一个相对明确的测试负荷模型的选择性注意。 项目叙述：除了更清楚地描绘我们的听觉感知和注意力系统的神经解剖学基础之外，这些发现将有助于识别和破译精神分裂症和阅读障碍中听觉注意力障碍的处理缺陷，这对于制定有效的补救方法将是非常宝贵的。

DESCRIPTION (provided by applicant): Sensory information continuously floods our perceptual systems. Success at attending selectively to a particular environmental stimulus requires us to ignore competing stimuli. This project examines the brain mechanisms that underlie perceptual processing of competing auditory distractors. Cognitive science has long debated the extent to which irrelevant stimuli are processed, with theorists since the 1950s advocating either early selection (gating at the sensory level leading to limited processing of distractors) or late selection (gating at the awareness level after complete sensory processing of distractors). The two views are reconciled in a recent model (Lavie, 1995, 2000; Lavie et al., 2004) that determines the locus of selection according to the load level (high, low) and the mental processing (perceptual, cognitive control) demanded by the attention task. According to this "load" model, successful selective attention is best achieved under conditions of high perceptual load or low cognitive control load. Considerable behavioral evidence and some neuroimaging data lend support to the load model, at least in the visual modality. Corresponding studies in the auditory modality are scarce and involve mainly behavioral and electrophysiological measures. We propose to investigate, using simultaneous recordings of ERPs and fMRI, how perceptual load and cognitive control load (i.e., working memory) each influence the perceptual processing of task-irrelevant speech sounds along the auditory pathway. Speech sounds are an ideal choice as distractors because they are highly relevant to humans, and their processing has been relatively well localized in the brain. In addition, complex acoustically-matched non- speech sounds will be employed to test the specificity of selective attention effects to phonemic perception. We propose to provide direct neural evidence bearing on the debate between early and late selection views in the auditory modality. Specific Aim 1 is to study the extent to which the processing of irrelevant speech sounds in the cortical auditory system is modulated by the perceptual demands of a primary task. In accordance with the load model, we hypothesize a reduction in brain activity in speech-related areas and smaller distractor-related ERP responses under conditions of high perceptual load. Specific Aim 2 is to study the extent to which the processing of irrelevant speech sounds in the cortical auditory system is modulated by the cognitive control demanded by the primary task. In accordance with the load model, we hypothesize a reduction in brain activity in speech-related areas and smaller distractor-related ERP responses under conditions of low working memory load. This project will provide some of the first neuroimaging evidence concerning cortical mechanisms of selective attention in the healthy human auditory system. The results should provide a relatively unambiguous test of the load model of selective attention. Project Narrative: In addition to more clearly delineating the neuroanatomic foundations of our auditory perceptual and attention system, the findings will help identify and decipher the processing deficits that underlie auditory attention impairments in schizophrenia and dyslexia, which will be invaluable for formulating effective approaches to remediation in these conditions.