Attentional Mechanisms in Multisensory Environments

描述(由申请人提供)：我们选择性地将注意力集中在感觉环境元素上的能力是一种关键的认知功能，使我们能够增强对高优先级刺激的处理。一个经典的例子是“鸡尾酒会”效应，即一个人可以选择性地专注于某个特定的演讲者，而忽略其他对话。在视觉上，注意视野的特定区域可以更快、更好地检测和辨别该区域的刺激。电生理和血液动力学脑成像研究都表明，自上而下的执行注意机制可以影响特定通道大脑皮层的早期感觉加工。最近在人类中使用事件相关功能磁共振成像(FMRI)的研究表明，额顶网络在视觉注意的执行控制中起作用。然而，到目前为止，研究注意力如何在感觉通道之间切换或协调的工作相对较少。因此，目前还不清楚哪些控制注意力的大脑机制、区域和资源是超通道的，哪些是通道特有的。此外，真实的物体，包括鸡尾酒会上的演讲者，都具有多感官特征，需要注意、感知和整合。由于多感觉整合涉及来自不同感觉通道的信息合成，目前尚不清楚在多感觉环境中是否会有与在单感觉环境中使用的相同的注意机制。例如，对多感官对象(例如，说话者的面部)的一个特征或方面的关注可能导致注意力的跨模式传播(例如，包围说话者的声音)。本研究计划结合事件相关电位(ERPs)和事件相关功能磁共振成像(FMRI)来研究注意在多感觉环境中的运作机制。这将包括研究在不同感觉模式之间协调和切换注意力的执行控制机制和大脑回路，以及注意力如何影响多感觉刺激的处理和整合并与之相互作用。记录注意任务中脑活动的ERP和fMRI测量将不仅揭示辅助多感觉注意操作的大脑区域，而且还将揭示其激活的时间和顺序，从而增强我们对潜在机制的理解。注意力缺陷形成了各种神经疾病和精神疾病的关键组成部分，从而阐明了其基本机制。

DESCRIPTION (provided by applicant): Our ability to selectively focus attention on elements of our sensory environment is a critical cognitive function that enables us to enhance the processing of high priority stimuli. A classic example is the "cocktail party" effect, in which a person can focus selectively on a particular speaker while tuning out other conversations. In vision, attending to a particular region of the visual field results in faster and better detection and discrimination of stimuli in that region. Both electrophysiological and hemodynamic brain imaging studies have shown that top-down executive attentional mechanisms can influence early sensory processing in modality-specific cortices. Recent studies using event-related functional MRI (fMRI) in humans have implicated a fronto-parietal network in the executive control of visual attention. As yet, however, relatively little work has investigated how attention is switched or coordinated between sensory modalities. Thus, it is not yet clear which brain mechanisms, regions, and resources controlling attention are supramodal and which are modality specific. Moreover, real objects, including speakers at cocktail parties, have multisensory characteristics that need to be attended, perceived, and integrated. Because multisensory integration involves synthesis of information derived from different sensory channels, it is not clear that the same attentional mechanisms will be operative in a multisensory environment as are employed in a unisensory situation. For example, attention to one feature or aspect of a multisensory object (e.g., the face of a speaker) might lead to a cross-modal spreading of attention (e.g., to encompass the speaker's voice). The present project proposes to combine event-related potentials (ERPs) and event-related fMRI to study the mechanisms by which attention operates in multisensory environments. This will include the study of executive control mechanisms and brain circuits that coordinate and switch attention between different sensory modalities, as well as how attention influences and interacts with the processing and integration of multisensory stimuli. Recording both ERP and fMRI measures of brain activity during the attentional tasks will reveal not only the brain areas that subserve multisensory attentional operations, but also the timing and sequence of their activations, thereby enhancing our understanding of the underlying mechanisms. Attentional deficits form key components of a variety of neurological disorders and mental illnesses, and thus elucidating the basic mechanism.