Neural Correlates of spatial and object-based selection

描述（由申请人提供）：大脑无法完全仔细检查每时每刻存在的丰富信息，因此选择过程不断地对环境进行采样。通过决定环境的哪些方面得到优先处理，这种选择过程无疑对几乎所有的大脑功能都有巨大的影响。因此，对共同决定选择的神经机制的理解，被广泛地称为选择性注意，一直是视觉神经科学的巨大挑战之一。选择性注意通常是由行为目标和刺激显著性共同引导的。例如，大脑有限的处理资源可以被部署在特定的位置，或者是在期待重要的事情时，或者是在对特别强烈或突然的刺激做出反应时。但选择性注意是一个动态的、持续的过程，对特定地点产生偏见只是这个过程中的一步。在注意聚光灯的部署之后，有一个后续的基于局部物体属性的注意调制级联。对人类的研究表明，即使物体的一部分延伸到与任务相关的位置之外，在提示位置的强化处理也会在物体的视觉边界内扩散。这种刺激驱动的选择性注意机制可以解释为空间选择的改进，被称为“基于对象的空间选择”。然而在这个连续的过程中第一步的神经关联

DESCRIPTION (provided by applicant): The brain cannot fully scrutinize the wealth of information that is present at each moment, and so a selection process continually samples the environment. By determining which aspects of the environment receive preferred processing, this selection process undoubtedly has a huge influence on nearly all brain functions. An understanding of the neural mechanisms that collectively determine selection, broadly referred to as selective attention, has therefore been one of the great challenges of visual neuroscience. Selective attention is often guided by a combination of behavioral goals and stimulus salience. For example, the brain's limited processing resources can be deployed at a specific location either in anticipation of something important, or in response to a particularly strong or sudden stimulus. But selective attention is a dynamic and ongoing process, and introducing a bias toward a particular location is just one step in this process. Following deployment of the attentional spotlight, there is a subsequent cascade of attentional modulation that continues based on local object properties. Studies in humans have shown that enhanced processing at a cued location spreads within an object's visual boundaries, even when part of the object extends outside the task-relevant location. This stimulus-driven mechanism of selective attention, which can be construed as a refinement of spatial selection, has been referred to as "object-based spatial selection". Whereas the neural correlates of the first step in this continual selection process, spatial selection, have been well-characterized, the neural correlates of object- based spatial selection are unknown. The first objective of the present proposal is therefore to bridge this gap by characterizing attentional modulation in monkey extrastriate neurons attributable to stimulus-driven, object- based spatial selection, and then comparing it to attentional modulation attributable to goal-oriented spatial selection (within the same experimental task). A second objective of the present proposal is to determine the extent to which attentional modulation in extrastriate neurons is driven by other brain regions known to be part of the network of structures that mediate attentional selection, and to determine whether such interareal interactions vary depending on the mechanism of attentional selection. The central hypothesis is that spatial selection and object-based spatial selection are mediated through separable neural processes that interact to parse and filter the visual environment. We will probe these objectives and our central hypothesis by recording simultaneously from area V4, the pulvinar, and the frontal eye field (FEF) in monkeys trained on performing an attention task that simultaneously taps into goal-oriented spatial selection and stimulus-driven, object-based spatial selection. The multi-site recording technique will utilize fMRI- and DTI-guided electrode placement to define matching network nodes. Attentional disorders have severe consequences for human health (e.g., spatial neglect after stroke, ADHD). A necessary first step toward improving treatment of these disorders, and the goal of this proposal, is to gain a better understanding of the neural mechanisms of selective attention.