Neural representation of scene context during visual search

描述（由申请人提供）：合成线索（例如，箭头和方框）预测目标位置加速了搜索时间并导致增加的决策准确性。类似地，当观察者在自然场景中搜索时，高度可见的对象（例如，房屋），其经常与所寻找的目标（例如，当目标出现在物体附近时，烟囱）会影响眼睛的运动并促进搜索。在过去的几十年里，单细胞神经生理学、人类电生理学和神经影像学的研究使人们对注意力和合成线索对神经活动的影响有了很大的了解，但人们对真实的场景中视觉搜索过程中介导上下文效应的潜在神经机制却知之甚少。在这里，我们建议使用功能性磁共振成像（fMRI）分别测量神经活动，而观察者在真实的场景中搜索目标并使用神经解码方法（多变量模式分析）和群体感受野方法的新变化，以：1）确定表示场景上下文的空间位置的脑区（fMRI），从而可能介导在真实的场景中搜索的引导; 2）评价场景上下文的编码是自动的还是受自上而下的视觉注意的调节。拟议的工作将提高我们的理解场景上下文的神经机制，这可以说是观察者在自然环境中优化视觉搜索的最重要的策略之一。我们的研究结果还将促进我们对与注意力、物体/场景以及视觉搜索的上下文关联相关的大脑区域的功能和作用的理解。这些进展可能有助于识别低视力和注意力缺陷患者在生态学上重要的任务（如真实的场景中的视觉搜索）中不良行为表现的神经相关性。

DESCRIPTION (provided by applicant): Synthetic cues (e.g., arrows and boxes) predictive of a target location speed up search times and result in increased decision accuracy. Similarly, when observers search in natural scenes, a highly visible object (e.g., house) that often co-occurs in natural environments with a sought target (e.g., chimney) will influence eye movements and facilitate search when the target appears close to the object. While the last few decades have seen single cell neurophysiology, human electrophysiology and neuroimaging lead to great advances in the understanding of the effects of attention and synthetic cues on neural activity, little is known about the underlying neural mechanisms mediating context effects during visual search in real scenes. Here, we propose to separately measure neural activity using functional magnetic resonance imaging (fMRI) while observers search for targets in real scenes and use neural decoding methods (multivariate pattern analysis) and a novel variation of population receptive field methods to: 1) Determine the brain areas (fMRI) that represent the spatial location of scene context and thus might mediate guidance of search in real scenes; 2) To evaluate whether the coding of scene context is automatic or whether it is modulated by top-down visual attention. The proposed work will improve our understanding of the neural mechanisms of scene context which arguably is one of the most important strategies used by observers to optimize visual search in natural environments. Our results will also advance our understanding of the function and role of brain regions related to attention, objects/scenes, and contextual associations for visual search. These advances might potentially help in identifying neural correlates of poor behavioral performance for patients with low-vision and attentional deficits in an ecologically important task such as visual search in real scenes.