Cognitive and Neural Mechanisms of Figure-Ground Segregation

这个项目将研究人类感知的一个基本方面，即将视觉世界组织成人物和背景的能力。在日常的视觉场景中，物体相互重叠和遮挡，这就需要一个视觉过程来确定哪些物体位于前景（图形），哪些位于背景。心理学家提出了一套描述图-底隔离的规则。例如，一个对称的区域更有可能被视为人物而不是背景。然而，这种描述性的方法并没有指定图地分离的机制——允许实例化这些规则的精确计算。相比之下，非人类灵长类动物的神经生理学研究显示出阐明图底分离机制的希望，但这些研究的结果很难与人类感知的研究联系起来。该项目的目标是通过对大脑活动（俗称“脑电波”，技术上称为“事件相关电位”）的无创电生理记录，弥合人类感知和猴子神经生理学在图-地分离方面的差距。这些记录将使我们能够评估图像-背景分离的时间过程和神经解剖学基础，从而阐明图像-背景分离的认知和神经机制。我们假设图形与背景的分离依赖于一种机制，该机制放大了相对于背景的神经表征的图形的神经表征。我们的研究使用非侵入性电生理方法，通过测量与“图形”和“场地”相关的感觉过程，可以更直接地验证这一假设。这项研究将提供对大脑如何处理复杂视觉场景的理解，这可能对人工视觉系统和脑损伤后视觉感知康复技术产生影响。

This project will investigate a fundamental aspect of human perception, the ability to organize the visual world into figures and backgrounds. In everyday visual scenes, objects overlap and occlude one another, which necessitates a visual process for determining which objects lie in the foreground (figures) and which lie in the background. Psychologists have proposed a set of rules that describe figure-ground segregation. For example, a symmetrical region is more likely to be perceived as a figure than as the background. However, this descriptive approach does not specify the mechanisms of figure-ground segregation-the precise computations that allow these rules to be instantiated. Neurophysiological studies in nonhuman primates, in contrast, show promise for elucidating the mechanisms of figure-ground segregation, but the results of these studies are difficult to link with studies of human perception. The goal of this project is to bridge the gap between human perception and monkey neuro-physiology in figure-ground segregation by using noninvasive electro-physiological recordings of the brain's activity (colloquially known as 'brain waves' and technically as 'event-related potentials'). These recordings will allow us to assess the time course and neuroanatomical substrates of figure-ground segregation, thereby elucidating both the cognitive and neural mechanisms of figure-ground segregation. We hypothesize that figure-ground segregation relies on a mechanism that amplifies the neural representation of a figure relative to the neural representation of the ground. Our research uses non-invasive electro-physiological methods that can test this hypothesis more directly by measuring the sensory processes associated with both "figures" and "grounds." This research will provide an understanding of how the brain processes complex visual scenes, which may have implications for artificial vision systems and techniques for rehabilitation of visual perception following brain injury.