Department of Psychology, Center for the Study of Brain, Mind, and Behavior, Princeton University, Princeton, NJ 08544, USA.
J Cogn Neurosci. 2010 Nov;22(11):2417-26. doi: 10.1162/jocn.2009.21391.
Multiple stimuli that are present simultaneously in the visual field compete for neural representation. At the same time, however, multiple stimuli in cluttered scenes also undergo perceptual organization according to certain rules originally defined by the Gestalt psychologists such as similarity or proximity, thereby segmenting scenes into candidate objects. How can these two seemingly orthogonal neural processes that occur early in the visual processing stream be reconciled? One possibility is that competition occurs among perceptual groups rather than at the level of elements within a group. We probed this idea using fMRI by assessing competitive interactions across visual cortex in displays containing varying degrees of perceptual organization or perceptual grouping (Grp). In strong Grp displays, elements were arranged such that either an illusory figure or a group of collinear elements were present, whereas in weak Grp displays the same elements were arranged randomly. Competitive interactions among stimuli were overcome throughout early visual cortex and V4, when elements were grouped regardless of Grp type. Our findings suggest that context-dependent grouping mechanisms and competitive interactions are linked to provide a bottom-up bias toward candidate objects in cluttered scenes.
多个同时出现在视野中的刺激物会争夺神经表示。然而，与此同时，杂乱场景中的多个刺激物也会根据格式塔心理学家最初定义的某些规则（如相似性或邻近性）进行感知组织，从而将场景分割成候选对象。这两个似乎在视觉处理流中早期发生的、完全不同的神经过程如何协调？一种可能性是，竞争发生在知觉群体之间，而不是群体内部的元素之间。我们通过评估包含不同程度感知组织或感知分组（Grp）的显示中的跨视觉皮层的竞争相互作用，使用 fMRI 来探测这个想法。在强 Grp 显示中，元素的排列方式使得存在幻象图形或一组共线元素，而在弱 Grp 显示中，相同的元素随机排列。当元素无论分组类型如何分组时，刺激之间的竞争相互作用在整个早期视觉皮层和 V4 中都被克服了。我们的发现表明，上下文相关的分组机制和竞争相互作用是相关的，为杂乱场景中的候选对象提供了自下而上的偏见。
