Cortical responses to contextual influences in amodal completion
Cortical responses to contextual influences in amodal completion
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DOI：
10.1016/j.neuroimage.2006.05.008
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发表时间：
2006-10-01
期刊：
影响因子：
5.7
通讯作者：
van Lier, Rob
中科院分区：
文献类型：
--
作者：
de Wit, Tessa C. J.;Bauer, Markus;van Lier, Rob
非情态补全指的是视觉系统中使我们能够将部分遮挡的物体作为整体感知的过程。视觉对象的整体形状(全局方面)和紧邻遮盖器周围的区域(局部方面)两者都是已知的，以确定完成的过程。我们利用脑磁图记录研究了完成期整体形状背景对人脑活动的影响。受试者被呈现了两种不同类型的形状，它们被一个矩形部分遮挡住了。在所谓的收敛形状中，局部和全局上下文触发相同的补全，而在所谓的发散形状中，局部和全局上下文触发不同的补全。在1个S之后移除封堵器，揭示了基于局部和全球背景的预期可能被满足或被违反的整个(完整)形状。我们发现了一个早期(从200ms以后)的左枕部成分，它主要对未被覆盖的延续的图形方面敏感，但也受到物理形状和感知形状(基于上下文线索)之间的一致性的调节。相反，早期的右枕叶部分和较晚的(400ms)前颞叶部分仅对物理形状和感知形状之间的一致性敏感，这表明全局背景与无节律完成的相关性。(C)2006 Elsevier Inc.保留所有权利。
Amodal completion refers to the process in the visual system that enables us to perceive partly occluded objects as whole objects. Both the overall shape of a visual object (global aspect) and the region immediately surrounding the occluder (local aspect) are known to determine the process of completion. We investigated the influence of overall shape context in completion on human brain activity using MEG recordings. Subjects were presented with two different types of shapes that were partly occluded by a rectangle. In the so-called convergent shapes, the local and global contexts trigger the same completion, and in the so-called divergent shapes, local and global contexts trigger different completions. The occluder was removed after 1 s, revealing the whole (completed) shape where expectancies based on the local and global context could either be fulfilled or violated. We found an early (from 200 ms on) left occipital component, which was predominantly sensitive to the figural aspects of the uncovered continuation, but was also modulated by the congruency between the physical shape and the perceived shape (based on the contextual cues). In contrast, an early right occipital component and a later (400 ms) anterior temporal component were sensitive only to the congruency between the physical and the perceived shape, showing the relevance of the global context in amodal completion. (c) 2006 Elsevier Inc. All rights reserved.