Object-completion effects in the human lateral occipital complex
Object-completion effects in the human lateral occipital complex
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DOI：
10.1093/cercor/12.2.163
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发表时间：
2002-02-01
期刊：
影响因子：
3.7
通讯作者：
Malach, R
中科院分区：
文献类型：
--
作者：
Lerner, Y;Hendler, T;Malach, R
人类视觉系统识别部分遮挡物体的能力是一项惊人的壮举，这已经获得了广泛的心理物理学文献。本文研究了完成效应在功能性磁共振成像（fMRI）高阶目标区（枕侧复合体- LOC）激活中的表现。研究人员向受试者展示了三种类型的图像：(i)动物或不熟悉形状的全线画（“全线”）；（ii）由平行条纹遮挡的相同形状，这些条纹约占图像表面面积的一半（“网格”）；（iii）对相同的条纹进行“打乱”，使得条纹之间区域的相对位置发生了变化，而局部特征结构保持不变。行为测量显示，在“网格”条件下，物体完成度很高，而在“乱置”条件下则不然。fMRI结果显示，与“打乱”的图像相比，“网格”图像的激活程度明显更高。由于两组图像的局部特征相同，这种增强的激活表明非局部补全效应的操作。显示出最高“完成”效应的皮质区域与LOC区域共定位，LOC区域对“完整”图像的激活程度高于对“混乱”图像的激活程度。在“网格”和“混乱”条件下，早期视网膜区域的激活是相似的。我们的研究结果表明，LOC是对象补全效应表现的中心部位。
The ability of the human visual system to recognize partially occluded objects is a striking feat, which has received extensive psychophysical documentation. Here we studied the manifestation of completion effects in the functional magnetic resonance imaging (fMRI) activation of high-order object areas (the lateral occipital complex - LOC). Subjects were presented with three types of images: (i) whole line drawings of animal or unfamiliar shapes ('whole'); (ii) the same shapes, occluded by parallel stripes which occupied roughly half of the surface area of the images ('grid'); and (iii) the same stripes, 'scrambled' so that the relative position of the regions between the stripes was changed while the local feature structure remained intact. Behavioral measurements showed a high degree of object completion in the 'grid' condition, but not in the 'scrambled' condition. The fMRI results show a significantly higher activation to the 'grid' images compared to the 'scrambled' images. This enhanced activation indicates the operation of non-local completion effects, since the local features in both sets of images were the same. The cortical regions showing the highest 'completion' effects co-localized with regions in the LOC which showed the highest activation to the 'whole' images compared to the 'scrambled' images. Activation in early retinotopic areas was similar in both the 'grid' and the 'scrambled' conditions. Our results point to the LOC as a central site in which object completion effects are manifested.