Privileged coding of convex shapes in human object-selective cortex
Privileged coding of convex shapes in human object-selective cortex
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DOI：
10.1152/jn.90310.2008
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发表时间：
2008-08-01
影响因子：
2.5
通讯作者：
Kanwisher, Nancy
中科院分区：
文献类型：
--
作者：
Haushofer, Johannes;Baker, Chris I.;Kanwisher, Nancy
物体形状的神经编码是什么？尽管进行了深入的研究，但高级视觉皮质中对象表征的确切性质仍然难以捉摸。在这里，我们使用功能磁共振成像(FMRI)来显示凸起形状是由人类侧枕复合体(LOC)以一种特权的方式编码的，该区域已经被牵连到物体识别。在每个试验中，顺序呈现两个相同或不同的凸形或凹形。关键的是，凸面和凹面刺激是相同的，除了双眼视差的变化颠倒了图形-背景的分配。LOC对不同凸形刺激的fMRI反应高于相同形状对的fMRI反应，表明凸形刺激对不同形状的反应敏感。然而，当相同的刺激被视为凹面时，不同和相同的对的反应是相同的，这表明对凹面形状变化的敏感性低于凸面形状。这一模式在LOC的前部比后部更为明显。这些结果表明，凸起的轮廓可能是皮层物体表征中的重要元素。
What is the neural code for object shape? Despite intensive research, the precise nature of object representations in high-level visual cortex remains elusive. Here we use functional magnetic resonance imaging (fMRI) to show that convex shapes are encoded in a privileged fashion by human lateral occipital complex (LOC), a region that has been implicated in object recognition. On each trial, two convex or two concave shapes that were either identical or different were presented sequentially. Critically, the convex and concave stimuli were the same except for a binocular disparity change that reversed the figure-ground assignment. The fMRI response in LOC for convex stimuli was higher for different than that for identical shape pairs, indicating sensitivity to differences in convex shape. However, when the same stimuli were seen as concave, the response for different and identical pairs was the same, indicating lower sensitivity to changes in concave shape than convex shape. This pattern was more pronounced in the anterior than that in the posterior portion of LOC. These results suggest that convex contours could be important elements in cortical object representations.