Typicality sharpens category representations in object-selective cortex.
Typicality sharpens category representations in object-selective cortex.
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DOI：
10.1016/j.neuroimage.2016.04.012
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发表时间：
2016-07-01
期刊：
影响因子：
5.7
通讯作者：
Fei-Fei L
中科院分区：
文献类型：
--
作者：
Iordan MC;Greene MR;Beck DM;Fei-Fei L
分类的目的是识别可概括的对象类，其成员可以被等效对待。然而，在一个类别中，有些例子比其他例子更能代表这个概念。尽管长期存在的行为效应，很少有人知道典型性如何影响来自同一类别的现实世界对象的神经表征。使用fMRI，我们向参与者展示了64个从属对象类别（样本），分为8个基本类别。对每个样本的典型性进行了行为评估，我们使用了几种多体素模式分析来表征典型性如何影响在早期视觉和对象选择区域引起的反应模式：V1，V2，V3v，hV4，V3。我们发现，在早期的领域，但不是在早期，典型的样例引起的活动更类似于中央类别的倾向，并创建更清晰的类别边界比不典型的样例，这表明典型性增强类内相似性和类间相异。此外，我们发现了一个大脑区域（cIPL），其中类别边界有利于不太典型的类别。我们的研究结果表明，典型性可能构成了一个以前未探索的原则，组织内的类别神经结构，而且，这种表示是不直接反映在图像特征描述自然输入，而是由视觉系统建立在一个中间处理阶段。
The purpose of categorization is to identify generalizable classes of objects whose members can be treated equivalently. Within a category, however, some exemplars are more representative of that concept than others. Despite long-standing behavioral effects, little is known about how typicality influences the neural representation of real-world objects from the same category. Using fMRI, we showed participants 64 subordinate object categories (exemplars) grouped into 8 basic categories. Typicality for each exemplar was assessed behaviorally and we used several multi-voxel pattern analyses to characterize how typicality affects the pattern of responses elicited in early visual and object-selective areas: V1, V2, V3v, hV4, LOC. We found that in LOC, but not in early areas, typical exemplars elicited activity more similar to the central category tendency and created sharper category boundaries than less typical exemplars, suggesting that typicality enhances within-category similarity and between-category dissimilarity. Additionally, we uncovered a brain region (cIPL) where category boundaries favor less typical categories. Our results suggest that typicality may constitute a previously unexplored principle of organization for intra-category neural structure and, furthermore, that this representation is not directly reflected in image features describing natural input, but rather built by the visual system at an intermediate processing stage.