Object-Specific Semantic Coding in Human Perirhinal Cortex
Object-Specific Semantic Coding in Human Perirhinal Cortex
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DOI：
10.1523/jneurosci.2828-13.2014
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发表时间：
2014-04-02
影响因子：
5.3
通讯作者：
Tyler, Lorraine K.
中科院分区：
文献类型：
--
作者：
Clarke, Alex;Tyler, Lorraine K.
人类后腹侧颞叶皮层对各种物体类别具有类别特异性。尽管腹侧视觉通路内的物体表征必须足够丰富和复杂以支持单个物体的识别，但对于如何表征特定物体却知之甚少。在这里，我们使用表征相似性分析来确定 fMRI 激活模式中反映了哪些不同类型的对象信息，并揭示了分类和特定对象语义表征之间的关系。我们的结果显示了沿着腹侧流的信息特异性的梯度，从早期视觉皮层中基于图像的视觉特性的表示到后腹侧流中的分类表示。一项重要发现表明，特定于物体的语义信息在鼻周皮层中得到了独特的表达，而鼻周皮层也越来越多地参与语义上更容易混淆的物体。这些发现表明，鼻周皮层在表示和处理特定于对象的语义信息方面发挥着关键作用，这对于高度混淆的对象更为重要。我们的研究结果扩展了当前的分布式模型，显示了后腹侧皮层中的对象之间的粗略分离，以及由前内侧颞叶（包括鼻周皮层）支持的对象之间的细粒度区别，其用于整合复杂的对象信息。
Category-specificity has been demonstrated in the human posterior ventral temporal cortex for a variety of object categories. Although object representations within the ventral visual pathway must be sufficiently rich and complex to support the recognition of individual objects, little is known about how specific objects are represented. Here, we used representational similarity analysis to determine what different kinds of object information are reflected in fMRI activation patterns and uncover the relationship between categorical and object-specific semantic representations. Our results show a gradient of informational specificity along the ventral stream from representations of image-based visual properties in early visual cortex, to categorical representations in the posterior ventral stream. A key finding showed that object-specific semantic information is uniquely represented in the perirhinal cortex, which was also increasingly engaged for objects that are more semantically confusable. These findings suggest a key role for the perirhinal cortex in representing and processing object-specific semantic information that is more critical for highly confusable objects. Our findings extend current distributed models by showing coarse dissociations between objects in posterior ventral cortex, and fine-grained distinctions between objects supported by the anterior medial temporal lobes, including the perirhinal cortex, which serve to integrate complex object information.