Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Cereb Cortex. 2013 Jul;23(7):1673-84. doi: 10.1093/cercor/bhs158. Epub 2012 Jun 12.
Current research on the neurobiological bases of reading points to the privileged role of a ventral cortical network in visual word processing. However, the properties of this network and, in particular, its selectivity for orthographic stimuli such as words and pseudowords remain topics of significant debate. Here, we approached this issue from a novel perspective by applying pattern-based analyses to functional magnetic resonance imaging data. Specifically, we examined whether, where and how, orthographic stimuli elicit distinct patterns of activation in the human cortex. First, at the category level, multivariate mapping found extensive sensitivity throughout the ventral cortex for words relative to false-font strings. Secondly, at the identity level, the multi-voxel pattern classification provided direct evidence that different pseudowords are encoded by distinct neural patterns. Thirdly, a comparison of pseudoword and face identification revealed that both stimulus types exploit common neural resources within the ventral cortical network. These results provide novel evidence regarding the involvement of the left ventral cortex in orthographic stimulus processing and shed light on its selectivity and discriminability profile. In particular, our findings support the existence of sublexical orthographic representations within the left ventral cortex while arguing for the continuity of reading with other visual recognition skills.
当前有关阅读的神经生物学基础的研究表明，腹侧皮质网络在视觉单词处理中具有特殊作用。然而，这个网络的特性，特别是它对字形刺激（如单词和伪词）的选择性，仍然是一个备受争议的话题。在这里，我们从一个新的角度来解决这个问题，即通过应用基于模式的分析方法来研究功能磁共振成像数据。具体来说，我们研究了在人类大脑皮层中，字形刺激是否以及如何引发独特的激活模式。首先，在类别水平上，多元映射发现，相对于假字体字符串，单词在腹侧皮层中具有广泛的敏感性。其次，在身份水平上，多体素模式分类提供了直接的证据，表明不同的伪词是由不同的神经模式编码的。第三，对伪词和面孔识别的比较表明，这两种刺激类型都利用了腹侧皮质网络中的共同神经资源。这些结果为左腹侧皮层在字形刺激处理中的参与提供了新的证据，并揭示了其选择性和可区分性特征。特别是，我们的研究结果支持了左腹侧皮层中存在亚词形的字形表示，同时也支持了阅读与其他视觉识别技能的连续性。
