Reinke Karen, Fernandes Myra, Schwindt Graeme, O'Craven Kathleen, Grady Cheryl L
Department of Psychology, Southern Illinois University, Carbondale, IL, USA.
Brain Lang. 2008 Feb;104(2):180-9. doi: 10.1016/j.bandl.2007.04.006. Epub 2007 May 24.
The functional specificity of the brain region known as the Visual Word Form Area (VWFA) was examined using fMRI. We explored whether this area serves a general role in processing symbolic stimuli, rather than being selective for the processing of words. Brain activity was measured during a visual 1-back task to English words, meaningful symbols (e.g., $, %), digits, words in an unfamiliar language (Hebrew), and geometric control stimuli. Mean activity in the functionally defined VWFA, as well as a pattern of whole-brain activity identified using a multivariate technique, did not differ for words and symbols, but was distinguished from that seen with other stimuli. However, functional connectivity analysis of this region identified a network of regions that was specific to words, including the left hippocampus, left lateral temporal, and left prefrontal cortex. Results support the hypothesis that activity in the VWFA plays a general role in processing abstract stimuli; however, the left VWFA is part of a unique network of brain regions active only during the word condition. These findings suggest that it is the neural "context" of the VWFA, i.e., the broader activity distributed in the brain that is correlated with VWFA, that is specific for visual word representation, not activity in this brain region per se.
使用功能磁共振成像（fMRI）对被称为视觉词形区（VWFA）的脑区的功能特异性进行了研究。我们探究了该脑区在处理符号刺激时是否发挥一般作用，而非仅对单词处理具有选择性。在一项视觉1-回溯任务中，测量了大脑对英语单词、有意义的符号（如$、%）、数字、陌生语言（希伯来语）的单词以及几何对照刺激的活动。在功能定义的VWFA中的平均活动，以及使用多变量技术确定的全脑活动模式在单词和符号之间并无差异，但与其他刺激所观察到的情况有所区别。然而，对该脑区的功能连接分析确定了一个仅在单词条件下活跃的特定脑区网络，包括左侧海马体、左侧颞叶外侧和左侧前额叶皮质。结果支持了这样的假设，即VWFA中的活动在处理抽象刺激中发挥一般作用；然而，左侧VWFA是仅在单词条件下活跃的独特脑区网络的一部分。这些发现表明，是VWFA的神经“背景”，即大脑中与VWFA相关的更广泛分布的活动，对视觉单词表征具有特异性，而非该脑区本身的活动。
