Department of Cognitive Science, University of California, San Diego, CA, USA.
Neuroimage. 2010 Feb 15;49(4):3286-94. doi: 10.1016/j.neuroimage.2009.12.009. Epub 2009 Dec 11.
Studies with monolingual adults have identified successive stages occurring in different brain regions for processing single written words. We combined magnetoencephalography and magnetic resonance imaging to compare these stages between the first (L1) and second (L2) languages in bilingual adults. L1 words in a size judgment task evoked a typical left-lateralized sequence of activity first in ventral occipitotemporal cortex (VOT: previously associated with visual word-form encoding) and then ventral frontotemporal regions (associated with lexico-semantic processing). Compared to L1, words in L2 activated right VOT more strongly from approximately 135 ms; this activation was attenuated when words became highly familiar with repetition. At approximately 400 ms, L2 responses were generally later than L1, more bilateral, and included the same lateral occipitotemporal areas as were activated by pictures. We propose that acquiring a language involves the recruitment of right hemisphere and posterior visual areas that are not necessary once fluency is achieved.
研究表明，处理单个书面单词时，单语成年人的大脑中会出现不同区域的连续阶段。我们结合脑磁图和磁共振成像，比较了双语成年人的第一语言（L1）和第二语言（L2）之间的这些阶段。在大小判断任务中，L1 单词首先在腹侧枕颞叶皮层（VOT：先前与视觉单词形式编码相关）和腹侧额颞叶区域（与词汇语义处理相关）中引发典型的左侧序列活动。与 L1 相比，L2 单词在大约 135 毫秒时从右侧 VOT 激活更强；当单词因重复而变得非常熟悉时，这种激活会减弱。大约 400 毫秒时，L2 的反应通常比 L1 更晚、更双边，并且包括与图片激活相同的外侧枕颞叶区域。我们提出，习得一门语言涉及到对右半球和后部视觉区域的招募，而一旦达到流利程度，这些区域就不再必要了。
