Cao Fan, Young Kim Say, Liu Yanni, Liu Li
Michigan State University, East Lansing, MI, USA.
Nanyang Technological University, Singapore, Singapore.
Neuropsychologia. 2014 Oct;63:275-84. doi: 10.1016/j.neuropsychologia.2014.09.001. Epub 2014 Sep 8.
It has been evidenced that both similarities and differences exist in the brain network involved in second language reading in comparison to the first language reading. However, very few studies have been done to compare functional connectivity in L1 and L2 reading. Brain activation and functional connectivity during English pseudoword rhyming judgment in a group of late Chinese-English bilinguals (the CE group) were compared to a Chinese word rhyming judgment task in another group of late Chinese-English bilinguals (the CC group). Brain activation analyses revealed that the two groups engaged a similar network and that the only significant group difference was greater involvement of the right middle occipital gyrus in the CC group than in the CE group, due to greater holistic visuospatial processing of Chinese characters. English pseudowords can be read using the same network as Chinese characters, whereas psychophysiological interaction (PPI) analyses revealed different connectivity within the reading network between the two groups. Greater functional connectivity was found between three visuo-orthographic seed regions and the right precentral gyrus in the CC group, suggesting that the sensorimotor patterns of Chinese syllables are activated during Chinese word rhyming judgment. In contrast, we found greater connectivity between the three seed regions and the left postcentral gyrus in the CE group. In addition, the connectivity between one of the three seed regions (i.e. the right middle occipital gyrus) and the left postcentral gyrus was positively correlated with English proficiency in the CE group. This suggests that somatosensory feedback plays a key role in processing the foreign phonemes of English pseudowords and those highly proficient bilinguals tend to rely on this information to a greater degree. We also found that within the CE group, the connectivity between the right middle occipital gyrus and the left inferior parietal lobule was positively correlated with accuracy, and that the connectivity between the right middle occipital gyrus and the left superior temporal gyrus was negatively correlated with reaction time. These results suggest that even if a Chinese network is used in reading English pseudowords, the classic grapheme-phoneme-correspondence regions that are important for native English reading are involved in highly performing bilinguals by connecting them with the visuo-orthographic region.
已有证据表明，与第一语言阅读相比，第二语言阅读所涉及的大脑网络既有相似之处，也有不同之处。然而，很少有研究对第一语言和第二语言阅读中的功能连接进行比较。将一组晚期中英双语者（CE组）在英语假词押韵判断过程中的大脑激活和功能连接与另一组晚期中英双语者（CC组）的中文单词押韵判断任务进行了比较。大脑激活分析显示，两组使用了相似的网络，唯一显著的组间差异是CC组比CE组右侧枕中回的参与度更高，这是由于汉字的整体视觉空间处理更强。英语假词可以使用与汉字相同的网络进行阅读，而心理生理交互作用（PPI）分析显示两组阅读网络内的连接不同。在CC组中，三个视觉正字法种子区域与右侧中央前回之间发现了更强的功能连接，这表明在中文单词押韵判断过程中，中文音节的感觉运动模式被激活。相比之下，我们在CE组中发现三个种子区域与左侧中央后回之间的连接更强。此外，CE组中三个种子区域之一（即右侧枕中回）与左侧中央后回之间的连接与英语水平呈正相关。这表明体感反馈在处理英语假词的外语音素方面起关键作用，而且那些高度熟练的双语者往往在更大程度上依赖这一信息。我们还发现，在CE组内，右侧枕中回与左侧下顶叶之间的连接与准确性呈正相关，右侧枕中回与左侧颞上回之间的连接与反应时间呈负相关。这些结果表明，即使在阅读英语假词时使用中文网络，对于以英语为母语的阅读很重要的经典字素-音素对应区域也会通过将它们与视觉正字法区域连接起来而参与到高水平双语者的阅读中。
