State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China.
Bilingual Cognition and Development Lab, Center for Linguistics and Applied Linguistics, Guangdong University of Foreign Studies, Guangzhou, 510420, China.
Neuropsychologia. 2020 Oct;147:107592. doi: 10.1016/j.neuropsychologia.2020.107592. Epub 2020 Aug 25.
When bilinguals intend to speak in their first (L1) or second language (L2) according to the environment, a brain network involving cortical-subcortical regions is recruited to resolve cross-language interference. Research has found that the activation of these brain regions varies with language contexts. However, previous studies have not yet examined adaptive changes in the interactions of brain regions for different language contexts. To address this gap, we adopted extended unified structural equation modeling (euSEM) to identify the connectivity patterns of the bilingual control network. Twenty-one unbalanced Chinese-English bilinguals were instructed to name pictures in L1-single, L2-single, and dual-language contexts while undergoing functional magnetic resonance imaging (fMRI). We found that unbalanced bilinguals relied on a more functional integrated brain network, which was reflected by clearer core-periphery structures and increased global efficiency, in dual-language and L2-single contexts compared to L1-single context. Furthermore, the pattern of brain connectivity in the dual-language context was more similar to that in the L1-single context than the L2-single context. More importantly, we found more similarities between the connectivity patterns of dual-language and L1-single contexts in bilinguals with lower inhibitory control abilities. These findings provide the first connectivity evidence for the effect of language context on the bilingual language control network, which inhibits the base language and underpins bilinguals' change along the monolingual-bilingual mode continuum.
当双语者根据环境意图使用第一语言（L1）或第二语言（L2）进行交流时，一个涉及皮质-皮质下区域的大脑网络被招募来解决跨语言干扰。研究发现，这些大脑区域的激活随语言语境而变化。然而，以前的研究尚未检查不同语言语境下大脑区域相互作用的适应性变化。为了解决这一差距，我们采用了扩展的统一结构方程模型（euSEM）来识别双语控制网络的连接模式。21 名不平衡的中英双语者在进行功能磁共振成像（fMRI）时被要求在 L1 单语、L2 单语和双语语境中命名图片。我们发现，与 L1 单语语境相比，不平衡的双语者在双语和 L2 单语语境中依赖于更功能整合的大脑网络，这反映在更清晰的核心-边缘结构和增加的全局效率上。此外，双语语境中的大脑连接模式与 L1 单语语境更相似，而与 L2 单语语境不相似。更重要的是，我们发现，在抑制控制能力较低的双语者中，双语和 L1 单语语境的连接模式更相似。这些发现为语言语境对双语语言控制网络的影响提供了第一个连接证据，该网络抑制母语，并支持双语者沿着单语-双语模式连续体的变化。
