Department of Speech, Language, and Hearing Sciences, Boston University, Boston, Massachusetts, USA.
Department of Psychology, University of Houston, Houston, Texas, USA.
Hum Brain Mapp. 2024 Feb 1;45(2):e26608. doi: 10.1002/hbm.26608.
Emerging research has provided valuable insights into the structural characteristics of the bilingual brain from studies of bilingual adults; however, there is a dearth of evidence examining brain structural alterations in childhood associated with the bilingual experience. This study examined the associations between bilingualism and white matter organization in bilingual children compared to monolingual peers leveraging the large-scale data from the Adolescent Brain Cognitive Development (ABCD) Study. Then, 446 bilingual children (ages 9-10) were identified from the participants in the ABCD data and rigorously matched to a group of 446 monolingual peers. Multiple regression models for selected language and cognitive control white matter pathways were used to compare white matter fractional anisotropy (FA) values between bilinguals and monolinguals, controlling for demographic and environmental factors as covariates in the models. Results revealed significantly lower FA values in bilinguals compared to monolinguals across established dorsal and ventral language network pathways bilaterally (i.e., the superior longitudinal fasciculus and inferior frontal-occipital fasciculus) and right-hemispheric pathways in areas related to cognitive control and short-term memory (i.e., cingulum and parahippocampal cingulum). In contrast to the enhanced FA values observed in adult bilinguals relative to monolinguals, our findings of lower FA in bilingual children relative to monolinguals may suggest a protracted development of white matter pathways associated with language and cognitive control resulting from dual language learning in childhood. Further, these findings underscore the need for large-scale longitudinal investigation of white matter development in bilingual children to understand neuroplasticity associated with the bilingual experience during this period of heightened language learning.
新兴研究通过对双语成年人的研究，为双语大脑的结构特征提供了有价值的见解；然而，几乎没有证据研究与双语经验相关的儿童期大脑结构变化。本研究利用青少年大脑认知发展（ABCD）研究的大规模数据，比较了双语儿童和单语同伴之间的双语与白质组织之间的关联。然后，从 ABCD 数据中的参与者中确定了 446 名双语儿童（9-10 岁），并严格匹配了一组 446 名单语同伴。使用针对所选语言和认知控制白质通路的多元回归模型，比较了双语者和单语者之间的白质分数各向异性（FA）值，在模型中控制了人口统计学和环境因素作为协变量。结果表明，与单语者相比，双语者双侧（即上纵束和下额枕束）和与认知控制和短期记忆相关的右半球区域（即扣带和海马旁扣带）的既定背侧和腹侧语言网络通路的 FA 值显著降低。与成人双语者相对于单语者观察到的增强的 FA 值相反，我们在双语儿童相对于单语者中观察到的较低 FA 值可能表明，由于儿童时期的双语学习，与语言和认知控制相关的白质通路的发育延长。此外，这些发现强调了需要对双语儿童的白质发育进行大规模的纵向研究，以了解在此期间高度语言学习期间与双语经验相关的神经可塑性。
