East China Normal University.
Freie Universität Berlin.
J Cogn Neurosci. 2024 May 1;36(5):836-853. doi: 10.1162/jocn_a_02128.
Experience in bilingual language control is often accompanied by changes in the structure and function of the brain. Brain structural changes are also often closely related to changes in functions. Previous studies, however, have not directly explored the relationship between structural connectivity and effective functional connectivity of the brain during bilingual language control, and whether the two types of connectivity are associated with behavioral performance of language control. Using behavioral performance, functional, and diffusion imaging techniques, we found that: (1) during language control, the left dorsal lateral prefrontal cortex (dlPFC), left caudate nucleus (CN), inferior parietal lobe, precuneus, and dorsal anterior cingulate cortex (dACC)/pre-SMA were significantly activated. (2) In the language control model with left dlPFC, dACC/pre-SMA, and left CN as ROIs (selected based on activation results and language control models from previous studies), stimuli first enter dACC/pre-SMA and then to left CN. At the left CN, a bidirectional effective connectivity is formed with left dlPFC. (3) There is a nonlinear relationship between effective connectivity during language control and the structural connectivity of the second language learners' brains. Specifically, the fiber density between dACC/pre-SMA and left dlPFC has a positive influence on the bidirectional effective connectivity between left dlPFC and left CN. Findings of the present study contribute evidence toward functional effective connectivity during bilingual language control; toward structural connectivity in the brains of second language learners; as well as toward nonlinear relationships between functional effective connectivity, structural connectivity, and behavioral performance in relation to bilingual language control.
双语语言控制经验通常伴随着大脑结构和功能的变化。大脑结构的变化也常常与功能的变化密切相关。然而，以前的研究并没有直接探讨双语语言控制过程中大脑结构连接和有效功能连接之间的关系，以及这两种连接类型是否与语言控制的行为表现有关。使用行为表现、功能和扩散成像技术，我们发现：（1）在语言控制过程中，左背外侧前额叶皮层（dlPFC）、左尾状核（CN）、下顶叶、楔前叶和背侧前扣带皮层（dACC）/前运动区（pre-SMA）显著激活。（2）在以左 dlPFC、dACC/pre-SMA 和左 CN 为 ROI 的语言控制模型中（基于激活结果和先前研究中的语言控制模型选择），刺激首先进入 dACC/pre-SMA，然后进入左 CN。在左 CN 处，与左 dlPFC 形成双向有效连接。（3）语言控制过程中的有效连接与第二语言学习者大脑的结构连接之间存在非线性关系。具体来说，dACC/pre-SMA 和左 dlPFC 之间的纤维密度对左 dlPFC 和左 CN 之间的双向有效连接有正向影响。本研究的发现为双语语言控制过程中的功能有效连接提供了证据；为第二语言学习者大脑的结构连接提供了证据；为功能有效连接、结构连接与双语语言控制行为表现之间的非线性关系提供了证据。
