Effects of language proficiency on cognitive control: Evidence from resting-state functional connectivity.

Cognitive studies suggest that bilingualism plays an additional role in the development of cognitive control, specifically in that bilingualism has been found to promote cognitive abilities in switching and inhibition. In recent years functional neuroimaging studies suggest that long-term experience of speaking two languages results in changes of neural activity in the cognitive control network. Here we explore the impacts of second language proficiency on intrinsic functional connectivity of the executive function network using resting-state functional MRI. Seed regions centering on different components of cognitive control were selected for the resting-state functional connectivity (rsFC) analysis based on previous studies. We performed a functional connectivity analysis of high- versus low-proficiency bilinguals and found that language proficiency affected distinct components of the cognitive control system. Specifically, for switching, the rsFC of high-proficiency bilinguals was weaker than that of the low-proficiency peers in the left anterior cingulated cortex and for inhibition, in the right middle frontal gyrus. For working memory, however, the rsFC showed no difference as a result of proficiency. Finally, the strength of rsFC showed a significant negative correlation with behavioral performance in both bilingual groups. These findings were interpreted within the current debates on bilingualism and cognitive control.