Bilingual Language Control in the Brain: Evidence from Structural and Effective Functional Brain Connectivity

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Bilingualism induces brain structural and functional changes.
• Previous research has not directly linked structural and functional brain connectivity during bilingual language control.

Purpose of the Study:

• To investigate the relationship between structural and functional brain connectivity during bilingual language control.
• To determine if connectivity is associated with behavioral performance in language control.

Main Methods:

• Utilized behavioral, functional, and diffusion imaging techniques.
• Analyzed brain activation in regions including the left dorsal lateral prefrontal cortex (dlPFC) and dorsal anterior cingulate cortex (dACC)/pre-SMA.
• Modeled effective connectivity using regions of interest (ROIs) like dlPFC, dACC/pre-SMA, and left caudate nucleus (CN).

Main Results:

• Significant brain activation observed in dlPFC, CN, inferior parietal lobe, precuneus, and dACC/pre-SMA during language control.
• A specific effective connectivity pathway was identified: dACC/pre-SMA to left CN, with bidirectional connectivity between left CN and dlPFC.
• Found a nonlinear relationship between effective connectivity and structural connectivity, with fiber density between dACC/pre-SMA and dlPFC positively influencing connectivity between dlPFC and CN.

Conclusions:

• Provides evidence for functional effective connectivity patterns in bilingual language control.
• Contributes to understanding structural connectivity in second language learners' brains.
• Highlights nonlinear associations between functional connectivity, structural connectivity, and behavioral performance in bilinguals.