Dynamic Language Network in Early and Late Cantonese-Mandarin Bilinguals

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Second language acquisition significantly shapes bilingual brain organization.
• While age of acquisition (AoA) effects on brain structure are known, dynamic language network properties in early versus late bilinguals remain understudied.

Purpose of the Study:

• To investigate differences in dynamic functional connectivity (dFC) and network topology of the language network between early and late bilinguals.
• To explore how AoA-L2 influences temporal neural activation patterns.

Main Methods:

• Acquired resting-state fMRI data from early and late Cantonese (L1)-Mandarin (L2) bilinguals with high proficiency.
• Analyzed dFC using a sliding-windows approach and k-means clustering to identify distinct network states.
• Calculated dynamic topological properties of the language network.

Main Results:

• Identified four dFC states potentially linked to phonetic, semantic, language control, and syntactic processing.
• Early bilinguals showed increased dFC in specific frontal-temporal and cerebellar regions compared to late bilinguals.
• Early bilinguals demonstrated altered network topology, including higher clustering and efficiency in certain states.

Conclusions:

• AoA-L2 significantly impacts the temporal dynamics and topological organization of the bilingual language network.
• These findings offer novel insights into how L2 learning experience shapes brain function in bilingual individuals.