The differences of functional brain network in processing auditory phonological tasks between Cantonese-Mandarin bilinguals and Mandarin monolinguals

Objective: To explore the differences of functional brain networks in processing auditory phonological tasks between Cantonese-Mandarin bilinguals and Mandarin monolinguals.Methods: 31 Cantonese-Mandarin bilinguals and 31 Mandarin monolinguals performed auditory rhyming tasks under a functional magnetic resonance imaging (fMRI) scanning. Bilinguals performed two language tasks (Cantonese, CC; Mandarin, CM), while monolinguals performed only one task (Mandarin, MM). Graph theory and network-based statistic (NBS) analyses were used to reveal the differences of functional brain networks among CC, CM and MM. Results: The functional brain networks of CC, CM and MM were all small-world, and there were no differences in network properties, but widespread differences in functional connectivity among distributed brain regions.Conclusions: The Cantonese-Mandarin bilingualism and Mandarin monolingualism shared similar efficient to-pological structure of brain network for auditory phonological processing, but varied in widespread functional connectivity. And the two languages within bilingualism employed different functional brain networks for auditory phonological processing.