The effect of bilingualism on the functional neuroplasticity of the cerebellum

Previous studies revealed structural differences in cerebellar regions between monolinguals and bilinguals. However, the effect of bilingual experiences on cerebellar functional neuroplasticity remains unclear. Using resting-state functional magnetic resonance imaging (fMRI) data, we compared cerebellar functional connectivity (FC) between monolinguals and bilinguals, and then examined how age of second language acquisition (AoA-L2), immersion of L2 (Immersion-L2), proficiency level of L2 (PL-L2) and usage of L2 (Usage-L2) influence cerebellar FC in bilinguals. We found monolinguals exhibited increased FC between lobules VI, VIIIa and superior temporal gyrus. Increased AoA-L2 was related to decreased cerebello-cortical FC involving lobules VI, CrusI and precentral gyrus. Increased Immersion-L2 was associated with decreased cerebello-orbitofrontal FC. Higher PL-L2 corresponded to stronger cerebellar FC with posterior cingulate gyrus. Bilinguals who used L2 more frequently at home exhibited decreased cerebellar FC, while increased social Usage-L2 was associated with increased FC. These findings highlight bilingualism’s impact on cerebellar functional neuroplasticity, shaped by different bilingual experiences.