Inhibitory control occurs at the language execution stage: evidence from an fMRI study of bilingual language switching.

Inhibitory control mechanisms enable bilinguals to switch flexibly between two languages. However, the stage at which inhibitory control occurs during language production remains unclear, as traditional language-switching paradigms do not separately assess language selection and language execution. In the current functional magnetic resonance imaging (fMRI) study, a task-cueing paradigm was employed, where participants were prompted to focus on a specific language prior to naming a stimulus picture. This approach aimed to minimize the likelihood of language switching during the naming task. The experiment involved 20 unbalanced bilinguals, with Chinese as their native language and English as their second language. During the language selection stage, bilinguals activated brain regions associated with visual processing and information retrieval, most notably the temporal lobe and the parahippocampal gyrus. During the language execution stage, significant activation was observed in the caudate, cingulate gyrus, and prefrontal cortex—regions related to inhibitory control. These neural areas exhibited greater activation when participants named pictures in English (L2) than in Chinese (L1), with increased activation occurring when switching languages as opposed to maintaining the same language. The results suggest that inhibitory control occurs during the language execution stage of bilingual language switching.