Functional Connectivity Signatures Underlying Simultaneous Language Translation in Interpreters and Non-Interpreters of Mandarin and English: An fNIRS Study

Abstract

Recent neuroimaging research has suggested that interpreters and non-interpreters elicit different brain activation patterns during simultaneous language translation. However, whether these two groups have different functional connectivity during such a task, and how the neural coupling is among brain subregions, are still not well understood. In this study, we recruited Mandarin (L1)/English (L2) interpreters and non-interpreter bilinguals, whom we asked to perform simultaneous language translation and reading tasks. Functional near-infrared spectroscopy (fNIRS) was used to collect cortical brain data for participants during each task, using 68 channels that covered the prefrontal cortex and the bilateral perisylvian regions. Our findings revealed both interpreter and non-interpreter groups recruited the right dorsolateral prefrontal hub when completing the simultaneous language translation tasks. We also found different functional connectivity between the groups. The interpreter group was characterized by information exchange between the frontal cortex and Wernicke’s area. In comparison, the non-interpreter group revealed neural coupling between the frontal cortex and Broca’s area. These findings indicate expertise modulates functional connectivity, possibly because of more developed cognitive skills associated with executive functions in interpreters.

Causal evidence for the involvement of Broca’s area in second language acquisition: A longitudinal HD-tDCS study

“…Broca’s area (left inferior frontal gyrus (lIFG)/BA 44/45) has been implicated in various language-related tasks via a variety of neuroimaging techniques. To name a few, fMRI has indicated that the lIFG plays a role in phonetic encoding (Papoutsi et al, 2009); MEG/fMRI has shown stronger activation of Broca’s area during verb generation (Pang, Wang, Malone, Kadis, & Donner, 2011); electrocorticography has revealed a cortical network for speech planning that includes Broca’s area (Castellucci, Kovach, Howard, Greenlee, & Long, 2022), and fNIRS has shown that bilingual interpretation relies on functional connectivity between Broca’s area and Wernicke’s area (He & Hu, 2022). While these studies offer strong correlational evidence, they are, by nature, correlation studies.…”