Abstract
This functional magnetic resonance imaging study established whether
different portions of the ventro-lateral prefrontal cortex (vlPFC) support
reactive and proactive language control processes during multilingual
word-retrieval. Furthermore, this study also determined whether proactive
language control consists in the suppression of the non-target lexicon.
Healthy multilingual volunteers participated in a task that required them
to name pictures alternatively in their dominant and less-dominant
languages. Two crucial variables were manipulated: the cue-target interval
(CTI) to either engage (long CTI) or prevent proactive control processes
(short CTI), and the cognate status of the to-be-named pictures
(non-cognates versus cognates) to capture the presence of selective
pre-activation of the target language. The results from functional
connectivity analysis showed a clear segregation between functional
networks related to mid-vlPFC and anterior vlPFC during bilingual language
production. Furthermore, the results revealed that multilinguals engage in
proactive to prepare the target language. This proactive modulation,
enacted by anterior vlPFC, is achieved by boosting the activation of
lexical representations of the target language.
Finally, control processes supported by mid-vlPFC and left inferior
parietal lobe together,were similarly engaged in reactive and proactive
control, possibly exerted on phonological representations to reduce
cross-language interference.
