[PS-2.54] Proactive and reactive control during bilingual lexical access is driven by different portions within the prefrontal cortex

Branzi, F. M. 1, 2 , Martin, C. . 2, 3 , Carreiras, M. 2, 3 & Paz-Alonso, P. 2

1 The University of Manchester
2 Basque Center on Cognition, Brain and Language
3 IKERBASQUE, Basque Foundation for Science

Both proactive and reactive control processes support language switching in bilinguals, although their interaction with lexical access remains unclear. Using fMRI, we investigated this question by testing English-Spanish bilinguals in a language-switching task. We manipulated the cue-picture time interval (long and short) to engage or prevent proactive control, and the cognate status of the picture name (non-cognate and cognate) to capture the presence of the pre-activation of the target language.
According to a two-process model of the vlPFC function, we hypothesized that the anterior vlPFC (BA47) might be more sensitive to the proactive control demands (long versus short intervals) than the mid-vlPFC (BA45). Furthermore, we hypothesized that cross-language interference might be eliminated (null cognate effect) only when proactive control was engaged (long intervals), and we expected this modulation to occur in anterior vlPFC, but not in mid-vlPFC.
When task conditions relied mostly upon proactive control, we observed a stronger activation only in anterior vlPFC. Furthermore, when proactive control was engaged, cross-language interference was eliminated in the anterior vlPFC, but not in the mid-vlPFC.
We conclude that selective pre-activation of the target language is enacted by anterior vlPFC, whereas mid-vlPFC might support control processes that resolve competition between simultaneously active representations.