Cognitive control for language switching in bilinguals: A quantitative meta-analysis on functional neuroimaging studies

In a quantitative meta-analysis, using the activation likelihood estimation method, we
examined the neural regions involved in bilingual cognitive control, particularly when
engaging in switching between languages. The purpose of this study was to evaluate the
AQ2 bilingual cognitive control model based on a qualitative analysis. After reviewing 128
peer-reviewed articles, 10 neuroimaging studies met our inclusion criteria and in each
study, bilinguals switched between languages in response to cues. We isolated regions
involved in voluntary language switching, by including reported contrasts between the
switching conditions and high-level baseline conditions involving similar tasks but
requiring the use of only one language. Eight brain regions showed significant and reliable
activation: left inferior frontal gyrus, left middle temporal gyrus, left middle frontal gyrus,
AQ3 right precentral gyrus, right superior temporal gyrus, midline pre-SMA, and bilateral
caudate nuclei. This quantitative result is consistent with bilingual aphasia studies that
report switching deficits associated with lesions to the caudate nuclei or prefrontal cortex.
It also extends the previously reported qualitative model. We discuss the implications of
the findings for accounts of bilingual cognitive control.