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.