Functional and structural differences in brain networks involved in language processing and control in highly proficient early and late bilinguals

Age of acquisition and proficiency have been identified as possible determinants in the neural localization of second language representation and in the nature of control mechanisms. However, the relationship is not yet clear between age of acquisition and proficiency on the one hand, and language switching and executive functions on the other. In the present study, we used anatomical and functional Magnetic Resonance (MR) Imaging to investigate the impact of age of acquisition. Two groups of highly proficient early and late bilinguals, carefully matched in other measures of proficiency, performed an overt picture-naming task in blocked and switched conditions.