Microstructural plasticity in the bilingual brain

Abstract

The human brain has been uniquely equipped with the remarkable ability to acquire more than one language, as in bilingual individuals. Previous neuroimaging studies have indicated that learning a second language (L2) induced neuroplasticity at the macrostructural level. In this study, using the quantitative MRI (qMRI) combined with functional MRI (fMRI) techniques, we quantified the microstructural properties and tested whether second language learning modulates the microstructure in the bilingual brain. We found significant microstructural variations related to age of acquisition of second language in the left inferior frontal region and the left fusiform gyrus that are crucial for resolving lexical competition of bilinguals' two languages. Early second language acquisition contributes to enhance cortical development at the microstructural level. Significant statementThe human brain has been uniquely equipped with a remarkable ability to acquire more than one language, as in bilingual individuals. Previous neuroimaging studies have indicated that learning a second language (L2) induced neuroplasticity at the macrostructural level. In this study, using the quantitative MRI (qMRI) technique we quantified the microstructural properties and tested whether second language learning modulates the microstructure in the bilingual brain. We found a significant microstructural variation related to age of acquisition of second language in the left anterior prefrontal region that is crucial for resolving lexical competition of bilinguals' two languages. Early second language acquisition seems to enhance cortical development at the microstructural level.Keywords bilingualism, quantitative MRI, age of second language acquisition, lexical competition

Expertise, ecosystem, and emergentism: Dynamic developmental bilingualism

“…Earlier studies following the tradition of Critical Period Hypothesis tended to highlight AoA as a key variable for brain activity patterns (Kim et al, 1997;Weber-Fox & Neville, 2007), but later studies with fMRI/PET found that proficiency was more important (e.g., see Abutalebi et al, 2005 for review). However, various studies continued to point out the important role of AoA (e.g., Klein et al, 2014;Luo et al, 2019), and researchers have also been interested in disentangling the independent contributions of AoA and L2 proficiency (e.g., Nichols & Joanisse, 2016; see also Hernandez & Li, 2007). More recent work also has shown that bilinguals vary considerably in terms of cortical structure depending on AoA.…”