title: The timing of language learning shapes brain structure associated with articulation.
abstract: We compared the brain structure of highly proficient simultaneous (two languages from birth) and sequential (second language after age 5) bilinguals, who differed only in their degree of native-like accent, to determine how the brain develops when a skill is acquired from birth versus later in life. For the simultaneous bilinguals, gray matter density was increased in the left putamen, as well as in the left posterior insula, right dorsolateral prefrontal cortex, and left and right occipital cortex. For the sequential bilinguals, gray matter density was increased in the bilateral premotor cortex. Sequential bilinguals with better accents also showed greater gray matter density in the left putamen, and in several additional brain regions important for sensorimotor integration and speech-motor control. Our findings suggest that second language learning results in enhanced brain structure of specific brain areas, which depends on whether two languages are learned simultaneously or sequentially, and on the extent to which native-like proficiency is acquired.
authors.affiliation: Cognitive Neuroscience Unit, Montreal Neurological Institute, 3801 University Street, Room 264, Montreal, QC, H3A 2B4, Canada. jonathan.berken@gmail.com.|Centre for Research on Brain, Language, and Music, McGill University, Montreal, QC, H3G 2A8, Canada. jonathan.berken@gmail.com.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Berken
authors.affiliation: Centre for Research on Brain, Language, and Music, McGill University, Montreal, QC, H3G 2A8, Canada.|Haskins Laboratories, New Haven, CT, 06511, USA.
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Gracco
authors.affiliation: Cognitive Neuroscience Unit, Montreal Neurological Institute, 3801 University Street, Room 264, Montreal, QC, H3A 2B4, Canada.
authors.forename: Jen-Kai
authors.initials: JK
authors.lastname: Chen
authors.affiliation: Cognitive Neuroscience Unit, Montreal Neurological Institute, 3801 University Street, Room 264, Montreal, QC, H3A 2B4, Canada.|Centre for Research on Brain, Language, and Music, McGill University, Montreal, QC, H3G 2A8, Canada.
authors.forename: Denise
authors.initials: D
authors.lastname: Klein
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D007839:Functional Laterality; D066128:Gray Matter / Q000033:anatomy & histology*; D006801:Humans; D007858:Learning; D008279:Magnetic Resonance Imaging; D008297:Male; D019303:Multilingualism; D055815:Young Adult
keywords: Accent; Age of acquisition; Bilingualism; Brain structure; Gray matter density; Magnetic resonance imaging; Motor cortex; Plasticity; Putamen; Skill learning; Voxel-based morphometry