title: Mapping the unconscious maintenance of a lost first language.
abstract: Optimal periods during early development facilitate the formation of perceptual representations, laying the framework for future learning. A crucial question is whether such early representations are maintained in the brain over time without continued input. Using functional MRI, we show that internationally adopted (IA) children from China, exposed exclusively to French since adoption (mean age of adoption, 12.8 mo), maintained neural representations of their birth language despite functionally losing that language and having no conscious recollection of it. Their neural patterns during a Chinese lexical tone discrimination task matched those observed in Chinese/French bilinguals who have had continual exposure to Chinese since birth and differed from monolingual French speakers who had never been exposed to Chinese. They processed lexical tone as linguistically relevant, despite having no Chinese exposure for 12.6 y, on average, and no conscious recollection of that language. More specifically, IA participants recruited left superior temporal gyrus/planum temporale, matching the pattern observed in Chinese/French bilinguals. In contrast, French speakers who had never been exposed to Chinese did not recruit this region and instead activated right superior temporal gyrus. We show that neural representations are not overwritten and suggest a special status for language input obtained during the first year of development.
authors.affiliation: Department of Psychology, McGill University, Montreal, QC, Canada H3A 1B1; lara.pierce@mail.mcgill.ca.
authors.forename: Lara J
authors.initials: LJ
authors.lastname: Pierce
authors.affiliation: Neuropsychology/Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4; and.
authors.forename: Denise
authors.initials: D
authors.lastname: Klein
authors.affiliation: Neuropsychology/Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4; and.
authors.forename: Jen-Kai
authors.initials: JK
authors.lastname: Chen
authors.affiliation: École d'Orthophonie et d'Audiologie, Université de Montréal, Montreal, QC, Canada H3N 1X7.
authors.forename: Audrey
authors.initials: A
authors.lastname: Delcenserie
authors.affiliation: Department of Psychology, McGill University, Montreal, QC, Canada H3A 1B1;
authors.forename: Fred
authors.initials: F
authors.lastname: Genesee
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000293:Adolescent; D000300:Adoption; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D002681:China; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D005602:France; D006801:Humans; D007223:Infant; D007802:Language; D007804:Language Development; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019303:Multilingualism; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology; D014474:Unconsciousness
keywords: brain; early age effects; fMRI; language; neural representations