title: L2-Proficiency-Dependent Laterality Shift in Structural Connectivity of Brain Language Pathways.
abstract: Diffusion tensor imaging (DTI) and a longitudinal language learning approach were applied to investigate the relationship between the achieved second language (L2) proficiency during L2 learning and the reorganization of structural connectivity between core language areas. Language proficiency tests and DTI scans were obtained from German students before and after they completed an intensive 6-week course of the Dutch language. In the initial learning stage, with increasing L2 proficiency, the hemispheric dominance of the Brodmann area (BA) 6-temporal pathway (mainly along the arcuate fasciculus) shifted from the left to the right hemisphere. With further increased proficiency, however, lateralization dominance was again found in the left BA6-temporal pathway. This result is consistent with reports in the literature that imply a stronger involvement of the right hemisphere in L2 processing especially for less proficient L2 speakers. This is the first time that an L2 proficiency-dependent laterality shift in the structural connectivity of language pathways during L2 acquisition has been observed to shift from left to right and back to left hemisphere dominance with increasing L2 proficiency. The authors additionally find that changes in fractional anisotropy values after the course are related to the time elapsed between the two scans. The results suggest that structural connectivity in (at least part of) the perisylvian language network may be subject to fast dynamic changes following language learning.
authors.affiliation: 1 Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen, The Netherlands .
authors.forename: Huadong
authors.initials: H
authors.lastname: Xiang
authors.affiliation: 1 Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen, The Netherlands .
authors.forename: Tessa Marije
authors.initials: TM
authors.lastname: van Leeuwen
authors.affiliation: 1 Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen, The Netherlands .|2 Max Planck Institute for Psycholinguistics , Nijmegen, The Netherlands .
authors.forename: Dan
authors.initials: D
authors.lastname: Dediu
authors.affiliation: 2 Max Planck Institute for Psycholinguistics , Nijmegen, The Netherlands .|3 University of York , York, United Kingdom .
authors.forename: Leah
authors.initials: L
authors.lastname: Roberts
authors.affiliation: 1 Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen, The Netherlands .|4 Erwin L. Hahn Institute for Magnetic Resonance Imaging , Essen, Germany .|5 MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands .
authors.forename: David G
authors.initials: DG
authors.lastname: Norris
authors.affiliation: 1 Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen, The Netherlands .|2 Max Planck Institute for Psycholinguistics , Nijmegen, The Netherlands .
authors.forename: Peter
authors.initials: P
authors.lastname: Hagoort
mesh_terms: D000293:Adolescent; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D007858:Learning / Q000502:physiology*; D008297:Male; D019303:Multilingualism; D009434:Neural Pathways / Q000502:physiology; D055815:Young Adult
keywords: L2 acquisition; L2 learning; arcuate fasciculus; brain lateralization; diffusion tensor imaging; language network; laterality shift; structural connectivity