title: White-matter microstructure and language lateralization in left-handers: a whole-brain MRI analysis.
abstract: Most people are left-hemisphere dominant for language. However the neuroanatomy of language lateralization is not fully understood. By combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we studied whether language lateralization is associated with cerebral white-matter (WM) microstructure. Sixteen healthy, left-handed women aged 20-25 were included in the study. Left-handers were targeted in order to increase the chances of involving subjects with atypical language lateralization. Language lateralization was determined by fMRI using a verbal fluency paradigm. Tract-based spatial statistics analysis of DTI data was applied to test for WM microstructural correlates of language lateralization across the whole brain. Fractional anisotropy and mean diffusivity were used as indicators of WM microstructural organization. Right-hemispheric language dominance was associated with reduced microstructural integrity of the left superior longitudinal fasciculus and left-sided parietal lobe WM. In left-handed women, reduced integrity of the left-sided language related tracts may be closely linked to the development of right hemispheric language dominance. Our results may offer new insights into language lateralization and structure-function relationships in human language system.
authors.affiliation: Department of Neurology, University of Pecs, Ret U. 2, 7623 Pecs, Hungary.
authors.forename: Gabor
authors.initials: G
authors.lastname: Perlaki
authors.forename: Reka
authors.initials: R
authors.lastname: Horvath
authors.forename: Gergely
authors.initials: G
authors.lastname: Orsi
authors.forename: Mihaly
authors.initials: M
authors.lastname: Aradi
authors.forename: Tibor
authors.initials: T
authors.lastname: Auer
authors.forename: Eszter
authors.initials: E
authors.lastname: Varga
authors.forename: Gyongyi
authors.initials: G
authors.lastname: Kantor
authors.forename: Anna
authors.initials: A
authors.lastname: Altbäcker
authors.forename: Flora
authors.initials: F
authors.lastname: John
authors.forename: Tamas
authors.initials: T
authors.lastname: Doczi
authors.forename: Samuel
authors.initials: S
authors.lastname: Komoly
authors.forename: Norbert
authors.initials: N
authors.lastname: Kovacs
authors.forename: Attila
authors.initials: A
authors.lastname: Schwarcz
authors.forename: Jozsef
authors.initials: J
authors.lastname: Janszky
mesh_terms: D000328:Adult; D001921:Brain / Q000166:cytology* / Q000502:physiology*; D056324:Diffusion Tensor Imaging; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D055815:Young Adult
keywords: Atypical speech laterality; Diffusion tensor imaging; Functional magnetic resonance imaging; Left-handers; Superior longitudinal fasciculus; Superior parietal lobe