title: More is not always better: increased fractional anisotropy of superior longitudinal fasciculus associated with poor visuospatial abilities in Williams syndrome.
abstract: We used diffusion tensor imaging to examine white matter integrity in the dorsal and ventral streams among individuals with Williams syndrome (WS) compared with two control groups (typically developing and developmentally delayed) and using three separate analysis methods (whole brain, region of interest, and fiber tractography). All analysis methods consistently showed that fractional anisotropy (FA; a measure of microstructural integrity) was higher in the right superior longitudinal fasciculus (SLF) in WS compared with both control groups. There was a significant association with deficits in visuospatial construction and higher FA in WS individuals. Comparable increases in FA across analytic methods were not observed in the left SLF or the bilateral inferior longitudinal fasciculus in WS subjects. Together, these findings suggest a specific role of right SLF abnormality in visuospatial construction deficits in WS.
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California 94305-5795, USA. fumiko@stanford.edu
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hoeft
authors.forename: Naama
authors.initials: N
authors.lastname: Barnea-Goraly
authors.forename: Brian W
authors.initials: BW
authors.lastname: Haas
authors.forename: Golijeh
authors.initials: G
authors.lastname: Golarai
authors.forename: Derek
authors.initials: D
authors.lastname: Ng
authors.forename: Debra
authors.initials: D
authors.lastname: Mills
authors.forename: Julie
authors.initials: J
authors.lastname: Korenberg
authors.forename: Ursula
authors.initials: U
authors.lastname: Bellugi
authors.forename: Albert
authors.initials: A
authors.lastname: Galaburda
authors.forename: Allan L
authors.initials: AL
authors.lastname: Reiss
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016880:Anisotropy; D001931:Brain Mapping; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000209:etiology* / Q000473:pathology*; D019580:Perforant Pathway / Q000473:pathology*; D014796:Visual Perception / Q000502:physiology*; D018980:Williams Syndrome / Q000150:complications* / Q000473:pathology