title: Abnormal asymmetry in frontostriatal white matter in children with attention deficit hyperactivity disorder.
abstract: A growing body of work utilizing structural and functional brain imaging and neurocognitive measures of executive and attentional function indicates anomalous asymmetry in ADHD. This study examined the white-matter volume and diffusion properties of frontostriatal tracts, as a function of hemisphere, in ADHD and healthy controls. Forty-three young males (21 ADHD-Combined Type and 22 controls) aged 10-18 years underwent structural and diffusion weighted MRI. Tractography applying constrained spherical deconvolution (CSD) was used to construct frontostriatal tracts between each of caudate and putamen and each of dorsolateral prefrontal, ventrolateral prefrontal and orbitofrontal cortices (DLPFC, VLPFC and OFC) in each hemisphere, to examine both volumetric and diffusion microstructure properties. Young people with ADHD did not show the right hemisphere lateralization of volume in the Caudate-VLPFC and Caudate-DLPFC tracts that was evident in controls, however the ADHD group displayed a pronounced lateralization to the left for fractional anisotropy in the Putamen-VLPFC tracts. The degree of volume asymmetry did not correlate with symptom severity; however fractional anisotropy (FA) values that were more strongly lateralized to the left in the Putamen-VLPFC white matter were associated with greater symptom severity. ADHD was associated with anomalous hemispheric asymmetries in both tract volume and underlying white-matter microstructure in major fibre tracts of the frontostriatal system. Our observations of both weaker lateralization to the right in terms of tract volume and stronger lateralization to the left in terms of FA values for the ADHD group, suggests that previous inconsistencies in the literature may reflect the influence of such asymmetries.
authors.affiliation: Developmental Imaging, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, 3052, Australia. tim.silk@mcri.edu.au.|Department of Paediatrics, University of Melbourne, Melbourne, 3052, Australia. tim.silk@mcri.edu.au.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Silk
authors.affiliation: Developmental Imaging, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, 3052, Australia.|Academic Child Psychiatry Unit, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, 3052, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, 3052, Australia.
authors.forename: Veronika
authors.initials: V
authors.lastname: Vilgis
authors.affiliation: Developmental Imaging, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, 3052, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Adamson
authors.affiliation: Developmental Imaging, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, 3052, Australia.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: Developmental Imaging, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, 3052, Australia.|Department of Child and Adolescent Psychiatry, Erasmus University Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Lisa
authors.initials: L
authors.lastname: Smit
authors.affiliation: Academic Child Psychiatry Unit, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, 3052, Australia.
authors.forename: Alasdair
authors.initials: A
authors.lastname: Vance
authors.affiliation: School of Psychological Sciences, Monash University, Melbourne, 3800, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Bellgrove
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000000981:diagnostic imaging*; D002421:Caudate Nucleus / Q000000981:diagnostic imaging*; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D007839:Functional Laterality; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D009434:Neural Pathways / Q000000981:diagnostic imaging; D009929:Organ Size; D017397:Prefrontal Cortex / Q000187:drug effects*; D011569:Psychiatric Status Rating Scales; D011699:Putamen / Q000000981:diagnostic imaging*; D012044:Regression Analysis; D012720:Severity of Illness Index; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: ADHD; Asymmetry; Attention; Constrained spherical deconvolution; Frontostriatal; Tractography