title: White and grey matter relations to simple, choice, and cognitive reaction time in spina bifida.
abstract: Elevated reaction time (RT) is common in brain disorders. We studied three forms of RT in a neurodevelopmental disorder, spina bifida myelomeningocele (SBM), characterized by regional alterations of both white and grey matter, and typically developing individuals aged 8 to 48 years, in order to establish the nature of the lifespan-relations of RT and brain variables. Cognitive accuracy and RT speed and variability were all impaired in SBM relative to the typically developing group, but the most important effects of SBM on RT are seen on tasks that require a cognitive decision rule. Individuals with SBM are impaired not only in speeded performance, but also in the consistency of their performance on tasks that extend over time, which may contribute to poor performance on a range of cognitive tasks. The group with SBM showed smaller corrected corpus callosum proportions, larger corrected cerebellar white matter proportions, and larger corrected proportions for grey matter in the Central Executive and Salience networks. There were clear negative relations between RT measures and corpus callosum, Central Executive, and Default Mode networks in the group with SBM; relations were not observed in typically developing age peers. Statistical mediation analyses indicated that corpus callosum and Central Executive Network were important mediators. While RT is known to rely heavily on white matter under conditions of typical development and in individuals with adult-onset brain injury, we add the new information that additional involvement of grey matter may be important for a key neuropsychological function in a common neurodevelopmental disorder.
authors.affiliation: Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada.|Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Canada.|Music and Health Research Collaboratory, Faculty of Music, University of Toronto, Toronto, Canada.
authors.forename: Maureen
authors.initials: M
authors.lastname: Dennis
authors.affiliation: Department of Psychology, and Texas Institute for Measurement, Evaluation and Statistics (TIMES), University of Houston, Houston, TX, USA.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Cirino
authors.affiliation: Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada. simicn@hhsc.ca.
authors.forename: Nevena
authors.initials: N
authors.lastname: Simic
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center, Houston, TX, USA.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Juranek
authors.affiliation: Department of Psychology, and Texas Institute for Measurement, Evaluation and Statistics (TIMES), University of Houston, Houston, TX, USA.
authors.forename: W Pat
authors.initials: WP
authors.lastname: Taylor
authors.affiliation: Department of Psychology, and Texas Institute for Measurement, Evaluation and Statistics (TIMES), University of Houston, Houston, TX, USA.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D002755:Choice Behavior / Q000502:physiology; D003071:Cognition / Q000502:physiology; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009929:Organ Size; D011930:Reaction Time / Q000502:physiology; D016135:Spinal Dysraphism / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D066127:White Matter / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: FreeSurfer; Hydrocephalus; Magnetic resonance imaging; Reaction time; Spina bifida