title: Dissociations in Cortical Morphometry in Youth with Down Syndrome: Evidence for Reduced Surface Area but Increased Thickness.
abstract: Detailed descriptions of cortical anatomy in youth with Down syndrome (DS), the most common genetic cause of intellectual disability (ID), are scant. Thus, the current study examined deviations in cortical thickness (CT) and surface area (SA), at high spatial resolution, in youth with DS, to identify focal differences relative to typically developing (TD) youth. Participants included 31 youth with DS and 45 age- and sex-matched TD controls (mean age ∼16 years; range = 5-24 years). All participants completed T1-weighted ASSET-calibrated magnetization prepared rapid gradient echo scans on a 3-T magnetic resonance imaging scanner. Replicating prior investigations, cortical volume was reduced in DS compared with controls. However, a novel dissociation for SA and CT was found-namely, SA was reduced (predominantly in frontal and temporal regions) while CT was increased (notably in several regions thought to belong to the default mode network; DMN). These findings suggest that reductions in SA rather than CT are driving the cortical volume reductions reported in prior investigations of DS. Moreover, given the link between DMN functionality and Alzheimer's symptomatology in chromosomally typical populations, future DS studies may benefit from focusing on the cortex in DMN regions, as such investigations may provide clues to the precocious onset of Alzheimer's disease in this at-risk group.
authors.affiliation: Child Psychiatry Branch Department of Psychology, Drexel University, Philadelphia, PA 19104, USA.
authors.forename: Nancy Raitano
authors.initials: NR
authors.lastname: Lee
authors.affiliation: Child Psychiatry Branch.
authors.forename: Elizabeth I
authors.initials: EI
authors.lastname: Adeyemi
authors.affiliation: Child Psychiatry Branch.
authors.forename: Amy
authors.initials: A
authors.lastname: Lin
authors.affiliation: Child Psychiatry Branch.
authors.forename: Liv S
authors.initials: LS
authors.lastname: Clasen
authors.affiliation: Child Psychiatry Branch.
authors.forename: François M
authors.initials: FM
authors.lastname: Lalonde
authors.affiliation: Functional MRI Core Facility, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Condon
authors.affiliation: Child Psychiatry Branch.
authors.forename: David I
authors.initials: DI
authors.lastname: Driver
authors.affiliation: Social and Behavioral Research Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Shaw
authors.affiliation: Child Psychiatry Branch.
authors.forename: Nitin
authors.initials: N
authors.lastname: Gogtay
authors.affiliation: Child Psychiatry Branch.
authors.forename: Armin
authors.initials: A
authors.lastname: Raznahan
authors.affiliation: Child Psychiatry Branch Department of Psychiatry, University of California, La Jolla, CA 92093, USA.
authors.forename: Jay N
authors.initials: JN
authors.lastname: Giedd
mesh_terms: D000293:Adolescent; D000544:Alzheimer Disease / Q000000981:diagnostic imaging; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000254:growth & development; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D055815:Young Adult
keywords: Alzheimer's disease; Trisomy 21; cerebral cortex; intellectual disability; magnetic resonance imaging