title: Structural and functional connectivity of the human brain in autism spectrum disorders and attention-deficit/hyperactivity disorder: A rich club-organization study.
abstract: Attention-deficit/hyperactive disorder (ADHD) and autism spectrum disorders (ASD) are two of the most common and vexing neurodevelopmental disorders among children. Although the two disorders share many behavioral and neuropsychological characteristics, most MRI studies examine only one of the disorders at a time. Using graph theory combined with structural and functional connectivity, we examined the large-scale network organization among three groups of children: a group with ADHD (8-12 years, n = 20), a group with ASD (7-13 years, n = 16), and typically developing controls (TD) (8-12 years, n = 20). We apply the concept of the rich-club organization, whereby central, highly connected hub regions are also highly connected to themselves. We examine the brain into two different network domains: (1) inside a rich-club network phenomena and (2) outside a rich-club network phenomena. The ASD and ADHD groups had markedly different patterns of rich club and non rich-club connections in both functional and structural data. The ASD group exhibited higher connectivity in structural and functional networks but only inside the rich-club networks. These findings were replicated using the autism brain imaging data exchange dataset with ASD (n = 85) and TD (n = 101). The ADHD group exhibited a lower generalized fractional anisotropy and functional connectivity inside the rich-club networks, but a higher number of axonal fibers and correlation coefficient values outside the rich club. Despite some shared biological features and frequent comorbity, these data suggest ADHD and ASD exhibit distinct large-scale connectivity patterns in middle childhood.
authors.affiliation: Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center, Houston, Texas; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Ray
authors.forename: Meghan
authors.initials: M
authors.lastname: Miller
authors.forename: Sarah
authors.initials: S
authors.lastname: Karalunas
authors.forename: Charles
authors.initials: C
authors.lastname: Robertson
authors.forename: David S
authors.initials: DS
authors.lastname: Grayson
authors.forename: Robert P
authors.initials: RP
authors.lastname: Cary
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hawkey
authors.forename: Julia G
authors.initials: JG
authors.lastname: Painter
authors.forename: Daniel
authors.initials: D
authors.lastname: Kriz
authors.forename: Eric
authors.initials: E
authors.lastname: Fombonne
authors.forename: Joel T
authors.initials: JT
authors.lastname: Nigg
authors.forename: Damien A
authors.initials: DA
authors.lastname: Fair
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology* / Q000503:physiopathology*; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000473:pathology* / Q000503:physiopathology*; D015331:Cohort Studies; D063132:Connectome; D006801:Humans; D008279:Magnetic Resonance Imaging; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted
keywords: DW-MRI; attention-deficit/hyperactivity disorder; autism spectrum disorders; connectivity; diffusion tensor imaging; high angular resolution diffusion imaging; rich-club organization; rs-fMRI