title: Abnormal wiring of the connectome in adults with high-functioning autism spectrum disorder.
abstract: BACKGROUND
  Recent brain imaging findings suggest that there are widely distributed abnormalities affecting the brain connectivity in individuals with autism spectrum disorder (ASD). Using graph theoretical analysis, it is possible to investigate both global and local properties of brain's wiring diagram, i.e., the connectome.
  
  
  METHODS
  We acquired diffusion-weighted magnetic resonance imaging data from 14 adult males with high-functioning ASD and 19 age-, gender-, and IQ-matched controls. As with diffusion tensor imaging-based tractography, it is not possible to detect complex (e.g., crossing) fiber configurations, present in 60-90 % of white matter voxels; we performed constrained spherical deconvolution-based whole brain tractography. Unweighted and weighted structural brain networks were then reconstructed from these tractography data and analyzed with graph theoretical measures.
  
  
  RESULTS
  In subjects with ASD, global efficiency was significantly decreased both in the unweighted and the weighted networks, normalized characteristic path length was significantly increased in the unweighted networks, and strength was significantly decreased in the weighted networks. In the local analyses, betweenness centrality of the right caudate was significantly increased in the weighted networks, and the strength of the right superior temporal pole was significantly decreased in the unweighted networks in subjects with ASD.
  
  
  CONCLUSIONS
  Our findings provide new insights into understanding ASD by showing that the integration of structural brain networks is decreased and that there are abnormalities in the connectivity of the right caudate and right superior temporal pole in subjects with ASD.
authors.affiliation: Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering, Aalto University, Rakentajanaukio 2 C, FI-02150 Espoo, Finland ; Advanced Magnetic Imaging Centre, Aalto University, Otakaari 5, FI-02150 Espoo, Finland.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Roine
authors.affiliation: iMinds-Vision Lab, Department of Physics, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp), Belgium.
authors.forename: Timo
authors.initials: T
authors.lastname: Roine
authors.affiliation: Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering, Aalto University, Rakentajanaukio 2 C, FI-02150 Espoo, Finland ; Faculty of Arts, Psychology and Theology, Åbo Akademi University, Fabriksgatan 2, FI-20500 Turku, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Salmi
authors.affiliation: Neuropsychiatric Rehabilitation and Medical Centre Neuromental, Kaupintie 11 A, FI-00440 Helsinki, Finland.
authors.forename: Taina
authors.initials: T
authors.lastname: Nieminen-von Wendt
authors.affiliation: Clinic for Neuropsychiatry, Department of Psychiatry, Helsinki University Central Hospital, Tukholmankatu 8 F, FI-00290 Helsinki, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Tani
authors.affiliation: Clinic for Neuropsychiatry, Department of Psychiatry, Helsinki University Central Hospital, Tukholmankatu 8 F, FI-00290 Helsinki, Finland ; Finnish Institute of Occupational Health, Topeliuksenkatu 41, FI-00290 Helsinki, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Leppämäki
authors.affiliation: Clinic for Neuropsychiatry, Department of Psychiatry, Helsinki University Central Hospital, Tukholmankatu 8 F, FI-00290 Helsinki, Finland.
authors.forename: Pertti
authors.initials: P
authors.lastname: Rintahaka
authors.affiliation: School of Psychology, Australian Catholic University, Locked Bag 4115, Fitzroy MDC, VIC 3065 Melbourne, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Caeyenberghs
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: Leemans
authors.affiliation: Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering, Aalto University, Rakentajanaukio 2 C, FI-02150 Espoo, Finland ; Advanced Magnetic Imaging Centre, Aalto University, Otakaari 5, FI-02150 Espoo, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Sams
keywords: Autism spectrum disorder; Brain networks; Connectivity; Connectome; Diffusion magnetic resonance imaging; Graph theoretical analysis; Tractography; White matter tract