title: Altered development and multifaceted band-specific abnormalities of resting state networks in autism.
abstract: BACKGROUND
  Extensive evidence indicates that cortical connectivity patterns are abnormal in autism spectrum disorders (ASD), showing both overconnectivity and underconnectivity. Since, however, studies to date have focused on either spatial or spectral dimensions, but not both simultaneously, much remains unknown about the nature of these abnormalities. In particular, it remains unknown whether abnormal connectivity patterns in ASD are driven by specific frequency bands, by spatial network properties, or by some combination of these factors.
  
  
  METHODS
  Magnetoencephalography recordings (15 ASD, 15 control subjects) mapped back onto cortical space were used to study resting state networks in ASD with both spatial and spectral specificity. The data were quantified using graph theoretic metrics.
  
  
  RESULTS
  The two major factors that drove the nature of connectivity abnormalities in ASD were the mediating frequency band and whether the network included frontal nodes. These factors determined whether clustering and integration were increased or decreased in cortical resting state networks in ASD. These measures also correlated with abnormalities in the developmental trajectory of resting state networks in ASD. Lastly, these measures correlated with ASD severity in some frequency bands and spatially specific subnetworks.
  
  
  CONCLUSIONS
  Our findings suggest that network abnormalities in ASD are widespread, are more likely in subnetworks that include the frontal lobe, and can be opposite in nature depending on the frequency band. These findings thus elucidate seemingly contradictory prior findings of both overconnectivity and underconnectivity in ASD.
authors: Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.
authors: Manfred G
authors: MG
authors: Kitzbichler
authors: Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts.
authors: Sheraz
authors: S
authors: Khan
authors: Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts.
authors: Santosh
authors: S
authors: Ganesan
authors: Massachusetts General Hospital/Masachusetts Institute of Technology General Clinical Research Center, Biomedical Imaging Core, Massachusetts General Hospital, Charlestown, Massachusetts.
authors: Mark G
authors: MG
authors: Vangel
authors: Pediatric Neurology, Massachusetts General Hospital, Charlestown, Massachusetts.
authors: Martha R
authors: MR
authors: Herbert
authors: Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts.
authors: Matti S
authors: MS
authors: Hämäläinen
authors: Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts. Electronic address: tal@nmr.mgh.harvard.edu.
authors: Tal
authors: T
authors: Kenet
mesh_terms: D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D058256:Brain Waves; D002648:Child; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D012146:Rest; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Autism; Connectivity; Cortex; Development; MEG activity; Resting state