title: Altered resting perfusion and functional connectivity of default mode network in youth with autism spectrum disorder.
abstract: BACKGROUND
  Neuroimaging studies can shed light on the neurobiological underpinnings of autism spectrum disorders (ASD). Studies of the resting brain have shown both altered baseline metabolism from PET/SPECT and altered functional connectivity (FC) of intrinsic brain networks based on resting-state fMRI. To date, however, no study has investigated these two physiological parameters of resting brain function jointly, or explored the relationship between these measures and ASD symptom severity.
  
  
  METHODS
  Here, we used pseudo-continuous arterial spin labeling with 3D background-suppressed GRASE to assess resting cerebral blood flow (CBF) and FC in 17 youth with ASD and 22 matched typically developing (TD) children.
  
  
  RESULTS
  A pattern of altered resting perfusion was found in ASD versus TD children including frontotemporal hyperperfusion and hypoperfusion in the dorsal anterior cingulate cortex. We found increased local FC in the anterior module of the default mode network (DMN) accompanied by decreased CBF in the same area. In our cohort, both alterations were associated with greater social impairments as assessed with the Social Responsiveness Scale (SRS-total T scores). While FC was correlated with CBF in TD children, this association between FC and baseline perfusion was disrupted in children with ASD. Furthermore, there was reduced long-range FC between anterior and posterior modules of the DMN in children with ASD.
  
  
  CONCLUSIONS
  Taken together, the findings of this study--the first to jointly assess resting CBF and FC in ASD--highlight new avenues for identifying novel imaging markers of ASD symptomatology.
authors.affiliation: Laboratory of FMRI Technology (LOFT), Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, University of California Los Angeles, California.
authors.forename: Kay
authors.initials: K
authors.lastname: Jann
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, California.
authors.forename: Leanna M
authors.initials: LM
authors.lastname: Hernandez
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, California.
authors.forename: Devora
authors.initials: D
authors.lastname: Beck-Pancer
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, California.
authors.forename: Rosemary
authors.initials: R
authors.lastname: McCarron
authors.affiliation: Laboratory of FMRI Technology (LOFT), Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, University of California Los Angeles, California.
authors.forename: Robert X
authors.initials: RX
authors.lastname: Smith
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, California.
authors.forename: Mirella
authors.initials: M
authors.lastname: Dapretto
authors.affiliation: Laboratory of FMRI Technology (LOFT), Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, University of California Los Angeles, California.
authors.forename: Danny J J
authors.initials: DJ
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000473:pathology / Q000503:physiopathology*; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D002648:Child; D005260:Female; D059907:Functional Neuroimaging / Q000379:methods; D006179:Gyrus Cinguli / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009434:Neural Pathways / Q000503:physiopathology*; D012146:Rest
keywords: arterial spin labeling; autism spectrum disorder; cerebral blood flow; default mode network; dorsal ACC; functional connectivity