title: Mapping corpus callosum deficits in autism: an index of aberrant cortical connectivity.
abstract: BACKGROUND
  Volumetric studies have reported reductions in the size of the corpus callosum (CC) in autism, but the callosal regions contributing to this deficit have differed among studies. In this study, a computational method was used to detect and map the spatial pattern of CC abnormalities in male patients with autism.
  
  
  METHODS
  Twenty-four boys with autism (aged 10.0 +/- 3.3 years) and 26 control boys (aged 11.0 +/- 2.5 years) underwent a magnetic resonance imaging (MRI) scan at 3 Tesla. Total and regional areas of the CC were determined using traditional morphometric methods. Three-dimensional (3D) surface models of the CC were also created from the MRI scans. Statistical maps were created to visualize morphologic variability of the CC and to localize regions of callosal thinning in autism.
  
  
  RESULTS
  Traditional morphometric methods detected a significant reduction in the total callosal area and in the anterior third of the CC in patients with autism; however, 3D maps revealed significant reductions in both the splenium and genu of the CC in patients.
  
  
  CONCLUSIONS
  Statistical maps of the CC revealed callosal deficits in autism with greater precision than traditional morphometric methods. These abnormalities suggest aberrant connections between cortical regions, which is consistent with the hypothesis of abnormal cortical connectivity in autism.
authors.affiliation: Laboratory of Neuro Imaging, Brain Mapping Division, Department of Neurology, UCLA School of Medicine, Los Angeles, California 90095-7332, USA.
authors.forename: Christine N
authors.initials: CN
authors.lastname: Vidal
authors.forename: Rob
authors.initials: R
authors.lastname: Nicolson
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: DeVito
authors.forename: Kiralee M
authors.initials: KM
authors.lastname: Hayashi
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Geaga
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Drost
authors.forename: Peter C
authors.initials: PC
authors.lastname: Williamson
authors.forename: Nagalingam
authors.initials: N
authors.lastname: Rajakumar
authors.forename: Yihong
authors.initials: Y
authors.lastname: Sui
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Dutton
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001321:Autistic Disorder / Q000175:diagnosis* / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D003337:Corpus Callosum / Q000033:anatomy & histology / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D012016:Reference Values