Mapping corpus callosum deficits in autism: an index of aberrant cortical connectivity.
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.
Vidal
Christine N
CN
Laboratory of Neuro Imaging, Brain Mapping Division, Department of Neurology, UCLA School of Medicine, Los Angeles, California 90095-7332, USA.
Nicolson
Rob
R
DeVito
Timothy J
TJ
Hayashi
Kiralee M
KM
Geaga
Jennifer A
JA
Drost
Dick J
DJ
Williamson
Peter C
PC
Rajakumar
Nagalingam
N
Sui
Yihong
Y
Dutton
Rebecca A
RA
Toga
Arthur W
AW
Thompson
Paul M
PM
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