We used surface-based morphometry to test for differences in cortical shape between children with simplex autism (n = 34, mean age 11.4 years) and typical children (n = 32, mean age 11.3 years). This entailed testing for group differences in sulcal depth and in 3D coordinates after registering cortical midthickness surfaces to an atlas target using 2 independent registration methods. We identified bilateral differences in sulcal depth in restricted portions of the anterior-insula and frontal-operculum (aI/fO) and in the temporoparietal junction (TPJ). The aI/fO depth differences are associated with and likely to be caused by a shape difference in the inferior frontal gyrus in children with simplex autism. Comparisons of average midthickness surfaces of children with simplex autism and those of typical children suggest that the significant sulcal depth differences represent local peaks in a larger pattern of regional differences that are below statistical significance when using coordinate-based analysis methods. Cortical regions that are statistically significant before correction for multiple measures are peaks of more extended, albeit subtle regional differences that may guide hypothesis generation for studies using other imaging modalities.
Bibliographical noteFunding Information:
This work was supported by a grant from the Simons Foundation Autism Research Initiative (Brain Circuitry in Simplex Autism, S.E.P. PI), NIH grant 1U54MH091657, funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; by the McDonnell Center for Systems Neuroscience at Washington University (D.L.D. and D.C.V.E.), K12 EY016336 (J.R.P.), and the Intellectual and Developmental Disabilities Research Center at Washington University, National Institute of Health (NIH)/National Institute of Child Health and Development (NICHD) (P30 HD062171).
© The Author 2013. Published by Oxford University Press.
- simplex autism
- sulcal depth