The gray matter in the part of the brain that affects social communication has a distinct organization in those with autism, U.S. researchers say. Study leader Vinod Menon, a professor of psychiatry and behavioral sciences and of neurology, and colleagues at Stanford University School of Medicine and Lucile Packard Children's Hospital analyzed brain-scan data to distinguish children with autism from children developing typically. Autism diagnoses are based entirely on clinical observations, psychiatric and educational tests, but Menon says advances are being made in identifying anatomical features in the brain in those with autism. The researchers compared magnetic resonance imaging data from 24 autistic children ages 8-18 with scan data from 24 age-matched, typically developing children -- collected at the University of Pittsburgh. "Multivariate searchlight classification," an analysis method that divides the brain with a three-dimensional grid, Menon says. The researchers examined one cube of the brain at a time and identified regions in which the pattern of gray matter volume could be used to discern between children with autism and typically developing children. "The new findings give a uniquely comprehensive view of brain organization in children with autism and uncover a relationship between the severity of brain-structure differences and the severity of autism symptoms," Menon says in a statement. The findings are published online in Biological Psychiatry.