When thinking about themselves, adults with autism have lower activity in two specific brain regions than do healthy controls, according to an imaging study published in the February issue of Brain.

Studies on younger siblings of children with autism are finding that during tests of sensory or perceptual processing, these baby sibs show abnormally fast brain responses, rather than a delay.

Although the head overall is bigger in some children with autism, researchers have found more informative differences in size — some smaller, some larger — across regions of the brain.

Sitting on a sofa in his office at the Yale Child Study Center, Ami Klin plays a movie clip on a tiny laptop. The clip stars a younger Klin, with larger glasses but the same easy smile, vying for the attention of a young girl with autism. His face inches from hers, he speaks in a warm, animated voice. But the girl never looks from the toy blocks in her hands. Suddenly, she spots an orange M&M in the far corner of the room and scoots after it.