Children with autism avoid eye contact because they experience uncomfortably intense emotional reactions when looking at faces, a new brain-imaging study suggests. What’s more, a brain area needed for perception of faces fails to be activated in people with autism, proposes a team led by Kim M. Dalton of the University of Wisconsin–Madison.
The scientists recruited 25 boys with autism, but not in its severest form, and 28 boys with no psychiatric condition. All the children were between 11 and 21 years old. Each participant reclined in a functional magnetic resonance imaging scanner while looking at a computer screen and was asked either to identify images of familiar faces or to tell whether or not facial images displayed emotion. A remote device tracked eye gaze.
Boys with autism often looked away from faces in both trials. But their glances at both familiar and emotional faces evoked pronounced blood flow—a sign of neural activity—in the amygdala, a brain region implicated in regulating emotions. Amygdala responses were strongest in autistic boys who looked at faces the longest. No such amygdala response occurred in healthy boys.
Boys with autism showed minimal activity in a right brain structure required for face perception (SN: 7/7/01, p. 10: Faces of Perception), Dalton and her colleagues also found. Their study will appear in Nature Neuroscience.