Last month I reported on a finding that toddlers with autism spectrum disorder showed a strong preference for looking at moving shapes rather than active people. This lower interest in people is supported by a new imaging study involving 62 children aged 4-17, of whom 25 were diagnosed with autistic spectrum disorder and 20 were siblings of children with ASD.

In the study, participants were shown point-light displays (videos created by placing lights on the major joints of a person and filming them moving in the dark). Those with ASD showed reduced activity in specific regions (right amygdala, ventromedial prefrontal cortex, right posterior superior temporal sulcus, left ventrolateral prefrontal cortex, and the fusiform gyri) when they were watching a point-light display of biological motion compared with a display of moving dots. These same regions have also been implicated in previous research with adults with ASD.

Moreover, the severity of social deficits correlated with degrees of activity in the right pSTS specifically. More surprisingly, other brain regions (left dorsolateral prefrontal cortex, right inferior temporal gyrus, and a different part of the fusiform gyri) showed reduced activity in both the siblings group and the ASD group compared to controls. The sibling group also showed signs of compensatory activity, with some regions (right posterior temporal sulcus and a different part of the ventromedial prefrontal cortex) working harder than normal.

The implications of this will be somewhat controversial, and more research will be needed to verify these findings.