Kids with autism tend to have a different pattern of brain activity as compared to normal kids, a new brain-imaging study suggests.

The work on Autism Spectrum Disorder (ASD) finds out which parts of the brain leads to the condition and note how sometimes those with a genetic risk tend to escape. Dr Martha Kaiser and Professor Kevin Pelphrey of Yale University and a team of researchers analyzed the condition by studying how kids responded to videos of people moving around them.

"As intrinsically social creatures, humans typically exhibit robust visual sensitivity to other people's movements," they wrote in the journal Proceedings of the National Academy of Sciences.

"This is well illustrated by the discovery that point-light displays ( videos created by placing lights on the major joints of a person and filming them moving in the dark), although relatively impoverished stimuli, contain sufficient information to identify the kind of motion being produced (e.g. walking, dancing, reaching) as well as the identity of the agent."

Earlier research noted that two-year-old kids with autism “did not turn to face point-light displays of biological motion.”

Sixty two children between ages 4 and 17 were taken for study, and their brains were monitored using functional magnetic resonance imaging (fMRI) scanners. 25 of them had ASD, 20 of them were siblings of ASD patients, and did not display any symptoms in particular.

Researchers noted three different kinds of brain activity that corresponded to different responses. They found that there was reduced activity in brain regions of kids with ASD. They also found additional brain regions that showed reduced activity in both the siblings group and the ASD group.

The scientists also found that specific regions in the brain of autistic kids, including the right posterior temporal sulcus and the ventromedial prefrontal cortex, working harder than the rest.

"These regions might reflect the absence of additional genetic or environmental factors that confer risk for ASD," the researchers wrote. "Alternatively, they could represent a process through which brain function was altered over development to compensate for an increased genetic risk to develop ASD."

Dorothy Bishop, a professor of developmental neuropsychology at Oxford University, said: "This is a potentially interesting study that looks for brain markers of underlying abnormality in children with autism in response to viewing dot patterns that indicate biological motion." However researchers noted that more studies should be undertaken.

These could "represent important targets for treatments and provide a measure of the effectiveness of intervention, as well as a better understanding of the mechanisms through which successful treatments function," the researchers wrote.