Irish scientists have identified differences in the brain activity of people with autism, which may explain some of their behaviour.

They have found that an area of the brain called the gyrus of the anterior cingulate cortex (ACCg) signals when something surprising takes place in people without an autism spectrum disorder (ASD). However, people with ASD lack this typical response.

In other words, the part of the brain that is key when it comes to tracking expectations and outcomes does not function the same in people with ASD. As a result, they may respond inappropriately to unexpected events.

The finding was made by an international team of scientists from Trinity College Dublin (TCD), Oxford University and Royal Holloway in the UK and ETH Zurich in Switzerland. The lead researcher was Dr Joshua Henk Balsters, who carried out a lot of the research in TCD.

"The ability to understand how other people make decisions and what happens to them as a result is key to successful social interaction. Unfortunately, individuals with ASD often find it very difficult to understand why the decisions of other people have the consequences that they do, and this can lead to social problems in everyday life," he said.

He explained that when something unexpected happens, a number of brain regions are activated.

"But there is a special part of the brain called the ACCg that signals when something surprising happens to other people. We found that individuals with an ASD are less accurate at identifying other people's expectations, but they also lack the typical response in the ACCg when surprising things happen to other people," Dr Balsters noted.

He said that the study also found that those who experienced the biggest problems with social interaction had the least responsive ACCg and this could therefore be a promising target for therapeutics.

"Given that brain responses in the ACCg correspond to social deficits in ASD, we hope that this will become a new therapeutic target. In the future we want to see whether pharmaceuticals or neurofeedback training, where we teach people to increase or decrease activity in this brain area, could complement existing behavioural therapies to improve social interaction," Dr Balsters added.

Details of these findings are published in the journal, Brain.