Two parts of the brain that are believed to play a key role in social interaction and communication respond normally in autistic individuals, new research suggests.

A group of scientists from New York University, Carnegie Mellon University, the Weizmann Institute in Israel and the University of Pittsburgh have found that the mirror neuron system behaves the same way in people with autism and in individuals without the condition.

The system is made up of two parts of the brain and leads people to recognize movements and respond to them.

In the past, scientists have theorized that dysfunction in this area leads to the social issues faced by people with this condition. Autism spectrum disorder (ASD), a complex neurobiological condition, impairs normal brain development, leaving most individuals with communication problems, difficulty with typical social interactions and a tendency to repeat specific patterns of behaviour, according to Autism Canada.

Using MRIs, scientists studied the brain responses of both autistic and non-autistic individuals who were asked to passively witness and then perform a series of hand movements, such as picking up a cup of coffee.

Through the neural responses to the movements, scientists were able to determine the functioning of the mirror system part of the brain. In both groups, individuals responded strongly during the movement exercises and had unique neural responses to them.

Integrity intact

"The fact that these movement-selective neural circuits respond normally in individuals with autism suggests that the functional integrity of their mirror system areas is intact," reads the study. "These results argue against a mirror system dysfunction in autism."

What the researchers did notice, however, was that study participants with autism behaved less consistently during the experiments than those without the condition, displaying more "variable visual responses," referred to as "noisy" eye movements by researchers.

"Several theories have proposed that ASD may be caused by the early development of abnormally connected 'noisy' and 'hyper-plastic' cortical networks," reads the study.

"These theories suggest that noisy neural responses may cause the environment to be perceived as inconsistent and noisy, making it difficult for the child to cope with the outside world."

The study is published in the May 13 issue of Neuron.