Autistic children, who are hindered in their social interactions and communication skills, appear to have fewer "mirror neurons" brain cells that govern empathy and learning by observation, according to a study released Thursday.
"Our findings suggest that the inability of autistic children to relate to people and life situations in an ordinary way may be the result of an abnormally functioning mirror neuron system," said Dr Manzar Ashtari of the Children's Hospital of Philadelphia in Pennsylvania.
Using a novel imaging technique called diffusion tensor imaging (DTI), that tracks the movement of water molecules in the brain, Ashtari's research team was able to highlight subtle but potentially significant changes in the volume of gray matter in the brains of its research subjects.
Researchers found increased gray matter in the brains of autistic children, which usually translates to higher intelligence.
But the finding of higher intelligence proved not to be the case for the autistic children, said Ashtari.
"In the autistic brain, increased gray matter does not correspond to IQ, because this gray matter is not functioning properly," he said at a meeting of the Radiological Society of North America (RSNA).
Although they have more gray matter, the autistic research subjects appeared have fewer mirror neurons -- brain cells that are activated when an individual performs an action, experiences an emotion or sensation, and witnesses the same, researchers said.