Researchers from the University of Washington's Autism Center measured in this study neural activity by using high-resolution electroencephalography (EEG) to examine connections in the cerebral cortex, the part of the brain that deals with higher cognitive processes.

"Our findings indicate adults with autism show differences in coordinated neural activity," said Michael Murias, a postdoctoral researcher who headed the study, "which implies poor internal communication between the parts of the brain."

The University of Washington researchers analysed EEGs from 36 adults, ranging in age from 19 to 38. Half the adults had autism and all had IQs of at least 80. The EEGs, which measure the activity of hundreds of millions of brain cells, were collected with an array of 124 electrodes while the people were seated and relaxed with their eyes closed for two minutes.

The researchers found patterns of higher than normal neural connectivity in the left hemisphere, particularly in the temporal lobe of the persons with autism within two different frequencies of brain waves, the delta and theta bands. This part of the brain is associated with language, which is impaired in many people with autism.

A global pattern of decreased neural connectivity between the frontal lobes and the rest of autistic brain showed up on the alpha wave band. These findings support several other studies using functional magnetic resonance imaging and positron emission tomography, both of which gauge brain activity by measuring blood flow. Post-mortem studies also suggest impairments in communication at the level of individual brain cells.

This over and under abundance of neural connections suggests inefficient and inconsistent communication inside the brains of people with autism and may explain some of the deficits shown by people who have the disorder.; Source: University of Washington