Functional Underconnectivity

Electrophysiological studies provide direct support of the "functional underconnectivity" theory of autism

Studies from several labs in the past few years have hinted that the deficits in autism may not be found in any single structure of the brain, but rather in wiring of the neural networks that connect the different parts of our brain together. This has lead to a theory of autism called "functional underconnectivity," which hypothesizes that brain regions are not properly linked to each other, causing them to be functionally out-of-synch.

Scientists managed to directly test this hypothesis in 2007 by recording in real time the electrical signals that travel from one part of the brain to another. University of Washington researchers were the first to use a technique called "EEG coherence" to demonstrate underconnectivity in the brains of individuals with autism, finding that brain regions that were far apart did not "talk" to each other as typical. A collaborative team from the University of Colorado and the University of California at Davis also listened in on the brain activity of individuals with autism using a second technique called "MEG." It appeared as if the brain regions that should normally be synchronized with each other were not, and that the front of the brain may be especially disconnected with other brain regions.

Our most complex cognitive and executive functions, such as perception, attention, and learning and memory, require the coordinated function of brain activity. In order to conceive targeted therapies that overcome deficits in these areas, we need to first understand the biological problems that are generating them. These studies added critical evidence that communication problems between regions of the brain may be central to the impairments in autism, and could be directing us toward the ultimate design of strategies to re-synchronize brain activity.