Autism's social struggles due to disrupted communication networks in brain

Faulty brain connections conceal intentions of others in autism

Picking up on innuendo and social cues is a central component of engaging in conversation, but people with autism often struggle to determine another person's intentions in a social interaction. New research from Carnegie Mellon University sheds light on the neural mechanisms that are responsible for such social difficulties in autism, and on the workings of these social brain mechanisms in all of us.

According to the study, which is available on the Web site of the journal Social Neuroscience, inefficient pathways for transmitting information between certain brain regions are to blame. The research implicates abnormalities in the brain's inter-regional communication system, which connects the gray matter's computing centers.

"The communication between the frontal and posterior areas of the social brain network is impaired in autism, making it difficult to understand the intentions of others" said the study's senior author, Marcel Just, the D.O. Hebb Professor of Psychology at Carnegie Mellon.

The study is the first to measure the synchronization between the brain areas that make up the Theory of Mind (ToM) network, which is responsible for processing the intentions and thoughts of others. It is the first to provide such concrete evidence of faulty social network connections.

To measure the ToM network's effectiveness, the researchers asked 12 high-functioning autistic adults and 12 control participants to view animations of interacting geometric figures, an example of which can be viewed at www.ccbi.cmu.edu/reprints/reprints.htm.

Participants then were asked to select the word from several choices that best described the interaction. For example, a large triangle would nudge a small triangle to move outside its enclosure, and the correct word choice would be "persuading." The control subjects were consistently better at inferring the intention from the action than the participants with autism were.