Saturday, June 30, 2007

New study on Autism Spectrum Disorder

A new study has revealed that individuals with autism spectrum disorders (ASDs) including autism, pervasive developmental disorder and Asperger's syndrome can be trained to understand the subtle meanings conveyed by a person's face and tone of voice.

UCLA researchers have shown that ASD children can be trained with explicit instructions to pay more attention to facial expressions and tone of voice elicited an increased response in the medial prefrontal cortex, part of the brain's network for understanding the intentions of others. "That's significant. The fact that you can 'normalize' activity in this region in the ASD group by directing their attention to these important social cues clearly indicates there's nothing ntrinsically wrong with this region in the autistic brain," said Mirella Dapretto, associate professor of psychiatry and bio-behavioural sciences at the Semel Institute for Neuroscience and Human Behavior at UCLA and a member of the UCLA Ahmanson-Lovelace Brain Mapping Center. Dapretto co-authored the study with her former graduate student Ting Wang, who is now a postdoctoral fellow at Mount Sinai School of Medicine. "This is a very positive thing because these findings have implications for future interventions - they suggest that you could train the autistic brain to make use of the information conveyed by the human face and voice to successfully navigate social interactions," Dapretto added.
The authors wanted to examine the neural circuitry in the brain that underlies the problems ASD children face in interpreting communicative intent. They also wanted to determine whether explicit instructions to pay attention to facial expressions and tone of voice would elicit more normal patterns of brain activity in these children.

While undergoing functional magnetic resonance imaging (fMRI), 18 ASD boys between the ages of 7 and 17, as well as a control group of 18 typically developing (TD) boys, viewed cartoon drawings of children in conversational settings while listening to short vignettes that ended with a potentially ironic remark. Researchers found that, compared with the TD control group, the ASD children had reduced activity in two areas of the brain - the medial prefrontal cortex and right superior temporal gyrus. But when the researchers gave both groups explicit instructions to pay attention to the speaker's facial expression and tone of voice, only the ASD children showed a significant increase in activity in the medial prefrontal cortex. "The typically developing kids recognized and interpreted these cues automatically when trying to infer if a speaker's remark was sincere or sarcastic, so their brains were already responding appropriately," said Dapretto. "But not so with the ASD kids, who did not show activity in this area when specific instructions weren't provided. This is the first study to show that you can normalize activity in a key region of the so-called 'social brain' in individuals with autism by simply directing their attention to these important social cues," Dapretto said. The study, that is available online, is published in the current issue of the journal Archives of General Psychiatry.