Scientists trying to understand and treat autism have discovered that the brains of people with autism function differently than those of normal people when they view pictures of unfamiliar people. However, when people with autism look at a picture of a very familiar face, such as their mother's, their brain activity is similar to that of control subjects.
The new study indicates that in people with autism the fusiform gyrus, a region in the brain's temporal lobe that is associated with face processing, has the potential to function normally, but may need special training to operate properly, according to University of Washington researchers Geraldine Dawson and Elizabeth Aylward. They will present their findings today (Feb. 12) at a press briefing at the annual meeting of the American Association for the Advancement of Science in Seattle.
"It appears that our brains have evolved to have special processors to recognize that something is a face because faces are important in survival, in understanding emotions and in forming special relationships with others," said Dawson, director of the UW's Autism Center and a professor of psychology. "We have special and distinct regions for perceiving faces and others for perceiving objects. These regions are located in different parts of the temporal lobe. Our brain imaging studies are finding that people with autism often use object processing areas when they are looking at faces."
"Children with autism often don't make much eye contact with other people and have little experience in learning to recognize faces," said Aylward, a professor of radiology who interpreted the functional Magnetic Resonance Imaging (fMRI) used in the study.
She said that in adults the fusiform gyrus is reliably activated in face processing, but it takes time for a child's brain wiring to become functional. This process starts early and by age 12 normally developing children show activation in the fusiform gyrus when viewing faces.
"People with autism tend to activate object-related brain regions when they are viewing unfamiliar faces. They also tend to focus on particular features, such as a mustache or a pair of glasses. Normal individuals, whose fusiform gyrus shows activation, look at the whole face and the relationship of features on a face," Aylward said.
In the study, which involved 11 adolescents and adults with autism and 10 age-matched controls, the subjects viewed pictures of cars and people's faces while the fMRI examined their patterns of brain activity. The fusiform gyrus was activated in the control subjects when they were exposed to faces and the inferior temporal gyrus, an area associated with objects, was activated when they looked at cars. However, among subjects with autism only the inferior temporal gyrus was activated when they looked at most faces and the cars. The exception was a picture of the subject's mother, which activated the fusiform gyrus.
This finding could have important implications for intervention. Dawson said the UW's Autism Center is involved in two follow-up studies designed help people with autism to become "face experts." In one project, UW researchers are working with the same 11 adolescents and adults who have autism and are teaching them how to look at a face and what is important about a face to see if the training can help activate the fusiform gyrus. The second is a randomized controlled study involving 24 toddlers and preschool children diagnosed with autism and 24 control subjects. Through behavioral interventions, the children are taught to make eye contact and thus have more experience looking at faces. It involves intensive training – 25 hours a week for two years. Dawson and her team will be examining whether such intervention affects brain circuitry.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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