'Faulty' brain connections may be responsible for social impairments in autism

[Guest guest]

Contact: Schwarzjoels@....eduUniversity of Washington <http://www.uwnews.org/> 'Faulty' brain connections may be responsible for social impairments inautismNew evidence shows that the brains of adults with autism are "wired"differently from people without the disorder, and this abnormal patternof connectivity may be responsible for the social impairments that arecharacteristic of autism.Using functional magnetic resonance imaging, a team of researchersaffiliated with the University of Washington's Autism Center also foundthat the most severely socially impaired subjects in the study exhibitedthe most abnormal pattern of connectivity among a network of brainregions involved in face processing."This study shows that these brain regions are failing to work togetherefficiently," said Natalia Kleinhans, a research assistant professor ofradiology and lead author of the paper published in the journal Brain."Our work seems to indicate that the brain pathways of people withautism are not completely disconnected, but they are not as strong as inpeople without autism."The study is the first to look at brain connectivity and socialimpairment, and focused on how the brain processes information aboutfaces. Deficits in face processing are one of the earliestcharacteristics to emerge in people with autism.The research team led by Aylward, a UW professor of radiology,examined connectivity in the limbic system, or the network of brainregions that are involved with processing social and emotionalinformation. Participants in the study included 19 high-functioningadults with autism who had IQs of at least 85. They ranged in age from18 to 44 and were compared with an age- and intelligence-matched sampleof 21 typically developed adults. The group with autism spectrumdisorder included eight individuals diagnosed with autism, nine withAsperger's syndrome and two diagnosed with pervasive developmentaldisorder not otherwise specified. The level of social impairment foreach autistic participant was drawn from records of clinicalobservations and diagnoses that confirmed that each had autism.Each participant had his or her brain scanned while looking at picturesof faces or houses. Participants were shown four series of 12 picturesof faces and a similar number of series showing houses. Each individualpicture was seen for three seconds. Occasionally the same face or housepicture was repeated, and participants were told to press a button whenthis occurred.There was no significant difference on the two groups' performance,because the task was so basic, said Todd s, a professor ofradiology and co-author of the paper. "Differences might have shown upif they had been asked to do something more complicated."However, the two groups exhibited different patterns of brain activity.The researchers focused on the fusiform face area of the brain, a regionthat is involved in face identification. Compared to the participantswith autism, the typically developing adults showed significantly moreconnectivity between the fusiform face area and two other brain regions,the left amygdala and the posterior cingulate. In addition, autisticparticipants who had the largest social impairment showed the lowestlevel of connectivity between the right fusiform face area and the leftamygdala and increased connectivity between the right fusiform face areaand the right inferior frontal gyrus."This study shows that the brains of people with autism are not workingas cohesively as those of people without autism when they are looking atfaces and processing information about them," said Kleinhans.###Other co-authors of the papers are Stegbauer and Roderick Mahurinof the UW department of radiology; L. of the UW departmentof psychosocial and community health; and Lindsey Sterling, Greenson and Geraldine Dawson of the UW Autism Center. Dawson is now thechief science officer of Autism Speaks, a national organizationpromoting and funding autism research and education.The research was supported by the National Institute of Child Health andHuman Development and the National Institute of Mental Health.For more information, contact Kleinhans at or nkleinha@...on.edu or s at