Social Cognitive and Affective Neuroscience Advance Access published online on April 28, 2008
Social Cognitive and Affective Neuroscience, doi:10.1093/scan/nsn011
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Functional abnormalities of the default network during self- and other-reflection in autism
1Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0662, and 2Center for Autism Research, Rady Children's Hospital Research Center, 8110 La Jolla Shores Drive, Suite 201, La Jolla, CA 92037, USA
Recent studies of autism have identified functional abnormalities of the default network during a passive resting state. Since the default network is also typically engaged during social, emotional and introspective processing, dysfunction of this network may underlie some of the difficulties individuals with autism exhibit in these broad domains. In the present experiment, we attempted to further delineate the nature of default network abnormality in autism using experimentally constrained social and introspective tasks. Thirteen autism and 12 control participants were scanned while making true/false judgments for various statements about themselves (SELF condition) or a close other person (OTHER), and pertaining to either psychological personality traits (INTERNAL) or observable characteristics and behaviors (EXTERNAL). In the ventral medial prefrontal cortex/ventral anterior cingulate cortex, activity was reduced in the autism group across all judgment conditions and also during a resting condition, suggestive of task-independent dysfunction of this region. In other default network regions, overall levels of activity were not different between groups. Furthermore, in several of these regions, we found group by condition interactions only for INTERNAL/EXTERNAL judgments, and not SELF/OTHER judgments, suggestive of task-specific dysfunction. Overall, these results provide a more detailed view of default network functionality and abnormality in autism.
Keywords: autism spectrum disorders; retrosplenial cortex; posterior cingulate cortex; default mode; rest
Correspondence should be addressed to Daniel P. Kennedy, Division of Humanities and Social Sciences, California Institute of Technology, HSS 228-77, Pasadena, CA 91125, USA. Email: kennedy{at}caltech.edu
Present address: Daniel P. Kennedy, Division of Humanities and Social Sciences, California Institute of Technology, HSS 228-77, Pasadena, CA 91125, USA.
Received July 25, 2007. Accepted March 20, 2008.