This is a mentored Research Career Development Award to support the career development of clinical investigators in patient-oriented research. Cortico-cortical functional connectivity (FC), defined as the temporal correlations between remote neurophysiological events, has not been systematically studied in children and adolescents with autism. As a first step towards understanding how brain functional connectivity develops in autism, this study will examine the cross-sectional development of FC of the pregenual anterior cingulate cortex (pgACC) in children and adolescents using functional magnetic resonance imaging (fMRI). This network was selected because of its involvement in social processes, preliminary reports of structural and functional abnormalities in autism, and its prolonged maturational course. The hypothesis of this work is that the derangements in FC within the pgACC network in autism reflect a fundamental failure of brain maturation and that social impairment in autism can be directly related to abnormal pgACC connectivity. Brain functional connectivity will be examined in 40 male children and adolescents with high-functioning autism (HFA) compared to equal numbers of healthy controls. The aims are to use resting state fMRI to examine differences in short- and long-range FC in the pgACC network, to test the relationship between social impairment and measures of short- and long-range FC in the pgACC network, and to examine the rates of age-related decreases in short-range FC and age-related increases in long-range FC in the pgACC network. This project has the potential to inform understanding of the neural bases of autism, which is needed to improve early identification, refine diagnostic assessments, and yield novel treatments.