Effects of Adolescent Synaptic Pruning

Inclusion Criteria: * Males or females between 18-26 years of age, AND currently enrolled in the Parent Project (R01MH067924) Exclusion Criteria: (these exclusion criteria are outlined in the Parent Project) * Head injury with loss of consciousness over an hour. * A vision problem or eye movement problem (such as lazy eye, double vision, blurred vision, or color blindness). * A learning disability and/or ever had an Individualized Education Plan (IEP) in school. * Significant neurological or metabolic illness: Epilepsy, Meningitis, Encephalitis, Diabetes, Huntington's disease. * Diagnosed with a psychiatric disorder. * Participants with, or with a first degree relative, having a DSM IV Axis l psychiatricdisorder. * Metal implants or ferromagnetic objects contained within the body which may interfere with the MRI scan (but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant.) Dental fillings do not present a risk for MRI. If there is a possibility of metal being present in the participant's body, the participant will be excluded from the study. * Weight more than 250 pounds. * Claustrophobia or uncomfortable in small spaces. * \<70% on the Achenbach scale (either from Youth Self Report (YSR) or Adult Self Report (ASR)). * IQ \< 80 or IQ \> 130. * Pregnancy or lactation, lack of effective birth control during 15 days before the scans. * Currently employed as radiation worker; or participation in radioactive…