Neurocircuitry of Autism- fMRI and Transcranial Magnetic Stimulation Studies

Inclusion Criteria: * for Healthy volunteer: * no current psychiatric disorder meeting Axis 1 DSM-4 criteria. * English speaking, * verbal and full scale IQ \> 65, * capacity to give consent and signed HIPPA authorization. * for Autism Spectrum Disorders: * diagnosed with Autism, Asperger or Pervasive Developmental Disorder not otherwise specified, * English speaking, * capacity to give consent and verbal and full scale IQ \> 65, * signed HIPPA authorization, * participants currently taking psychotropic medications must be at the same stable doses and be willing to continue at the same dose through out the study Exclusion Criteria: * for Healthy control and ASD: * women of child bearing potential not using birth control pills or breast feeding, * h/o bipolar disorder (lifetime), * any psychotic disorder( lifetime), * history of major depressive disorder or of substance abuse or dependence within the past year, * verbal or full scale IQ less than or equal to 65, * intracranial implants, * metallic implants, * shrapnel in the body, * metallic braces, * cardiac pacemakers or * vagus nerve stimulation device, * claustrophobia, * prior dx of seizure, * increased intracranial pressure or history of significant head trauma with loss of consciousness for at least 5 minutes * current significant laboratory abnormality, * neurological disorder including but not limited to space occupying brain lesion, * any history of seizures, * history of cerebrovascular accidents, * fainting, * cerebral aneurysm, * dementia, * huntington, * chorea, * multiple sclerosis