Inclusion Criteria:  PTSD Group:  English speaking age: 18-65 meets diagnostic criteria for PTSD (as determined by study assessment)  Control Group:  English speaking age: 18-65  Exclusion Criteria:  All participants:  Individuals with any implants, conditions, etc. that do not comply with 3-Tesla fMRI research safety standards (e.g., certain implants, pregnancy) history of neurological disorder history of any pervasive developmental disorder history of significant head injury/lengthy loss of consciousness (e.g., a Glasgow Coma Scale Score < 15 at the time of incident assessed retrospectively by participant) significant untreated medical illness alcohol/substance abuse or dependence within the last 3 months  PTSD Group:  history of bipolar disorder history of psychosis extensive current use of narcotic medications  Control Group:  any current or past mental health disorders extensive current or past psychotherapy extensive current or past use of psychotropic or narcotic medications