Using functional magnetic resonance imaging approaches, the present research aims to examine the relationship between traumatic experience and the neural mechanisms of various PTSD symptoms, and determine how this relationship changes during PTSD extinction. Also, this proposal aims to better understand how the genetic/epigenetic profile of several genes predicts, and perhaps changes, in response to recovery from PTSD along with its neural correlates. This understanding will help identify individuals who will respond most optimally to a specific empirically based PTSD treatment, Cognitive Processing Therapy, while further connecting genetic biomarkers of risk with neural intermediate phenotypes underlying PTSD symptomatology.This study is observational as the investigator does not assign specific interventions to the participants of the study.