Project Summary Traumatic experience leads to development of posttraumatic stress disorder (PTSD) in some, but not all, trauma survivors. The funded R01 grant is focused on identifying human brain emotion circuit changes within early post-trauma weeks that predict subsequent PTSD versus non-PTSD diagnosis in the months-years after trauma (Specific Aim 1). The grant further examines progressive changes in brain emotion circuits that associate with PTSD symptom progression from weeks to a year after the trauma (Specific Aim 2). The approved study design requires recruiting 283 traumatized patients from Emergency Departments (EDs) to provide longitudinal sampling over a year in 144 subjects, about 35% (50 subjects) of which will likely develop PTSD. Study recruiting and longitudinal retention progressed as planned over the initial 3.7 years until the COVID-19 pandemic forestalled recruitment and reduced retention after March 2020 during year 4. Due to federal, state, county, and University of Toledo mandatory guidelines, the research team has had to modify protocols in attempts to maintain progress. Modified procedures include e.g., consent over the phone, online surveys and virtual diagnostic interviews, disinfecting study areas frequently, and providing MRI compatible personal protection equipment (PPE) to study personnel and subjects. Pandemic disruptions have also required increased efforts in subject recruitment and retention. Procedural changes are gradually allowing us to resume the study and have been effective in protecting subjects and researchers. However, this is at the price of unavoidable, unanticipated slow-downs and costs. To complete the proposed sampling and final data analyses, this requested Administrative Supplement will underwrite these unexpected costs and is critical for completing the originally planned work.