Targeting the Default Mode Network: A TMS-fMRI Study

Inclusion Criteria: * Between 18 and 55 years of age * Ability to maintain a Motor Threshold (MT) with single pulse TMS * Ability to safely and comfortably undergo an MRI and TMS * Able to read, verbalize, understand, and voluntarily sign the Informed Consent Form prior to participating in any study-specific procedures or assessments. * PTSD diagnosis according to the DSM 5, as determined by the Clinician administered PTSD scale (CAPS-5) criteria. * Commitment to maintaining a stable medication regimen between the two fMRI sessions Exclusion Criteria: * Inability to safely and comfortably undergo an MRI. MRI safety will be determined by the center where MRI's are collected. * Inability to safely and comfortably undergo TMS. TMS exclusions include any history or condition that puts patients at risk. * Significant dementia as determined by the Montreal Cognitive Assessments (MoCA) * Common comorbid disorders of Veterans are allowed, but PTSD must be a primary diagnosis causing significant impairment that could not be accounted for by another diagnosis. Medical or mental health conditions that interact with or confound interpretation of PTSD symptoms and anxiety would be exclusionary. * Being in urgent need of care that would make participation impossible * Currently taking medications that increase the risk of seizure or influence hemodynamic response * Presence of any other condition that has the potential to prevent study completion and/or have a confounding effect on the interpretation of results.