Targeting the Default Mode Network: A TMS-fMRI Study

In post-traumatic stress disorder (PTSD), intrusive, traumatic, autobiographical memories lead to anxiety symptoms. Recent work suggests a new repetitive pulse transcranial magnetic stimulation (rTMS) brain target that might bring relief. Since this proposed target is not well understood, our goal is to use functional magnetic resonance imaging (fMRI) to identify the brain regions and networks that change with rTMS stimulation at this target area in PTSD patients. It is our hope that our work will lead to a personalized approach to rTMS treatment of PTSD based on brain imaging that can be used in a future clinical trial.Participants will be asked to complete psychological testing and questionnaires as well as an initial MRI and two separate TMS-fMRI sessions. Total participation time across all visits is estimated to be five to six hours.Research participation will take place at VA Palo Alto as well as at Stanford University.

Inclusion Criteria:Between 18 and 55 years of ageAbility to maintain a Motor Threshold (MT) with single pulse TMSAbility to safely and comfortably undergo an MRI and TMSAble 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 sessionsExclusion 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 impossibleCurrently taking medications that increase the risk of seizure or influence hemodynamic responsePresence of any other condition that has the potential to prevent study completion and/or have a confounding effect on the interpretation of results.