Mechanisms Of Orbitofrontal Stimulation in Depression

Inclusion Criteria: * Age 18-65 years * Must be able to read, speak and understand English * DSM-5 diagnosis of major depressive disorder, experiencing a moderate to severe depressive episode (Hamilton Depression Rating Scale score greater than or equal to 17 points) * Must be judged by study staff to be capable of completing the study procedures * Participants will be in stable outpatient treatment with no recent (within the past 30 days) hospitalizations or changes in their medication regimens Exclusion Criteria: * DSM-5 moderate to severe substance use disorder within the past three months, based on Structured Clinical Interview for DSM-5 * Conditions that might result in increased risks of side effects or complications from rTMS or MRI, including: * History of fainting spells of unknown or undetermined etiology that might constitute seizures * Diagnosis of epilepsy with the exception of a single seizure of benign etiology (e.g., febrile seizures) in the judgment of a board-certified neurologist * Current or past history of a neurological disorder, such as stroke, a progressive neurologic disease, or intracranial brain lesion(s); and history of previous neurosurgery or head trauma that resulted in residual neurologic impairment * Any unstable medical condition * Any metal in the brain or skull (excluding dental fillings) unless cleared by the responsible covering MD * Any devices which could be affected by TMS or MRI such as a pacemaker, medication pump, nerve stimulator, cochlear implant, TENS unit, ventriculo-peritoneal shunt unless cleared by the responsible covering MD * Pregnancy; All female participants will be required to have a pregnancy test; any participant who is pregnant will not be enrolled in the study. The pregnancy test will be administered by study staff trained to administer point of care pregnancy testing that complies with institutional laboratory policies