Cognitive Process-based Real-time fMRI Neurofeedback in MDD and Rumination

Inclusion Criteria: * Good general health * DSM-5 diagnosis of major depressive disorder (MDD) Exclusion Criteria: General Exclusion Criteria: * Pregnancy Medical Conditions: * Moderate to severe traumatic brain injury (\>30 min. loss of consciousness or \>24 hours posttraumatic amnesia) or other neurocognitive disorder with evidence of neurological deficits. * Presence of co-morbid medical conditions not limited to but including cardiovascular (e.g., history of acute coronary event, stroke) and neurological diseases (e.g., Parkinson's disease), as well as pain disorders. * Presence of an uncontrolled medical condition that is deemed by the investigators to interfere with the proposed study procedures, or to put the study participant at undue risk. Psychiatric Disorders: * Current severe suicidal ideation or attempt within the past 12 months. * Psychosis * Bipolar disorder * Substance abuse or dependence within the previous 6 months Contraindications for MRI: * Bodily implants of unsafe paramagnetic materials such as pace-makers and aneurysm clips. * Claustrophobia that is severe enough to preclude MRI scanning. Medications: * Evidence of recreational drug use from a urine test.