 Study Design Subjects: Ten patients will be enrolled in this pilot study. Eligibility criteria: i age 30-70 years old, ii diagnosis of refractory unipolar major depression, iii recurrent illness with a minimum four major depressive episodes, iv current episode duration of no less than twelve months; v current episode treatment failure to a minimum of four treatment classes-including serotonin-reuptake inhibitors SSRI, other novel agents, monoamine oxidase inhibitors MAOI, tricyclics; somatic treatments such as ECT or vagus nerve stimulation VNS; some form of psychotherapy. Exclusion criteria i previous brain surgery ii neurological disorder of any type, iii significant psychiatric comorbidity as defined by DSM IV diagnostic criteria such as schizophrenia, panic disorder iv serious medical conditions or contraindication for surgery such as cardiac pacemakerdefibrillator or other implanted devices. Full medical records from a treating psychiatrist will first be reviewed by Dr. Kennedy. Eligible patients will then undergo a full psychiatric, neurological and neuropsychological evaluation Appendix 1 and 2. Final selection will be made by consensus of the investigative team in collaboration with a senior independent psychiatrist Robert Cooke, MD with expertise in intractable mood disorders. Informed consent will be obtained prior to entering the study. 