The purpose of this pilot study is to evaluate safety and efficacy of a novel treatment, low intensity focused ultrasound pulsation (LIFUP) for treatment resistant depression (TRD). The initial visit will involve consent and an MRI scan, followed by two more treatment visits over the course of one week. During the first treatment day, participants will receive either focused ultrasound or sham stimulation. On the second treatment day, all participants will receive focused ultrasound. Response and potential side effects will be monitored pre- and post- each treatment along with one week and one month follow-up assessments. Follow-up assessments will also involve an MRI scan.