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). Participants will receive either LIFUP or sham stimulation with crossover of sham participants into the treatment group halfway through the treatment course. The initial visit will involve consent and an MRI scan, followed by several more either active or sham treatments outside of the MRI environment delivered over the course of two days over one week. Response and potential side effects will be monitored pre- and post- each treatment along with one week and one month follow-up assessments.