AUTHOR=Rotstein Natalie M. , Cohen Zachary D. , Welborn Amelia , Zbozinek Tomislav D. , Akre Samir , Jones Keith G. , Null Kaylee E. , Pontanares Jillian , Sanchez Katy L. , Flanagan Demarko C. , Halavi Sabrina E. , Kittle Evan , McClay Mason G. , Bui Alex A. T. , Narr Katherine L. , Welsh Robert C. , Craske Michelle G. , Kuhn Taylor P. TITLE=Investigating low intensity focused ultrasound pulsation in anhedonic depression—A randomized controlled trial JOURNAL=Frontiers in Human Neuroscience VOLUME=Volume 19 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2025.1478534 DOI=10.3389/fnhum.2025.1478534 ISSN=1662-5161 ABSTRACT=IntroductionAnhedonic depression is a subtype of depression characterized by deficits in reward processing. This subtype of depression is associated with higher suicide risk and longer depressive episodes, underscoring the importance of effective treatments. Anhedonia has also been found to correlate with alterations in activity in several subcortical regions, including the caudate head and nucleus accumbens. Low intensity focused ultrasound pulsation (LIFUP) is an emerging technology that enables non-invasive stimulation of these subcortical regions, which were previously only accessible with surgically-implanted electrodes.MethodsThis double-blinded, sham-controlled study aims to investigate the effects of LIFUP to the left caudate head and right nucleus accumbens in participants with anhedonic depression. Participants in this protocol will undergo three sessions of LIFUP over the span of 5–9 days. To investigate LIFUP-related changes, this 7-week protocol collects continuous digital phenotyping data, an array of self-report measures of depression, anhedonia, and other psychopathology, and magnetic resonance imaging (MRI) before and after the LIFUP intervention. Primary self-report outcome measures include Ecological Momentary Assessment, the Positive Valence Systems Scale, and the Patient Health Questionnaire. Primary imaging measures include magnetic resonance spectroscopy and functional MRI during reward-based tasks and at rest. Digital phenotyping data is collected with an Apple Watch and participants' personal iPhones throughout the study, and includes information about sleep, heart rate, and physical activity.DiscussionThis study is the first to investigate the effects of LIFUP to the caudate head or nucleus accumbens in depressed subjects. Furthermore, the data collected for this protocol covers a wide array of potentially affected modalities. As a result, this protocol will help to elucidate potential impacts of LIFUP in individuals with anhedonic depression.