PROJECT SUMMARY/ABSTRACT The applicant, Jennifer J. Thomas, Ph.D., is the Co-Director of the Eating Disorders Clinical and Research Program at Massachusetts General Hospital and Associate Professor of Psychiatry at Harvard Medical School. Over the last decade Dr. Thomas’s research has focused on the pathophysiology and treatment of feeding and eating disorders, particularly the newly recognized avoidant/restrictive food intake disorder (ARFID). Her successful mentoring experience, publication record, and current funding demonstrate her commitment and passion for patient-oriented research and provide an excellent foundation to accomplish the goals and objectives of the proposed K24 Award. Dr. Thomas’s career development goals will enable her to (1) deepen her expertise in multimodal neuroimaging techniques (integrating structural, functional, and diffusion MRI) to enhance her multidisciplinary collaborations and ability to provide translational mentorship; (2) create a sustainable infrastructure for continued research mentorship of diverse scholars to develop their own unique expertise within ARFID that will extend beyond her laboratory and beyond the K24 period; and (3) bring together her two lines of research (on behavioral treatment of ARFID and neurobiology of ARFID) to develop new treatments that modify target neural mechanisms using advanced clinical trial designs. The proposed award will enable Dr. Thomas to redistribute her effort to 30% mentorship; 60% research; and 10% patient care. Dr. Thomas will further establish a patient-oriented research program that uses innovative multidisciplinary techniques to investigate the neurobiology underlying avoidant and restrictive eating, and that provides an ideal environment to develop future leaders in clinical research across disciplines. The training environment is outstanding in terms of didactic resources and availability of techniques to assess cross-disciplinary endpoints. Importantly, Dr. Thomas has a strong commitment from Psychology and Psychiatry leadership, and a cadre of multidisciplinary collaborators and senior advisors, who have enthusiastically endorsed her research program, mentoring, and K24 proposal. The specific research aims of the application are based on a recently funded R01 investigating the link between hormones, brain function and clinical features in adults with ARFID. Important new directions under the auspices of this award will feature multimodal neuroimaging, including assessment of brain structure (gray matter volume and white matter connectivity) and its relationship with functional brain abnormalities and clinical features. In the long-term, this K24 award will build capacity in the next generation of scholars to advance research in biobehavioral mechanisms of feeding and eating disorders.