The National Institute of Neurological Disorders and Stroke (NINDS) invites applications for research programs designed to advance our understanding of the neurobiological mechanisms and epidemiology of Complex Regional Pain Syndrome (CRPS)/Reflex Sympathetic Dystrophy (RSD). A major goal of this initiative is to facilitate the development of novel collaborative research programs among physiologists, neuroscientists, behavioral neuroscientists, imaging specialists and clinicians in order to develop integrative research programs to accelerate progress in CRPS/RSD research. This PA is intended to encourage cross-disciplinary research focused on a mechanism-based diagnostic classification of CRPS/RSD, which might lead to mechanism-based therapeutic strategy for this chronic condition.