The proposed mentored research scientist award aims to develop the applicant's basic research skills in order to prepare for independent investigations directed toward improving clinical rehabilitation for individuals with movement impairments. The applicant's academic and research training are as follows: following clinical training in Occupational Therapy (B Sc.), the candidate received advanced degrees in Physiology/Neurobiology (M.Sc.) and in Neuroscience (Ph.D.). The primary sponsor for this plan is Dr. Claude Ghez, a neuroscientist who has worked in the field of motor control for over 25 years. Dr. John Medige, a senior biomechanics faculty, and Dr. David Lichter, a clinical neurology faculty will also serve as mentors. The plan will be carried out at the School of Health Related Professions, department of Occupational Therapy, an outstanding and developing multidisciplinary research environment. RESEARCH PLAN: The goal of the current project is to characterize the sensorimotor mechanisms through which the nervous system achieves accurate control over hand trajectories during reaching movements. This work builds on previous findings obtained by the applicant which showed that in the absence of proprioceptive information and specific learning, mechanical interactions generated at each joint by the motions at other joints produce profound incoordination and distortions in the hand path. The proposed work provides a unique approach in which the mass distribution of the forearm is experimentally manipulated to systematically vary the amplitude of these interactions at the elbow. In this way, we will explore how interaction torques are learned and how this learning is represented by the nervous system. Specifically, the research will examine the degree to which the learning of limb interaction torques generalizes across different task parameters, the nature of muscle strategies used to adapt to novel interaction torques, and the roles of different types of feedback in this adaptation. We hope, through this study, to establish the feasibility of using auditory substitution of kinesthetic input in the rehabilitation of patients with impaired coordination due to sensory loss.