The candidate's primary interest is to understand the reorganization and recruitment associated with sensorimotor learning in healthy and stroke populations. The proposed research will test two primary hypotheses: 1) that a relatively new brain imaging technique, diffuse optical tomography (DOT), is able to detect and map learning-related modulations in brain function, and 2) that learning-related modulations in primary and secondary motor cortices are larger - both spatially and in amplitude - and less lateralized in hemiparetic stroke patients than the changes in these regions in control subjects. To test these hypotheses, the research project will first characterize and validate the DOT technique by employing simultaneous DOT and functional magnetic resonance imaging (fMRI) as both healthy and patient volunteers perform motor tasks. The fMRI activation maps will serve as a spatial """"""""gold standard"""""""" to which the simultaneously acquired optical imaging maps will be co-registered and compared. Comparisons will be performed within and between populations, with data analysis enhanced by models of the physiological noise in the DOT recordings as well as tuning of DOT image reconstruction algorithms. We expect this approach to provide a validated technique for detecting hemodynamic changes in the brain with the advantages of portability, unobtrusiveness, low cost, and spectroscopic information. The final component of the research plan will be a pilot application of DOT brain imaging during a gait re-acquisition task. This DOT application will be performed in a rehabilitation setting, infeasible for other brain imaging methods. In conjunction with the proposed research plan, the candidate seeks training in one primary and one secondary area. The primary area of training will be in stroke: The etiology and consequences thereof, associated rehabilitation, as well as general patient-focused research methods. The secondary area will cover cutting-edge DOT image reconstruction and data analysis techniques. Completion of this training will allow the candidate to pursue an independent research program in basic and clinical neuroscience addressing questions related to functional brain reorganization in healthy and patient populations. Importantly, use of the DOT technology in such a research program is expected to enable the investigation of tasks and populations that are otherwise beyond the reach of existing brain imaging technologies. ? ?
