Movement Velocity Effect on Cortical Reorganization and Finger Function in Stroke

Aim 1. Determine whether higher-velocity finger tracking training improves hand function more than slower velocity training. Working hypotheses: The higher-velocity training will have significantly greater functional improvement compared to the lower-velocity training, as measured by standardized upper extremity functional tests (Jebsen Taylor test, Box \& Block Test, and Finger extension force test) Aim 2. Ascertain whether higher-velocity finger tracking training differentially induces cortical reorganization as compared to lower-velocity finger tracking training. Working hypotheses: The higher-velocity training will have significantly greater cortical reorganization compared to the lower-velocity training, as measured by: 1. TMS - increased amplitude of motor evoked potentials (MEP) from paretic extensor digitorum muscle in response to paired-pulse TMS to ipsilesional primary motor area (M1). 2. fMRI - increased volume of activation, signal intensity, and laterality of ipsilesional M1. Aim 3. Explore whether the functional improvements correlate with the cortical reorganization. Working hypotheses: The functional improvements will correlate with the cortical reorganization.