This research is being done to find out if brain stimulation combined with a rehabilitation therapy improves arm weakness as a result of having a stroke. The stimulation technique is called transcranial direct current stimulation (tDCS). The treatment uses direct electrical currents to stimulate specific parts of the brain. The rehabilitation therapy is called "modified Constraint Induced Movement Therapy" (mCIMT). During this rehabilitation therapy study participants will wear a mitt on the hand of the arm that was not affected by their stroke. It is designed to restrain the use of the unaffected arm, while performing therapy with impaired one.
It is not known if brain stimulation combined with rehabilitation therapy will improve arm weakness. Study participants will receive rehabilitation therapy while on this study. Study participants may or may not receive the brain stimulation therapy.

Rehabilitation interventions including resistance training, functional and task-specific therapy, and gait or locomotor training have been shown to be successful in improving motor function in individuals with neurologic disease or injury. Recent investigations conducted in our laboratory indicate that intense resistance training coupled with task-specific functional training lead to significant gains in functional motor recovery. Similarly, gait rehabilitation involving intense treadmill training and/or task-specific locomotor training has been shown to be effective in improving locomotor ability. However, the underlying neural adaptations associated with these therapeutic approaches are not well understood. Our primary goal is to understand the motor control underpinnings of neurologic rehabilitation in order to apply this knowledge to future generations of therapeutic interventions.