The purpose of the study is to determine the best treatment for the arm that has been affected by a stroke. The investigators plan to determine if the arm affected by a stroke will improve with a combination of motor priming and motor training. Motor priming provides a warm up for the brain so that the brain and body will better respond to treatment. There are two types of priming in this study. One is called bilateral motor priming which involves using both hands. Bilateral priming requires that the individual make continuous wrist movements in a low-tech gadget called the Exsurgo primer, a piece of equipment in which each hand goes between two plates that are connected together so that the stronger wrist moves the weaker wrist in and out at the same time. The second type of priming includes use of low intensity stimulation for your affected arm. The investigators expect the bilateral priming group will have more improvement. The study team anticipates enrolling approximately 76 individuals with stroke at Northwestern University and Shirley Ryan AbilityLab into this study. Each participant will have 24 visits. Nine visits will be for evaluation and fifteen for therapy. Each visit will be two to three hours depending on the type of visit and tests being done. Participants who are eligible and want to participate in this study will be randomized (selected by chance) to one of the two groups. The possible groups are: 1) bilateral priming plus motor training and 2) electrical stimulation priming and motor training. Participants are not blinded. Evaluation sessions consist of three separate days of testing and will occur at three time points: (1) before treatment starts; (2) after treatment is completed; and (3) 8 weeks later (follow-up evaluation: visits 22-24). There are three motor assessments and an evaluation of cortical excitability using TMS. After a stroke, there is often an imbalance of excitability between the affected and less affected parts of the brain. The imbalance will be measured using Transcranial Magnetic Stimulation (TMS), a technique used in neurorehabilitation research.