Investigators will consecutively enroll subacute (1-4 weeks after stroke onset) patients with first-time, unilateral, subcortical stroke and age-matched healthy controls. All participants will carry on 2 sequential experiments. In the first experiment, participants will perform 2 motor tasks using either paretic/nondominant upper extremity or non-paretic/dominant upper extremity, called motor attempt (M) condition or calibration condition. The second experiment contains 3 conditions: cyclic functional electrical stimulation (cFES), cFES during motor attempt (M-cFES), and functional electrical stimulation during brain-computer interface (BCI-FES) in random order. The sensorimotor oscillations from the electroencephalography (EEG), upper extremity sensorimotor function score (Fugl-Meyer test, Action Research Arm test, and Revised Nottingham Sensation Assessment), corticospinal excitability from the transcranial magnetic stimulation (TMS), and resting-state functional and structural neuroimage from magnetic resonance imaging (MRI) will be assessed before and after the final experiment, as well as 3 months after stroke.