Inclusion Criteria:  aged 20-80; first-onset stroke brain image confirmed unilateral subcortical infarction moderate to severe upper-limb impairment (SAFE score <8). 3 days to 4 weeks after stroke onset stable medical condition  Exclusion Criteria:  metal implants, such as electrodes or pacemaker epilepsy history or active spikes from EEG recording major depression or taking psychoactive drugs alcoholism or drug abuse history combined with other severe neurological or psychiatric diagnoses pregnancy or breastfeeding; other contraindications to brain MRI, such as severe claustrophobia intolerance to electrical stimulation