Explore the Effects of Cortical Priming on Visuomotor Stepping Learning in Persons With Chronic Stroke

Inclusion Criteria: 1. Age between 21 and 90 years 2. Medical history of a unilateral stroke occurring ≥ 6 months prior to enrollment 3. MRI or CT evidence from the imaging report shown that the stroke involves the corticospinal tract 4. Hemiparesis involving the lower extremity (Fulg-Meyer LE motor test) 5. No passive range of motion limitation in bilateral hips and knees 6. Limitation of ankle passive range of motion to 10 degrees of dorsiflexion or less 7. Visual acuity can be corrected by glasses or contact lens to 20/20 8. Able to walk independently with/without assistant devices for 10 meters 9. Able to maintain standing position without any assistance \> 30 sec (Short Physical Performance Battery) 10. Evaluation of cognitive status: Mini-mental status examination (MMSE) score ≥ 24 Exclusion Criteria: 1. Pregnant women 2. MRI or CT evidence of involvement of the basal ganglia or cerebellum, evidence of multiple lesions, or evidence of any other brain damage or malignant neoplasm or tumors 3. Have any metal implants, cardiac pacemakers, or history of seizures 4. Ongoing orthopedic or other neuromuscular disorders that will restrict exercise training 5. Any vestibular dysfunction or unstable angina 6. Significant cognitive deficits (inability to follow a 2-step command) or severe receptive or global aphasia\*