Inclusion Criteria1. first ever cortical or cortical/subcortical stroke confirmed by MRI/CT and medically stable;
2. sub-acute stage of stroke (3 wk to 6 mo post-stroke);
3. arm paresis (Chedoke-McMaster Arm Scale of 2-6 /7; Gowland et al. 1993) but able to perform voluntary elbow flexion/extension of at least 30° per direction;
4. elbow flexor and/or extensor spasticity (> 1+/4 on Modified Ashworth Scale; Ashworth 1964; Bohannon and Smith 1987);
5. able to provide informed consent.
Exclusion Criteria1. major neurological (other than stroke) / neuromuscular / orthopaedic problems or pain that may interfere with interpretation of results;
2. major cognitive deficits (a score <20 on the Montreal Cognitive Assessment, Nasreddine et al. 2005);
3. history of psychiatric disorders, alcohol or drug abuse, skin sensitivity, seizures, migraines, metal in cranium and other implants (cochlear, cardiac);
4. taking medications (e.g. epileptic and psychoactive drugs) that could affect brain activity (Poreisz 2007).