Blocking NMDA receptors abolished any after-effect caused by prolonged tDCS, thus favouring a prominent role of this receptor in the evolvement of neuroplastic effects induced by this kind of stimulation. Asterisks indicate significant differences between the drug conditions regarding identical current conditions and time points, filled symbols significant deviations from baseline in regard to each drug condition (Student's t test, two-tailed, repeated measures, P < 0.05). Error bars indicate s.e.m.