Time courses of MEP amplitude following QPS at various ISIs with (▴) and without (○) QPS-5 ms priming over SMA (mean ±s.e.m.). A, SMA priming did not change subsequent LTP-like plasticity induced by QPS-1.5 ms. B and C, priming reversed MEP sizes induced by QPS-5 ms (B) or QPS-10 ms (C). D, priming enhanced suppression of MEP by QPS-30 ms. E and F, MEP suppression induced by QPS-50 ms (E) and QPS-100 ms (F) were not enhanced, but shortened with SMA priming. Asterisks denote significant difference of MEP sizes with priming from those without priming at each time point (P < 0.05 by post hoc paired t tests).