Statistical effects in nogo-trials. Means ± SE are shown. Left-top: Highly significant medication × latency interaction effect. Under methylphenidate (MPH, blue squares), MEP amplitudes increase in the time range analyzed. In the placebo condition (black squares), the opposite behaviour can be seen. Right-top: Under MPH, short-interval intracortical inhibition (SICI) is smaller than in the placebo condition. Left-bottom: SICI decreases linearly from 120 ms to 350 ms. Right-bottom: MEP amplitudes show a quadratic behaviour. They are smallest at latency 230 ms.