Figure 1.

Course of the experiment. MEPs elicited from single-pulse TMS over the motor hot spot were recorded at 1 mV intensity before drug intake [baseline 1 (BL1)]. One hour after drug intake, baseline 2 (BL2) was recorded to look for an effect of the drug on cortical excitability. In case of any individual MEP alterations from baseline 1, baseline 3 (BL3) was recorded by adjusting the stimulator output to obtain a mean of 1 mV. Then PAS-10 or PAS-25 was administered and was immediately followed by MEP after-measurements that lasted 120 min. For all sessions except the placebo medication sessions, after-measurements were performed until the morning of the third day following the stimulation.