Figure 1.

Experimental design and time line of the cerebellum (CB)→motor cortex (M1) paired associative stimulation (PAS) study. Four PAS protocols were applied in healthy subjects: CB→M1 PAS_{10 ms} [i.e., interstimulus interval between magnetic pulses to right lateral CB and hand area of left M1 (M1_HAND) was 10 ms], CB→M1 PAS_{6 ms} (interstimulus interval of 6 ms), CB→M1 PAS_{2 ms} (interstimulus interval of 2 ms), and CB→M1 PAS_Control (randomly alternating intervals of 2 and 10 ms). The timeline in the lower part of the diagram shows the order of measurements and their approximate durations (in min) before (B0) and after CB→M1 PAS (P0, P30, and P60: immediately and 30 and 60 min post-PAS). Abbreviations: MT, motor threshold; MEP, motor-evoked potential; SICI, short-interval intracortical inhibition; CBI, cerebellar-motor cortex inhibition; ICF, intracortical facilitation.