Figure 4.

IHI during all experimental Tasks. Group averaged timecourse of IHI for each task. The top graph shows IHI recorded in right FDI muscle whereby CS was applied to right M1 (non-dominant) and TS to left M1 (dominant). The bottom graph shows IHI recorded in left FDI muscle. Right isometric refers to isometric contraction made with the right hand while the left hand is at rest, Left isometric is contraction with the left hand while the right hand is at rest, Right pen hold refers to holding a pen with the right hand while the left hand is relaxed, Left pen hold is holding a pen with the left hand while the right hand is relaxed. All active tasks reduced IHI across a wide range of ISIs that included both SIHI and LIHI. There was no difference between the active tasks (isometric versus pen hold) or the direction of IHI (non-dominant to dominant versus dominant to non-dominant). Values above the dashed horizontal line indicate facilitation. Those below the dashed line indicate inhibition.