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. 2013 Oct 23;111(2):405–414. doi: 10.1152/jn.00322.2013

Fig. 3.

Fig. 3.

A: raw EMG traces recorded from the biceps brachii muscles in a representative subject during all conditions tested (flexion-rest, flexion-flexion, and flexion-extension) with TMS applied to the ipsilateral motor cortex. Traces show the average rectified (left column) and unrectified (right column) EMG data in 30 trials. The onset and offset of the iSP is shown between broken lines. The same time period is also shown on the unrectified data. Notice that the subject shows more inhibition in the EMG during bilateral flexion-flexion and less inhibition in the EMG during flexion-extension compared with unilateral elbow flexion. B shows individual subject data in all conditions tested; in C, group data (n = 15) show the depth of the iSP in all conditions tested. The abscissa shows the conditions tested, and the ordinate shows the depth of the iSP. Similar to what was observed in the triceps, note here the increase in the iSP during bilateral activation of agonist muscles (flexion-flexion) and the decrease during bilateral activation of antagonist muscles (flexion-extension) compared with a unilateral contraction. Error bars indicate SE. *P < 0.05.