Figure 5.

EMG activity in arm and leg muscles during a rapid unilateral arm raise in a neurologically intact individual when standing. (A) Time course of the EMG responses following the “Go!” command (indicated by the green horizontal line). Note the modulation of EMG activity in the soleus muscle prior to the onset of the response in the anterior deltoid muscles (indicated by the blue horizontal line). Right panels show a higher magnification of the responses for the time window (brown dashed square) in the left panel. (B) Spinally evoked motor potentials obtained under control conditions (blue traces, n = 4), and 90 ms prior to the anterior deltoid EMG response (“90 ms prior AD”, red traces, n = 3). Note the modulation of the evoked potentials in the posteriorly located leg muscles, that is, medial hamstring and soleus, whereas there was a lack of change in the response magnitude in the anteriorly located vastus lateralis and tibialis anterior.