Fig 4. Beta power timecourses time-locked to the response (button press at time zero), expressed as percent change from baseline in the SMOT areas.

Darker colors in each condition signify the contralateral hemisphere to the responding hand, which always has more beta decrease than the ipsilateral hand (lighter color) at the time of the response. On RI trials, the early time window of -300 to -200ms pre-response (highlighted in peach color) shows that the ipsilateral (primed) hemisphere has more beta decrease, but the two hemispheres switch at 173 ms before the response, marked by the arrow. After the switch and immediately preceding the response (highlighted in dark blue color), the primed hemisphere rebounds back to baseline while the responding hemisphere continues to decrease. In the right panel, lateralized beta power is presented in the bar graphs as a subtraction of beta power in the contralateral—ipsilateral SMOT in the early (-300 to -200 ms) vs late (-100 to 0 ms) time windows.