Fig 1. Trial design for calibration and feedback runs.

First row: design of the trial for the ME and MI-Cb runs. The trial starts with a warning cue in the center of the screen in form of a cross at t = [−2 0]s (baseline or pre-stimulus interval). After 2s (i.e. at t = 0), the stimulus appears in form of an arrow. The direction of the arrow indicates the task to execute: left for left hand movement, right for right hand movement, down for foot movement. After 4s, cross and arrow disappear, and the screen stays blank for 2s. Then a new trial starts. One trial lasts therefore 8s in total. Second row: design of the trial for the MI-Fb runs. A fixation cross appears for 2s (baseline or pre-stimulus interval) at t = [−2 0]s. At t = 0 the stimulus appears. After 1s, the cross turns purple and starts to move depending on the classifier output (feedback). After 4s the cross turns black again and freezes for 2s while the result is visualized on the screen. One trial lasts therefore 9s in total.