Fig. 1.

Experimental design and possible trial outcomes. (A) The experiment consisted of three consecutive stages. During stage I, the stop signals were random. After stage I, a classifier was trained on button presses from stage I and the BCI predictor was activated. In the subsequent stages II and III, stop signals were elicited in real time by the BCI predictor. After stage II, subjects were informed about the predictor and instructed to try and move unpredictably. (B) Possible trial outcomes (see main text).