Fig. 4

Correlation measurements between the amplitude of peaks of the training-ERN signal and the psychological and cognitive states of the participants. The solid blue lines in the scatter plots show the linear-regression lines, and the dotted red curves show the upper and lower limit of 95% confidence interval (CI) estimated using bootstrap distribution repeated over 10,000 times. The x-axis of the figures represents the scores (levels) of the MEPA states of the participants, ranging from 1 to 7