Figure 5: Comparison of off-line (in blue) versus on-line (in red) estimates of alpha power modulations over the PO ROI. The traces of the time-resolved power estimates are plotted over time and were standardized over the 20-s baseline period immediately preceding the first eyes-closed segment. As expected, eye blinks (marked with an “x”) were detected from the EOG channel during the segments where the subject had his eyes open. The transitions from open to closed eyes are marked at the time the subject was given an auditory stimulus (marked with an “o”) every 20 s. In this particular run (300 s), the root-mean-square (RMS) difference between the online and offline time series reached 29.2%. Both time series indicate lower and more sustained decreases of alpha power in the PO region with respect to baseline, when feedback was provided to the subject than when no feedback was shown.