Figure 12
From: Real-time feature extraction of P300 component using adaptive nonlinear principal component analysis
The averages of eight-electrode data in Figure 8 (350 ms ISI): P300s are not detected in some periods. By averaging, the amplitude of a target gets bigger compared to that of a non-target, if the signal is long time stationary. But, this will fail for dissimilar trials as indicated with the ellipse mark (i.e., solid circle for the target and dash circle for the non-target).