Figure 3.

EEG waveforms at nine electrodes. Event-related potentials (ERPs) from the nine of the electrodes placed at 27 locations (Fz, Cz, P7, P3, Pz, P4, P8, O1, and O2; red circle) that have been used in previous P300-BCI studies. Dashed lines indicate non-target ERPs, and solid lines indicate the target. The green/blue or white/gray condition is shown in blue or gray, respectively. Asterisks indicate significantly larger amplitudes under the green/blue condition than under the white/gray condition (P7, P3, Pz, P4, P8, O1, and O2; p < 0.05, paired t-test).