The individual ERPs waveforms were averaged over subjects to obtain grand average ERPs for each group, and the grand average ERPs were computed separately for standard and target stimuli. The P300 component was defined as the largest positive deflection occurring within the time window of 280–500 ms, while the peak latency was defined as the time from stimulus onset to the peak of P300. Topographical maps of scalp potential were calculated for response to target and standard stimuli.
