Figure 4.
Left column: ERP waveforms and topographies in the early window immediately after onset of the music note from the Cz electrode group. The waveforms are based on analysis of 1-note before (dashed gray line) and 1-note after (solid black line) a salient change, in addition to a difference curve (solid red line). The shaded curves indicate a standard error around the mean waveform. A shaded time interval indicates a 30 ms window where a statistically significant N1 peak is observed, along with the full head scalp topography of the N1 peak in the same analysis window. Middle column: ERP waveforms and topographies in the late window after note onset corrected for onset effects of the following note from the Cz electrode group. The analysis follows the same structure shown in the left column and time intervals and topographies indicate significant P300 peaks in a 30 ms time window. Right column: ERP waveforms and topographies immediately after onset from analysis of 3-notes before and after a salient change from the Fz electrode group. The first significant time interval indicates timing of the P1 peak (analyzed from the Cz electrode group—not shown); while the second time interval around 160 ms indicates the significant interval where an MMN-like component is observed in the Fz electrode group. Topographies shown correspond to the P1 and MMN intervals respectively. Note that non-significant intervals and topographies are not shown. All topographies and waveforms are kept to the same scale for ease of comparison of amplitudes.