Time-frequency plots (Fz, Cz, and Pz sensors) of mean N-back test.

This is a 3D plot with time reference to stimulus onset (x axis in ms), frequency (y axis in Hz), and power (color scale in dB units) during 0-back (A) and 2-back (B) test. The rectangle indicates the representative alpha ERDs (250~750 ms, 8~15 Hz) that were compared between CH-NAT and CH-PAT groups in Fz, Cz, and Pz sensors. Alpha ERDs were lower during 0-back in CH-PAT (-1.93+/-1.77, N = 14) vs. CH-NAT (-0.56+/-1.29, N = 10) participants in Fz sensor, p = 0.0498. Column 1 shows power from Fz, column 2 Cz, and column 3 Pz.