Figure 4.

Lateralized posterior α power. a, Time-frequency plots per condition (rows) of contralateral minus ipsilateral power at the average of O1/2, PO3/4, and PO7/8 for the first and second delay (columns). Black outline indicates significant power difference between contralateral and ipsilateral in grand average at p < 0.01, cluster corrected. For the first delay, t = 0, t = 400, and t = 2200 indicate the memory display onset, start of first delay, and end of first delay, respectively. For the second delay, t = 0 and t = 1800 indicate the start and end of second delay, respectively. b, Full topographies, Grand average scalp distributions of α power on trials with the lateralized memory item on the right subtracted from those with the memory item on the left. Half topographies, Grand average scalp distributions of α power at ipsilateral electrodes subtracted from those at contralateral electrodes, collapsed across hemispheres. Power was averaged over the significant time-frequency cluster (first delay) or averaged over a window of 0–1000 ms by 8–14 Hz (second delay) (see a, black outline). c, Bars per condition of contralateral (black) and ipsilateral (gray) power averaged over the time-frequency cluster highlighted in a. Error bars indicate SEM for normalized data. d, Time series of contralateral minus ipsilateral α power during the first delay for the conditions where both the currently relevant and prospectively relevant item had to be remembered. Gray areas between the curves represent time points with a significant difference between the conditions after cluster correction at p < 0.05.