Participants completed a visual-spatial processing task while undergoing MEG recording. This task has been used to elicit multiple spectrally-specific patterns of neural activity24,34. While participants were seated in a non-magnetic chair in a magnetically-shielded room, they were instructed to focus on a centrally located fixation crosshair for about 2000 ms (variable inter-stimulus range of 1900–2100 ms). An 8 × 8 stimulus grid was then shown for 800 ms in one of four positions relative to the fixation point: above and to the right, above left, below right, or below left (Fig. 4). A photodiode was used to measure the trigger to stimulus delay, and this delay was accounted for throughout the analysis. Participants were instructed to respond as fast as they could using their right hand placed on a five finger button pad, indicating whether the grid was presented to the left or the right of the fixation crosshair (Fig. 4). Each individual underwent 240 trials of this task and only the correct trials were analyzed. To account for spurious reaction times, we performed standard data trimming procedures for each participant by excluding reaction times 3 SD above or below each participant’s mean prior to averaging.
