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. Author manuscript; available in PMC: 2016 Aug 1.
Published in final edited form as: Cortex. 2015 May 9;69:121–130. doi: 10.1016/j.cortex.2015.04.022

Figure 2.

Figure 2

Group-Averaged Time-Frequency Spectra During Encoding, Maintenance, and Retrieval Phases. Time (in ms) is denoted on the x-axis, with 0 ms defined as onset of the encoding grid. Frequency (in Hz) is shown on the y-axis. All signal power data is expressed as a percent difference from baseline (−0.4 to 0.0 s), with the color legend shown to the far right. Data represent a group-averaged gradiometer sensor that was near the parietal-occipital region in each participant (the same sensor was selected in each participant). As can be discerned, alpha/beta activity in this brain area strongly decreased (i.e., desynchronization) during the encoding phase, then shifted toward robust increases (i.e., synchronization) in a more narrow (alpha) band during the maintenance phase. Time periods with significant oscillatory activity (relative to baseline) were subjected to beamforming in 0.4 s non-overlapping time bins.