Prior work has shown that topography of alpha-band activity tracks locations maintained in spatial working memory (WM). Here, we tested whether dynamic changes in alpha activity track the updating of information in spatial WM. Subjects were shown a memory location followed by an auditory cue which instructed subjects to update the location held in memory. Subjects used the mouse to click on the updated location. We used an inverted spatial encoding model to reconstruct the spatially-selective response profiles from the topographic distribution of alpha power. This time-resolved analysis showed that spatially-specific alpha activity tracked the initial location held in working memory, and revealed the transition to the newly updated location. Furthermore, the location specificity of the estimated response profiles, or Channel Tuning Functions (CTFs), showed that subjects with a stronger focus on the updated location were faster to report that location at the end of the trial. These findings highlight a new approach for observing active updating of the contents of spatial WM.
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