Abstract
Recent studies have shown that the contents of spatial working memory can be reconstructed from EEG oscillatory activity in the alpha frequency band (8-12 Hz; e.g., Foster et al. 2016). Here, we leverage the excellent temporal resolution of this approach to track dynamic changes in the content and quality of spatial working memory over time. Specifically, we used an inverted encoding model and a retro-cue experimental design to probe dynamic changes in representations of spatial locations following changes in task demands. We recorded EEG while participants encoded the locations of two dots. A retro cue instructed participants to remember the location of a single dot (valid cues), or to continue remembering both dots (neutral cues). Cues were presented immediately after the offset of the sample display, during the midpoint of the subsequent maintenance period, or at the end of the trial. Our preliminary findings (N = 10) suggest that while encoding locations into WM is rapid (complete ~250 ms after stimulus onset) purging a location from memory is much more sluggish (complete ~650 ms after cue onset). Location information is less robust when participants are required to remember two locations relative to one location, but representations cued locations show a modest recovery once an uncued location has been purged from memory. Both results are consistent with recent findings in the neuroimaging literature (Sprague et al., 2014; 2016). Collectively, our findings highlight the prospective utility of using alpha band EEG activity to track dynamic changes in the contents and quality of working memory representations over time.
Meeting abstract presented at VSS 2018