Electrophysiological correlates of encoding processes in a full-report visual working memory paradigm
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Why are some visual stimuli remembered, whereas others are forgotten? A limitation of recognition paradigms is that they measure aggregate behavioral performance and/or neural responses to all stimuli presented in a visual working memory (VWM) array. To address this limitation, we paired an electroencephalography (EEG) frequency-tagging technique with two full-report VWM paradigms. This permitted the tracking of individual stimuli as well as the aggregate response. We recorded high-density EEG (256 channel) while participants viewed four shape stimuli, each flickering at a different frequency. At retrieval, participants either recalled the location of all stimuli in any order (simultaneous full report) or were cued to report the item in a particular location over multiple screen displays (sequential full report). The individual frequency tag amplitudes evoked for correctly recalled items were significantly larger than the amplitudes of subsequently forgotten stimuli, regardless of retrieval task. An induced-power analysis examined the aggregate neural correlates of VWM encoding as a function of items correctly recalled. We found increased induced power across a large number of electrodes in the theta, alpha, and beta frequency bands when more items were successfully recalled. This effect was more robust for sequential full report, suggesting that retrieval demands can influence encoding processes. These data are consistent with a model in which encoding-related resources are directed to a subset of items, rather than a model in which resources are allocated evenly across the array. These data extend previous work using recognition paradigms and stress the importance of encoding in determining later VWM retrieval success.
KeywordsEEG Encephalography Attention
This research was funded by grants awarded to GPC and MEB from the National Institutes of Health: R15EY022775, 1P20GM103650 and the National Science Foundation: NSF OIA 1632849 and NSF OIA 1632738.
- Appelbaum, L. G., Wade, A. R., Pettet, M. W., Vildavski, V. Y., & Norcia, A. M. (2006). Cue-invariant networks for figure background processing in human visual cortex. Journal of Neuroscience, 26, 11695–11708. doi: https://doi.org/10.1523/JNEUROSCI.2741-06.2006 CrossRefPubMedPubMedCentralGoogle Scholar
- Deiber, M. P., Missonnier, P., Bertrand, O., Gold, G., Fazio-Costa, L., Ibañez, V., & Giannakopoulos, P. (2007). Distinction between perceptual and attentional processing in working memory tasks: A study of phase-locked and induced oscillatory brain dynamics. Journal of Cognitive Neuroscience, 19, 158–172. doi: https://doi.org/10.1162/jocn.2007.19.1.158 CrossRefPubMedGoogle Scholar
- Emrich, S. M., Riggall, A. C., LaRocque, J. J., & Postle, B. R. (2013). Distributed patterns of activity in sensory cortex reflect the precision of multiple items maintained in visual short-term memory. Journal of Neuroscience, 33, 6516–6523. doi: https://doi.org/10.1523/JNEUROSCI.5732-12.2013 CrossRefPubMedPubMedCentralGoogle Scholar
- Gurariy, G., Killebrew, K. W., Berryhill, M. E., & Caplovitz, G. P. (2016). Induced and evoked human electrophysiological correlates of visual working memory set-size effects at encoding. PLoS ONE, 11, e0167022. doi: https://doi.org/10.1371/journal.pone.0167022 CrossRefPubMedPubMedCentralGoogle Scholar
- Peterson, D. J., Gurariy, G., Dimotsantos, G. G., Arciniega, H., Berryhill, M. E., & Caplovitz, G. P. (2014). The steady-state visual evoked potential reveals neural correlates of the items encoded into visual working memory. Neuropsychologia, 63, 145–153. doi: https://doi.org/10.1016/j.neuropsychologia.2014.08.020 CrossRefPubMedPubMedCentralGoogle Scholar
- Postle, B. R. (2006). Working memory as an emergent property of the mind and brain. Neuroscience, 139, 23–28. doi: https://doi.org/10.1016/j.neuroscience.2005.06.005 CrossRefPubMedGoogle Scholar