Oscillatory Correlates of Selective Restudy.

Michael Wirth,Karl-Heinz T Bäuml,Bernhard Pastötter

doi:10.3389/fnhum.2021.679823

Michael Wirth, Karl-Heinz T Bäuml + Show 1 more

Open Access

https://doi.org/10.3389/fnhum.2021.679823

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Abstract

Prior behavioral work has shown that selective restudy of some studied items leaves recall of the other studied items unaffected when lag between study and restudy is short, but improves recall of the other items when lag is prolonged. The beneficial effect has been attributed to context retrieval, assuming that selective restudy reactivates the context at study and thus provides a retrieval cue for the other items (Bäuml, 2019). Here the results of two experiments are reported, in each of which subjects studied a list of items and then, after a short 2-min or a prolonged 10-min lag, restudied some of the list items. Participants' electroencephalography (EEG) was recorded during both the study and restudy phases. In Experiment 2, but not in Experiment 1, subjects engaged in a mental context reinstatement task immediately before the restudy phase started, trying to mentally reinstate the study context. Results of Experiment 1 revealed a theta/alpha power increase from study to restudy after short lag and an alpha/beta power decrease after long lag. Engagement in the mental context reinstatement task in Experiment 2 eliminated the decrease in alpha/beta power. The results are consistent with the view that the observed alpha/beta decrease reflects context retrieval, which became obsolete when there was preceding mental context reinstatement.

Highlights

Regarding the long lag condition, the analysis revealed two clusters of power decrease from study to restudy in the alpha (9– 11 Hz) and beta frequency range (14–20 Hz), which extended approximately from 50 to 350 ms, pclust < 0.001, and 100– 650 ms after stimulus onset, pclust = 0.022
This interaction is due to a theta/alpha power increase from study to restudy in the short lag condition and an alpha/beta power decrease from study to restudy in the long lag condition
While it appears likely that the effect reflects some form of memory reactivation, it is unclear whether this reactivation reflects context retrieval, as is suggested by the two-factor framework (Bäuml, 2019), or reactivation of the restudied items themselves

Summary

Introduction

When subjects study a list of items and, after a short lag, are asked to selectively retrieve a subset of these items, recall of the remaining unpracticed items is typically impaired relative to a no-practice control condition (e.g., Anderson et al, 1994; Anderson and Spellman, 1995; Bäuml and Kliegl, 2017, for a review) This detrimental effect of selective retrieval, termed retrieval-induced forgetting, has often been attributed to inhibitory processes, assuming that during practice the not-to-be-practiced items interfere and are reduced in strength to attenuate the interference (e.g., Anderson, 2003). The beneficial effect has been attributed to context retrieval, assuming that, after prolonged lag between study and selective item repetition, the repetition of some of the studied items—be it via retrieval or restudy—reactivates the study context, providing a retrieval cue for the remaining items and enhancing their recall performance (see Bäuml, 2019)

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