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The forward testing effect (FTE) refers to the finding that testing of previously studied information improves memory for subsequently studied newer information. Recent research showed that the FTE is immune to acute psychosocial encoding/retrieval stress, i.e., stress that is induced before initial encoding. The present study investigated whether the FTE is also robust to acute psychosocial retrieval stress, i.e., stress that is induced after encoding but before retrieval of the critical item list. Participants (N=128) studied three lists of words in anticipation of a final cumulative recall test. Participants were tested immediately on lists 1 and 2 (testing condition) or restudied lists 1 and 2 after initial study (restudy condition). After study of the critical list 3, psychosocial stress was induced in half of the participants (stress group), whereas no stress was induced in the other half (control group). The Trier-Social-Stress-Test-for-Groups (TSST-G) was used for stress induction. Salivary cortisol, alpha amylase, and subjective stress were repeatedly measured. The results of the criterion test showed a generally detrimental effect of psychosocial retrieval stress on list 3 recall. Importantly, the FTE was unaffected by stress. The findings are discussed with respect to current theories of the FTE.

Self-relevance is a very influential modulator of human information processing. Still, little is known about the time-frequency dynamics of the self-relevance network. In this EEG study, we used the matching task to investigate the spectral dynamics of self-prioritization. Human participants (N = 40) repeatedly associated arbitrary geometric shapes with either “the self” or “a stranger”. Behavioural results demonstrated prominent self-prioritization effects (SPEs) in reaction time and accuracy, indicated by faster and more accurate responses in self-match than in stranger-match trials. Remarkably, EEG cluster analysis also revealed two significant SPEs, one in delta/theta power (2-7 Hz) and one in beta power (19-29 Hz) over parietal, midfrontal, and occipital sites. Drift diffusion modelling indicated that beta activity was associated with evidence accumulation, whereas delta/theta activity was associated with response caution. These findings indicate dynamic cortical exchange between parietal attention allocation and top-down self-representation.

Abstract: The forward testing effect refers to the finding that testing of previously studied information improves memory for subsequently studied newer information. Recent research showed that the effect is immune to acute psychosocial encoding/retrieval stress, i.e., stress that is induced before initial encoding. The present study investigated whether the forward testing effect is also robust to acute psychosocial retrieval stress, i.e., stress that is induced after encoding but before retrieval of the critical item list. Participants ( N = 128) studied three lists of words in anticipation of a final cumulative recall test. Participants were tested immediately on Lists 1 and 2 (testing condition) or restudied the two lists after initial study (restudy condition). After study of the critical List 3, psychosocial stress was induced in half of the participants (stress group), whereas no stress was induced in the other half (control group). The Trier Social Stress Test for Groups (TSST-G) was used for stress induction. Salivary cortisol, alpha amylase, and subjective stress were repeatedly measured. The results of the criterion test showed a generally detrimental effect of psychosocial retrieval stress on List 3 recall. Importantly, the forward testing effect was unaffected by retrieval stress. The findings are discussed with respect to current theories of the forward testing effect.

A growing body of research implies a decline in core executive functions, such as cognitive inhibition, caused by experimental stress manipulation (Arnsten, 2009; Shields et al., 2016). On the contrary, the conflict literature reports rather inconsistent results due to greater control over response execution under stress. It is still under debate, whether stress affects response conflict and stimulus conflict monitoring in the anterior cingulate cortex (ACC) distinctively. This study aims at investigating the influence of socially-evaluated cold pressor stress (adapted SECPT; Schwabe et al., 2008) on Stroop interference in EEG time-frequency analysis. Based on prior EEG findings (Dierolf et al., 2017, 2018), we expect a stress-modulated rise in interference control, indexed by brain oscillatory power increase in midfrontal theta frequency (3 – 9 Hz) especially during response conflict but not during stimulus conflict. Furthermore, we investigate the time-dependent modulation of conflict under stress and cortisol responsiveness as potential moderator variables. Our investigation will enable new insight into the neural basis of cognitive conflict processing concerning time-sensitive stress effects in executive control.

When facing particular combinations of stimuli and responses, people create temporary event-files integrating the corresponding stimulus and response features. Subsequent repetition of one or more of these features retrieves the entire event-file, which impairs performance if not all features are repeated (partial-repetition costs). In the literature, different decay functions have been reported presumably dependent on the type of feature that is repeated (e.g. target vs. distractor features). Here, we use a variant of the S1R1-S2R2 and distractor-response binding task and analyze for the first time target-based and distractor-based event-file decay functions within the same task and sample. While we found evidence for decay functions and also stronger retrieval due to target than distractor repetitions, slopes of the decay functions were comparable suggesting that the decay process itself is equal irrespective of the type of stimulus feature that is repeated. Our study thereby confirms overarching approaches that summarize paradigm specific findings with the same set of core processes.

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.

Influence of tDCS during retrieval on DRM performance by Maximilian A. Friehs, Ciara Greene & Bernhard Pastötter

The human brain is in distinct processing modes at different times. Specifically, a distinction can be made between encoding and retrieval modes, which refer to the brain's state when it is storing new information or searching for old information, respectively. Recent research has proposed the idea of a "ready-to-encode" mode, which describes a prestimulus effect in brain activity that predicts subsequent memory performance. Whether there is also a corresponding "ready-to-retrieve" mode in human brain activity is currently unclear. Here we demonstrate that prestimulus alpha power decrease can be linked to such ready-to-retrieve mode. We found that cuing participants to prepare for retrieval in comparison to restudy led to a significant decrease of prestimulus alpha power before the onset of stimuli. Beamformer analysis localized this effect in the right secondary visual cortex (Brodmann area 18), which is located in parts of the lingual gyrus. Correlation analysis showed that the prestimulus alpha power effect is positively related to stimulus-related alpha/beta power, which in turn predicts participants’ memory performance. Complementing recent evidence for the ready-to-encode mode, the results provide evidence for the existence of a ready-to-retrieve mode in brain oscillatory activity. Specifically, prestimulus attention to retrieval is suggested to “ramp up” visual imagery and the processing of conceptual features, which promotes the reconstruction and long-term consolidation of episodic memories. Future research on brain-computer interfaces may find these results interesting regarding the potential of using online measures of spontaneous fluctuating alpha oscillations to trigger the presentation and sequencing of restudy and retrieval trials.