Background: Poor sleep quality is a common complaint, affecting over one third of people in the United States. While sleep quality is thought to be related to slow-wave sleep (SWS), there has been little investigation to address whether modulating slow-wave oscillations (SWOs) that characterize SWS could impact sleep quality. Here we examined whether closed-loop transcranial alternating current stimulation (CL-tACS) applied during sleep impacts sleep quality and efficiency. Methods: CL-tACS was used in 21 participants delivered at the same frequency and in phase with endogenous SWOs during sleep. Sleep quality was assessed in the morning following either verum or sham control stimulation during sleep, with order counterbalanced within participants. Results: Higher sleep quality and efficiency were found after verum stimulation nights compared to control. The largest effects on sleep quality were found immediately following an adaptation night in the laboratory for which sleep quality was reduced. Conclusions: Applying CL-tACS at the same frequency and phase as endogenous SWOs may offer a novel method to improve subjective sleep quality after a night with poor quality sleep. CL-tACS might be helpful for increasing sleep quality and efficiency in otherwise healthy people, and in patients with clinical disorders that involve sleep deficits.

Many studies have indicated that abrupt onsets have the power to capture attention against our will. In the present study, we tested the hypothesis that abrupt onsets can be suppressed, but only when there is a strong incentive to do so. We presented a highly-salient flurry of distracting, irrelevant abrupt onsets immediately prior to each target display. This should incentivize participants to suppress the disruptive onsets (if that is an available strategy) and/or habituate to the abrupt onsets. In Experiment 1, the flurry of onsets was composed of dots. Experiment 2 greatly increased the size of the flashing onsets (10-fold increase in pixels) to make them even more salient and worthy of suppression. Experiment 3 used premasks, so that the search items would be offsets rather than onsets. Experiment 4 created more direct competition between the salient onsets and the search display. Surprisingly, despite the variety of approaches employed specifically to promote suppression of capture by abrupt onsets, we were unable to eliminate, or even noticeably reduce, capture effects. The present data support the hypothesis that the visual system is incapable of suppressing abrupt onsets in diffusely attended regions of visual space.

Facial expressions of emotion are critical to survival and social interaction. Their importance is underscored by evolutionary adaptations that enable their automatic production and recognition. As a result, emotional faces may receive attentional prioritization, even when completely irrelevant to the task at hand. Although attentional bias is theoretically plausible, empirical findings have been inconsistent: Some studies have reported bias toward emotional faces, whereas many others have not. To clarify this discrepancy, we conducted a meta-analysis of attentional bias for task-irrelevant emotional expressions, including studies using the additional singleton and spatial cuing paradigms (which includes dot probe paradigms). We found an overall effect between zero and small (Hedges's g = 0.08), based on 160 cases. The only significant moderator was the data set from which the emotional face stimuli were drawn, with the Gur data set (Gur et al., 2002) producing the strongest bias. In a second meta-analysis, we examined studies where the emotional expression was task relevant because both the expression and the target were singletons. Here, the overall attentional bias was small to medium (g = 0.41), based on 25 cases. We conclude that facial expressions of emotion do not bias attention when they are task irrelevant. In the discussion, we highlight some empirical and theoretical challenges to emotion automaticity and offer explanations for why the effect was between zero and small. One potential explanation is studies often utilize static photographs of actors portraying facial expressions of emotion, which are low in salience and ecological validity because they lack context. (PsycInfo Database Record (c) 2025 APA, all rights reserved).