Manipulating memory processing during sleep to explore the critical duration of reactivation events

Newly encoded memories are reactivated and consolidated during sleep. However, how the reactivation of a specific memory unfolds over time is poorly understood. What are the temporal dynamics of a single reactivation event within a period of sleep? Does extending a single reactivation opportunity translate to stronger memory benefits? We explored these dynamics by utilizing targeted memory reactivation (TMR), a technique that biases the consolidation of memories via the unobtrusive presentation of memory-associated cues during sleep. Participants learned the on-screen positions of sixty objects, each linked with a unique sound (e.g., cat - meow). Some sounds were then presented during non-REM sleep, with the duration allotted for reactivation causally controlled by varying the timing of the interstimulus interval. TMR did not lead to uniform improvement in memory, and no differences were observed between objects allotted short (2.5 s) and long (7.5 s) reactivation windows. However, memory for objects allotted short windows was impacted by TMR in an encoding-strength-dependent manner, with poorly encoded objects benefiting the most. Classification models trained on EEG data revealed memory reactivation that was time-locked to sound onset during sleep, and this measure of reactivation was linked with memory gains one week later. We did not find evidence for reactivation that extended beyond the time window immediately after sound onset (<2 s). Although our results are not entirely conclusive, they suggest that the critical processes supporting memory consolidation conclude within <2 s after reactivation onset and that extended reactivation windows do not confer additional benefits

Awake reactivation is not a uniform process

Memories are consolidated during restful wakefulness, but the mechanisms underlying this process are poorly understood. We argue that wakeful reactivation is not monolithic: it encompasses non-conscious and conscious processes with varying levels of elaboration and diverging consequences. Refining reactivation as a concept may help avoid conflicting results on wake consolidation

Examining sleep’s role in memory generalization and specificity through the lens of targeted memory reactivation

Two vital memory functions — remembering specific experiences and generalizing across many experiences — are in tension with each other. In the complementary-learning-systems model, the hippocampus allows for fast learning of unique episodic memories while the cortex slowly extracts regularities from overlapping representations. Whereas episodic memories undergo consolidation over protracted time periods, many questions remain about how memory generalization evolves over time. Sleep's role in consolidating individual memories has been convincingly demonstrated using targeted memory reactivation, a method whereby memories can be selectively strengthened through the unobtrusive presentation of learning-related stimuli during sleep. In this review, we argue that targeted memory reactivation can help advance understanding of memory transformation and the contrast between specificity and generalization

Sleep reactivation did not boost suppression-induced forgetting.

Sleep's role in memory consolidation is widely acknowledged, but its role in weakening memories is still debated. Memory weakening is evolutionary beneficial and makes an integral contribution to cognition. We sought evidence on whether sleep-based memory reactivation can facilitate memory suppression. Participants learned pairs of associable words (e.g., DIET-CREAM) and were then exposed to hint words (e.g., DIET) and instructed to either recall ("think") or suppress ("no-think") the corresponding target words (e.g., CREAM). As expected, suppression impaired retention when tested immediately after a 90-min nap. To test if reactivation could selectively enhance memory suppression during sleep, we unobtrusively presented one of two sounds conveying suppression instructions during sleep, followed by hint words. Results showed that targeted memory reactivation did not enhance suppression-induced forgetting. Although not predicted, post-hoc analyses revealed that sleep cues strengthened memory, but only for suppressed pairs that were weakly encoded before sleep. The results leave open the question of whether memory suppression can be augmented during sleep, but suggest strategies for future studies manipulating memory suppression during sleep. Additionally, our findings support the notion that sleep reactivation is particularly beneficial for weakly encoded information, which may be prioritized for consolidation

Sleep reactivation did not boost suppression-induced forgetting.

Sleep's role in memory consolidation is widely acknowledged, but its role in weakening memories is still debated. Memory weakening is evolutionary beneficial and makes an integral contribution to cognition. We sought evidence on whether sleep-based memory reactivation can facilitate memory suppression. Participants learned pairs of associable words (e.g., DIET-CREAM) and were then exposed to hint words (e.g., DIET) and instructed to either recall ("think") or suppress ("no-think") the corresponding target words (e.g., CREAM). As expected, suppression impaired retention when tested immediately after a 90-min nap. To test if reactivation could selectively enhance memory suppression during sleep, we unobtrusively presented one of two sounds conveying suppression instructions during sleep, followed by hint words. Results showed that targeted memory reactivation did not enhance suppression-induced forgetting. Although not predicted, post-hoc analyses revealed that sleep cues strengthened memory, but only for suppressed pairs that were weakly encoded before sleep. The results leave open the question of whether memory suppression can be augmented during sleep, but suggest strategies for future studies manipulating memory suppression during sleep. Additionally, our findings support the notion that sleep reactivation is particularly beneficial for weakly encoded information, which may be prioritized for consolidation

Ten simple rules for queer data collection and analysis by STEM researchers.

Queer people are still underrepresented both as STEM researchers and participants, partially due to a dearth of accurate data on this demographic. The lack of consideration for queer identities in data collection and dissemination causes a vicious cycle of exclusion. To address this invisibility, it is important to collect and report data in an inclusive and accurate manner across all areas of research, including in studies that are not specifically focused on queer populations. However, STEM researchers are often unsure of how to properly collect data in a manner that fairly represents queer people. We have developed a list of Ten Simple rules to aid researchers to perform data collection on queer individuals, focusing on study design and data dissemination. We address several issues in queer data, such as language use, dealing with small populations, and balancing demands. We also discuss how to extend this inclusive practice for studies on animal populations. These rules are aimed at anybody surveying populations which may contain queer individuals, including for example research studies and inclusivity surveys for conferences. By providing practical tips, we hope to alleviate insecurity and confusion around this topic

Using odors to selectively reactivate learning contexts during sleep

In this study, we aim to conceptually replicate and extend a study published by Rasch et al (2007; Science). The original study had one odor linked with a memory task and then presented overnight during slow-wave sleep. It showed improvement relative to non-cued sleep. We will have an identical memory task with three separate blocks, two of which will be linked with distinct odors. Only one of the odors will be cued during an afternoon nap, and we predict that memory for the linked block will be selectively enhanced