scholarly journals 0084 Sleep Consolidates Incidentally Encoded Information After Deep but Not Shallow Encoding

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A34-A34
Author(s):  
E M Wernette ◽  
K M Fenn
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory ◽  
Memory Performance ◽  
Memory Test ◽  
Memory Traces ◽  
Incidental Encoding ◽  
The Relationship ◽  
With Memory

Abstract Introduction Slow wave sleep (SWS) strengthens declarative memory for information studied for a later test. However, research on the effect of sleep on information that is not intentionally remembered is scare. Previous research from our lab suggests sleep consolidates some, but not all, information that has been encoded incidentally, meaning that it has been acted on but not intentionally remembered. It remains unclear what determines which information benefits from sleep-dependent consolidation processes and what aspects of sleep are related to these mnemonic benefits. In two experiments, we test the hypothesis that sleep consolidates strong but not weak memory traces following incidental encoding, and assess the relationship between memory performance and objective sleep characteristics. Methods In Experiment 1, participants rated words one (weak traces) or three times (strong traces) in a deep or shallow incidental encoding task. Participants either rated words on a scale from ‘concrete’ to ‘abstract’ (deep) or counted the vowels in the words (shallow). Following a 12-hour period containing sleep or wakefulness, participants took a surprise memory test. In Experiment 2, participants rated words one or three times in the deep encoding task, received an 8-hour sleep opportunity with polysomnography, and took the surprise memory test. Results In Experiment 1, participants remembered words better after sleep than wake regardless of whether words were encoded one or three times, but only after deep encoding. Sleep did not consolidate information following shallow encoding. Experiment 2 is ongoing, but we predict that the amount of SWS will correlate positively with memory. Conclusion Results thus far suggest sleep may have consolidated information based on the strength of memory traces. Because deep encoding results in stronger memory traces than shallow encoding, this work is broadly consistent with theories of memory consolidation that predict sleep is more beneficial for strong memory traces than weak, such as the synaptic downscaling hypothesis. Support N/A

032 Sleep Consolidates Memory for Strong but not Weak Information After Incidental Encoding

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A14-A15
Author(s):  
Elle Wernette ◽  
Kimberly Fenn
Keyword(s):  
Slow Wave ◽  
Response Latency ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Memory Test ◽  
Memory Strength ◽  
Memory Traces ◽  
Incidental Encoding ◽  
The Relationship

Abstract Introduction Slow wave sleep (SWS) strengthens memory for studied information, but research on the effect of sleep on information that is not intentionally remembered is scarce. Previous research from our lab suggests sleep consolidates some information that has been encoded incidentally, meaning that it has been acted on but not intentionally remembered. It remains unclear what determines which information is consolidated during sleep after incidental encoding and what aspects of sleep are related to this mnemonic benefit. In two experiments, we test the hypothesis that sleep consolidates strong but not weak memory traces following incidental encoding and assess the relationship between memory performance and sleep attributes. Methods In Experiment 1, we manipulated memory strength within- and between-subjects. Participants rated words one or three times (within) in a shallow or deep incidental encoding task (between). In the shallow task, participants counted vowels in each word; in the deep task, participants rated each word on a scale from ‘concrete’ to ‘abstract’. Following a 12-hour period containing sleep or wakefulness, participants took a surprise memory test. In Experiment 2, participants rated words one or three times in the deep encoding task, received an 8-hour sleep opportunity with partial PSG, and took the surprise memory test. Results In Experiment 1, participants remembered words better after sleep than wake regardless of number of encoding trials, but only after deep encoding. There was not an effect of sleep following shallow encoding. In Experiment 2, SWS correlated negatively with response latency for correctly recognized words encoded once, but not those encoded three times. That is, participants who received more SWS showed faster performance. Conclusion Results suggest sleep consolidated information based on the depth of encoding, and this benefit was related to SWS. This work is broadly consistent with theories of memory consolidation that predict sleep is more beneficial for strong than weak memory traces, such as the synaptic downscaling hypothesis. Support (if any):

scholarly journals Bi-temporal anodal tDCS during slow-wave sleep boosts episodic memory consolidation in high performers

2019 ◽  
Author(s):  
Matthias Grieder ◽  
Yosuke Morishima ◽  
Stephanie Winkelbeiner ◽  
Sarah M Mueller ◽  
Kristoffer Feher ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Anodal Tdcs ◽  
Double Blind ◽  
High Performers

Background: Sleep is crucial for sound memory functioning in humans. In particular, the slow waves that occur predominantly during slow wave sleep (SWS) are associated with hippocampus-dependent declarative memory consolidation. Making use of this association, boosting SWS to improve memory performance would be appealing for both healthy and memory-impaired populations. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation that modulates the brain’s excitability and has shown promising results in improving memory performance. However, owing to differing stimulation protocols and contradictory findings, there is insufficient evidence for the efficacy of tDCS-modulated hippocampal excitability on SWS and sleep-dependent memory consolidation.Hypotheses: We aimed to enhance sleep-dependent memory consolidation and augment slow wave amplitudes.Methods: We applied bi-temporal anodal tDCS to the left and right lateral temporal lobes of 31 healthy participants in a double-blind, sham-controlled, randomized crossover study. State-dependent tDCS was administered during slow wave sleep only. A pair-associate episodic memory task was used to assess sleep-dependent memory consolidation with face-occupation stimuli with baseline retrieval before sleep and delayed retrieval after sleep.Results: Sleep-dependent memory consolidation was increased by tDCS only in participants who showed above-average performance (i.e. high performers) in baseline memory retrieval. Moreover, tDCS increased the slow wave amplitudes compared to sham.Conclusions: When targeting a specialized brain mechanism such as memory consolidation with tDCS during slow wave sleep, only those who were high performers at baseline achieved a memory boost.

scholarly journals The modulatory effect of oscillatory reinstatement during slow-wave sleep on declarative memory consolidation

2019 ◽  
Author(s):  
Becky Crowley ◽  
Amir-Homayoun Javadi
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Oscillatory Activity ◽  
Dorsolateral Prefrontal ◽  
Transcranial Alternating Current Stimulation ◽  
Human Participants

Consistent with the context-dependent memory literature, previous research suggests that when the same frequency of neural oscillations is reinstated between memory encoding and retrieval, engram reactivation is facilitated, and thus declarative memory recall is enhanced. Importantly, engram reactivation is also fundamental for the redistribution process that underlies sleep-dependent memory consolidation. Therefore, the current study investigated whether reinstating frequency-specific oscillatory activity between encoding and sleep would facilitate the engram reactivation implicated in sleep-dependent memory consolidation, and thus enhance post-sleep declarative memory performance. Transcranial alternating current stimulation (tACS) was administered to the left dorsolateral prefrontal cortex (DLPFC) of human participants during a declarative memory task. Participants received 60 Hz of stimulation during encoding, and 60 Hz, 90 Hz, or sham stimulation during post-learning slow-wave sleep (SWS) or rapid eye-movement (REM) sleep. In immediate and delayed free recall sessions, declarative memory performance was significantly enhanced if participants had received the same frequency of stimulation during encoding and SWS compared to any other stimulation condition. This finding supports a novel theoretical proposal, which assumes that an intrinsic neurobiological mechanism for coordinating frequency-specific oscillatory activity, during SWS, underlies sleep-dependent declarative memory consolidation.

scholarly journals Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation

2021 ◽  
Vol 11 (4) ◽  
pp. 410
Author(s):  
Simon Ruch ◽  
Kristoffer Fehér ◽  
Stephanie Homan ◽  
Yosuke Morishima ◽  
Sarah Maria Mueller ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Slow Wave ◽  
Direct Current ◽  
Memory Consolidation ◽  
Transcranial Direct Current Stimulation ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Direct Current Stimulation ◽  
Sleep Parameters ◽  
Episodic Memories

Slow-wave sleep (SWS) has been shown to promote long-term consolidation of episodic memories in hippocampo–neocortical networks. Previous research has aimed to modulate cortical sleep slow-waves and spindles to facilitate episodic memory consolidation. Here, we instead aimed to modulate hippocampal activity during slow-wave sleep using transcranial direct current stimulation in 18 healthy humans. A pair-associate episodic memory task was used to evaluate sleep-dependent memory consolidation with face–occupation stimuli. Pre- and post-nap retrieval was assessed as a measure of memory performance. Anodal stimulation with 2 mA was applied bilaterally over the lateral temporal cortex, motivated by its particularly extensive connections to the hippocampus. The participants slept in a magnetic resonance (MR)-simulator during the recordings to test the feasibility for a future MR-study. We used a sham-controlled, double-blind, counterbalanced randomized, within-subject crossover design. We show that stimulation vs. sham significantly increased slow-wave density and the temporal coupling of fast spindles and slow-waves. While retention of episodic memories across sleep was not affected across the entire sample of participants, it was impaired in participants with below-average pre-sleep memory performance. Hence, bi-temporal anodal direct current stimulation applied during sleep enhanced sleep parameters that are typically involved in memory consolidation, but it failed to improve memory consolidation and even tended to impair consolidation in poor learners. These findings suggest that artificially enhancing memory-related sleep parameters to improve memory consolidation can actually backfire in those participants who are in most need of memory improvement.

scholarly journals Autonomic activity during sleep predicts memory consolidation in humans

2016 ◽  
Vol 113 (26) ◽  
pp. 7272-7277 ◽  
Author(s):  
Lauren N. Whitehurst ◽  
Nicola Cellini ◽  
Elizabeth A. McDevitt ◽  
Katherine A. Duggan ◽  
Sara C. Mednick
Keyword(s):  
Memory Consolidation ◽  
Memory Performance ◽  
Sleep Stages ◽  
Remote Associates Test ◽  
Daytime Nap ◽  
The Relationship ◽  
With Memory ◽  
Good Sleep ◽  
Variance Explained

Throughout history, psychologists and philosophers have proposed that good sleep benefits memory, yet current studies focusing on the relationship between traditionally reported sleep features (e.g., minutes in sleep stages) and changes in memory performance show contradictory findings. This discrepancy suggests that there are events occurring during sleep that have not yet been considered. The autonomic nervous system (ANS) shows strong variation across sleep stages. Also, increases in ANS activity during waking, as measured by heart rate variability (HRV), have been correlated with memory improvement. However, the role of ANS in sleep-dependent memory consolidation has never been examined. Here, we examined whether changes in cardiac ANS activity (HRV) during a daytime nap were related to performance on two memory conditions (Primed and Repeated) and a nonmemory control condition on the Remote Associates Test. In line with prior studies, we found sleep-dependent improvement in the Primed condition compared with the Quiet Wake control condition. Using regression analyses, we compared the proportion of variance in performance associated with traditionally reported sleep features (model 1) vs. sleep features and HRV during sleep (model 2). For both the Primed and Repeated conditions, model 2 (sleep + HRV) predicted performance significantly better (73% and 58% of variance explained, respectively) compared with model 1 (sleep only, 46% and 26% of variance explained, respectively). These findings present the first evidence, to our knowledge, that ANS activity may be one potential mechanism driving sleep-dependent plasticity.

036 The Effect of Exercise on Sleep Architecture and Memory Consolidation during a Daytime Nap

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A16-A16
Author(s):  
Megan Collins ◽  
Erin Wamsley ◽  
Hailey Napier ◽  
Madeline Ray
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory ◽  
Sleep Stage ◽  
Sleep Time ◽  
Learning Task ◽  
Memory Retention ◽  
Verbal Information ◽  
Significant Difference

Abstract Introduction Slow wave sleep (SWS) is thought to especially benefit declarative memory (i.e., memory for facts and events). As such, recent studies have used various methods to experimentally increase the amount of slow wave sleep that participants obtain, with the goal of assessing how SWS affects declarative memory consolidation. Studies dating back decades have reported that exercising before sleep may increase time spent in SWS. Thus, the aim of the current project was to determine whether exercising after learning verbal information enhances slow wave sleep during a subsequent nap and/or enhances memory for verbal information. Methods Participants who exercised regularly were recruited to attend two 2.5hr laboratory sessions. During each session, they trained on a paired associates learning task and then completed either a 20min cardiovascular exercise routine or a 20min stretching routine. Following a 1hr nap opportunity, participants were tested on their memory. PSG was recorded during the nap, and scored following AASM criteria. Participants were excluded from analysis if they failed to sleep for at least 10 min. Following exclusions, n=30 participants were included in analysis. Results Contrary to our hypotheses, there was no significant difference between the exercise and stretching conditions for minutes spent in slow wave sleep (p=.16), % time spent in slow wave sleep (p=.22), or raw improvement in paired associated performance (p=.23). The amount of SWS obtained during the nap did not correlate with performance in either condition (SWS min vs. memory in exercise condition: r28=.10, p=.60; sleep condition: r28=-.06, p=.74). Exercise did not affect time spent in any other sleep stage, nor did it affect total sleep time. Conclusion Contrary to our hypotheses and the results of prior research, we were unable to detect a significant effect of exercise on slow wave sleep. Also contrary to our hypotheses, exercise did not affect memory retention across the nap interval. These null results could indicate that there is no effect of exercise on nap sleep and/or associated memory retention. However, it could also be that we lacked sufficient power to detect effects that were smaller than expected. Support (if any):

scholarly journals Midlife decline in declarative memory consolidation is correlated with a decline in slow wave sleep

2007 ◽  
Vol 14 (5) ◽  
pp. 336-341 ◽  
Author(s):  
J. Backhaus ◽  
J. Born ◽  
R. Hoeckesfeld ◽  
S. Fokuhl ◽  
F. Hohagen ◽  
...  
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory
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