0100 Effect of Naps on Preschoolers’ Consolidation of an Emotional Storybook

Abstract Introduction Naps are known to benefit emotional memory consolidation in preschoolers, though improvement is not evident until the following day. The mechanisms by which naps aid emotional memory, and how they differ from those facilitating more neutral declarative memory consolidation, are currently unknown. In this study, we used an emotional storybook task to assess change in memory for emotionally salient vs. neutral events across a nap and overnight sleep. PSG was included to explore sleep physiology correlates. Methods Preschool children (n = 9; Mage= 43.2 months) were read a novel storybook featuring negative and neutral events. Memory of story events was probed through sets of multiple-choice questions and assessed at three time points: immediately following the story, following a nap or equivalent wake period (within-subject; counterbalanced; separated by ~1 week), and 24h post-encoding. PSG was recorded during the nap period and both subsequent overnight sleep bouts. Results Memory performance across time points was assessed via change scores. Recall of story events did not differ between conditions from immediate to post-nap/wake assessment. When probed the following morning, children better remembered events when a nap took place the day prior (F(1,7) = 8.848, p=.021). This delayed nap benefit correlated with time spent in NREM2 during the nap (r=.91, p=.017). No differences were found between recall of negative vs. neutral events at any time point or between conditions. Conclusion Our results show a delayed benefit of napping on recall of a storybook, though at present no preference for emotional events is seen. Time spent in NREM2 during the nap was strongly associated with our finding, likely reflecting the declarative memory benefits conferred from this stage. Further analyses will include overnight sleep physiology to explore differential enhancement between event types, and possible interactions with nap microstructure. Support This work was supported by NIH R01 HL111695.

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Pharmacologically Increasing Sleep Spindles Enhances Recognition for Negative and High-arousal Memories

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00433 ◽

2013 ◽

Vol 25 (10) ◽

pp. 1597-1610 ◽

Cited By ~ 65

Author(s):

Erik J. Kaestner ◽

John T. Wixted ◽

Sara C. Mednick

Keyword(s):

Rem Sleep ◽

Memory Consolidation ◽

Declarative Memory ◽

Memory Performance ◽

Emotional Memory ◽

Limited Range ◽

Sleep Spindles ◽

Sleep Spindle ◽

Emotional Stimuli ◽

Valence And Arousal

Sleep affects declarative memory for emotional stimuli differently than it affects declarative memory for nonemotional stimuli. However, the interaction between specific sleep characteristics and emotional memory is not well understood. Recent studies on how sleep affects emotional memory have focused on rapid eye movement sleep (REM) but have not addressed non-REM sleep, particularly sleep spindles. This is despite the fact that sleep spindles are implicated in declarative memory as well as neural models of memory consolidation (e.g., hippocampal neural replay). Additionally, many studies examine a limited range of emotional stimuli and fail to disentangle differences in memory performance because of variance in valence and arousal. Here, we experimentally increase non-REM sleep features, sleep spindle density, and SWS, with pharmacological interventions using zolpidem (Ambien) and sodium oxybate (Xyrem) during daytime naps. We use a full spread of emotional stimuli to test all levels of valence and arousal. We find that increasing sleep spindle density increases memory discrimination (da) for highly arousing and negative stimuli without altering measures of bias (ca). These results indicate a broader role for sleep in the processing of emotional stimuli with differing effects based on arousal and valence, and they raise the possibility that sleep spindles causally facilitate emotional memory consolidation. These findings are discussed in terms of the known use of hypnotics in individuals with emotional mood disorders.

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

SLEEP ◽

10.1093/sleep/zsaa056.082 ◽

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

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Coupling of autonomic and central events during sleep benefits declarative memory consolidation

10.1101/195586 ◽

2017 ◽

Author(s):

Mohsen Naji ◽

Giri P. Krishnan ◽

Elizabeth A McDevitt ◽

Maxim Bazhenov ◽

Sara C. Mednick

Keyword(s):

Memory Consolidation ◽

Declarative Memory ◽

Memory Performance ◽

Memory Task ◽

Nrem Sleep ◽

Heart Beat ◽

Vagal Activity ◽

Rr Intervals ◽

Slow Oscillations ◽

Event Based

AbstractWhile anatomical pathways between forebrain cognitive and brainstem autonomic nervous centers are well defined, autonomic–central interactions during sleep and their contribution to waking performance are not understood. Here, we analyzed simultaneous central activity via electroencephalography (EEG) and autonomic heart beat-to-beat intervals (RR intervals) from electrocardiography (ECG) during wake and daytime sleep. We identified bursts of ECG activity that lasted 4-5 seconds and predominated in non-rapid-eye-movement sleep (NREM). Using event-based analysis of NREM sleep, we found an increase in delta (0.5-4Hz) and sigma (12-15Hz) power and an elevated density of slow oscillations (0.5-1Hz) about 5 secs prior to peak of the heart rate burst, as well as a surge in vagal activity, assessed by high-frequency (HF) component of RR intervals. Using regression framework, we show that these Autonomic/Central Events (ACE) positively predicted post-nap improvement in a declarative memory task after controlling for the effects of spindles and slow oscillations from sleep periods without ACE. No such relation was found between memory performance and a control nap. Additionally, NREM ACE negatively correlated with REM sleep and learning in a non-declarative memory task. These results provide the first evidence that coordinated autonomic and central events play a significant role in declarative memory consolidation.

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Transcranial stimulation enhances memory-relevant sleep oscillations and their functional coupling in mild cognitive impairment

10.1101/095588 ◽

2016 ◽

Author(s):

Julia Ladenbauer ◽

Josef Ladenbauer ◽

Nadine Külzow ◽

Rebecca de Boor ◽

Elena Avramova ◽

...

Keyword(s):

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Memory Consolidation ◽

Declarative Memory ◽

Activity Patterns ◽

Functional Coupling ◽

Dependent Manner ◽

Sleep State ◽

Sleep Physiology ◽

Spindle Power

AbstractAlzheimer’s disease (AD) not only involves loss of memory functions but also prominent deterioration of sleep physiology, already evident in the stage ofmild cognitive impairment(MCI). Cortical slow oscillations (SO, 0.5-1 Hz) and thalamo-cortical spindle activity (12-15 Hz) during sleep, and their temporal coordination, are considered critical for memory formation. We investigated the potential of slow oscillatory transcranial direct current stimulation (so-tDCS), applied during a daytime nap in a sleep state-dependent manner, to modulate these activity patterns and sleep-related memory consolidation in 16 patients with MCI.Stimulation significantly increased overall SO and spindle power, amplified spindle power during SO up-phases, and led to stronger synchronization between SO and spindle power fluctuations in electroencephalographic recordings. Moreover, visual declarative memory was improved by so-tDCS compared to sham stimulation, associated with stronger synchronization. These findings indicate a well-tolerated therapeutic approach for disordered sleep physiology and deficits in memory consolidation in MCI patients.

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0099 The Effects of Sleep on the Consolidation of Fearful Memories

SLEEP ◽

10.1093/sleep/zsaa056.097 ◽

2020 ◽

Vol 43 (Supplement_1) ◽

pp. A39-A40

Author(s):

M Arsic ◽

L Heiss ◽

A M Chambers

Keyword(s):

Memory Consolidation ◽

Emotional Memory ◽

Neutral Condition ◽

Emotion Induction ◽

Induction Procedure ◽

Main Effect ◽

Before And After ◽

Real World Learning ◽

Emotional Events ◽

The Impact

Abstract Introduction Previous research has found that emotionally intense stimuli are better remembered than neutral stimuli, especially after a period of sleep. However, few studies have examined memory for experienced emotional events, especially fearful ones. The purpose of the current study was to investigate the impact of sleep on memory consolidation using a fearful emotion induction task. Methods Thirty-three young adults (18.94±1.06 years; 64% female) were randomly assigned to either a fearful or neutral emotion induction condition. Participants were induced into their assigned emotion by visualizing each of eight emotion-congruent scenarios while corresponding music played in the background. Emotional state was measured using the Affect Grid before and after the emotion induction procedure. Twelve hours later, spanning either a day of wakefulness (wake group) or night of sleep (sleep group), participants were asked to recall the previously presented scenarios. Results A 2 x 2 ANOVA examined differences in the number of scenarios recalled between the conditions. A significant main effect of sleep was found, F(1,29)=8.41, p=.007, η 2p=.23, reflecting better recall in the sleep (3.21±1.78) vs. the wake group (1.79±1.72). There was also a main effect of emotion, F(1,29)=22.17, p<.001, η 2p=.43, reflecting better recall in the fear (3.58±1.54) vs. the neutral condition (1.29±1.44). However, there was no interaction. Results were similar for the number of details recalled between the conditions. The sleep group (12.74±9.09) recalled more details than the wake group (5.50±5.81), F(1,29)=8.05, p=.008, η 2p=.22. More details were also recalled in the fear condition (13.16±8.73) than the neutral condition (4.93±5.77), F(1,29)=10.54, p=.003, η 2p=.27. There was again no interaction. Conclusion Results demonstrate that both sleep and fearful emotion facilitate memory consolidation. This work both supports and extends existing research by examining emotional memory consolidation through the manipulation of experienced events, which may more closely approximate real world learning than previous methods. Support N/A

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0094 The Effect of Zolpidem on Sleep-Dependent Declarative Memory Consolidation

SLEEP ◽

10.1093/sleep/zsaa056.092 ◽

2020 ◽

Vol 43 (Supplement_1) ◽

pp. A38-A38

Author(s):

J Zhang ◽

S Mednick

Keyword(s):

Memory Consolidation ◽

Declarative Memory ◽

Brain Activity ◽

Memory Performance ◽

Critical Role ◽

Naval Research ◽

Memory Retention ◽

Double Blind ◽

Drug Ingestion ◽

Paired Associates

Abstract Introduction Sleep plays a critical role in memory consolidation. At the same time, about 20% of population in the U.S. suffer from sleep disorders or deprivation, and about 16% of them reported using sleep aids (CDC, 2015). However, the effect of sleep aids on sleep-dependent memory consolidation remains unclear. Previous studies have observed an improvement in sleep-dependent declarative memory consolidation with zolpidem over a daytime nap (Mednick et al., 2013). The current study investigates the effect of zolpidem on declarative memory consolidation over a night of sleep and over 24 hours. Methods This study employed a double-blind, placebo-controlled, within-subject design, in which every subject (N=26, 12 females) experienced both zolpidem and placebo. All subjects were healthy, college-aged adults without sleep disorder. A 32-channel electroencephalogram cap was used to record brain activity during sleep. Word paired-associates task was used to evaluate memory performance. Participants reported to the laboratory in the evening, performed word paired-associates task (test1), then ingested either zolpidem or placebo before sleep. They were tested on the task in the following morning (test2) as well as in the following evening (test3). Paired-sample t-tests for retrieval difference scores between placebo and zolpidem conditions were conducted. Results Participants showed similar baseline performance on the word paired-associates task (test 1, p=0.45). Zolpidem condition showed higher memory retention compared to placebo 24hr after drug ingestion (test3-test1, t₂ 5=2.09, p<0.05). The improvement in performance for zolpidem condition occurred across the following day (test3-test2, t₂ 5=2.22, p<0.05), as no difference was observed between conditions after sleep (test2-test1, t₂ 5=0.34, p=0.74) Conclusion Consistent with previous studies, participants showed better memory performance after taking zolpidem compared to placebo. However, the current study showed that the improvement in memory occurred across a day of wakefulness after nighttime drug ingestion, while other studies observed improvements shortly after sleep, indicating a potential delayed benefit of zolpidem on memory consolidation. Support This work was supported by the Office of Naval Research grant N00014-14-1-0513

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

10.31234/osf.io/jb9f4 ◽

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.

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Direct electrical stimulation of the amygdala enhances declarative memory in humans

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1714058114 ◽

2017 ◽

Vol 115 (1) ◽

pp. 98-103 ◽

Cited By ~ 32

Author(s):

Cory S. Inman ◽

Joseph R. Manns ◽

Kelly R. Bijanki ◽

David I. Bass ◽

Stephan Hamann ◽

...

Keyword(s):

Electrical Stimulation ◽

Memory Consolidation ◽

Emotional Response ◽

Declarative Memory ◽

Perirhinal Cortex ◽

Memory Systems ◽

Brain Regions ◽

Memory Test ◽

Depth Electrodes ◽

Emotional Events

Emotional events are often remembered better than neutral events, a benefit that many studies have hypothesized to depend on the amygdala’s interactions with memory systems. These studies have indicated that the amygdala can modulate memory-consolidation processes in other brain regions such as the hippocampus and perirhinal cortex. Indeed, rodent studies have demonstrated that direct activation of the amygdala can enhance memory consolidation even during nonemotional events. However, the premise that the amygdala causally enhances declarative memory has not been directly tested in humans. Here we tested whether brief electrical stimulation to the amygdala could enhance declarative memory for specific images of neutral objects without eliciting a subjective emotional response. Fourteen epilepsy patients undergoing monitoring of seizures via intracranial depth electrodes viewed a series of neutral object images, half of which were immediately followed by brief, low-amplitude electrical stimulation to the amygdala. Amygdala stimulation elicited no subjective emotional response but led to reliably improved memory compared with control images when patients were given a recognition-memory test the next day. Neuronal oscillations in the amygdala, hippocampus, and perirhinal cortex during this next-day memory test indicated that a neural correlate of the memory enhancement was increased theta and gamma oscillatory interactions between these regions, consistent with the idea that the amygdala prioritizes consolidation by engaging other memory regions. These results show that the amygdala can initiate endogenous memory prioritization processes in the absence of emotional input, addressing a fundamental question and opening a path to future therapies.

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Sleep-Related Declarative Memory Consolidation in Children and Adolescents with Developmental Dyslexia

Brain Sciences ◽

10.3390/brainsci11010073 ◽

2021 ◽

Vol 11 (1) ◽

pp. 73

Author(s):

Flaminia Reda ◽

Maurizio Gorgoni ◽

Aurora D'Atri ◽

Serena Scarpelli ◽

Matteo Carpi ◽

...

Keyword(s):

Developmental Dyslexia ◽

Memory Consolidation ◽

Declarative Memory ◽

Memory Performance ◽

Therapeutic Interventions ◽

Before And After ◽

Consolidation Rate ◽

Oscillation Dynamics ◽

Shed Light ◽

Local Sleep

Sleep has a crucial role in memory processes, and maturational changes in sleep electrophysiology are involved in cognitive development. Albeit both sleep and memory alterations have been observed in Developmental Dyslexia (DD), their relation in this population has been scarcely investigated, particularly concerning topographical aspects. The study aimed to compare sleep topography and associated sleep-related declarative memory consolidation in participants with DD and normal readers (NR). Eleven participants with DD and 18 NR (9–14 years old) underwent a whole-night polysomnography. They were administered a word pair task before and after sleep to assess for declarative memory consolidation. Memory performance and sleep features (macro and microstructural) were compared between the groups, and the intercorrelations between consolidation rate and sleep measures were assessed. DD showed a deeper worsening in memory after sleep compared to NR and reduced slow spindles in occipito-parietal and left fronto-central areas. Our results suggest specific alterations in local sleep EEG (i.e., sleep spindles) and in sleep-dependent memory consolidation processes in DD. We highlight the importance of a topographical approach, which might shed light on potential alteration in regional cortical oscillation dynamics in DD. The latter might represent a target for therapeutic interventions aimed at enhancing cognitive functioning in DD.

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

10.31219/osf.io/8yxge ◽

2019 ◽

Cited By ~ 2

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.

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