scholarly journals Multiple memories can be simultaneously reactivated during sleep as effectively as a single memory

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Eitan Schechtman ◽  
James W. Antony ◽  
Anna Lampe ◽  
Brianna J. Wilson ◽  
Kenneth A. Norman ◽  
...  
Keyword(s):  
Group Size ◽  
Memory Consolidation ◽  
Sleep Spindles ◽  
Future Studies ◽  
Alternative Models ◽  
Theta Power ◽  
Memory Traces ◽  
Previous Learning ◽  
Screen Location

AbstractMemory consolidation involves the reactivation of memory traces during sleep. If different memories are reactivated each night, how much do they interfere with one another? We examined whether reactivating multiple memories incurs a cost to sleep-related benefits by contrasting reactivation of multiple memories versus single memories during sleep. First, participants learned the on-screen location of different objects. Each object was part of a semantically coherent group comprised of either one, two, or six items (e.g., six different cats). During sleep, sounds were unobtrusively presented to reactivate memories for half of the groups (e.g., “meow”). Memory benefits for cued versus non-cued items were independent of the number of items in the group, suggesting that reactivation occurs in a simultaneous and promiscuous manner. Intriguingly, sleep spindles and delta-theta power modulations were sensitive to group size, reflecting the extent of previous learning. Our results demonstrate that multiple memories may be consolidated in parallel without compromising each memory’s sleep-related benefit. These findings highlight alternative models for parallel consolidation that should be considered in future studies.

scholarly journals Multiple memories can be simultaneously reactivated during sleep as effectively as a single memory

2019 ◽  
Author(s):  
Eitan Schechtman ◽  
James W. Antony ◽  
Anna Lampe ◽  
Brianna J. Wilson ◽  
Kenneth A. Norman ◽  
...  
Keyword(s):  
Group Size ◽  
Memory Consolidation ◽  
Sleep Spindles ◽  
Future Studies ◽  
Alternative Models ◽  
Theta Power ◽  
Memory Traces ◽  
Previous Learning ◽  
Screen Location

AbstractMemory consolidation involves the reactivation of memory traces during sleep. If many memories are reactivated each night, how much do they interfere with one another? To explore this question, we examined whether reactivating multiple memories incurs a cost to sleep-related benefits by contrasting reactivation of multiple memories versus single memories during sleep. First, participants learned the on-screen location of different images. Each image was part of a semantically interconnected group (e.g., images of different cats). Groups were comprised of either one, two, or six images. During sleep, group-related sounds (e.g., “meow”) were unobtrusively presented to reactivate memories for half of the groups. The benefit in location recall for cued versus non-cued items was independent of the number of items in the group, suggesting that reactivation occurs in a simultaneous, promiscuous manner. Intriguingly, sleep spindles and delta-theta power modulations were sensitive to group size and reflected the extent of previous learning. Our results demonstrate that multiple memories may be consolidated in parallel without compromising each memory’s sleep-related benefit, suggesting that the brain’s capacity for reactivation is not strictly limited by separate resources needed for individual memories. These findings highlight alternative models for parallel consolidation that should be considered in future studies.

scholarly journals Sleep spindles facilitate selective memory consolidation

2020 ◽  
Author(s):  
Dan Denis ◽  
Dimitris Mylonas ◽  
Craig Poskanzer ◽  
Verda Bursal ◽  
Jessica D. Payne ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Initial Strength ◽  
Long Term Storage ◽  
Cortical Oscillations ◽  
Memory Traces ◽  
New Evidence ◽  
The Brain

AbstractSleep has been shown to be critical for memory consolidation, and recent research has demonstrated that this consolidation effect is selective, with certain memories being prioritized for strengthening. Initial strength of a memory appears to be one metric the brain uses to prioritize memory traces for sleep-based consolidation, but the role of consolidation-mediating cortical oscillations, such as sleep spindles and slow oscillations, has not been explored. Here, N=54 participants studied pairs of words to three distinct encoding strengths, with recall being tested immediately following learning and again six hours later. N=36 had a two-hour afternoon nap opportunity following learning, whilst the remaining (n=18) remained awake throughout. Results showed a selective benefit of sleep on memory, with sleep preferentially consolidating weakly encoded items (p=.003). The magnitude of this effect (d=0.90, 95% CI=0.29-1.50) was similar when compared to a previous study examining the benefits of a full night of sleep (d=1.36, 95% CI=0.59-2.12). Within the nap group, consolidation of weakly encoded items was associated with sleep spindle density during slow wave sleep (r=.48, p=.003). This association was present when separately examining spindles coupled (r=.41, p=.013), and uncoupled (r=.44, p=.007) with slow oscillations. Memory was significantly better in individuals who showed an amount of slow oscillation-spindle coupling that was greater than what would be expected by chance (p=.006, d=1.15). These relationships were unique to weakly encoded items, with spindles not correlating with memory for intermediate or strong items. This suggests that sleep spindles facilitate selective memory consolidation, guided in part by memory strength.Significance statementGiven the countless pieces of information we encode each day, how does the brain select which memories to commit to long-term storage? Sleep is known to aid in memory consolidation, but less research has examined which memories are prioritized to receive this benefit. Here, we found that compared to staying awake, sleep was associated with better memory for weakly encoded information. This suggests sleep helps to rescue weak memory traces from being forgotten. Sleep spindles, a hallmark oscillation of non-rapid eye movement sleep, mediates consolidation processes. We extended this to show that spindles selectively facilitated consolidation of weakly encoded memories. This provides new evidence for the selective nature of sleep-based consolidation and elucidates a physiological correlate of this preferential benefit.

scholarly journals Shining a Light on the Mechanisms of Sleep for Memory Consolidation

2021 ◽  
Author(s):  
Michelle A. Frazer ◽  
Yesenia Cabrera ◽  
Rockelle S. Guthrie ◽  
Gina R. Poe
Keyword(s):  
Rem Sleep ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Strong Support ◽  
Nrem Sleep ◽  
Future Research ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Theta Waves ◽  
Learning Tasks

Abstract Purpose of review This paper reviews all optogenetic studies that directly test various sleep states, traits, and circuit-level activity profiles for the consolidation of different learning tasks. Recent findings Inhibiting or exciting neurons involved either in the production of sleep states or in the encoding and consolidation of memories reveals sleep states and traits that are essential for memory. REM sleep, NREM sleep, and the N2 transition to REM (characterized by sleep spindles) are integral to memory consolidation. Neural activity during sharp-wave ripples, slow oscillations, theta waves, and spindles are the mediators of this process. Summary These studies lend strong support to the hypothesis that sleep is essential to the consolidation of memories from the hippocampus and the consolidation of motor learning which does not necessarily involve the hippocampus. Future research can further probe the types of memory dependent on sleep-related traits and on the neurotransmitters and neuromodulators required.

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

2013 ◽  
Vol 25 (10) ◽  
pp. 1597-1610 ◽  
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.

Chlorpromazine and Memory Consolidation

1965 ◽  
Vol 17 (3) ◽  
pp. 705-706 ◽  
Author(s):  
Henry E. Adams ◽  
L. J. Peacock ◽  
John F. Glenn
Keyword(s):  
Factorial Design ◽  
Memory Consolidation ◽  
Water Deprivation ◽  
Straight Alley ◽  
Learning Trial ◽  
Water Reward ◽  
Simple Task ◽  
Memory Traces ◽  
Main Effects

To determine whether chlorpromazine affects learning by disrupting memory traces 40 23-hr. water-deprived rats were given 1 trial per day in a straight alley maze for a water reward. The factorial design included (a) chlorpromazine vs saline and (b) injection 10 sec. after a learning trial vs injection 30 min. after a learning trial. All groups learned but there were no significant main effects or interaction, which indicates that chlorpromazine does not affect learning this simple task under water-deprivation.

P384 The role of sleep spindles in overnight verbal memory consolidation in temporal lobe epilepsy patients

2017 ◽  
Vol 128 (9) ◽  
pp. e302-e303
Author(s):  
Márta Virág ◽  
Róbert Bódizs ◽  
Ferenc Gombos ◽  
Anna Kelemen ◽  
Dániel Fabó
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Memory Consolidation ◽  
Verbal Memory ◽  
Sleep Spindles

scholarly journals Selection of stimulus parameters for enhancing slow wave sleep events with a Neural-field theory thalamocortical computational model

2021 ◽  
Author(s):  
Felipe A. Torres ◽  
Patricio Orio ◽  
María-José Escobar
Keyword(s):  
Computational Model ◽  
Slow Wave ◽  
Memory Consolidation ◽  
Closed Loop ◽  
Slow Wave Sleep ◽  
Brain Activity ◽  
Sensory Stimulation ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Closed Loop Stimulation

AbstractSlow-wave sleep cortical brain activity, conformed by slow-oscillations and sleep spindles, plays a key role in memory consolidation. The increase of the power of the slow-wave events, obtained by auditory sensory stimulation, positively correlates to memory consolidation performance. However, little is known about the experimental protocol maximizing this effect, which could be induced by the power of slow-oscillation, the number of sleep spindles, or the timing of both events’ co-occurrence. Using a mean-field model of thalamocortical activity, we studied the effect of several stimulation protocols, varying the pulse shape, duration, amplitude, and frequency, as well as a target-phase using a closed-loop approach. We evaluated the effect of these parameters on slow-oscillations (SO) and sleep-spindles (SP), considering: (i) the power at the frequency bands of interest, (ii) the number of SO and SP, (iii) co-occurrences between SO and SP, and (iv) synchronization of SP with the up-peak of the SO. The first three targets are maximized using a decreasing ramp pulse with a pulse duration of 50 ms. Also, we observed a reduction in the number of SO when increasing the stimulus energy by rising its amplitude. To assess the target-phase parameter, we applied closed-loop stimulation at 0º, 45º, and 90º of the phase of the narrow-band filtered ongoing activity, at 0.85 Hz as central frequency. The 0º stimulation produces better results in the power and number of SO and SP than the rhythmic or aleatory stimulation. On the other hand, stimulating at 45º or 90º change the timing distribution of spindles centers but with fewer co-occurrences than rhythmic and 0º phase. Finally, we propose the application of closed-loop stimulation at the rising zero-cross point using pulses with a decreasing ramp shape and 50 ms of duration for future experimental work.Author summaryDuring the non-REM (NREM) phase of sleep, events that are known as slow oscillations (SO) and spindles (SP) can be detected by EEG. These events have been associated with the consolidation of declarative memories and learning. Thus, there is an ongoing interest in promoting them during sleep by non-invasive manipulations such as sensory stimulation. In this paper, we used a computational model of brain activity that generates SO and SP, to investigate which type of sensory stimulus –shape, amplitude, duration, periodicity– would be optimal for increasing the events’ frequency and their co-occurrence. We found that a decreasing ramp of 50 ms duration is the most effective. The effectiveness increases when the stimulus pulse is delivered in a closed-loop configuration triggering the pulse at a target phase of the ongoing SO activity. A desirable secondary effect is to promote SPs at the rising phase of the SO oscillation.

scholarly journals Procedural memory consolidation is associated with heart rate variability and sleep spindles

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Frank J. van Schalkwijk ◽  
Theresa Hauser ◽  
Kerstin Hoedlmoser ◽  
Mohamed S. Ameen ◽  
Frank H. Wilhelm ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Memory Consolidation ◽  
Procedural Memory ◽  
Sleep Spindles

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

scholarly journals 0086 Daytime Napping and Memory Consolidation of Novel Word Learning in Children and Adults

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A35-A35
Author(s):  
E van Rijn ◽  
S A Walker ◽  
V C Knowland ◽  
S A Cairney ◽  
A D Gouws ◽  
...  
Keyword(s):  
White Matter ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Diffusion Tensor ◽  
Brain Connectivity ◽  
Nrem Sleep ◽  
Sleep Spindles ◽  
Adults And Children ◽  
Structural Brain ◽  
Novel Words

Abstract Introduction Memory for novel words benefits from sleep, particularly non-rapid eye movement (NREM) sleep and its features, such as sleep spindles and slow oscillations. This is consistent with systems consolidation models, in which sleep supports transfer from hippocampal to neocortical memory networks. Larger amounts of slow wave sleep in children has been proposed to account for enhanced consolidation effects, but such studies have typically focused on nocturnal sleep. We examined whether daytime naps benefit word retention in adults and children aged 10–12 years, and whether this relationship in children is affected by differences in white matter pathway microstructure. We hypothesized that the link between memory consolidation and structural brain connectivity will be mediated by the degree of sleep spindles during the nap. Methods Adults (N = 31; mean age = 20.91, SD = 1.55) and children (N = 38; mean age = 11.95, SD = 0.88) learned spoken novel words, followed by a 90-minute nap opportunity monitored with polysomnography. Memory for the words was tested pre- and post-nap. Children’s structural brain connectivity was measured using diffusion tensor imaging (DTI). Results Word memory was preserved following sleep in adults, while an adult wake control condition showed deterioration. Similarly, in children memory performance was stable over the nap, with wake control data currently being collected. Analyses relating behavioral changes over the nap to NREM sleep features and structural brain connectivity will be presented. Conclusion In line with sleep-dependent memory consolidation models, daytime naps protect novel words from forgetting in adults and children. Examining potential relationships between nap-based consolidation and structural integrity has important theoretical implications, given the increase in brain connectivity in language areas during childhood, as well as white matter alterations in developmental populations. Support This research was supported by the UK Economic and Social Research Council, grant no. ES/N009924/1.

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