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Encoding was followed by an immediate recognition memory probe. Recognition memory was probed again following a nap/wake interval (Delayed) and again the following morning (24-Hour).
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Naps in early childhood support declarative memory consolidation. However, emotional memories are unique in the neural basis of encoding as well as the sleep physiology underlying consolidation. Specifically, while consolidation of declarative memories has been associated with slow wave sleep, a prevailing theory suggests that REM sleep is necessar...
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... Analyses. To assess changes in memory over naps and equivalent intervals of wake, baseline recognition accuracy (percent correct) was subtracted from delayed recognition accuracy (?Recall nap/wake = delayed recogni- tion ? immediate recognition accuracy; Fig. 1). ?Recall nap was also used for associations with nap physiology and memory performance change across this delay. ?Recall overnight (24-hr recognition ? delayed recognition accu- racy) was used to assess the change in memory across the overnight sleep period. ?Recall overnight was also used to correlate overnight sleep physiology with performance change across the overnight delay. Finally, ?Recall 24-hr (?Recall 24-hr = 24-hr recognition ? immediate recognition accuracy) was calculated to measure the change in performance across the entire 24-hr ...
Similar publications
Numerous studies have shown that sleep enhances the consolidation of episodic memory. However, it remains unclear whether this consolidation benefit is moderated by the emotional valence of the learned material. To clarify whether sleep selectively enhances the consolidation of emotional material, we conducted a meta-analysis including N = 1,059 ob...
Citations
... Im Kindesalter gibt es ebenfalls Hinweise darauf, dass Schlaf die Konsolidierung emotional relevanter Informationen bevorzugt unterstützt (Prehn-Kristensen et al., 2013). In der frühen Kindheit ist das Zusammenspiel von Nickerchen während des Tages und des Nachtschlafs bedeutsam für die Konsolidierung (Hanron et al., 2023;Kurdziel et al., 2018). ...
Zusammenfassung: Schlaf ist ein hoch komplexer Zustand. Wie, wann und wie lange Menschen schlafen verändert sich stark über die Lebensspanne. In jeder Entwicklungsphase gibt es aber enge Zusammenhänge zwischen Schlaf- und Wachphasen. Aktuelle Befunde zeigen einerseits, dass Schlaf wesentliche Auswirkungen auf verschiedene Bereiche des menschlichen Erlebens und Verhaltens hat. Andererseits wirken sich Umweltfaktoren und individuelle Faktoren auf das Schlafverhalten aus. Diese komplexen bidirektionalen Zusammenhänge werden kurz- und langfristig sichtbar. Das Wissen über Schlaf und Schlafstörungen, ihre Ursachen und Konsequenzen, ist jedoch bei weitem nicht vollständig, insbesondere für die frühen Entwicklungsabschnitte. Die Beiträge in dem vorliegenden Themenheft adressieren aktuelle Forschungslücken zum Themenbereich Schlaf und Schlafprobleme im Entwicklungsverlauf, vom Säuglings- bis zum Jugendalter.
... Notably, in the only study assessing the impact of child napping on longer-term social-emotional memory retention in early childhood, the benefit of a nap did not emerge until the following day. Kurdziel et al. (2018) showed children (3-5 years) pictures of neutral faces paired with negative and positive audio descriptions prior to their nap. When memory was assessed the same day, recognition memory for the faces did not differ between conditions in which children napped and when they stayed awake following learning. ...
... When memory was assessed the same day, recognition memory for the faces did not differ between conditions in which children napped and when they stayed awake following learning. However, when emotional memories were probed again following subsequent overnight sleep, the advantage of napping emerged: children showed superior 24-h delayed recognition of the face stimuli if they napped the previous day compared to when they stayed awake following learning (Kurdziel et al., 2018). This is in contrast to studies of neutral declarative memory in the same age group, which find sleep benefits immediately following the nap (Kurdziel et al., 2013;Spanò et al., 2018;Williams & Horst, 2014). ...
... We posit that naps interact with overnight sleep, yielding a delayed benefit. Specifically, emotional memories may be reactivated during naps even if behavioral evidence of consolidation is not evident until after additional overnight processing (Derégnaucourt et al., 2005;Kurdziel et al., 2018). However, it is currently unclear whether emotional memory processing begins during the nap. ...
Early childhood naps support emotional memory, but benefits are only observed after overnight sleep. Whether emotional memory consolidation occurs during naps, or whether napping only prepares memories for overnight consolidation is unknown. We investigated whether naps protect emotional memories from interference, indicating consolidation. Between 2018 and 2020, 63 children in western Massachusetts preschools (30 female, 33 male; 33–67 months; 23.8% Hispanic, 87.3% White) learned faces paired with negative or neutral descriptions, followed by nap or wake. Before delayed recognition, half completed an interference task. Without interference, napping benefited recognition. With interference, children recognized fewer negative faces post‐nap (compared to wake), with overnight sleep attenuating this difference. Results suggest that naps initially destabilize emotional memories, possibly reflecting partial processing that promotes long‐term consolidation.
... Memory replay also strengthens commonalities across existing and new memories, thereby contributing to memory integration and multi-item generalization (Lewis & Durrant, 2011). Several studies have reported a relationship between electrophysiological activity during sleep and subsequent memory performance (e.g., Rasch et al., 2007); evidence of these associations in children and infants have been sparse but compelling (Kurdziel et al., 2013(Kurdziel et al., , 2018Seehagen et al., 2019). Alternatively, sleep has been theorized to lower all the synaptic connections to a baseline level, thereby indirectly supporting memory: The synapses that were highly active in wakefulness (i.e., those activated by the specific experience or referent encountered and their connections to existing knowledge networks) would be the strongest after sleep (Tononi & Cirelli, 2003Vyazovskiy et al., 2008). ...
... 1-39 4 have also been found to be essential to early memory consolidation. Kurdziel et al. (2018) found that emotional memories in 34-to 64-month-olds were not consolidated immediately after a postlearning nap but only after nighttime sleep following learning, with the greatest memory improvements found in toddlers who had napped immediately after learning the previous day, suggesting that timely sleep might be as important at this older age as it is in early infancy, especially in combination with nocturnal sleep (Hupbach et al., 2009;Seehagen et al., 2015). In the next sections, we review how memory consolidation is associated with different aspects of word learning and the variables that have been found to mediate this relationship. ...
This systematic review surveyed research on the associations between sleep and the memory processes involved in word learning in infancy. We found only 16 studies that addressed this topic directly, identifying associations between infant sleep and the memory processes, the identification of word forms in running speech, and the stabilization and generalization of new word form–meaning associations. Some studies investigated changes in brain responses after word learning and in sleep parameters during postlearning sleep. Others investigated the long‐term effects of sleeping patterns on later vocabulary development. All but one of these studies identified positive associations between sleep and word learning in early childhood, extending similar findings from studies on adults and school‐aged children. However, there remain several gaps in the current research on early lexical development and sleep. Future investigations should address these gaps for researchers to better understand lexical development and to create links between memory and language acquisition research. A one‐page Accessible Summary of this article in non‐technical language is freely available in the Supporting Information online and at https://oasis‐database.org
... Interestingly, SWA in children's naps predicts the overnap protection of memory for emotional faces (80) and also, predicts reductions in the emotional attention bias following a nap in young children (81). We posit that consolidation of emotional memories from the morning decreases emotional load, and as a result, children are less reactive to emotional stimuli thereafter. ...
... Nonhabitual nappers, on the other hand, may have more developed memory storage and thus, be able to hold memories for longer without interference. Subsequently, other studies have found similar differences between habitually and nonhabitually napping children with a word-learning task (89) and an emotional face-learning task (80). Collectively, these studies provide evidence that naps are similarly beneficial regardless of nap habituality but that memory of habitually napping children is much more damaged by a missed nap compared with nonhabitually napping children. ...
The transition from multiple sleep bouts each day to a single overnight sleep bout (i.e., nap transition) is a universal process in human development. Naps are important during infancy and early childhood as they enhance learning through memory consolidation. However, a normal part of development is the transition out of naps. Understanding nap transitions is essential in order to maximize early learning and promote positive long-term cognitive outcomes. Here, we propose a novel hypothesis regarding the cognitive, physiological, and neural changes that accompany nap transitions. Specifically, we posit that maturation of the hippocampal-dependent memory network results in more efficient memory storage, which reduces the buildup of homeostatic sleep pressure across the cortex (as reflected by slow-wave activity), and eventually, contributes to nap transitions. This hypothesis synthesizes evidence of bioregulatory mechanisms underlying nap transitions and sheds new light on an important window of change in development. This framework can be used to evaluate multiple untested predictions from the field of sleep science and ultimately, yield science-based guidelines and policies regarding napping in childcare and early education settings.
... (b) Percentage of time spent in specific sleep stages from 6 months through young adulthood. Values from 6 months to preschool age include collapsed overnight and nap data [6-and 12-months data from Louis et al. (1997) and preschool-age data from Kurdziel et al. (2018)] while values from middle childhood to young adulthood are derived mainly from studies assessing overnight sleep only (Ohayon et al. 2004). Abbreviations: EEG, electroencephalogram; nREM, nonrapid eye movement; REM, rapid eye movement. ...
... Moreover, the benefit of having napped following learning remained the next day, suggesting that deficits in the wake condition were not due to sleepiness or inattentiveness from having stayed awake during the nap opportunity. Taken in conjunction with other studies of this age range (Axelsson et al. 2018(Axelsson et al. , 2021Desrochers et al. 2016;He et al. 2020;Kurdziel et al. 2013Kurdziel et al. , 2018Lokhandwala & Spencer 2021;Sandoval et al. 2017;Spanò et al. 2018;Werchan et al. 2021;Williams & Horst 2014), these findings provide evidence that memories benefit from sleep in early childhood. ...
... However, studies assessing generalization of novel word labels to new examples show that naps have a negative same-day effect (Werchan & Gómez 2014) but confer a generalization benefit after 24 hours (Sandoval et al. 2017, Werchan et al. 2021. Likewise, emotional memories (faces paired with negative or positive auditory descriptions) do not benefit from a nap when memory is probed immediately after the nap/wake interval, whereas a significant memory benefit of having napped after learning is observed the next day (Kurdziel et al. 2018). The same pattern of delayed nap benefits was found in a study of procedural memory in 3-to-6-year-olds, who also showed a next-day benefit of napping for motor sequence learning despite no immediate post-nap benefit (Desrochers et al. 2016). ...
Sleep supports memory processing. In adults, memories are consolidated to a greater extent over an interval of sleep than over intervals spent awake. Behavioral evidence supports a benefit of sleep for memory consolidation in infants and children as well. While mechanistic studies are few, current evidence supports a role in memory consolidation for slow-wave sleep in particular. Mounting evidence suggests that these effects are modulated by brain development and may evolve from infancy to adulthood. Moreover, as reviewed here, sleep benefits in infancy and early childhood may be dependent on the type of learning and sleep bout (nap versus overnight). Understanding the typical development of sleep-related memory processing is critical to understanding compromised or atypical development and to informing sleep-focused interventions to improve memory during critical periods of learning across childhood.
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... These findings suggest that reliance on subcortical reward memory mechanisms may be greater earlier in development. Moreover, offline consolidation during sleep is particularly beneficial for learning and memory in children (Kurdziel et al., 2013(Kurdziel et al., , 2018Wilhelm et al., 2013). Still, the contributions of encoding and postencoding brain activity to reward-motivated memory across development have not been studied. ...
... Our results suggest that offline postencoding subcortical interactions involving the mesolimbic system may more strongly contribute to the formation of reward memory in younger individuals. This result aligns with prior work in children that has shown greater sleep-dependent learning and memory enhancements and increased gains in recall of prior learning in children, relative to adults, after sleep (Kurdziel et al., 2013(Kurdziel et al., , 2018Wilhelm et al., 2013). Both these studies of sleep and our work examining postencoding processes during awake rest suggest that offline consolidation processes may be particularly consequential for the formation of long-term memories in children, as more rapidly deployable online encoding mechanisms continue to develop. ...
Reward motivation enhances memory through interactions between mesolimbic, hippocampal, and cortical systems - both during and after encoding. Developmental changes in these distributed neural circuits may lead to age-related differences in reward-motivated memory and the underlying neural mechanisms. Converging evidence from cross-species studies suggests that subcortical dopamine signaling is increased during adolescence, which may lead to stronger memory representations of rewarding, relative to mundane, events and changes in the contributions of underlying subcortical and cortical brain mechanisms across age. Here, we used fMRI to examine how reward motivation influences the "online" encoding and "offline" post-encoding brain mechanisms that support long-term associative memory from childhood to adulthood in human participants of both sexes. We found that reward motivation led to both age-invariant enhancements and nonlinear age-related differences in associative memory after 24 hours. Furthermore, reward-related memory benefits were linked to age-varying neural mechanisms. During encoding, interactions between the prefrontal cortex and ventral tegmental area (VTA) were associated with better high-reward memory to a greater degree with increasing age. Pre- to post-encoding changes in functional connectivity between the anterior hippocampus and VTA were also associated with better high-reward memory, but more so at younger ages. Our findings suggest that there may be developmental differences in the contributions of offline subcortical and online cortical brain mechanisms supporting reward-motivated memory.SIGNIFICANCE STATEMENTA substantial body of research has examined the neural mechanisms through which reward influences memory formation in adults. However, despite extensive evidence that both reward processing and associative memory undergo dynamic change across development, few studies have examined age-related changes in these processes. We found both age-invariant and nonlinear age-related differences in reward-motivated memory. Moreover, our findings point to developmental differences in the processes through which reward modulates the prioritization of information in long-term memory - with greater early reliance on offline subcortical consolidation mechanisms and increased contribution of systems-level online encoding circuitry with increasing age. These results highlight dynamic developmental changes in the cognitive and neural mechanisms through which motivationally salient information is prioritized in memory from childhood to adulthood.
... For example, sleep-disordered breathing not only disrupts sleep but can also reduce SWS and declarative memory consolidation [74]. As children's naps contain high levels of SWS and SWS supports declarative memory [38,75], providing children with sleep difficulties the opportunity to nap could support declarative learning. Clear labelling and repetition of new words could help with long-term retention, particularly if children suffer from attention difficulties and if regular napping is less likely. ...
Children can easily link a novel word to a novel, unnamed object—something referred to as fast mapping. Despite the ease and speed with which children do this, their memories for novel fast-mapped words can be poor unless they receive memory supports such as further exposure to the words or sleep. Axelsson, Swinton, Winiger, and Horst (2018) found that 2.5-year-old children who napped after fast mapping had better retention of novel words than children who did not nap. Retention declined for those who did not nap. The children received no memory supports and determined the word–object mappings independently. Previous studies report enhanced memories after sleeping in children and adults, but the napping children’s retention in the Axelsson et al. study remained steady across time. We report a follow-up investigation where memory supports are provided after fast mapping to test whether memories would be enhanced following napping. Children’s retention of novel words improved and remained greater than chance; however, there was no nap effect with no significant difference between the children who napped and those who did not. These findings suggest that when memory supports are provided, retention improves, and the word–object mappings remain stable over time. When memory traces are weak and labile, such as after fast mapping, without further memory supports, sleeping soon after helps stabilise and prevent decay of word–object mappings.
... These findings suggest that reliance on subcortical reward memory mechanisms may be greater earlier in development. Moreover, offline consolidation during sleep is particularly beneficial for learning and memory in children (Kurdziel et al., 2013(Kurdziel et al., , 2018Wilhelm et al., 2013). Still, the contributions of encoding and post-encoding brain activity to reward-motivated memory across development have not been studied. ...
... Our results suggest that offline post-encoding subcortical interactions involving the mesolimbic system may more strongly contribute to the formation of reward memory in younger individuals. This result aligns with prior work in children that has shown greater sleepdependent learning and memory enhancements and increased gains in recall of prior learning in children, relative to adults, after sleep (Kurdziel et al., 2013(Kurdziel et al., , 2018Wilhelm et al., 2013). Both these studies of sleep and our work examining post-encoding processes during awake rest suggest that offline consolidation processes may be particularly consequential for the formation of long-term memories in children, as more rapidly deployable online encoding mechanisms continue to develop. ...
Reward motivation enhances memory through interactions between mesolimbic, hippocampal, and cortical systems — both during and after encoding. Developmental changes in these distributed neural circuits may lead to age-related differences in reward-motivated memory and the underlying neural mechanisms. Converging evidence from cross-species studies suggests that subcortical dopamine signaling is increased during adolescence, which may lead to stronger memory representations of rewarding, relative to mundane, events and changes in the contributions of underlying subcortical and cortical brain mechanisms across age. Here, we used fMRI to examine how reward motivation influences the “online” encoding and “offline” post-encoding brain mechanisms that support long-term associative memory from childhood to adulthood in human participants of both sexes. We found that reward motivation led to both age-invariant enhancements and nonlinear age-related differences in associative memory after 24 hours. Furthermore, reward-related memory benefits were linked to age-varying neural mechanisms. During encoding, interactions between the prefrontal cortex and ventral tegmental area (VTA) were associated with better high-reward memory to a greater degree with increasing age. Pre- to post-encoding changes in functional connectivity between the anterior hippocampus and VTA were also associated with better high-reward memory, but more so at younger ages. Our findings suggest that there may be developmental differences in the contributions of offline subcortical and online cortical brain mechanisms supporting reward-motivated memory.
Significance Statement
A substantial body of research has examined the neural mechanisms through which reward influences memory formation in adults. However, despite extensive evidence that both reward processing and associative memory undergo dynamic change across development, few studies have examined age-related changes in these processes. We found both age-invariant and nonlinear age-related differences in reward-motivated memory. Moreover, our findings point to developmental differences in the processes through which reward modulates the prioritization of information in long-term memory – with greater early reliance on offline subcortical consolidation mechanisms and increased contribution of systems-level online encoding circuitry with increasing age. These results highlight dynamic developmental changes in the cognitive and neural mechanisms through which motivationally salient information is prioritized in memory from childhood to adulthood.
... We have described general trends regarding sleep's influence on cognition, yet individual differences also impact sleep's effects. Specifically, nap habituality may predict the effects of wakefulness on memory in infants and young children ([7], but see [19]), and differences in spindle densities and SWA predict learning differences across same-age children [7,78]. ...
Emerging studies across learning domains have shed light on mechanisms underlying sleep’s benefits during numerous developmental periods. In this conceptual review, we survey recent studies of sleep and cognition across infancy, childhood, and adolescence. By summarizing recent findings and integrating across studies with disparate approaches, we provide a novel understanding of sleep’s role in human cognitive function. Collectively, these studies point to an interrelation between brain development, sleep, and cognition. Moreover, we point to gaps in our understanding, which inform the agenda for future research in developmental and sleep science.
... Participants Caregiver-child dyads were recruited as part of a larger study of the relation between sleep and learning in early childhood (Kurdziel, Kent, & Spencer, 2018). Participants were recruited from 30 preschools, including Head Start and private nonprofit preschools that serve families with lower income in western Massachusetts. ...
Objective:
The present study examined if caregivers' long work hours or shift work are related to children's sleep duration through the disruption of bedtime routines.
Method:
Work hours and schedules, bedtime routines and sleep (actigraph assessments) were examined in a sample of 250 caregivers and their preschool children.
Results:
Results revealed that consistent bedtime routines mediated the relationship between caregiver's work and children's sleep, such that longer hours and shift work predicted fewer routines that, in turn, predicted less child sleep.
Conclusion:
These results point to the crucial role of bedtime routines as a promising point of intervention for working parents. While caregivers may not be able to change their work hours or schedules, they can create more stable and consistent bedtime routines to mitigate the negative effects of their work on children's sleep.
