Sleep—A brain-state serving systems memory consolidation

Spontaneous memory reactivations can be decoded from EEG during SO-spindle complexes after learning word-image pairs using multivariate classification.

“Spontaneous memory reactivations can be decoded from the EEG signal during SO-spindle complexes after the participants had learned word-image pairs using multivariate classification 114 (Figure 3).”

• cites [114] 114. Khodagholy, D., Gelinas, J.N., and Buzsa ´ki, G. (2017). Learning- enhanced coupling between ripple oscillations in association cortices and hippocampus. Science 358, 369-372. 192. sourceDisputed

  The passages describing the methods and learning task state that this study recorded cortical and hippocampal activity in rats trained on a spatial cheeseboard maze, not EEG from participants learning word–image pairs. The reported result was stronger hippocampal–cortical ripple coupling during postlearning sleep; the source does not report decoding memory reactivations with multivariate classification. (LLM, conf=0.86)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

Slow oscillatory activity shows an inverted U-shaped trajectory peaking during early adolescence.

“Subsequently, slow oscillatory activity shows an inverted U-shaped trajectory peaking during early adolescence”

• cites [253] sourceDisputed

  The Introduction (p. 3) says slow wave activity reaches its maximum during childhood and declines throughout adolescence, contrary to a peak in early adolescence. The Age groups section (p. 5) places the maximum in the 5–8.9-year age group. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

Rat pups showed increases in spindle density in parallel with the emergence of hippocampal object-in-place memories during early development.

“Rat pups showed increases in spindle density in parallel with the emergence of hippocampal object-in-place memories during early development.275”

• cites [275] sourceDisputed

  The Results (Postnatal Hippocampal-Dependent Memory Onset; page unavailable) place the emergence of object-place recognition memory at P32. But the Discussion (page unavailable) explicitly reports no reliable developmental change in spindle density; it relates higher spindle density to better memory performance instead. That contradicts the claimed developmental increase in spindle density. (LLM, conf=0.89)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

The memory-related enhancement of hippocampal activation during sleep was still present when tested 1 week after the encoding session.

“The memory-related enhancement of hippocampal activation during sleep was still present when tested 1 week after the encoding session.”

• cites [272] sourcePartly supported

  The Results (fMRI results; page unavailable) report an association between temporal memory and hippocampal activation during sleep. The Methods (Procedure; page unavailable) place imaging after the one-week memory test, but also describe renewed exposure to the game and song before imaging. The paper therefore does not establish that an enhancement measured at encoding persisted unchanged for one week. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [273] sourceDisputed

  The Results section states that left hippocampal activation for newly learned words was associated with puppet-name memory only at the same-session test. At the one-week memory test, that association was not statistically significant (rs(30) = .33, p = .07). The paper therefore does not report that a memory-related hippocampal effect remained present at one week. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

A number of studies revealed signs of improved abstraction of rules and regularities at a later test session when participants had slept after encoding, compared with a wake control condition.

“a number of studies revealed signs of an improved abstraction of rules and regularities at a later test session when participants had slept after encoding of the stimulus materials, in comparison with a wake control condition.”

• cites [35] 35. Wagner, U., Gais, S., Haider, H., Verleger, R., and Born, J. (2004). Sleep in- spires insight. Nature 427, 352-355. https://doi.org/10.1038/nature02223. sourceNot checked — no full text of the source
• cites [36] 36. Lutz, N.D., Wolf, I., H€ ubner, S., and Rauss, K. (2018). Sleep strengthens predictive sequence coding. J. Neurosci. 17, 8989-9000. https://doi.org/ 10.1523/JNEUROSCI.1352-18.2018. sourceSupported
• cites [37] 37. Sanders, K.E.G., Osburn, S., Paller, K.A., and Beeman, M. (2019). Targeted memory reactivation during sleep improves next-day problem solving. Psychol. Sci. 30, 1616-1624. https://doi.org/10.1177/0956797619873344. sourcePartly supported

  The Abstract (page not provided) reports that numerous studies found better memory after sleep than after comparable time awake, and describes one study in which sleepers were more likely than awake participants to discover a hidden shortcut. It does not establish that a number of studies specifically found improved abstraction of rules and regularities at a later test; this paper’s own comparison is between cued and uncued puzzles among sleepers. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

Sleep-dependent gains in memories originally classified as non-hippocampus dependent can be abolished by suppressing hippocampal function during sleep.

“sleep-dependent gains in memories originally classified as ''non-hippocampus dependent'' can be abolished by suppressing hippocampal function during sleep.”

• cites [66] 66. Sawangjit, A., Oyanedel, C.N., Niethard, N., Salazar, C., Born, J., and In- ostroza, M. (2018). The hippocampus is crucial for forming non-hippo- campal long-term memory during sleep. Nature 564, 109-113. https:// doi.org/10.1038/s41586-018-0716-8. sourceNot checked — no full text of the source
• cites [74] 74. Schapiro, A.C., Reid, A.G., Morgan, A., Manoach, D.S., Verfaellie, M., and Stickgold, R. (2019). The hippocampus is necessary for the consol- idation of a task that does not require the hippocampus for initial learning. Hippocampus 29, 1091-1100. https://doi.org/10.1002/hipo.23101. sourcePartly supported

  The Discussion reports that patients with hippocampal damage learned the motor sequence task initially but, unlike controls, did not improve overnight. It also says the 24-hour design cannot establish whether the effect was specifically sleep-dependent. The study did not suppress hippocampal function during sleep; it compared patients with existing damage to controls. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Sleep exerts a more gradual ameliorating effect on the affective response to aversive pictures.

“with sleep exerting a more gradual ameliorating effect on the affective response.22,23”

• cites [22] 22. Zeng, S., Lin, X., Wang, J., and Hu, X. (2021a). Sleep's short-term mem- ory preservation and long-term affect depotentiation effect in emotional memory consolidation: behavioral and EEG evidence. Sleep 44, zsab155. https://doi.org/10.1093/sleep/zsab155. sourceNot checked — no full text of the source
• cites [23] 23. Cunningham, T.J., Stickgold, R., and Kensinger, E.A. (2022). Investi- gating the effects of sleep and sleep loss on the different stages of episodic emotional memory: A narrative review and guide to the future. Front. Behav. Neurosci. 16, 910317. https://doi.org/10.3389/fnbeh. 2022.910317. sourcePartly supported

  The Sleep post-retrieval/during reconsolidation section reports a reduced heart-rate response after a nap, supporting an ameliorating effect on responses to an aversive memory. But the stimulus was an autobiographical memory script, not aversive pictures, and the effect did not persist after one week; the passage does not establish a gradual effect. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

Tasks requiring motor adaptation might not benefit from sleep.

“tasks requiring motor adaptation (such as pursuit rotor task) might represent an exception as they do not seem to benefit from sleep.”

• cites [19] 19. Th€ urer, B., Weber, F.D., Born, J., and Stein, T. (2018). Variable training but not sleep improves consolidation of motor adaptation. Sci. Rep. 8, 15977. https://doi.org/10.1038/s41598-018-34225-w. sourcePartly supported

  The Discussion reports no significant sleep effect on consolidation of the force-field motor adaptation task. The Introduction notes that some visuomotor adaptation tasks do benefit from sleep, and the paper does not study the pursuit rotor task. It therefore supports the possibility of an exception, but not the broader implication about motor adaptation tasks or the named example. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

Studies experimentally enhancing or suppressing SO activity through closed-loop auditory or electrical stimulation support a causal role of SOs in enhancing consolidation.

“Studies experimentally enhancing or suppressing SO activity through closed-loop auditory or electrical stimulation support the view of a causal role of SOs in enhancing the consolidation process.”

• cites [50] 50. Marshall, L., Helgado ´ttir, H., Mo ¨lle, M., and Born, J. (2006). Boosting slow oscillations during sleep potentiates memory. Nature 444, 610-613. https://doi.org/10.1038/nature05278. sourceNot checked — no full text of the source
• cites [51] 51. Ngo, H.V., Martinetz, T., Born, J., and Mo ¨lle, M. (2013). Auditory closed- loop stimulation of the sleep slow oscillation enhances memory. Neuron 78, 545-553. https://doi.org/10.1016/j.neuron.2013.03.006. sourceNot checked — no full text of the source
• cites [52] 52. Harrington, M.O., and Cairney, S.A. (2021). Sounding it out: auditory stimulation and overnight memory processing. Curr. Sleep Med. Rep. 7, 112-119. https://doi.org/10.1007/s40675-021-00207-0. sourcePartly supported

  Box 1 reports that phase-locked auditory stimulation enhanced slow oscillations and improved overnight memory retention, supporting a causal role in consolidation. The Introduction reports improved retention after electrical induction of slow oscillations, but says those electrical studies were not synchronized with endogenous activity. The cited passages do not establish memory benefits from suppressing slow oscillations or from closed-loop electrical stimulation. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Contributions of REM sleep appear particularly strong for the consolidation of emotional materials.

“contributions of REM sleep appear to be particularly strong for the consolidation of emotional materials.”

• cites [25] 25. Nishida, M., Pearsall, J., Buckner, R.L., and Walker, M.P. (2009). REM sleep, prefrontal theta, and the consolidation of human emotional memory. Cereb. Cortex 19, 1158-1166. https://doi.org/10.1093/cercor/bhn155. sourceSupported
• cites [43] 43. Groch, S., Zinke, K., Wilhelm, I., and Born, J. (2015). Dissociating the con- tributions of slow-wave sleep and rapid eye movement sleep to emotional item and source memory. Neurobiol. Learn. Mem. 122, 122-130. https://doi.org/10.1016/j.nlm.2014.08.013. sourceNot checked — no full text of the source

Other studies revealed comparable benefits from sleep for neutral over emotional stimuli.

“other studies revealed comparable benefits from sleep for neutral over emotional stimuli.”

• cites [26] 26. Huguet, M., Payne, J.D., Kim, S.Y., and Alger, S.E. (2019). Overnight sleep benefits both neutral and negative direct associative and relational memory. Cogn. Affect. Behav. Neurosci. 19, 1391-1403. https://doi.org/ 10.3758/s13415-019-00746-8. sourceSupported
• cites [27] 27. Davidson, P., Jo ¨nsson, P., Carlsson, I., and Pace-Schott, E. (2021). Does sleep selectively strengthen certain memories over others based on emotion and perceived future relevance? Nat. Sci. Sleep 13, 1257- 1306. https://doi.org/10.2147/NSS.S286701. sourceSupported

Across experimental designs, post-encoding sleep enhances memory retrieval on non-verbal and verbal tasks assumed to assess hippocampus-dependent episodic memories.

“Across experimental designs, post-encoding sleep has been consistently found to enhance memory retrieval on non-verbal (e.g., object-location associations) and verbal (e.g., lists of word pairs) tasks assumed to assess hippocampus-dependent episodic types of memories.”

• cites [3] 3. Rasch, B., and Born, J. (2013). About sleep's role in memory. Physiol. Rev. 93, 681-766. https://doi.org/10.1152/physrev.00032.2012. sourceSupported
• cites [13] 13. Hanert, A., Weber, F.D., Pedersen, A., Born, J., and Bartsch, T. (2017). Sleep in humans stabilizes pattern separation performance. J. Neurosci. 37, 12238-12246. https://doi.org/10.1523/JNEUROSCI.1189-17.2017. sourcePartly supported

  The Introduction (page not supplied) says sleep following encoding appears to benefit hippocampus-dependent memory. The Results report better recognition of pictured objects after sleep than after wakefulness. The paper does not establish the claim across verbal and non-verbal tasks or experimental designs; its experiment did not test word pairs or object-location associations. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [14] 14. Zhang, J., Whitehurst, L.N., and Mednick, S.C. (2022). The role of sleep for episodic memory consolidation: stabilizing or rescuing? Neurobiol. Learn. Mem. 191, 107621. https://doi.org/10.1016/j.nlm.2022.107621. sourceNot checked — no full text of the source

REM sleep and associated theta activity was most consistently found to be involved in consolidation of emotional memories including social memory for a conspecific mouse.

“REM sleep and associated theta activity was most consistently found to be involved in the consolidation of emotional memories (e.g., fear conditioning 70,71 ) including social memory for a conspecific mouse.”

• cites [70] 70. Totty, M.S., Chesney, L.A., Geist, P.A., and Datta, S. (2017). Sleep-depen- dent oscillatory synchronization: A role in fear memory consolidation. Front. Neural Circuits 11, 49. https://doi.org/10.3389/fncir.2017.00049. sourcePartly supported

  The Abstract and Discussion link REM-sleep theta activity to emotional memory consolidation in a fear-conditioning study. The Methods identify the subjects as rats, and the paper does not address social memory for a conspecific mouse. It also does not establish that REM sleep and theta activity are the most consistently implicated factors across emotional-memory studies. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [71] 71. de Almeida-Filho, D.G., Koike, B.D.V., Billwiller, F., Farias, K.S., de Sales, I.R.P., Luppi, P.H., Ribeiro, S., and Queiroz, C.M. (2021). Hippocampus- retrosplenial cortex interaction is increased during phasic REM and con- tributes to memory consolidation. Sci. Rep. 11, 13078. https://doi.org/ 10.1038/s41598-021-91659-5. sourcePartly supported

  The Results section on fear memory expression and the Discussion link REM-sleep theta activity to contextual fear memory in rats. The paper does not study social memory for a conspecific mouse or establish that emotional memories are the memory type most consistently associated with REM sleep and theta activity. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [72] 72. Qin, H., Fu, L., Jian, T., Jin, W., Liang, M., Li, J., Chen, Q., Yang, X., Du, H., Liao, X., et al. (2022). REM sleep-active hypothalamic neurons may contribute to hippocampal social-memory consolidation. Neuron 110, 4000-4014.e6. https://doi.org/10.1016/j.neuron.2022.09.004. sourceNot checked — no full text of the source

Hippocampus often enters REM sleep while cortical areas remain in SWS.

“the hippocampus often enters REM sleep while cortical areas still remain in SWS”

• cites [9] 9. Dura ´n, E., Oyanedel, C.N., Niethard, N., Inostroza, M., and Born, J. (2018). Sleep stage dynamics in neocortex and hippocampus. Sleep 41, zsy060. https://doi.org/10.1093/sleep/zsy060. sourceNot checked — no full text of the source
• cites [10] 10. Emrick, J.J., Gross, B.A., Riley, B.T., and Poe, G.R. (2016). Different simultaneous sleep states in the hippocampus and neocortex. Sleep 39, 2201-2209. https://doi.org/10.5665/sleep.6326. sourcePartly supported

  The paper reports that, in rats, the hippocampus often entered REM before the neocortex. But the illustrated simultaneous state, described in “The Hippocampus and Neocortex Can Simultaneously Exist in Different Sleep States” and Figure 3 (page unavailable), is hippocampal REM with neocortical transition-to-REM (TR), not neocortical SWS. The claim therefore overstates which cortical state remained when hippocampal REM began. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

In comparison with post-encoding wakefulness, sleep increased recruitment of neocortical networks and functional connectivity between prefrontal cortex and hippocampus at a later retrieval test, especially with declarative memory.

“in comparison with post-encoding wakefulness, sleep increased the recruitment of neocortical networks and functional connectivity between prefrontal cortex and hippocampus at a later retrieval test, especially with declarative types of memory.”

• cites [33] 33. Gais, S., Albouy, G., Boly, M., Dang-Vu, T.T., Darsaud, A., Desseilles, M., Rauchs, G., Schabus, M., Sterpenich, V., Vandewalle, G., et al. (2007). Sleep transforms the cerebral trace of declarative memories. Proc. Natl. Acad. Sci. USA 104, 18778-18783. https://doi.org/10.1073/pnas. 0705454104. sourceNot checked — no full text of the source
• cites [34] 34. Cowan, E., Liu, A., Henin, S., Kothare, S., Devinsky, O., and Davachi, L. (2020). Sleep spindles promote the restructuring of memory representa- tions in ventromedial prefrontal cortex through enhanced hippocampal- cortical functional connectivity. J. Neurosci. 40, 1909-1919. https://doi. org/10.1523/JNEUROSCI.1946-19.2020. sourcePartly supported

  The Results section ('Overnight fast spindle density and next-day functional connectivity correlations: anterior hippocampus'; page unavailable) links greater overnight spindle density to stronger hippocampal–vmPFC connectivity when participants restudied object–word pairs learned before sleep. But it reports no significant overall connectivity difference between the presleep and morning lists. The comparison was with pairs encoded after sleep, not a matched post-encoding wakefulness condition, and the neural activity was measured during restudy rather than a later retrieval test; the cited passages also do not establish increased neocortical recruitment generally. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Inhibiting V1 engram cells during sleep induced a more generalized fear response irrespective of the visual cue presented.

“inhibiting V1 engram cells during sleep induced a more generalized fear response irrespective of the visual cue presented.”

• cites [87] 87. Clawson, B.C., Pickup, E.J., Ensing, A., Geneseo, L., Shaver, J., Gonza- lez-Amoretti, J., Zhao, M., York, A.K., Kuhn, F.R., Swift, K., et al. (2021). Causal role for sleep-dependent reactivation of learning-activated sen- sory ensembles for fear memory consolidation. Nat. Commun. 12, 1200. https://doi.org/10.1038/s41467-021-21471-2. sourceSupported

Multivariate pattern analyses have provided robust evidence that TMR induces a behaviorally relevant reactivation of cue-associated target information.

“Multivariate pattern analyses have provided robust evidence that TMR actually induces a behaviorally relevant reactivation of cue-associated target information.”

• cites [117] 117. Aston-Jones, G., and Bloom, F.E. (1981). Activity of norepinephrine-con- taining locus coeruleus neurons in behaving rats anticipates fluctuations in the sleep-waking cycle. J. Neurosci. 1, 876-886. https://doi.org/10. 1523/JNEUROSCI.01-08-00876.1981. 207. Berridge, C.W. (2008). Noradrenergic modulation of arousal. Brain Res. Rev. 58, 1-17. https://doi.org/10.1016/j.brainresrev.2007.10.013. 208. Rodenkirch, C., Liu, Y., Schriver, B.J., and Wang, Q. (2019). Locus coeru- leus activation enhances thalamic feature selectivity via norepinephrine regulation of intrathalamic circuit dynamics. Na sourceNot checked — no full text of the source
• cites [119] 119. Hobson, J.A. (2010). Sleeping, waking, and dreaming. In Encyclopedia of Behavioral Neuroscience (Elsevier Inc.), pp. 237-256. 221. sourceNot checked — no full text of the source
• cites [127] 127. Purcell, S.M., Manoach, D.S., Demanuele, C., Cade, B.E., Mariani, S., Cox, R., Panagiotaropoulou, G., Saxena, R., Pan, J.Q., Smoller, J.W., et al. (2017). Characterizing sleep spindles in 11,630 individuals from the National Sleep Research Resource. Nat. Commun. 8, 15930. https://doi.org/10.1038/ncomms15930. 253. sourceCould not verify

  The Results passages concern sleep-spindle measurements and associations, while Methods > Topographical spindle analyses describes identifying multivariate outliers, not multivariate pattern analysis of memory reactivation. Searches for TMR, cue-associated information, and behaviorally relevant reactivation found no passage in our copy addressing the claim. (LLM, conf=0.77)

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Several studies identified a causal relationship between reactivation and memory consolidation.

“several studies identified a causal relationship between reactivation and memory consolidation.”

• cites [83] 83. Dupret, D., O'Neill, J., Pleydell-Bouverie, B., and Csicsvari, J. (2010). The reorganization and reactivation of hippocampal maps predict spatial memory performance. Nat. Neurosci. 13, 995-1002. https://doi.org/10. 1038/nn.2599. sourcePartly supported

  The Discussion (page not provided) reports that reactivation predicts later spatial-memory performance and describes a functional link. It does not establish the claimed causal relationship: the authors say experimental evidence has been largely lacking and note that studies disrupting sharp-wave ripples could not rule out effects on consolidation through mechanisms other than reactivation. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [84] 84. Girardeau, G., Benchenane, K., Wiener, S.I., Buzsa ´ki, G., and Zugaro, M.B. (2009). Selective suppression of hippocampal ripples impairs spatial mem- ory. Nat. Neurosci. 12, 1222-1223. https://doi.org/10.1038/nn.2384. sourceNot checked — no full text of the source
• cites [85] 85. van de Ven, G.M., Trouche, S., McNamara, C.G., Allen, K., and Dupret, D. (2016). Hippocampal offline reactivation consolidates recently formed cell assembly patterns during sharp wave-ripples. Neuron 92, 968-974. https://doi.org/10.1016/j.neuron.2016.10.020. sourcePartly supported

  The Discussion reports that this study directly disrupted SWR reactivation and found impaired later reinstatement of newly formed hippocampal assembly patterns; it interprets this, together with earlier behavioral findings, as evidence that reactivation supports memory consolidation. But the Introduction and Discussion say earlier studies had not established whether their effects were caused by disrupted reactivation. This source therefore supports a causal role for reactivation in stabilizing the patterns, not the claim that several studies had identified that causal relationship. (LLM, conf=0.85)

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Intracranial recordings have provided corroborative evidence for stimulus-specific and sequential reactivations during human sleep.

“intracranial recordings have provided corroborative evidence for stimulus-specific and sequential reactivations during human sleep.”

• cites [110] 110. Wierzynski, C.M., Lubenov, E.V., Gu, M., and Siapas, A.G. (2009). State- dependent spike-timing relationships between hippocampal and pre- frontal circuits during sleep. Neuron 61, 587-596. https://doi.org/10. 1016/j.neuron.2009.01.011. 170. Eschenko, O., Magri, C., Panzeri, S., and Sara, S.J. (2012). Noradren- ergic neurons of the locus coeruleus are phase locked to cortical up- down states during sleep. Cereb. Cortex 22, 426-435. https://doi.org/ 10.1093/cercor/bhr121. 171. sourceNot checked — no full text of the source
• cites [112] 112. Helfrich, R.F., Lendner, J.D., Mander, B.A., Guillen, H., Paff, M., Mnatsa- kanyan, L., Vadera, S., Walker, M.P., Lin, J.J., and Knight, R.T. (2019). Bidirectional prefrontal-hippocampal dynamics organize information transfer during sleep in humans. Nat. Commun. 10, 3572. https://doi. org/10.1038/s41467-019-11444-x. 187. sourcePartly supported

  The Results report intracranial recordings during human sleep, and the Discussion interprets the findings as supporting hippocampal information reactivation and transfer. The paper does not report stimulus-specific or sequential reactivation of learned content; the Discussion notes that the study obtained no concomitant behavior. (LLM, conf=0.85)

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Offline memory reactivations and signs of sequential replay have been observed with noninvasive neuroimaging in humans.

“offline memory reactivations and recently also signs of sequential replay 104,105 have been observed with noninvasive neuroimaging in humans.”

• cites [104] 104. Cousins, J.N., El-Deredy, W., Parkes, L.M., Hennies, N., and Lewis, P.A. (2014). Cued memory reactivation during slow-wave sleep promotes explicit knowledge of a motor sequence. J. Neurosci. 34, 15870- 15876. https://doi.org/10.1523/JNEUROSCI.1011-14.2014. 125. Nicolas, J., King, B.R., Levesque, D., Lazzouni, L., Coffey, E., Swinnen, S., Doyon, J., Carrier, J., and Albouy, G. (2022). Sigma oscillations pro- tect or reinstate motor memory depending on their temporal coordination with slow waves. eLife 11, e73930. https://doi.org/10.7554/eLife.73930. 126. van Dongen, E.V., Takashima, A., Ba sourcePartly supported

  The Introduction (page unavailable) says human neuroimaging studies show reactivation of learning-related brain regions during post-encoding sleep. It describes reinstatement of neuronal firing sequences in rodents, not noninvasive observation of sequential replay in humans. Thus the reactivation portion is supported, but the human sequential-replay portion is not. (LLM, conf=0.86)

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• cites [105] 105. Batterink, L.J., Creery, J.D., and Paller, K.A. (2016). Phase of sponta- neous slow oscillations during sleep influences memory-related process- ing of auditory cues. J. Neurosci. 36, 1401-1409. https://doi.org/10. 1523/JNEUROSCI.3175-15.2016. 130. Bendor, D., and Wilson, M.A. (2012). Biasing the content of hippocampal replay during sleep. Nat. Neurosci. 15, 1439-1444. https://doi.org/10. 1038/nn.3203. 131. Kudrimoti, H.S., Barnes, C.A., and McNaughton, B.L. (1999). Reactiva- tion of hippocampal cell assemblies: effects of behavioral state, experi- ence, and EEG dynamics. J. Neurosci. 19, sourcePartly supported

  The Abstract reports offline reactivation of activity patterns in rat hippocampal recordings, and the Discussion mentions evidence of sequence reactivation during slow-wave sleep. Neither passage supports the claim that these observations were made in humans using noninvasive neuroimaging; the paper describes implanted tetrode recordings in rats (Recording protocol). (LLM, conf=0.88)

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Using machine learning classifiers, categories of previously encoded stimuli could be decoded solely from sleep EEG, revealing category-specific information is reactivated during sleep.

“Using machine learning classifiers, categories of previously encoded stimuli (e.g., faces vs. houses; objects vs. scenes) could be decoded solely from sleep EEG, revealing that category-specific information is reactivated during sleep.”

• cites [113] 113. Niethard, N., Burgalossi, A., and Born, J. (2017). Plasticity during sleep is linked to specific regulation of cortical circuit activity. Front. Neural Cir- cuits 11, 65. https://doi.org/10.3389/fncir.2017.00065. 188. Schreiner, T., Kaufmann, E., Noachtar, S., Mehrkens, J.H., and Staudigl, T. (2022). The human thalamus orchestrates neocortical oscillations dur- ing NREM sleep. Nat. Commun. 13, 5231. https://doi.org/10.1038/ s41467-022-32840-w. 189. Alizadeh, Z., Azimi, A., and Ghorbani, M. (2022). Enhancement of hippo- campal-thalamocortical temporal coordination during slow-frequency lon sourcePartly supported

  The ‘Sleep and Structural Synaptic Changes’ section reports reactivation of motor-task-related neurons in mice during sleep, supporting the general idea of sleep reactivation. Neither that section nor the EEG discussion in ‘Sleep’s Effect on Neuronal Excitability’ reports machine-learning decoding of previously encoded stimulus categories from sleep EEG; searches for those methods and categories found no such passage. Page numbers are unavailable in our copy. (LLM, conf=0.82)

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• cites [114] 114. Khodagholy, D., Gelinas, J.N., and Buzsa ´ki, G. (2017). Learning- enhanced coupling between ripple oscillations in association cortices and hippocampus. Science 358, 369-372. 192. sourceCould not verify

  Our copy reports NeuroGrid and hippocampal recordings in rats and stronger ripple coupling during sleep after spatial learning (Abstract; page unavailable). Searches for machine-learning classification, stimulus categories, and decoding from sleep EEG found no passage addressing those claims. (LLM, conf=0.76)

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There is evidence for hippocampus-independent replay in extrahippocampal sites, e.g., in superficial layers of medial entorhinal cortex and prefrontal cortex.

“There is, however, also evi-dence for hippocampus-independent replay in extrahippocampal sites, e.g., in superficial layers of medial entorhinal cortex and in prefrontal cortex.”

• cites [91] 91. O'Neill, J., Boccara, C.N., Stella, F., Schoenenberger, P., and Csicsvari, J. (2017). Superficial layers of the medial entorhinal cortex replay inde- pendently of the hippocampus. Science 355, 184-188. https://doi.org/ 10.1126/science.aag2787. sourceNot checked — no full text of the source
• cites [93] 93. Trettel, S.G., Trimper, J.B., Hwaun, E., Fiete, I.R., and Colgin, L.L. (2019). Grid cell co-activity patterns during sleep reflect spatial overlap of grid fields during active behaviors. Nat. Neurosci. 22, 609-617. https://doi. org/10.1038/s41593-019-0359-6. sourcePartly supported

  The Discussion reports that superficial-layer medial entorhinal grid cells rarely reactivate in coordination with hippocampal place cells, and the References identify a study of replay independent of the hippocampus in those layers. For medial prefrontal cortex, however, the Discussion describes activity correlated with hippocampal activity during replay, not hippocampus-independent replay. No page numbers are provided in our copy. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [98] 98. Kaefer, K., Nardin, M., Blahna, K., and Csicsvari, J. (2020). Replay of behavioral sequences in the medial prefrontal cortex during rule switch- ing. Neuron 106, 154-165.e6. https://doi.org/10.1016/j.neuron.2020. 01.015. sourceNot checked — no full text of the source

The beneficial effect of TMR during non-REM sleep on memory performance is well established across a variety of memory domains.

“The beneficial effect of TMR during non-REM sleep on memory performance is well established across a variety of memory domains, 115 including visuospatial 116-119 and verbal 120,121 declarative memory as well as motor learning.”

• cites [115] 115. Dickey, C.W., Verzhbinsky, I.A., Jiang, X., Rosen, B.Q., Kajfez, S., Stede- lin, B., Shih, J.J., Ben-Haim, S., Raslan, A.M., Eskandar, E.N., et al. (2022). Widespread ripples synchronize human cortical activity during sleep, waking, and memory recall. Proc. Natl. Acad. Sci. USA 119. e2107797119. https://doi.org/10.1073/pnas.2107797119. 193. Ferna ´ndez-Ruiz, A., Oliva, A., Fermino de Oliveira, E.F., Rocha-Almeida, F., Tingley, D., and Buzsa ´ki, G. (2019). Long-duration hippocampal sharp wave ripples improve memory. Science 364, 1082-1086. https://doi.org/ 10.1126/science.aax0758. 194. Ol sourceCould not verify

  The Discussion describes spontaneous ripple coupling during NREM sleep and a possible role in memory consolidation. The Results concern cued recall while patients were awake, not targeted memory reactivation during sleep. Searches for TMR and for the specified memory domains found no passage establishing a benefit across those domains. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [116] 116. Staresina, B.P., Bergmann, T.O., Bonnefond, M., van der Meij, R., Jen- sen, O., Deuker, L., Elger, C.E., Axmacher, N., and Fell, J. (2015). Hierar- chical nesting of slow oscillations, spindles and ripples in the human hip- pocampus during sleep. Nat. Neurosci. 18, 1679-1686. https://doi.org/ 10.1038/nn.4119. 198. Mo ¨lle, M., and Born, J. (2011). Slow oscillations orchestrating fast oscil- lations and memory consolidation. In Prog. Brain Res., 193, pp. 93-110. 199. Oyanedel, C.N., Dura ´n, E., Niethard, N., Inostroza, M., and Born, J. (2020). Temporal associations between sleep slow osci sourceCould not verify

  The Introduction says NREM sleep facilitates memory consolidation, and the Discussion reports that externally facilitating slow oscillations can boost later retrieval. Neither passage addresses targeted memory reactivation (TMR) or establishes its benefits across memory domains. Searches for TMR, reactivation cues, and the named domains found no passage that verifies the attributed claim. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• cites [117] 117. Aston-Jones, G., and Bloom, F.E. (1981). Activity of norepinephrine-con- taining locus coeruleus neurons in behaving rats anticipates fluctuations in the sleep-waking cycle. J. Neurosci. 1, 876-886. https://doi.org/10. 1523/JNEUROSCI.01-08-00876.1981. 207. Berridge, C.W. (2008). Noradrenergic modulation of arousal. Brain Res. Rev. 58, 1-17. https://doi.org/10.1016/j.brainresrev.2007.10.013. 208. Rodenkirch, C., Liu, Y., Schriver, B.J., and Wang, Q. (2019). Locus coeru- leus activation enhances thalamic feature selectivity via norepinephrine regulation of intrathalamic circuit dynamics. Na sourceNot checked — no full text of the source
• cites [118] 118. Sara, S.J. (2015). Locus Coeruleus in time with the making of memories. Curr. Opin. Neurobiol. 35, 87-94. https://doi.org/10.1016/j.conb.2015. 07.004. 210. Tronel, S., Feenstra, M.G., and Sara, S.J. (2004). Noradrenergic action in prefrontal cortex in the late stage of memory consolidation. Learn. Mem. 11, 453-458. https://doi.org/10.1101/lm.74504. 211. Menon, J.M.L., Nolten, C., Achterberg, E.J.M., Joosten, R.N.J.M.A., De- matteis, M., Feenstra, M.G.P., Drinkenburg, W.H.P., and Leenaars, C.H.C. (2019). Brain microdialysate monoamines in relation to circadian rhythms, sleep, and sleep dep sourceNot checked — no full text of the source
• cites [119] 119. Hobson, J.A. (2010). Sleeping, waking, and dreaming. In Encyclopedia of Behavioral Neuroscience (Elsevier Inc.), pp. 237-256. 221. sourceNot checked — no full text of the source
• cites [120] 120. Boyce, R., Glasgow, S.D., Williams, S., and Adamantidis, A. (2016). Causal evidence for the role of REM sleep theta rhythm in contextual memory consolidation. Science 352, 812-816. https://doi.org/10.1126/ science.aad5252. 222. sourceNot checked — no full text of the source
• cites [121] 121. Izawa, S., Chowdhury, S., Miyazaki, T., Mukai, Y., Ono, D., Inoue, R., Oh- mura, Y., Mizoguchi, H., Kimura, K., Yoshioka, M., et al. (2019). REM sleep-active MCH neurons are involved in forgetting hippocampus- dependent memories. Science 365, 1308-1313. https://doi.org/10. 1126/science.aax9238. 223. Tononi, G., and Cirelli, C. (2014). Sleep and the price of plasticity: from synaptic and cellular homeostasis to memory consolidation and integra- tion. Neuron 81, 12-34. https://doi.org/10.1016/j.neuron.2013.12.025. 224. Tononi, G., and Cirelli, C. (2003). Sleep and synaptic homeostasis: a hy sourcePartly supported

  In “Synaptic renormalization by down-selection and memory” (page unavailable), the review reports experimental benefits of cuing during sleep and discusses selective enhancement in a model of declarative learning. It does not establish that targeted memory reactivation during non-REM sleep benefits performance across the range of memory domains claimed; its discussion of visuomotor learning concerns sleep benefits generally, not cuing. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Inducing reactivations of V1 engram cells during sleep after conditioning enhanced formation of a cue-specific fear memory.

“Inducing reactivations of the V1 engram cells during sleep after conditioning enhanced the formation of a cue-specific fear memory.”

• cites [87] 87. Clawson, B.C., Pickup, E.J., Ensing, A., Geneseo, L., Shaver, J., Gonza- lez-Amoretti, J., Zhao, M., York, A.K., Kuhn, F.R., Swift, K., et al. (2021). Causal role for sleep-dependent reactivation of learning-activated sen- sory ensembles for fear memory consolidation. Nat. Commun. 12, 1200. https://doi.org/10.1038/s41467-021-21471-2. sourcePartly supported

  The Introduction and Results (Fig. 7; page unavailable) report that V1 engram neurons reactivate during post-conditioning sleep and that inhibiting them during sleep disrupts cue-specific fear memory consolidation. The paper does not report that experimentally inducing reactivation during sleep enhanced fear memory; its optogenetic activation experiments assessed other outcomes or conditions. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Memory reactivation is observed in many brain regions beyond hippocampus, including sensory, motor, entorhinal, parietal, prefrontal, and subcortical areas.

“memory reactivation is a far more ubiquitous phenomenon, as it is observed in many brain regions, ranging from early sensory [87][88][89] and motor cortices, 65,90 over medial entorhinal cortex [91][92][93] and higher-order association areas like the parietal [94][95][96] and prefrontal cortices [97][98][99] to different subcortical areas.”

• cites [87] 87. Clawson, B.C., Pickup, E.J., Ensing, A., Geneseo, L., Shaver, J., Gonza- lez-Amoretti, J., Zhao, M., York, A.K., Kuhn, F.R., Swift, K., et al. (2021). Causal role for sleep-dependent reactivation of learning-activated sen- sory ensembles for fear memory consolidation. Nat. Commun. 12, 1200. https://doi.org/10.1038/s41467-021-21471-2. sourceSupported
• cites [88] 88. Ji, D., and Wilson, M.A. (2007). Coordinated memory replay in the visual cortex and hippocampus during sleep. Nat. Neurosci. 10, 100-107. https://doi.org/10.1038/nn1825. sourceNot checked — no full text of the source
• cites [89] 89. Rothschild, G., Eban, E., and Frank, L.M. (2017). A cortical-hippocampal- cortical loop of information processing during memory consolidation. Nat. Neurosci. 20, 251-259. https://doi.org/10.1038/nn.4457. sourceSupported

Parallel recordings revealed close temporal coordination of reactivation across hippocampus and cortical/subcortical regions.

“parallel recordings from both hippocampus and cortical or subcortical regions revealed a close temporal coordination of reactivation across sites 92,100,102”

• cites [92] 92. O ´lafsdo ´ttir, H.F., Carpenter, F., and Barry, C. (2016). Coordinated grid and place cell replay during rest. Nat. Neurosci. 19, 792-794. https:// doi.org/10.1038/nn.4291. sourceSupported
• cites [100] 100. Maquet, P., Laureys, S., Peigneux, P., Fuchs, S., Petiau, C., Phillips, C., Aerts, J., Del Fiore, G., Degueldre, C., Meulemans, T., et al. (2000). Expe- rience-dependent changes in cerebral activation during human REM sleep. Nat. Neurosci. 3, 831-836. https://doi.org/10.1038/77744. 107. Peigneux, P., Laureys, S., Fuchs, S., Collette, F., Perrin, F., Reggers, J., Phil- lips, C., Degueldre, C., Del Fiore, G., Aerts, J., et al. (2004). Are spatial mem- ories strengthened in the human hippocampus during slow wave sleep? Neuron 44, 535-545. https://doi.org/10.1016/j.neuron.2004.10.007. 108. Be sourceNot checked — no full text of the source
• cites [102] 102. Antony, J.W., Gobel, E.W., O'Hare, J.K., Reber, P.J., and Paller, K.A. (2012). Cued memory reactivation during sleep influences skill learning. Nat. Neurosci. 15, 1114-1116. https://doi.org/10.1038/nn.3152. 117. Cairney, S.A., Guttesen, A.A ´.V., El Marj, N., and Staresina, B.P. (2018). Memory consolidation is linked to spindle-mediated information pro- cessing during sleep. Curr. Biol. 28, 948-954.e4. https://doi.org/10. 1016/j.cub.2018.01.087. 118. Rasch, B., B€ uchel, C., Gais, S., and Born, J. (2007). Odor cues during slow-wave sleep prompt declarative memory consolidation. Science 31 sourceCould not verify

  The Online Methods, ‘Sleep Recording’ section (page not provided) describes scalp EEG recordings, not parallel recordings from the hippocampus and cortical or subcortical sites. The copy does not report temporal coordination of reactivation across those sites; searches for parallel recordings and hippocampal–cortical coordination found no such passage. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

In both of these studies, the accuracy of the classifier to correctly identify the previously encoded stimulus category was positively correlated to later memory recall.

“In both of these studies, the accuracy of the classifier to correctly identify the previously encoded stimulus category was positively correlated to later memory recall”

• cites [113] 113. Niethard, N., Burgalossi, A., and Born, J. (2017). Plasticity during sleep is linked to specific regulation of cortical circuit activity. Front. Neural Cir- cuits 11, 65. https://doi.org/10.3389/fncir.2017.00065. 188. Schreiner, T., Kaufmann, E., Noachtar, S., Mehrkens, J.H., and Staudigl, T. (2022). The human thalamus orchestrates neocortical oscillations dur- ing NREM sleep. Nat. Commun. 13, 5231. https://doi.org/10.1038/ s41467-022-32840-w. 189. Alizadeh, Z., Azimi, A., and Ghorbani, M. (2022). Enhancement of hippo- campal-thalamocortical temporal coordination during slow-frequency lon sourceCould not verify

  The Conclusion discusses sleep-related changes in cortical activity and their possible role in strengthening memories, but does not report classifier results. Searches for classifier accuracy, encoded stimulus categories, and correlations with later recall found no passage in our copy addressing the claimed finding in either study. (LLM, conf=0.74)

  Experimental — accuracy not yet measured
• cites [114] 114. Khodagholy, D., Gelinas, J.N., and Buzsa ´ki, G. (2017). Learning- enhanced coupling between ripple oscillations in association cortices and hippocampus. Science 358, 369-372. 192. sourceCould not verify

  The study description and results (indexed under Abstract; page unavailable) concern rats learning reward locations and increased hippocampal–cortical ripple coupling after training. Searches for classifier accuracy, encoded stimulus categories, and subsequent recall found no passage reporting the claimed correlation. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

Reactivation of task-relevant regions was particularly prominent during sleep oscillatory events linked to memory consolidation, such as spindles and SOs.

“The reactivation of task-relevant regions was found to be particular prominent during sleep oscillatory events linked to memory consolidation, such as spindles and SOs.”

• cites [108] 108. Davidson, T.J., Kloosterman, F., and Wilson, M.A. (2009). Hippocampal replay of extended experience. Neuron 63, 497-507. https://doi.org/10. 1016/j.neuron.2009.07.027. 149. O ´lafsdo ´ttir, H.F., Barry, C., Saleem, A.B., Hassabis, D., and Spiers, H.J. (2015). Hippocampal place cells construct reward related sequences through unexplored space. eLife 4, e06063. https://doi.org/10.7554/eL- ife.06063. 150. Stella, F., Baracskay, P., O'Neill, J., and Csicsvari, J. (2019). Hippocam- pal reactivation of random trajectories resembling brownian diffusion. Neuron 102, 450-461.e7. e457. https://doi. sourcePartly supported

  The Discussion (page not provided) reports coordinated memory reactivation in the hippocampus and visual cortex during sleep up-states associated with slow oscillations. It does not say that reactivation was particularly prominent during spindles, or establish the claimed prominence across both types of event. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [109] 109. Roumis, D.K., and Frank, L.M. (2015). Hippocampal sharp-wave ripples in waking and sleeping states. Curr. Opin. Neurobiol. 35, 6-12. https:// doi.org/10.1016/j.conb.2015.05.001. 156. Tang, W., Shin, J.D., Frank, L.M., and Jadhav, S.P. (2017). Hippocampal- prefrontal reactivation during learning is stronger in awake compared with sleep states. J. Neurosci. 37, 11789-11805. https://doi.org/10. 1523/JNEUROSCI.2291-17.2017. 157. de Sousa, A.F., Cowansage, K.K., Zutshi, I., Cardozo, L.M., Yoo, E.J., Leutgeb, S., and Mayford, M. (2019). Optogenetic reactivation of memory ensembles in the retros sourcePartly supported

  The Role of Sleep SWR Replay reports cortical reactivation during slow-wave sleep, and The Fidelity of Replay says prefrontal reactivation strength peaked near a transition in cortical slow oscillations. The paper mentions sleep spindles in its references, but our copy does not say that task-related reactivation was particularly prominent during spindles. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Reactivation and replay in both wake and sleep states display largely similar features.

“In general, reactivation and replay in both wake and sleep states display largely similar features.”

• cites [140] sourceSupported

Signs of reward-related biasing of reactivations during sleep and wake have been observed in humans using fMRI.

“Signs of reward-related biasing of reactivations during sleep and wake have been likewise observed in humans using fMRI.”

• cites [111] 111. Adamantidis, A.R., Gutierrez Herrera, C., and Gent, T.C. (2019). Oscil- lating circuitries in the sleeping brain. Nat. Rev. Neurosci. 20, 746-762. https://doi.org/10.1038/s41583-019-0223-4. 172. Fellin, T., Halassa, M.M., Terunuma, M., Succol, F., Takano, H., Frank, M., Moss, S.J., and Haydon, P.G. (2009). Endogenous nonneuronal mod- ulators of synaptic transmission control cortical slow oscillations in vivo. Proc. Natl. Acad. Sci. USA 106, 15037-15042. https://doi.org/10.1073/ pnas.0906419106. 173. Crunelli, V., and Hughes, S.W. (2010). The slow (<1 Hz) rhythm of non- REM sleep: a dialog sourceNot checked — no full text of the source
• cites [147] sourcePartly supported

  The Results report preferential reactivation of high-reward contexts in human hippocampal fMRI data during post-learning rest, supporting the wakeful-rest portion of the claim. The Discussion’s references to sleep concern rodent replay and human intracranial recordings, not reward-biased reactivation during sleep measured with human fMRI. Page numbers are unavailable in our copy. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

TMR in rodent studies confirmed that auditory cues paired to specific trajectories during spatial learning enhance hippocampal reactivation of the associated trajectory when delivered during subsequent sleep.

“TMR has also been used in rodent studies, confirming that auditory cues, which had been paired to specific trajectories dur-ing a spatial learning task, enhance hippocampal reactivation of the associated trajectory when delivered during subsequent sleep.”

• cites [89] 89. Rothschild, G., Eban, E., and Frank, L.M. (2017). A cortical-hippocampal- cortical loop of information processing during memory consolidation. Nat. Neurosci. 20, 251-259. https://doi.org/10.1038/nn.4457. sourcePartly supported

  The Results describe rats learning a sound-guided Y-track task and show that sounds delivered during sleep biased auditory-cortex patterns that predicted subsequent hippocampal CA1 activity. They do not establish enhanced reactivation of the trajectory associated with a cue: the Results state that sound identity could not be significantly decoded from CA1 ensembles. The Discussion distinguishes this paper’s finding from a previous study showing that sleep sounds can bias hippocampal reactivation. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [130] 130. Friedrich, M., Mo ¨lle, M., Friederici, A.D., and Born, J. (2020). Sleep- dependent memory consolidation in infants protects new episodic mem- ories from existing semantic memories. Nat. Commun. 11, 1298. https:// doi.org/10.1038/s41467-020-14850-8. 271. sourceCould not verify

  The Introduction and Discussion discuss memory during infant sleep, but do not describe rodent targeted memory reactivation. Searches for auditory cues paired with spatial trajectories and for rodent targeted memory reactivation found no passage addressing the claimed hippocampal reactivation effect. The retrieved passages have no page numbers. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

Awake memory reactivations have been shown to enhance subsequent recall performance.

“awake memory reactivations have been shown to enhance subsequent recall performance.”

• cites [83] 83. Dupret, D., O'Neill, J., Pleydell-Bouverie, B., and Csicsvari, J. (2010). The reorganization and reactivation of hippocampal maps predict spatial memory performance. Nat. Neurosci. 13, 995-1002. https://doi.org/10. 1038/nn.2599. sourcePartly supported

  The Results section (‘Reactivation of waking firing patterns during rest’; page unavailable) reports that goal-related reactivation during rest predicted subsequent spatial-memory performance, and the Discussion says reactivation predicted how well a location was remembered. The paper does not show that awake reactivations themselves enhanced recall: the reported relationship is predictive, and the rest-period events are not identified as exclusively awake. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [151] sourcePartly supported

  In “Linking awake replay and memory consolidation” (page unavailable), the review reports that the strength of awake reactivation predicted subsequent memory-task performance in animals. That supports an association, but not the claim that reactivation was shown to enhance subsequent recall performance: the passage does not establish a causal improvement or identify a recall measure. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [152] sourceSupported

This time course fits with findings in humans of preferential time windows for memory reactivations 3 and 6 h into sleep after encountering a novel visuospatial memory paradigm.

“This time course fits with findings in humans of preferential time windows for memory reactivations 3 and 6 h into sleep after encountering a novel visuospatial memory paradigm.”

• cites [113] 113. Niethard, N., Burgalossi, A., and Born, J. (2017). Plasticity during sleep is linked to specific regulation of cortical circuit activity. Front. Neural Cir- cuits 11, 65. https://doi.org/10.3389/fncir.2017.00065. 188. Schreiner, T., Kaufmann, E., Noachtar, S., Mehrkens, J.H., and Staudigl, T. (2022). The human thalamus orchestrates neocortical oscillations dur- ing NREM sleep. Nat. Commun. 13, 5231. https://doi.org/10.1038/ s41467-022-32840-w. 189. Alizadeh, Z., Azimi, A., and Ghorbani, M. (2022). Enhancement of hippo- campal-thalamocortical temporal coordination during slow-frequency lon sourceCould not verify

  The section on excitation/inhibition balance discusses replay of newly encoded memories during sleep, but it does not report preferential reactivation windows in humans. Searches for visuospatial learning and reactivation at 3 and 6 hours found no passage addressing those details; the copy’s relevant studies instead concern cortical activity in mice. (LLM, conf=0.74)

  Experimental — accuracy not yet measured

Memory reactivations occur preferentially in non-REM sleep.

“Memory reactivations occur preferentially in non-REM sleep.”

• cites [131] 131. Friedrich, M., Mo ¨lle, M., Born, J., and Friederici, A.D. (2022). Memory for nonadjacent dependencies in the first year of life and its relation to sleep. Nat. Commun. 13, 7896. https://doi.org/10.1038/s41467-022-35558-x. 272. Mooney, L.N., Johnson, E.G., Prabhakar, J., and Ghetti, S. (2021). Mem- ory-related hippocampal activation during sleep and temporal memory in toddlers. Dev. Cogn. Neurosci. 47, 100908. https://doi.org/10.1016/j. dcn.2020.100908. 273. Johnson, E.G., Mooney, L., Graf Estes, K., Nordahl, C.W., and Ghetti, S. (2021). Activation for newly learned words in left medial-t sourceCould not verify

  The Introduction (page unavailable) describes sleep spindles during non-REM sleep as involved in memory consolidation, and the Results relate spindle activity to later memory. Neither passage addresses memory reactivation or whether it occurs preferentially in non-REM sleep. Searches for “reactivation” and a REM-versus-non-REM comparison found no passage that settles the claim. (LLM, conf=0.73)

  Experimental — accuracy not yet measured
• cites [100] 100. Maquet, P., Laureys, S., Peigneux, P., Fuchs, S., Petiau, C., Phillips, C., Aerts, J., Del Fiore, G., Degueldre, C., Meulemans, T., et al. (2000). Expe- rience-dependent changes in cerebral activation during human REM sleep. Nat. Neurosci. 3, 831-836. https://doi.org/10.1038/77744. 107. Peigneux, P., Laureys, S., Fuchs, S., Collette, F., Perrin, F., Reggers, J., Phil- lips, C., Degueldre, C., Del Fiore, G., Aerts, J., et al. (2004). Are spatial mem- ories strengthened in the human hippocampus during slow wave sleep? Neuron 44, 535-545. https://doi.org/10.1016/j.neuron.2004.10.007. 108. Be sourceNot checked — no full text of the source

Generalization of a specific contextual fear memory to a similar context, but not consolidation of individual contexts, critically depended on the co-reactivation of engram ensembles for both context experiences during sleep.

“Moreover, generalization of a specific contextual fear memory to a similar context, but not consolidation of individual contexts, critically depended on the co-reactivation of engram ensembles for both context experiences during sleep 97 (Figure 1).”

• cites [97] 97. Aly, M.H., Abdou, K., Okubo-Suzuki, R., Nomoto, M., and Inokuchi, K. (2022). Selective engram coreactivation in idling brain inspires implicit learning. Proc. Natl. Acad. Sci. USA 119. e2201578119. https://doi.org/ 10.1073/pnas.2201578119. sourceSupported

Accumulating evidence indicates the importance of precise phase-amplitude coupling between classical fast spindles and SO upstates for effective consolidation.

“As to the classical fast spindle, accumulating evidence indicates the importance of precise phase-amplitude coupling between these spindles and SO upstates for effective consolidation.61,186”

• cites [61] 61. Helfrich, R.F., Mander, B.A., Jagust, W.J., Knight, R.T., and Walker, M.P. (2018). Old brains come uncoupled in sleep: slow wave-spindle syn- chrony, brain atrophy, and forgetting. Neuron 97, 221-230.e4. https:// doi.org/10.1016/j.neuron.2017.11.020. sourceSupported
• cites [186] sourceSupported

In the same experiments, suppression during delta wave upstates improved memory.

“By contrast, suppression during delta wave upstates improved memory.”

• cites [178] sourceSupported

Noninvasive brain stimulation during sleep to induce slow waves enhances memory retention.

“enhanced memory retention after applying noninvasive brain stimulation during sleep to induce slow waves.[50][51][52]63,175”

• cites [50] 50. Marshall, L., Helgado ´ttir, H., Mo ¨lle, M., and Born, J. (2006). Boosting slow oscillations during sleep potentiates memory. Nature 444, 610-613. https://doi.org/10.1038/nature05278. sourceNot checked — no full text of the source
• cites [51] 51. Ngo, H.V., Martinetz, T., Born, J., and Mo ¨lle, M. (2013). Auditory closed- loop stimulation of the sleep slow oscillation enhances memory. Neuron 78, 545-553. https://doi.org/10.1016/j.neuron.2013.03.006. sourceNot checked — no full text of the source
• cites [52] 52. Harrington, M.O., and Cairney, S.A. (2021). Sounding it out: auditory stimulation and overnight memory processing. Curr. Sleep Med. Rep. 7, 112-119. https://doi.org/10.1007/s40675-021-00207-0. sourceSupported

In rats trained to control individual motor neurons, suppressing motor cortex activity during the SO upstate impaired memory for the trained motor neuron response.

“Suppressing motor cortex activity during the SO upstate, as expected, impaired memory for the trained motor neuron response.”

• cites [178] sourceSupported

Sleep replay features a less faithful recapitulation of previous experience compared with wake replay.

“Generally, sleep replay appears to feature a less faithful recapitulation of previous experience compared with wake replay.137,[154][155][156]”

• cites [137] sourceSupported
• cites [154] sourceCould not verify

  The indexed passages (labeled Abstract; page unavailable) discuss replay during waking immobility and sleep, and report increased maze-related sequences from pre- to postexperience sleep. Searches for replay fidelity and wake-versus-sleep comparisons found no passage saying that sleep replay recapitulates experience less faithfully than wake replay. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [155] sourceSupported

Stimulating somatostatin-positive interneurons increased slow-wave amplitudes and their slopes.

“Stimulating somatostatin positive interneurons increased slow-wave amplitudes and their slopes.174”

• cites [174] sourcePartly supported

  The Results section on chemogenetic activation (page unavailable) reports a 16.8% increase in slow-wave slope after SOM-positive cell activation. It also reports increased slow-wave activity and incidence, but does not establish that the amplitudes of individual slow waves increased; that part of the claim is unsupported. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

Spindles also reach the hippocampus possibly via the nucleus reuniens.

“They also reach the hippocampus possibly via the nucleus reuniens.179”

• cites [179] sourcePartly supported

  The Introduction (page unavailable) says spindle oscillations are coordinated with hippocampal sharp-wave ripples and that nucleus reuniens connects CA1 and mPFC, making it a candidate to coordinate their activity. The Discussion (page unavailable) also reports spindle–CA1 correlations. These passages support an association and a possible role for reuniens, but do not establish that spindles reach the hippocampus via that route. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Intrathalamic recordings from epilepsy patients suggest additional thalamic contributions to SO-spindle events, specifically from anterior thalamic nuclei (ANT).

“While SO-spindle events are traditionally assumed to originate at the cortical level, i.e., from cortical SO driving thalamic spindles, intrathalamic recordings from epilepsy patients suggest additional thalamic contributions, specifically from anterior thalamic nuclei (ANT 188 ).”

• cites [188] sourceSupported

Somatostatin-positive interneurons inhibiting pyramidal dendrites appear to be specifically implicated in the induction of downstates, apart from thalamic afferents and cortical astrocytes.

“Apart from thalamic afferents and cortical astrocytes, somatostatin positive interneurons inhibiting pyramidal dendrites appear to be specifically implicated in the induction of downstates.161,172,173”

• cites [161] sourceNot checked — no full text of the source
• cites [172] sourcePartly supported

  The Abstract and Results (page not provided) show that cortical astrocytes modulate slow oscillations and that impaired gliotransmission prolongs down-states. The paper does not establish that somatostatin-positive interneurons inhibit pyramidal dendrites or specifically induce downstates; the cited source supports only the astrocyte part of the sentence. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [173] sourcePartly supported

  The Neocortex section (page unavailable) identifies layer-5 Martinotti cells as cells that intrinsically generate UP and DOWN states, providing limited support for interneuron involvement. It does not identify them as somatostatin-positive, describe inhibition of pyramidal dendrites, or specifically implicate them in inducing DOWN states; the passage instead discusses a current involved in generating their UP states. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

In mice, optogenetically reactivating retrosplenial engram ensembles representing a recently acquired contextual fear memory produced a memory trace displaying all features of a remote, systems-consolidated memory, including higher engagement of neocortical areas during retrieval, contextual generalization, and decreased hippocampal dependence.

“In mice, optogenetically reactivating retrosplenial engram ensembles representing a recently acquired contextual fear memory produced a memory trace displaying all features of a remote, systems consolidated memory including higher engagement of neocortical areas during retrieval, contextual generalization, and decreased hippocampal dependence.157”

• cites [157] sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

In human EEG, spindle amplitudes during post-learning sleep specifically over areas engaged in prior encoding were most distinctly correlated with later retrieval performance.

“Thus, using a temporospatial association task, Petzka et al. 182 observed in human EEG recordings that spindle amplitudes during postlearning sleep specifically over those areas that had engaged in prior encoding of the task were most distinctly correlated with later retrieval performance.”

• cites [182] sourceSupported

The anterior thalamus might be specifically involved in coordinating hippocampal memory replay with thalamocortical activity.

“The anterior thalamus might be specifically involved in coordinating hippocampal memory replay with thalamocortical activity.189”

• cites [189] sourcePartly supported

  The Abstract and Discussion report that anterodorsal thalamic spindles are temporally coupled with CA1 activity and hippocampal ripples, with stronger coupling after spatial exploration. This supports a possible coordinating role, but the paper measures spiking and ripples, not hippocampal memory replay itself. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

The effect of optogenetic reactivation of retrosplenial engram ensembles on producing a remote memory trace only appeared when stimulation was performed during sleep or light anesthesia, but not during wakefulness.

“Intriguingly, this effect only appeared when stimulation was performed during sleep or light anesthesia, but not during wakefulness.”

• cites [157] sourceSupported

Brain oscillations with a shared frequency synchronize membrane potential depolarization and hyperpolarization across extended neuronal networks, thereby achieving precise temporal synchronization of distributed neuronal reactivations.

“This is generally achieved by brain oscillations that, with a shared frequency, synchronize membrane potential depolarization and hyperpolarization across extended neuronal networks.159,160”

• cites [159] sourceNot checked — no full text of the source
• cites [160] sourcePartly supported

  In the Abstract and Conclusions (pages unavailable), Fries describes rhythmic excitation and inhibition coordinated between pre- and postsynaptic groups, producing precisely timed neuronal communication. The paper supports coordination between connected groups, but does not establish synchronized membrane-potential depolarization and hyperpolarization across extended networks generally, or specifically describe distributed neuronal reactivations. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

In humans, higher spindle density during sleep after learning object-word pairs and scene-word pairs increased functional connectivity between hippocampus and neocortex during recall testing on the next day, with effect pertaining to anterior hippocampus-vmPFC for object-word pairs and posterior hippocampus-posteromedial cortex for scene-word pairs.

“In humans, higher spindle density during sleep after learning of object-word pairs and scene-word pairs increased functional connectivity between hippocampus and neocortex during recall testing on the next day, with this effect pertaining to functional connectivity between anterior hippocampus and ventromedial prefrontal cortex (vmPFC) for object-word pairs, and between posterior hippocampus and”

• cites [34] 34. Cowan, E., Liu, A., Henin, S., Kothare, S., Devinsky, O., and Davachi, L. (2020). Sleep spindles promote the restructuring of memory representa- tions in ventromedial prefrontal cortex through enhanced hippocampal- cortical functional connectivity. J. Neurosci. 40, 1909-1919. https://doi. org/10.1523/JNEUROSCI.1946-19.2020. sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

Sleep spindles are associated with signs of increased synchronization between hippocampal and neocortical activity in both mice and humans.

“Indeed, sleep spindles have been found to be associated with signs of increased synchronization between hippocampal and neocortical activity in both mice 189 and humans.34”

• cites [189] sourceSupported
• cites [34] 34. Cowan, E., Liu, A., Henin, S., Kothare, S., Devinsky, O., and Davachi, L. (2020). Sleep spindles promote the restructuring of memory representa- tions in ventromedial prefrontal cortex through enhanced hippocampal- cortical functional connectivity. J. Neurosci. 40, 1909-1919. https://doi. org/10.1523/JNEUROSCI.1946-19.2020. sourceSupported

Ripples induced optogenetically in CA2 neurons following encoding of a social memory task enhanced recall 24 h later.

“In a recent study, ripples induced optogenetically in CA2 neurons following encoding of a social memory task enhanced recall 24 h later.194”

• cites [194] sourceSupported

Hippocampal ripples can facilitate cortical SOs.

“However, hippocampal ripples can facilitate cortical SOs.”

• cites [199] sourceSupported
• cites [200] sourceNot checked — no full text of the source

Field potentials and unit activity during phasic REMs resemble those observed during image presentation in the wake state.

“Field potentials and unit activity during phasic REMs resemble those observed during image presentation in the wake state.217”

• cites [217] sourceSupported

At the morphological level, synaptic downscaling during sleep is not ubiquitous but may spare some select synapses that are particularly large or were involved in prior encoding, resulting in increased connectivity at these synapses.

“At the morphological level, there is evidence that synaptic downscaling during sleep is not ubiquitous but may spare some select synapses that are particularly large or were involved in prior encoding, resulting in increased connectivity at these synapses 163,164,228,231 (Figure 2C).”

• cites [163] sourcePartly supported

  The Abstract reports that sleep-related downscaling is selective and spares some large synapses. It does not establish that the spared synapses were involved in prior encoding or that their connectivity increased; it says only that a few synapses might upscale during sleep. No page numbers are available in our copy. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [164] sourcePartly supported

  The paper reports that sleep after motor learning promotes new spine formation on selected dendritic branches in mouse motor cortex, and that sleep improves the survival of some new spines (Abstract; page unavailable). This supports selective increases in learning-related connectivity, but the paper does not show that particularly large synapses are spared or directly test whether synaptic downscaling spares those synapses. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [228] sourcePartly supported

  The imaging passage (labeled Abstract in our copy; no page given) shows that sleep-related changes were not uniform: some spines gained GluA1, and low-GluA1 spines showed no change in GluA1 or size. But the larger, high-GluA1 spines disproportionately lost GluA1 and shrank. The passage does not establish that synapses involved in prior encoding were spared or that connectivity increased at them. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Hippocampal ripple activity is suppressed during the SO downstate.

“Hippocampal ripple activity is, in addition, suppressed during the SO downstate.198,199”

• cites [198] sourceNot checked — no full text of the source
• cites [199] sourceSupported

Ripples during SWS tend to nest into the excitable troughs of the spindle oscillation, forming spindle-ripple events.

“Ripples during SWS tend to nest into the excitable troughs of the spindle oscillation thereby forming spindle-ripple events.[195][196][197]”

• cites [195] sourceNot checked — no full text of the source
• cites [196] sourceNot checked — no full text of the source
• cites [197] sourceSupported

Rats training a prehension skill task initially showed increased hippocampal ripples coupled to SOs in primary motor cortex during post-training SWS.

“Likewise, rats training a prehension skill task initially showed increased hippocampal ripples coupled to SOs in primary motor cortex during post-training SWS.201”

• cites [201] sourceSupported

The max spines-those with largest increase in GluA1 during learning-although also undergoing some downscaling, kept a relatively higher GluA1 expression after sleep than after a post-training period of wakefulness.

“Importantly, this comparison revealed that the max spines-although also undergoing some downscaling-kept a relatively higher GLuA1 expression after sleep than after a post-training period of wakefulness.”

• cites [165] sourceSupported

At the level of global network regulation, sleep is considered to primarily serve downregulation (down-selection) of synaptic connectivity.

“At the level of global network regulation, sleep is considered to primarily serve the downregulation, i.e., in a strict sense a down-selection of synaptic connectivity.223”

• cites [223] sourceSupported

In humans, transcranial direct current stimulation and transcranial magnetic stimulation studies provided functional evidence for sleep decreasing cortical excitability.

“Using transcranial direct current stimulation and transcranial magnetic stimulation, studies in humans provided functional evidence for sleep decreasing cortical excitability.230”

• cites [230] sourceSupported

The primary effect of sleep might be to reduce overall network activity and connectivity at excitatory synapses by increasing inhibition, pushing cortical E-I balance toward increased synaptic inhibition.

“The primary effect of sleep might well be to reduce overall network activity, and connectivity at excitatory synapses 233 by increasing inhibition, i.e., by pushing the cortical E-I balance toward increased synaptic inhibition.”

• cites [233] sourcePartly supported

  The Results (Spine shrinkage by two-color glutamate and GABA uncaging; page unavailable) report GABA-associated spine shrinkage, elimination, and reduced glutamate sensitivity, supporting a local mechanism for weakening excitatory connections. The paper does not examine sleep or establish that sleep reduces overall network activity or shifts cortical excitation–inhibition balance toward inhibition. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

During succeeding REM sleep epochs, activity of these spindle-active cells decreased in parallel with overall population.

“During succeeding REM sleep epochs activity of these cells decreased, in parallel with the overall population.”

• cites [166] sourceSupported

Dendrites in layer 1 appear to mainly encode more abstract information compared with deeper layers where perceptual features are encoded.

“For example, dendrites in layer 1 appear to mainly encode more abstract information compared with deeper layers where perceptual features are encoded.241”

• cites [241] sourceSupported

REM sleep probably particularly contributes to the regulation of synaptic plasticity during development.

“with the latter probably particularly contributing to the regulation of synaptic plasticity during development.231,249”

• cites [231] sourceSupported
• cites [249] sourceSupported

REM sleep is characterized by enhanced synaptic pruning that selectively omitted subsets of synapses formed during encoding of new motor memory prior to sleep.

“By contrast, REM sleep was found to be characterized by enhanced synaptic pruning that selectively omitted subsets of synapses formed during encoding of new motor memory prior to sleep.231”

• cites [231] sourceSupported

Compared with adults, infants and children spend more time in SWS and REM sleep.

“Compared with adults, infants and children spent more time in SWS and REM sleep”

• cites [246] sourceCould not verify

  The Abstract says children spend much of their early years asleep, and “Nap Transitions in Infants and Children” describes newborns’ total sleep time, but neither compares time in SWS or REM with adults. Searches for REM sleep and age-related sleep-stage duration found no passage in our copy making that comparison; page numbers were unavailable. (LLM, conf=0.74)

  Experimental — accuracy not yet measured
• cites [248] sourceCould not verify

  The Introduction (p. 193) describes a study of sleep EEG in ages 6–18, and EEG Recording and Analysis discusses sleep duration only in explaining the analysis window. Neither passage reports whether infants or children spend more time in SWS and REM sleep than adults; searches for that comparison found no supporting passage. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

Spine formation during post-training SWS only pertained to select dendritic branches of motor cortex pyramidal cells, similar to spine formation during learning.

“Thus, similar to spine formation during learning, also spine formation during post-training SWS only pertained to select dendritic branches of motor cortex pyramidal cells.164”

• cites [164] sourcePartly supported

  The Abstract reports that post-training sleep promotes spine formation on a subset of dendritic branches of mouse motor-cortex layer V pyramidal neurons. The sleep-deprivation and REM-deprivation passages support sleep-dependent, branch-specific formation, but the paper does not establish that the spines formed specifically during slow-wave sleep rather than another part of non-REM sleep. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

SWS following motor task training supports branch-specific spine formation in a subset of cells in motor cortex.

“On a morphological level, SWS following motor task training was found to support branch-specific spine formation in a subset of cells in motor cortex.164”

• cites [164] sourcePartly supported

  The Abstract reports that sleep after motor learning promotes spine formation on a subset of dendritic branches in mouse motor-cortex neurons, and that task-related neurons reactivate during NREM sleep. It does not specifically identify slow-wave sleep (SWS) as the supporting sleep stage, or describe the spine formation as occurring in a subset of cells rather than a subset of branches. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Corresponding effects of sleep on inhibition and excitation were found in humans.

“Corresponding effects were found in humans.234”

• cites [234] sourcePartly supported

  The Abstract (page unavailable) reports human evidence that cortical excitability depends on sleep homeostasis and describes this study’s measurements of excitation/inhibition balance during sleep deprivation. But the Discussion (page unavailable) says the measured balance returned to baseline without sleep and may be under a prominent circadian influence. The paper therefore supports changes in human excitation/inhibition balance across the sleep–wake cycle, but not an unqualified attribution of those changes to sleep itself. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Cortical and hippocampal neuronal activity showed more robust decreases across periods of REM sleep than SWS.

“Moreover, cortical and hippocampal neuronal activity showed more robust decreases across periods of REM sleep than SWS.166,232”

• cites [166] sourcePartly supported

  The Results (page unavailable) report decreased calcium activity in cortical pyramidal cells during both SWS and REM sleep; the Discussion describes broader cortical downregulation during REM sleep. The paper does not establish that the decreases were larger during REM than SWS, and it did not measure hippocampal neurons; its Discussion only mentions a separate hippocampal study. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [232] sourcePartly supported

  The Results report that hippocampal firing rates decreased during REM episodes but increased during non-REM episodes. The Discussion says it remains unknown whether these CA1 findings extend to other cortical regions, so the claim’s cortical component is not supported by this paper. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

The scarce available evidence suggests that SO-spindle coupling might be weak or even entirely absent during infancy.

“By contrast, the scarce available evidence suggests that such coupling might be weak or even entirely absent during infancy.275”

• cites [275] sourcePartly supported

  The Results (Hippocampal-Cortical Oscillatory Coupling Through Development) report that significant SO–spindle phase coupling emerged by postnatal day 32 in rats, while the number of temporally coupled events increased with age. This supports weaker coupling at younger ages, but the paper also observes temporal coupling during the study period; it does not establish that coupling is entirely absent during infancy generally. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

• AssumptionThe authors state this as an assumption: The hippocampal-neocortical dialog underlying sleep-dependent systems consolidation is mediated through a triple coupling between hippocampal ripples, spindles, and neocortical SO.

The greater gain in explicit knowledge in children was associated with higher amounts of slow oscillatory activity.

“The greater gain in explicit knowledge in the children was associated with higher amounts of slow oscillatory activity.263”

• cites [263] sourceCould not verify

  The Results report greater slow-wave slopes in prepubertal children than in adolescents, and the introduction mentions memory consolidation generally. Neither passage reports gains in explicit knowledge or tests whether those gains were associated with slow oscillatory activity (searched: explicit knowledge, learning, memory consolidation). (LLM, conf=0.76)

  Experimental — accuracy not yet measured

Findings generally agree that sleep supports processing of episodic-like memories and their precursors at early developmental stages.

“Findings generally agree with the notion that sleep supports processing of episodic-like memories and its precursors also at this early developmental stage”

• cites [258] sourceSupported
• cites [267] sourceSupported

Overall, studies indicate sleep-dependent benefits across a large variety of memory tasks in human infants and children, such as memory for objects and actions, declarative, emotional and language-related memories.

“Overall, these studies indicate sleepdependent benefits across a large variety of memory tasks, such as memory for objects and actions, declarative, emotional and language-related memories”

• cites [257] sourceNot checked — no full text of the source
• cites [258] sourceSupported

A similar parallel developmental course between the emergence of SO-spindle coupling and of object-in-place memory has been shown in rat pups.

“and a similar parallel developmental course between the emergence of SOspindle coupling and of object-in-place memory has been shown in rat pups.275”

• cites [275] sourceSupported

• AssumptionThe authors state this as an assumption: The hippocampal-neocortical dialog underlying sleep-dependent systems consolidation is mediated through a triple coupling between hippocampal ripples, spindles, and neocortical SO.

In 6- to 8-month-old infants, indicators of memory for sequential rules were enhanced after sleep.

“In even younger 6-to 8-month-old infants, indicators of memory for sequential rules (nonadjacent dependencies in spoken artificial word strings) were found to be enhanced after sleep.271”

• cites [271] sourcePartly supported

  The Results report indicators of memory for nonadjacent dependencies in both the nap and wake groups of 6- to 8-month-olds. The Discussion says sleep altered a specific stage of processing, but memory of the regularities was generally independent of sleep. Thus, describing the indicators as broadly enhanced after sleep overstates the finding. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Toddlers who later remembered where, in which temporal order, and in the presence of which toy character they had heard the song exhibited stronger hippocampal activation when the song was played to them during sleep.

“Specifically, toddlers who later remembered where, in which temporal order, and in the presence of which toy character they had heard the song exhibited stronger hippocampal activation when the song was played to them during sleep.”

• cites [272] sourcePartly supported

  The Results (fMRI results; page unavailable) report stronger right-hippocampal activation during sleep in association with better memory for temporal order. They report no such association for spatial location. Although the Methods (Procedure; page unavailable) mention puppets, the paper does not report an activation association with remembering which puppet was present; the Introduction attributes a room-and-puppet finding to an earlier study. (LLM, conf=0.90)

  Experimental — accuracy not yet measured
• cites [273] sourcePartly supported

  The Introduction reports that 28-month-olds showed greater hippocampal activation during sleep for newly learned songs than for novel songs, and that activation was associated with memory for events linked to the songs. It does not specify memory for where or in what order the songs were heard, or which toy character was present. The paper reports this as a finding of earlier studies, rather than its own song experiment. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Children aged 7-12 years showed greater sleep-dependent gain than adult controls for associative memories between artificial objects and their functions.

“Children of similar age (7-12 years) showed likewise a greater sleep-dependent gain than adult controls for associative memories between artificial objects and their functions.264”

• cites [264] sourceSupported

Sleep helps infants acquire the semantic meaning of words.

“Sleep, thus, helps the infants to acquire the semantic meaning of words.”

• cites [269] sourceSupported

In 7- to 11-year-old children, superior recall of spatial memories for card pairs showing the same object after post-encoding nocturnal sleep compared with a daytime wake interval was found only when these memories were associated with a high reward.

“For example, testing 7-to 11-year-old children's spatial memories for card pairs showing the same object, Prehn-Kristensen et al. 262 found superior recall after post-encoding nocturnal sleep, in comparison with a daytime wake interval only when these memories were associated with a high reward.”

• cites [262] sourceSupported

There is consistent evidence of an association of sleep spindles with memory consolidation in infancy and childhood.

“There is consistent evidence of an association of sleep spindles with memory consolidation in infancy and childhood (e.g., Friedrich et al. 269 and Friedrich et al. 274 ).”

• cites [269] sourcePartly supported

  The Discussion reports a correlation between sleep spindle activity and semantic generalization in infants aged 9–16 months, supporting the infancy part of the claim. The paper does not establish consistent evidence across infancy and childhood: it describes its infant result as the first such correlation, while the childhood evidence appears only as a cited preschool study in the References. No page numbers are available in our copy. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [274] sourceNot checked — no full text of the source

In 9- to 16-month-old infants, sleep during a 1.5-h napping period after encoding facilitated generalization of spoken artificial words to novel but similar objects, indicating a categorization process.

“Friedrich et al. 269 found in 9-to 16-month-old infants that the occurrence of sleep during a 1.5-h napping period after encoding facilitated the generalization of the words to novel but similar objects, indicating a categorization process.”

• cites [269] sourceSupported

In humans, the ability to form episodic memories for events bound into a specific spatiotemporal context emerges at an age between 3 and 4 years.

“In humans, the ability to form episodic memories for events bound into a specific spatiotemporal context already emerges at an age between 3 and 4 years.266”

• cites [266] sourcePartly supported

  The General Discussion (page unavailable) reports that 4-year-olds could bind list contexts with items when the context cue was made more salient. But the study did not test 3-year-olds or establish that this ability emerges between ages 3 and 4; it found that more complex binding continues to develop later. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Some findings suggest that sleep in infancy particularly supports the formation of abstracted and generalized representations.

“with some findings suggesting that sleep in infancy particularly supports the formation of abstracted and generalized representations.268”

• cites [268] sourceSupported

In 14-17-month-old infants, sleep facilitated formation of episodic-like memory for a unique word-object association.

“the same group also demonstrated a facilitating effect of sleep on the formation of episodic-like memory, i.e., the memory for a unique word-object association.270”

• cites [270] sourceSupported

Sleep restriction impairs memory in human infants and children.

“and impaired memory after sleep restriction (e.g., Lo et al. 259 ).”

• cites [259] sourcePartly supported

  The Methods (Participants; page unavailable) identify the participants as adolescents aged 15–19, not infants or younger children. The Discussion (The impact of sleep in retaining important memories; page unavailable) reports no significant difference in overall memory performance between the sleep-restricted and control groups. The Conclusion (page unavailable) supports the narrower finding that sleep restriction may attenuate the memory benefit of prioritizing information. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Sleep-independent memory formation in starved flies depended on the hunger signal neuropeptide F.

“Sleep-independent memory formation in starved flies depended on the hunger signal neuropeptide F.”

• cites [7] 7. Chouhan, N.S., Griffith, L.C., Haynes, P., and Sehgal, A. (2021). Availabil- ity of food determines the need for sleep in memory consolidation. Nature 589, 582-585. https://doi.org/10.1038/s41586-020-2997-y. sourceSupported

Offline replay of ensemble firing patterns in conjunction with hippocampal ripples occurs also during quiet wakefulness.

“However, the offline replay of ensemble firing patterns in conjunction with hippocampal ripples occurs also during quiet wakefulness.138,150”

• cites [138] sourceSupported
• cites [150] sourcePartly supported

  The Results section (“Reactivation of 2D trajectories after random foraging”; page unavailable) reports trajectory reactivation during sharp-wave ripples in quiet immobility after exploration. But the Methods (“Novel Environment Analysis”; page unavailable) calls the rest sessions sleep periods, so this paper does not establish that the recorded offline replay occurred during quiet wakefulness. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

Wake replay is expected not to interfere with consolidation only when it is not offline but occurs briefly after encoding in the very same context as the encoded event.

“Along this line, wake replay is expected not to interfere with consolidation only when it is not ''offline'' but occurs briefly after encoding in the very same context as the encoded event.284,285,293”

• cites [284] sourcePartly supported

  The Results report that activity during awake sharp-wave ripples promotes stabilization of hippocampal place representations, and the Discussion links this effect to learning new map configurations. The paper does not establish that wake replay avoids interfering with consolidation only if it occurs briefly after encoding in the same context; its manipulation took place during learning, and it makes no such exclusive claim. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [285] sourcePartly supported

  The Abstract describes awake replay during learning and distinguishes its role from rest/sleep SWR activity associated with consolidation. It does not say that wake replay avoids interfering with consolidation only if it occurs briefly after encoding in the same context; that timing and exclusivity condition is unsupported. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [293] sourcePartly supported

  The Introduction (page unavailable) describes repeated encoding followed by free recall, and the Discussion says rehearsal rapidly initiates systems consolidation. But the paper does not say that wake replay avoids interfering with consolidation only when it occurs shortly after encoding in the same context, or establish that contrast with offline replay. (LLM, conf=0.79)

  Experimental — accuracy not yet measured

Spontaneous offline replay activity in hippocampal networks enhancing memory appears to be a unique feature of sleep-dependent consolidation.

“Thus, spontaneous offline replay activity in hippocampal networks enhancing memory indeed appears to be a unique feature of sleep-dependent consolidation 66,74”

• cites [66] 66. Sawangjit, A., Oyanedel, C.N., Niethard, N., Salazar, C., Born, J., and In- ostroza, M. (2018). The hippocampus is crucial for forming non-hippo- campal long-term memory during sleep. Nature 564, 109-113. https:// doi.org/10.1038/s41586-018-0716-8. sourceNot checked — no full text of the source
• cites [74] 74. Schapiro, A.C., Reid, A.G., Morgan, A., Manoach, D.S., Verfaellie, M., and Stickgold, R. (2019). The hippocampus is necessary for the consol- idation of a task that does not require the hippocampus for initial learning. Hippocampus 29, 1091-1100. https://doi.org/10.1002/hipo.23101. sourcePartly supported

  The Introduction describes hippocampal replay during sleep and says hippocampal–cortical dialogue is thought to facilitate memory consolidation. The Discussion also proposes that replay during sleep may benefit motor-sequence consolidation. Neither passage establishes that memory-enhancing offline replay is unique to sleep-dependent consolidation. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Natural awake consolidation was superior to sleep consolidation when object recognition after 1 week was tested in an environmental context entirely different from that during encoding.

“Interestingly, in the experiments natural awake consolidation turned out to be also superior to sleep consolidation when object recognition after 1 week was tested in an environmental context entirely different from that during encoding.”

• cites [6] 6. Sawangjit, A., Harkotte, M., Oyanedel, C.N., Niethard, N., Born, J., and Inostroza, M. (2022). Two distinct ways to form long-term object recog- nition memory during sleep and wakefulness. Proc. Natl. Acad. Sci. USA 119. e2203165119. https://doi.org/10.1073/pnas.2203165119. sourceSupported

Unlike sleep consolidation, wake consolidation strongly depends on internal organismic states such as hunger.

“Beyond pointing to distinct mechanisms mediating wake and sleep-dependent consolidation processes, the findings show that unlike sleep consolidation, wake consolidation strongly depends on internal organismic states such as hunger.”

• cites [7] 7. Chouhan, N.S., Griffith, L.C., Haynes, P., and Sehgal, A. (2021). Availabil- ity of food determines the need for sleep in memory consolidation. Nature 589, 582-585. https://doi.org/10.1038/s41586-020-2997-y. sourcePartly supported

  The Abstract reports that hunger-related NPF signaling helps select the sleep-independent memory pathway in starved flies, supporting the point about wake consolidation. But the Abstract and Discussion describe a feeding/hunger-dependent switch between both pathways; they do not support the contrast that sleep-dependent consolidation is unlike wake consolidation in this respect. The study concerns appetitive memory in Drosophila. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Sleep and wake-associated consolidation has been dissociated in Drosophila.

“Against the backdrop that the mammalian hippocampus shows some homologies with the insect mushroom bodies in structure and function, 283 it is interesting that sleep and wake-associated consolidation has been also dissociated in Drosophila.”

• cites [7] 7. Chouhan, N.S., Griffith, L.C., Haynes, P., and Sehgal, A. (2021). Availabil- ity of food determines the need for sleep in memory consolidation. Nature 589, 582-585. https://doi.org/10.1038/s41586-020-2997-y. sourceSupported

Challenging the view of systems consolidation as a process exclusively linked to sleep, signs of systems consolidation can be also observed under certain conditions in the wake state.

“However, challenging the view of systems consolidation as a process exclusively linked to sleep, signs of systems consolidation can be also observed under certain conditions in the wake state.[290][291][292][293]”

• cites [290] sourceCould not verify

  The Introduction (page unavailable) describes memory reactivation and consolidation during sleep, and the Discussion (page unavailable) addresses spindle timing during sleep. A References entry names a study of reactivation during wakefulness and sleep, but our copy does not state that signs of systems consolidation occur in the wake state. Searches for wakefulness and systems consolidation found no passage establishing that claim. (LLM, conf=0.73)

  Experimental — accuracy not yet measured
• cites [291] sourceNot checked — no full text of the source
• cites [292] sourceSupported
• cites [293] sourceSupported

When starved, flies formed long-term memory also in sleep-deprived conditions.

“By contrast, when starved the flies formed such long-term memory also in sleep-deprived conditions.”

• cites [7] 7. Chouhan, N.S., Griffith, L.C., Haynes, P., and Sehgal, A. (2021). Availabil- ity of food determines the need for sleep in memory consolidation. Nature 589, 582-585. https://doi.org/10.1038/s41586-020-2997-y. sourceSupported

Naturally low glucocorticoid concentrations are important for consolidation during nocturnal sleep.

“underlining the importance of naturally low glucocorticoid concentrations for consolidation during nocturnal sleep.”

• cites [281] sourceSupported

Synaptic AMPA receptor density increases during learning.

“(D)Synaptic AMPA receptor density increases during learning and is globally reduced during subsequent sleep.”

• cites [165] sourceSupported

Conditions such as globally low levels of acetylcholine and glucocorticoids together with the occurrence of SO, spindles and ripples that hallmark SWS facilitate hippocampal replay, output, and the transmission of reactivated memory information toward neocortical long-term storage sites.

“Indeed, conditions such as the globally low levels of acetylcholine and glucocorticoids together with the occurrence of SO, spindles and ripples that hallmark SWS, facilitate hippocampal replay, output, and the transmission of reactivated memory information toward neocortical long-term storage sites.281,[286][287][288][289]”

• cites [281] sourcePartly supported

  The Results report that high-dose corticosterone reduced sharp-wave frequency in mouse hippocampal slices, and the Discussion links elevated glucocorticoids to impaired memory formation during slow-wave sleep. This supports a role for glucocorticoid levels in memory-related oscillations, but the paper does not establish that the combined conditions of low acetylcholine, slow oscillations, spindles and ripples facilitate replay or transfer of memories to neocortex. Page numbers are unavailable in our copy. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [286] sourceNot checked — no full text of the source
• cites [287] sourceNot checked — no full text of the source
• cites [288] sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites [289] sourceNot checked — no full text of the source

Synaptic AMPA receptor density is globally reduced during subsequent sleep.

“(D)Synaptic AMPA receptor density increases during learning and is globally reduced during subsequent sleep.”

• cites [165] sourcePartly supported

  The Discussion reports a net decrease in spine-surface GluA1-containing AMPA receptors after sleep in adult mouse primary motor cortex. But it explicitly describes sleep-related synaptic decreases as widespread, not global, and says it is unknown whether the result extends to other adult brain areas or layers. The claim overstates both the extent of the reduction and the receptor types measured. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

Sleep, particularly REM sleep, globally downregulates calcium activity in cortical pyramidal cells.

“(E) Sleep, particularly REM sleep, globally downregulates calcium activity in cortical pyramidal cells.”

• cites [166] sourceSupported
• cites [167] sourceNot checked — no full text of the source

Downscaling includes the synapses that were upscaled during learning, although to a lesser extent.

“Downscaling includes the synapses that were upscaled during learning, although to a lesser extent.165”

• cites [165] sourcePartly supported

  The Results report that spines with the largest post-learning GluA1 increases lost some GluA1 over the next seven hours, while other spines lost GluA1 after sleep. But the learning-associated spines also lost GluA1 after sleep deprivation, so the paper does not establish that sleep-dependent downscaling included them; the Discussion also notes that regression to the mean may explain some of their decrease (pages not provided). (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Cells that are particularly active during sleep spindles are spared from this downregulation during non-REM sleep where these cells even increase their activity.

“Cells that are particularly active during sleep spindles are spared from this downregulation during non-REM sleep where these cells even increase their activity.166,167”

• cites [166] sourceSupported
• cites [167] sourceNot checked — no full text of the source

Selective optogenetic suppression of hippocampal theta activity during REM sleep impaired consolidation of object-location memory.

“Selective optogenetic suppression of hippocampal theta activity during REM sleep impaired consolidation of object-location memory.221”

• cites [221] sourceNot checked — no full text of the source

Ripples appear to be directly implicated in synaptic scaling, as closed-loop optogenetic suppression of hippocampal ripples in dorsal CA3 prevented spontaneous synaptic downscaling in these circuits.

“Interestingly, ripples appear to be also directly implicated in synaptic scaling, as closed-loop optogenetic suppression of hippocampal ripples in dorsal CA3 prevented spontaneous synaptic downscaling in these circuits.132”

• cites [132] 132. Contreras, M.P., Fechner, J., Born, J., and Inostroza, M. (2023). Acceler- ating maturation of spatial memory systems by experience -evidence from sleep oscillation signatures of memory processing. J. Neurosci. JN-RM-1967-22. https://doi.org/10.1523/JNEUROSCI.1967-22.2023. 279. Kelemen, E., Bahrendt, M., Born, J., and Inostroza, M. (2014). Hippocam- pal corticosterone impairs memory consolidation during sleep but im- proves consolidation in the wake state. Hippocampus 24, 510-515. https://doi.org/10.1002/hipo.22266. 280. Wilhelm, I., Wagner, U., and Born, J. (2011b). Opposite effects of c sourceNot checked — no full text of the source

In specific task conditions, the benefit of sleep for episodic memory during development can be even greater than in the mature brain.

“In specific task conditions, this benefit can be even greater than in the mature brain”

• cites [265] sourceNot checked — no full text of the source

In rat pups, the sleep-dependent occurrence of adult-like persisting spatial object-in-place representations could be advanced to PD31 by repeatedly exposing them to 5-min periods of discrete spatial experiences on the days before.

“Interestingly, in rat pups the sleep-dependent occurrence of adult-like persisting spatial object-in-place representations could be advanced to PD31 (corresponding to late childhood) by repeatedly exposing them to 5-min periods of discrete spatial experiences (configurational changes in two identical objects) on the days before 278”

• cites [278] sourceNot checked — no full text of the source

Children around 10 years of age showed greater sleep-dependent gains in explicit knowledge of a sequence than their adult controls.

“Contrasting with this hypothesis, children around 10 years of age showed greater sleep-dependent gains in explicit knowledge of a sequence than their adult controls.46”

• cites [46] 46. Wilhelm, I., Rose, M., Imhof, K.I., Rasch, B., B€ uchel, C., and Born, J. (2013). The sleeping child out-plays the adult's capacity to convert im- plicit into explicit knowledge. Nat. Neurosci. 16, 391-393. https://doi. org/10.1038/nn.3343. sourceNot checked — no full text of the source

In school children aged 7-15 years, the coupling strength of spindles to the SO upstate during post-encoding sleep predicted recall of word lists on the next day, independently of the children's age.

“Moreover, in school children aged 7-15 years the coupling strength of spindles to the SO upstate during post-encoding sleep predicted recall of word lists on the next day, with this relationship occurring independently of the children's age, 277”

• cites [277] sourceNot checked — no full text of the source

• AssumptionThe authors state this as an assumption: The hippocampal-neocortical dialog underlying sleep-dependent systems consolidation is mediated through a triple coupling between hippocampal ripples, spindles, and neocortical SO.

Some studies in children suggest more robust benefits from sleep for episodic and declarative types of memory compared with task aspects less reliant on the hippocampus, such as procedural motor skills or object recognition.

“some studies in children suggest more robust benefits from sleep for episodic and declarative types of memory in comparison with task aspects less reliant on the hippocampus, similar to procedural motor skills or object recognition.257,260”

• cites [257] sourceNot checked — no full text of the source
• cites [260] sourceNot checked — no full text of the source

In 6-month-old infants following a nap, signs of memory for semantic categories associated to artificial words were positively correlated with local spindle activity during the nap.

“For example, 6-month-old infants following a nap showed signs of memory for semantic categories associated to artificial words, which were positively correlated with local spindle activity during the nap.274”

• cites [274] sourceNot checked — no full text of the source

Inhibiting the hippocampus by muscimol injection during post-encoding sleep impaired object recognition tested 1 week later in adult rats.

“Inhibiting the hippocampus by muscimol injection during post-encoding sleep impaired object recognition tested 1 week later.”

• cites [66] 66. Sawangjit, A., Oyanedel, C.N., Niethard, N., Salazar, C., Born, J., and In- ostroza, M. (2018). The hippocampus is crucial for forming non-hippo- campal long-term memory during sleep. Nature 564, 109-113. https:// doi.org/10.1038/s41586-018-0716-8. sourceNot checked — no full text of the source

Sleep supports long-term memory consolidation.

“Although long-term memory consolidation is supported by sleep, it is unclear how it differs from that during wakefulness.”

• Also stated in: § INTRODUCTION · boosted

  “Sleep has been known to support the formation of long-term memory since the first experimental evidence was provided about a century ago.”

• cites Rasch and Born, 3Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Klinzing et al., 4Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Girardeau et al. 5Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Post-encoding sleep produces more long-lasting and stable memories than wakefulness.

“hundreds of studies in humans and animals have shown that in comparison with wakefulness, sleep following the encoding of experimental stimuli, produces more long-lasting and stable memories”

• cites Rasch and Born, 3Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Klinzing et al., 4Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Girardeau et al. 5Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Sleep benefits for non-hippocampus-dependent kinds of memory are explained by such memories being embedded into hippocampus-dependent episodic representations.

“it also explains sleep benefits for non-hippocampus-dependent kinds of memory (e.g., procedural skills), as such memories are naturally experienced in the context of specific episodes implicating that they are always embedded into hippocampus-dependent episodic representations.”

Studies revealed stronger influences of SWS than REM sleep on memory consolidation across a great variety of tasks.

“Across a great variety of tasks, these studies revealed stronger influences of SWS than REM sleep on memory consolidation.”

In mice, optogenetic induction of spindles confirmed their causal contribution to memory consolidation.

“in mice, the optogenetic induction of spindles has confirmed their causal contribution to memory consolidation.”

• cites [58] 58. Latchoumane, C.V., Ngo, H.V., Born, J., and Shin, H.S. (2017). Thalamic spindles promote memory formation during sleep through triple phase- locking of cortical, thalamic, and hippocampal rhythms. Neuron 95, 424-435.e6. https://doi.org/10.1016/j.neuron.2017.06.025. sourceNot checked — no full text of the source

Post-encoding sleep enhanced generalization of memory recall to a category prototype not presented during encoding, at a recall test 1 year but not 1 day after encoding.

“using visual patterns, Lutz et al. 41 found that post-encoding sleep enhanced generalization of memory recall to a category prototype not presented during encoding, at a recall test 1 year but not 1 day after encoding.”

• cites Lutz et al. 41Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

The link between sleep spindle activity during post-encoding sleep and later memory performance is more consistent than that for measures of SWA.

“The link between sleep spindle activity during post-encoding sleep and later memory performance is even more consistent than that for measures of SWA”

• cites Alger et al., 53Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Peyrache and Seibt, 54Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Lutz et al. 55Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

No robust associations have been found between EEG signatures of REM sleep and memory consolidation in humans.

“No robust associations have been found between the EEG signatures of REM sleep and memory consolidation in humans”

In rodents, place cells coding for specific locations replay in the same sequential order during sleep as during prior awake spatial navigation.

“place cells coding for specific locations in an environment replay in the same sequential order during sleep as during prior awake spatial navigation.”

• cites [78] 78. Lee, A.K., and Wilson, M.A. (2002). Memory of sequential experience in the hippocampus during slow wave sleep. Neuron 36, 1183-1194. https://doi.org/10.1016/s0896-6273(02)01096-6. sourceNot checked — no full text of the source
• cites [79] 79. Wilson, M.A., and McNaughton, B.L. (1994). Reactivation of hippocam- pal ensemble memories during sleep. Science 265, 676-679. https:// doi.org/10.1126/science.8036517. sourceNot checked — no full text of the source

The coupling of hippocampal replay to depolarizing upstates of SOs and thalamic spindles supports transmission of reactivated memory information and its storage into neocortical networks.

“The coupling of hippocampal replay to the depolarizing upstates of SOs emerging from neocortical networks and to thalamic spindles represents a mechanism that supports the transmission of the reactivated memory information and its storage, through synaptic consolidation mechanisms, into respective neocortical networks serving as long-term store.”

At the core of active systems consolidation is neuronal replay of memory: repeated reactivations of firing patterns in neuron ensembles that were activated during encoding, re-occurring in hippocampal networks during post-encoding SWS in coordination with SPW-Rs.

“At the core of this process is the neuronal replay of memory, i.e., repeated reactivations of firing patterns in neuron ensembles that were activated and used for encoding of the episodes during prior wake phases, and which re-occur in hippocampal networks during post-encoding SWS in coordination with hippocampal sharp wave-ripples (SPW-Rs).”

• cites [4] 4. Klinzing, J.G., Niethard, N., and Born, J. (2019). Mechanisms of systems memory consolidation during sleep. Nat. Neurosci. 22, 1598-1610. https://doi.org/10.1038/s41593-019-0467-3. sourceNot checked — no full text of the source
• cites [73] 73. Diekelmann, S., and Born, J. (2010). The memory function of sleep. Nat. Rev. Neurosci. 11, 114-126. https://doi.org/10.1038/nrn2762. sourceNot checked — no full text of the source

Disrupting only specific reactivation events of a prior learning experience revealed a selective recall deficit restricted to the spatial environment whose reactivation was disturbed.

“refining this approach by disrupting only specific reactivation events of a prior learning experience (through online decoding of the content of ensemble firing patterns) revealed a selective recall deficit that was restricted to the spatial environment whose reactivation was disturbed.”

• cites [86] 86. Gridchyn, I., Schoenenberger, P., O'Neill, J., and Csicsvari, J. (2020). As- sembly-specific disruption of hippocampal replay leads to selective memory deficit. Neuron 106, 291-300.e6. e296. https://doi.org/10. 1016/j.neuron.2020.01.021. sourceNot checked — no full text of the source

Neuronal reactivations of newly encoded experiences during sleep specifically contribute to reorganization of respective representations in hippocampal-cortical systems.

“Collectively, these findings support the notion that neuronal reactivations of newly encoded experiences during sleep specifically contribute to the reorganization of respective representations in hippocampal-cortical systems.”

Conjoint offline reactivation of engram cells in anterior cingulate cortex coding for distinct experiences is necessary for forming generalized representations of spatial context during sleep.

“Aly et al. 97 showed that the conjoint offline reactivation of engram cells in anterior cingulate cortex (ACC) coding for distinct experiences is necessary for forming generalized representations of spatial context during sleep.”

• cites Aly et al. 97Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Using representational similarity analysis, Cairney et al. reliably identified the image category associated with the verbal cue in raw EEG traces during a time window of increased fast spindle power 1.7-2.3s after cue onset.

“using representational similarity analysis, Cairney et al. 117 reliably identified the image category (object vs. scene) associated with the verbal cue (adjectives) in the raw EEG traces during a time window of increased fast spindle power 1.7-2.3s after cue onset.”

• cites Cairney et al. 117Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Several studies succeeded in identifying signs of spontaneous memory reprocessing during post-learning sleep.

“several studies succeeded in identifying signs of spontaneous memory reprocessing during post-learning sleep”

• cites Rubin et al., 110Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Sterpenich et al., 111Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Zhang et al. 112Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Reactivation and replay in both wake and sleep share factors that select which content is preferably reactivated, due to saliency or relevance, including novelty and reward.

“They also share the factors that select which content is preferably reactivated, due to saliency or relevance, including novelty and reward.”

• cites [80] 80. Diba, K., and Buzsa ´ki, G. (2007). Forward and reverse hippocampal place-cell sequences during ripples. Nat. Neurosci. 10, 1241-1242. https://doi.org/10.1038/nn1961. sourceNot checked — no full text of the source
• cites [81] 81. Foster, D.J., and Wilson, M.A. (2006). Reverse replay of behavioural se- quences in hippocampal place cells during the awake state. Nature 440, 680-683. https://doi.org/10.1038/nature04587. sourceNot checked — no full text of the source
• cites [141] sourceNot checked — no full text of the source

In rodents, an entirely novel environment produced sustained reactivations during sleep for up to 7 h with a peak after 3-5 h.

“the experience of an entirely novel environment inducing the emergence of a new hippocampal map produced sustained reactivations during sleep for up to 7 h with a peak after 3-5 h.”

• cites [133] 133. Antony, J.W., Piloto, L., Wang, M., Pacheco, P., Norman, K.A., and Paller, K.A. (2018). Sleep spindle refractoriness segregates periods of memory reactivation. Curr. Biol. 28, 1736-1743.e4. https://doi.org/10.1016/j. cub.2018.04.020. 291. sourceNot checked — no full text of the source

The time course of reactivations might depend on familiarity of encoded environments.

“The time course of reactivations might also depend on the familiarity of the encoded environments.”

The temporal dynamic of reactivations likely represents a general feature showing maximum rates within 30 min after encoding also during wakefulness.

“this temporal dynamic likely represents a general feature of reactivations showing maximum rates within 30 min after encoding also during wakefulness.”

• cites [81] 81. Foster, D.J., and Wilson, M.A. (2006). Reverse replay of behavioural se- quences in hippocampal place cells during the awake state. Nature 440, 680-683. https://doi.org/10.1038/nature04587. sourceNot checked — no full text of the source

Assuming underlying neuron ensembles are synaptically connected, this dynamic argues against an immediate effect of replay strengthening synaptic connectivity in these ensembles.

“Assuming that the underlying neuron ensembles are synaptically connected, this dynamic basically argues against an immediate effect of replay ''strengthening'' synaptic connectivity in these ensembles.”

• cites [132] 132. Contreras, M.P., Fechner, J., Born, J., and Inostroza, M. (2023). Acceler- ating maturation of spatial memory systems by experience -evidence from sleep oscillation signatures of memory processing. J. Neurosci. JN-RM-1967-22. https://doi.org/10.1523/JNEUROSCI.1967-22.2023. 279. Kelemen, E., Bahrendt, M., Born, J., and Inostroza, M. (2014). Hippocam- pal corticosterone impairs memory consolidation during sleep but im- proves consolidation in the wake state. Hippocampus 24, 510-515. https://doi.org/10.1002/hipo.22266. 280. Wilhelm, I., Wagner, U., and Born, J. (2011b). Opposite effects of c sourceNot checked — no full text of the source

• AssumptionThe authors state this as an assumption: The underlying neuron ensembles are synaptically connected.

In order to consolidate memory representations widely distributed across different brain regions, neuronal reactivations need to be temporally precisely synchronized between these distributed areas.

“However, in order to consolidate memory representations that are widely distributed across different brain regions, neuronal reactivations need to be temporally precisely synchronized between these distributed areas.”

By phase-coupling local gamma band activities, spindles might serve to synchronize memory processing in distributed cortical networks.

“By phase-coupling local gamma band activities, spindles might serve to synchronize memory processing in distributed cortical networks.”

The special contribution of sleep replay to systems consolidation might not be conveyed by the replay phenomenon itself but owed to the unique milieu during sleep.

“This contribution might not be conveyed by the replay phenomenon itself but owed to the unique milieu during sleep.”

Similarities between reactivations during sleep and wakefulness exclude that reactivation, and replay in the narrow sense, itself is the critical factor that explains superior consolidation effects during sleep.

“Altogether, these similarities between reactivations occurring during sleep and wakefulness exclude that reactivation, and replay in the narrow sense, itself is the critical factor that explains superior consolidation effects during sleep.”

Spindles are waxing and waning 11-16 Hz oscillatory events of 0.5-3 s duration generated in GABAergic feedback loops including the nucleus reticularis of the thalamus and via afferent fibers widely spread to the cortex, reaching predominantly central and parietal areas.

“Spindles are waxing and waning 11-16 Hz oscillatory events of 0.5-3 s duration that are generated in GABAergic feedback-loops including the nucleus reticularis of the thalamus and via afferent fibers widely spread to the cortex, reaching predominantly central and parietal areas.59”

• cites [59] 59. Fernandez, L.M.J., and L€ uthi, A. (2020). Sleep spindles: mechanisms and functions. Physiol. Rev. 100, 805-868. https://doi.org/10.1152/physrev. 00042.2018. sourceNot checked — no full text of the source

The embedding of replay within SPWs, spindles, and SOs may enable large-scale interaction between replay across hippocampal and thalamocortical networks supporting systems consolidation during sleep.

“Specifically, the embedding of replay within SPWs, spindles, and SOs may enable the large-scale interaction between replay across hippocampal and thalamocortical networks supporting systems consolidation during sleep.”

Oscillations prime synaptic plasticity by timing the firing properties of activated neurons to the excitable depolarizing phase of network oscillations.

“In this way, oscillations prime synaptic plasticity by timing the firing properties of activated neurons to the excitable depolarizing phase of network oscillations.”

These findings point to an upregulation of plasticity in cortical microcircuits during SO-spindle complexes.

“These findings point to an upregulation of plasticity in cortical microcircuits during SO-spindle complexes.”

During SWS, three cardinal rhythms-SOs, sleep spindles, and ripples-determine the efficacy of firing pattern reactivations occurring in local neuron ensembles.

“During SWS, three cardinal rhythms have been identified that eventually determine the efficacy of firing pattern reactivations occurring in local neuron ensembles, i.e., SOs, sleep spindles, and ripples (Figure 2A).”

Unlike SOs enhancing cortical representations, delta waves may primarily serve downscaling and forgetting.

“Thus, unlike SOs enhancing cortical representations, delta waves may primarily serve their downscaling and forgetting.”

These results confirm that global sleep-dependent synaptic downscaling also captures networks after they were engaged in training a specific task.

“These results confirm that global sleep-dependent synaptic downscaling also captures networks after they were engaged in training a specific task.”

Hippocampal ripples accompany replay of firing patterns of place cell ensembles that emerged during prior encoding.

“Hippocampal ripples accompany the replay of firing patterns of place cell ensembles that emerged during prior encoding.80”

• cites [80] 80. Diba, K., and Buzsa ´ki, G. (2007). Forward and reverse hippocampal place-cell sequences during ripples. Nat. Neurosci. 10, 1241-1242. https://doi.org/10.1038/nn1961. sourceNot checked — no full text of the source

This dual function of REM sleep theta may partly depend on input from melanin-concentrating hormone (MCH) producing hypothalamic neurons.

“This dual function of REM sleep theta may partly depend on input from melanin-concentrating hormone (MCH) producing hypothalamic neurons.”

Thalamic spindles serve as the core of this loop by precisely timing and synchronizing hippocampal processes of memory replay with regulation of plasticity in neocortical circuitry underlying long-term integration of memory information into cortical storage sites.

“Thalamic spindles, in this view, serve as the core of this loop in that they precisely time and synchronize hippocampal processes of memory replay with the regulation of plasticity in neocortical circuitry underlying the long-term integration of the memory information into respective cortical storage sites.”

SHY is supported by a great body of research in animals and humans.

“SHY is supported by a great body of research in animals and humans.”

In the neocortex, the soma and widespread dendritic trees of pyramidal neurons might represent separate computational elements subjected to differential regulation of synaptic plasticity during sleep.

“In the neocortex, the soma and widespread dendritic trees of pyramidal neurons might represent separate computational elements that are also subjected to a differential regulation of synaptic plasticity during sleep.”

The data suggest overall sleep-dependent synaptic downscaling effects are relatively weaker for synapses putatively contributing to a specific task memory than for non-contributing synapses.

“Thus, the data suggest the overall sleep-dependent synaptic downscaling effects to be relatively weaker for synapses putatively contributing to a specific task memory than for non-contributing synapses.”

Cortical inhibition is higher in REM sleep than SWS due to enhanced activity of parvalbumin-positive interneurons.

“Cortical inhibition is higher in REM sleep than SWS due to enhanced activity of parvalbumin-positive interneurons.161,167,235”

• cites [161] sourceNot checked — no full text of the source
• cites [167] sourceNot checked — no full text of the source
• cites [235] sourceNot checked — no full text of the source

Pyramidal cells most active during sleep spindles, which also showed enhanced activity during prior wake phases, were considered cells more likely engaged in prior encoding activity.

“Pyramidal cells most active during sleep spindles, which showed also enhanced activity during prior wake phases, were considered cells that more likely engaged in prior encoding activity.”

This functional immaturity in conjunction with signs of well-pronounced memory formation during sleep challenges the view of an active systems consolidation process that crucially relies on precise transmission of hippocampally replayed information to neocortical long-term storage sites.

“This functional immaturity in conjunction with signs of a well-pronounced memory formation during sleep challenges the view of an active systems consolidation process that crucially relies on the precise transmission of hippocampally replayed information to neocortical long-term storage sites.”

Overall, the available evidence suggests that the processing of episodic memory information profits from sleep during development.

“Overall, the available evidence suggests that the processing of episodic memory information profits from sleep during development.”

Hippocampal dependency might be one feature dissociating consolidation in sleep and wake states.

“Hippocampal dependency might be one feature dissociating consolidation in both brain states.”

At this age, the phase-locking of spindles to SO-up states is firmly established as a mechanism of memory consolidation.

“supporting the view that at this age the phase-locking of spindles to SO-up states is firmly established as a mechanism of memory consolidation.”

• cites [277] sourceNot checked — no full text of the source

• AssumptionThe authors state this as an assumption: The hippocampal-neocortical dialog underlying sleep-dependent systems consolidation is mediated through a triple coupling between hippocampal ripples, spindles, and neocortical SO.

Replay of sequential firing patterns during sleep appears to be the latest emerging signature of hippocampal activity during early development.

“In fact, replay of sequential firing patterns during sleep appears to be the latest emerging signature of hippocampal activity during early development.”

Beyond stabilizing representations formed during the wake state, sleep consolidation impacts different engrams.

“However, there are also reasons to assume that beyond stabilizing representations formed during the wake state, sleep consolidation impacts different engrams.”

Sleep downscaling entails a reduction in the average size of axon-spine interfaces of cortical dendrites.

“connectivity (downscaling) which entails a reduction in the average size of axon-spine interfaces of cortical dendrites (assessed by structural 3D electron microscopy; partly adapted from de Vivo et al., 163 right).”

• cites de Vivo et al., 163Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Given that retrieval-related reactivations during wakefulness are driven by a conscious prefrontal cortical top-down process, the fast formation of neocortical representations in the wake state is presumably determined to a greater extent by direct inputs from cortical areas engaging in sensory-motor processing than by hippocampal inputs.

“Given that retrievalrelated reactivations during wakefulness are driven by a conscious prefrontal cortical top-down process, the fast formation of neocortical representations in the wake state is presumably determined to a greater extent by direct inputs from cortical areas engaging in sensory-motor processing than by hippocampal inputs.”

The available evidence supports the notion that sleep promotes memory formation in an active systems consolidation process that is specifically established in the hippocampus-dependent episodic memory system.

“Although we identified a number of gaps in knowledge, the available evidence supports the notion that sleep promotes memory formation in an active systems consolidation process that is specifically established in the hippocampus-dependent episodic memory system.”

Such replay is distinct in that it involves, in hippocampal networks, a reinstatement of contextual features of various experienced episodes, tightly synchronized to memory processing in thalamocortical networks.

“Such replay is distinct in that it involves, in hippocampal networks, a reinstatement of contextual features of various experienced episodes, tightly synchronized to memory processing in thalamocortical networks.”

In this systems consolidation process, the synchronized occurrence of memory replay, hippocampal ripples, sleep spindles, and SOs during SWS provides a mechanism redistributing and transforming newly encoded experiences into longer-lasting representations residing preferentially in neocortical networks.

“In this systems consolidation process, the synchronized occurrence of memory replay, hippocampal ripples, sleep spindles, and SOs during SWS provides a mechanism redistributing and transforming newly encoded experiences into longer-lasting representations residing preferentially in neocortical networks.”

Consolidation during sleep is thought of as an active systems consolidation process in which SOs, spindles, and ripples repeatedly occurring in synchrony with memory replay transform memory representations such that they eventually reside primarily in neocortical long-term storage sites.

“Consolidation during sleep is thought of as an active systems consolidation process in which SOs, spindles, and ripples repeatedly occurring in synchrony with memory replay transform memory representations such that they eventually reside primarily in neocortical long-term storage sites.”

Memory reactivation in human sleep occurs time-locked to SO-spindle complexes.

“Figure 3. Memory reactivation in human sleep occurs time-locked to SO-spindle complexes”

• cites Schreiner et al. 114Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Reactivation strength as defined by the integrated classifier performance (area under the curve [AUC]) correlated positively with memory retention (Spearman's r = 0.45, p = 0.048).

“(C) Reactivation strength as defined by the integrated classifier performance (area under the curve [AUC]) correlated positively with memory retention (Spearman's r = 0.45, p = 0.048; adapted from Schreiner et al. 114 ).”

• cites Schreiner et al. 114Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

The reactivated EEG signal showed a significant cluster (p = 0.016 corrected).

“Contour lines indicate the extent of the significant cluster representing the reactivated EEG signal, p = 0.016 corrected”

• cites Schreiner et al. 114Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

The trained classifier reliably decoded the category of the previously encoded pictures from the EEG signal (at Cz) during non-REM sleep (stage 2, SWS) when applied during the occurrence of SO-spindle complexes.

“(B) The trained classifier reliably decoded the category of the previously encoded pictures from the EEG signal (at Cz) during non-REM sleep (stage 2, SWS) when applied during the occurrence of SO-spindle complexes.”

• cites Schreiner et al. 114Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.