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[0] Jackson A, Mavoori J, Fetz EE, Correlations between the same motor cortex cells and arm muscles during a trained task, free behavior, and natural sleep in the macaque monkey.J Neurophysiol 97:1, 360-74 (2007 Jan)

[0] Mehta MR, Cortico-hippocampal interaction during up-down states and memory consolidation.Nat Neurosci 10:1, 13-5 (2007 Jan)[1] Ji D, Wilson MA, Coordinated memory replay in the visual cortex and hippocampus during sleep.Nat Neurosci 10:1, 100-7 (2007 Jan)

[0] Ji D, Wilson MA, Coordinated memory replay in the visual cortex and hippocampus during sleep.Nat Neurosci 10:1, 100-7 (2007 Jan)

[0] Nishida M, Walker MP, Daytime naps, motor memory consolidation and regionally specific sleep spindles.PLoS ONE 2:4, e341 (2007 Apr 4)

[0] Tamaki M, Matsuoka T, Nittono H, Hori T, Fast sleep spindle (13-15 hz) activity correlates with sleep-dependent improvement in visuomotor performance.Sleep 31:2, 204-11 (2008 Feb 1)

[0] Morin A, Doyon J, Dostie V, Barakat M, Hadj Tahar A, Korman M, Benali H, Karni A, Ungerleider LG, Carrier J, Motor sequence learning increases sleep spindles and fast frequencies in post-training sleep.Sleep 31:8, 1149-56 (2008 Aug 1)

[0] Song S, Consciousness and the consolidation of motor learning.Behav Brain Res 196:2, 180-6 (2009 Jan 23)

[0] Rasch B, Gais S, Born J, Impaired Off-Line Consolidation of Motor Memories After Combined Blockade of Cholinergic Receptors During REM Sleep-Rich Sleep.Neuropsychopharmacology no Volume no Issue no Pages (2009 Feb 4)

[0] Dzirasa K, Ribeiro S, Costa R, Santos LM, Lin SC, Grosmark A, Sotnikova TD, Gainetdinov RR, Caron MG, Nicolelis MA, Dopaminergic control of sleep-wake states.J Neurosci 26:41, 10577-89 (2006 Oct 11)

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ref: Jackson-2007.01 tags: Fetz neurochip sleep motor control BMI free behavior EMG date: 09-13-2019 02:21 gmt revision:4 [3] [2] [1] [0] [head]

PMID-17021028[0] Correlations Between the Same Motor Cortex Cells and Arm Muscles During a Trained Task, Free Behavior, and Natural Sleep in the Macaque Monkey

  • used their implanted "neurochip" recorder that recorded both EMG and neural activity. The neurochip buffers data and transmits via IR offline. It doesn't have all that much flash onboard - 16Mb.
    • used teflon-insulated 50um tungsten wires.
  • confirmed that there is a strong causal relationship, constant over the course of weeks, between motor cortex units and EMG activity.
    • some causal relationships between neural firing and EMG varied dependent on the task. Additive / multiplicative encoding?
  • this relationship was different at night, during REM sleep, though (?)
  • point out, as Todorov did, that Stereotyped motion imposes correlation between movement parameters, which could lead to spurrious relationships being mistaken for neural coding.
    • Experiments with naturalistic movement are essential for understanding innate, untrained neural control.
  • references {597} Suner et al 2005 as a previous study of long term cortical recordings. (utah probe)
  • during sleep, M1 cells exhibited a cyclical patter on quiescence followed by periods of elevated activity;
    • the cycle lasted 40-60 minutes;
    • EMG activity was seen at entrance and exit to the elevated activity period.
    • during periods of highest cortical activity, muscle activity was completely suppressed.
    • peak firing rates were above 100hz! (mean: 12-16hz).

____References____

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ref: Wilson-1993.08 tags: Wilson McNaughton 1993 sleep hippocampus array recording date: 01-03-2012 00:57 gmt revision:2 [1] [0] [head]

PMID-8351520[0] Dynamics of the hippocampal ensemble code for space.

  • 73-148 neurons.
  • Could accurately decode the rat's movement through space.
  • "The parallel recording methods outlined here make possible the study of the dynamics of neuronal interactions during unique behavioral events."

PMID-8036517[1] Reactivation of hippocampal ensemble memories during sleep.

  • "Information acquired during active behavior is thus re-expressed in hippocampal circuits during sleep, as postulated by some theories of memory consolidation."

____References____

[0] Wilson MA, McNaughton BL, Dynamics of the hippocampal ensemble code for space.Science 261:5124, 1055-8 (1993 Aug 20)
[1] Wilson MA, McNaughton BL, Reactivation of hippocampal ensemble memories during sleep.Science 265:5172, 676-9 (1994 Jul 29)

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ref: Lin-2006.12 tags: nucleus_basalis GABA ACh attention basal_forebrain sleep date: 12-07-2011 03:51 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-16928796[0] Fast modulation of prefrontal cortex activity by basal forebrain noncholinergic neuronal ensembles

in the author's own words:

  • in the intro sections, you can find the summary background info you need, both anatomical and functional. Despite the fact that most people think of this as solely the cholinergic projection system, my data is pointing to a very important role for the non-ACh projection system (most likely GABAergic!) in fast cortical modulation and ATTENTION. The relevant thing for you here is that, when people stimulated nucleus basalis and claimed the effect to be cholinergic, I believe most stimulation protocols (short bursts) are in fact mimicking the natural activity pattern of non-ACh projection system, and therefore should be re-interpreted with caution.
  • the intro, as promised, is concise, relevant, and has a lot of references.
  • key hypothesis is that the BF has GABA projections onto GABAergic interneurons in the PFC
    • typically, people focus on ACh projections.. perhaps as a matter of tradition?
    • PFC is reciprocally connected to the BF
  • secondary thing to test was the difference in behavior of the basal-forebrain tonic neurons (BFTN) between sleep and wake states.

____References____

[0] Lin SC, Gervasoni D, Nicolelis MA, Fast modulation of prefrontal cortex activity by basal forebrain noncholinergic neuronal ensembles.J Neurophysiol 96:6, 3209-19 (2006 Dec)

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ref: BuzsAki-1996.04 tags: hippocampus neocortex theta gamma consolidation sleep Buzsaki review learning memory date: 12-07-2011 02:31 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-8670641[0] The hippocampo-neocortical dialogue.

  • the entorhinal ctx is bidirectionally conneted to nearly all areas of the neocortical mantle.
  • Buzsaki correctly predicts that information gathered during exploration is played back at a faster scale during synchronous population busts during (comnsummatory) behaviors.
  • looks like a good review of the hippocampus, but don't have time to read it now.
  • excellent explanation of the anatomy (with some omissions, click through to read the caption):
  • SPW = sharp waves, 40-120ms in duration. caused by synchronous firing in much of the cortex ; occur 0.02 - 3 times/sec in daily activity & during slow wave sleep.
    • BUzsaki thinks that this may be related to memory consolidation.
  • check the cited-by articles : http://cercor.oxfordjournals.org/cgi/content/abstract/6/2/8
____References____
[0] Buzsaiki G, The hippocampo-neocortical dialogue.Cereb Cortex 6:2, 81-92 (1996 Mar-Apr)

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ref: Huber-2004.07 tags: sleep REM SWS wilson synaptic strength date: 04-01-2009 17:50 gmt revision:2 [1] [0] [head]

http://www.the-scientist.com/2009/04/1/34/1/ -- good layperson-level review of the present research on sleep. Includes interviews with Strickgold and other prominents. References:

http://www.the-scientist.com/2009/04/1/15/1/ -- points out that Western sleep style is a relative outlier compared to sleeping in other cultures. More 'primitive' cultures have polyphasic sleep, with different stages of alertness, dozing, napping, disengaged, vigilance, etc.

  • Quote: Other cultures tend towards "multiple and multiage sleeping partners; frequent proximity of animals; embeddedness of sleep in ongoing social interaction; fluid bedtimes and wake times; use of nighttime for ritual, sociality, and information exchange; and relatively exposed sleeping locations that require fire maintenance and sustained vigilance."

____References____

[0] Huber R, Ghilardi MF, Massimini M, Tononi G, Local sleep and learning.Nature 430:6995, 78-81 (2004 Jul 1)
[1] Klintsova AY, Greenough WT, Synaptic plasticity in cortical systems.Curr Opin Neurobiol 9:2, 203-8 (1999 Apr)
[2] Vyazovskiy VV, Cirelli C, Pfister-Genskow M, Faraguna U, Tononi G, Molecular and electrophysiological evidence for net synaptic potentiation in wake and depression in sleep.Nat Neurosci 11:2, 200-8 (2008 Feb)
[3] Pavlides C, Winson J, Influences of hippocampal place cell firing in the awake state on the activity of these cells during subsequent sleep episodes.J Neurosci 9:8, 2907-18 (1989 Aug)
[4] Pompeiano M, Cirelli C, Arrighi P, Tononi G, c-Fos expression during wakefulness and sleep.Neurophysiol Clin 25:6, 329-41 (1995)
[5] Hill S, Tononi G, Modeling sleep and wakefulness in the thalamocortical system.J Neurophysiol 93:3, 1671-98 (2005 Mar)
[6] Aton SJ, Seibt J, Dumoulin M, Jha SK, Steinmetz N, Coleman T, Naidoo N, Frank MG, Mechanisms of sleep-dependent consolidation of cortical plasticity.Neuron 61:3, 454-66 (2009 Feb 12)

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ref: Ribeiro-2004.12 tags: Sidarta Ribeiro reverberation sleep consolidation integration replay REM SWS date: 03-26-2009 03:19 gmt revision:2 [1] [0] [head]

PMID-15576886[0] Reverberation, storage, and postsynaptic propagation of memories during sleep

  • Many references in the first paragraph! They should switch to the [n] notation; the names are disruptive.
  • Show reverberation (is this measured in a scale-invariant way?) increases after novel object is placed in cage. Recorded from a single rat for up to 96 hours.
  • also looked at Zif-268 activation in the cortex (autoradiogram);
    • Previous results showed that Zif-268 levels are up-regulated in REM but not SWS in the hippocampus and cerebral cortex of exposed animals. (Ribeiro 1999)
    • hippocampal inactivation during REM sleep blocked zif-268 upregulation.
    • quote: "Increased activity is necessary but not sufficient to induce zif-268 expression, which also requires calcium inflow via NMDA channels and phosphorilation of the cAMP response element-binding protein (CREB)"
  • Sleep deprivation is much more detrimental to implicit than to explicit memory consolidation (Fowler et al. 1973; Karni et al. 1994; Smith 1995, 2001; Stickgold et al. 2000a; Laureys et al. 2002; Walker et al. 2002; Maquet et al. 2003; Mednick et al. 2003)

____References____

[0] Ribeiro S, Nicolelis MA, Reverberation, storage, and postsynaptic propagation of memories during sleep.Learn Mem 11:6, 686-96 (2004 Nov-Dec)

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ref: Graves-2001.04 tags: sleep memory REM protein synthesis review date: 03-25-2009 15:23 gmt revision:1 [0] [head]

PMID-11250009[0] Sleep and memory: a molecular perspective.

  • inhibition of protein synthesis is most effective if it occurs at a time post-training when rapid eye movement (REM) sleep is required for memory consolidation
  • The neurochemical changes that occur across sleep/wake states, especially the cholinergic changes that occur in the hippocampus during REM sleep, might provide a mechanism by which sleep modulates specific cellular signaling pathways involved in hippocampus-dependent memory storage.
    • REM sleep could influence the consolidation of hippocampus-dependent long-term memory if it occurs during windows that are sensitive to cholinergic or serotonergic signaling.
    • PKA activation seems important to hippocampal long-term memory
    • NMDA affects PKA through Ca2+ to adenyl cyclase
    • 5-HT_1A receptor negatively coupled to adenyl cyclase (AC)
    • 5-HT concentrations go down in hippocampus during sleep ?

____References____

[0] Graves L, Pack A, Abel T, Sleep and memory: a molecular perspective.Trends Neurosci 24:4, 237-43 (2001 Apr)

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ref: MAPlle-2009.03 tags: sleep spindles learning ripples LFP hippocampus neocortex synchrony SWS REM date: 03-25-2009 15:05 gmt revision:2 [1] [0] [head]

PMID-19245368[0] The influence of learning on sleep slow oscillations and associated spindles and ripples in humans and rats

  • Here we examined whether slow oscillations also group learning-induced increases in spindle and ripple activity, thereby providing time-frames of facilitated hippocampus-to-neocortical information transfer underlying the conversion of temporary into long-term memories.
  • No apparent grouping effect between slow oscillations and learning-induced spindles and ripples in rats.
  • Stronger effect of learning on spindles (neocortex) and ripples (hippocampus) ; less or little effect of learning on slow waves in the neocortex.
  • have a good plot showing their time-series analysis:

____References____

[0] Mölle M, Eschenko O, Gais S, Sara SJ, Born J, The influence of learning on sleep slow oscillations and associated spindles and ripples in humans and rats.Eur J Neurosci 29:5, 1071-81 (2009 Mar)

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ref: BrashersKrug-1996.07 tags: motor learning sleep offline consolidation Bizzi Shadmehr date: 03-24-2009 15:39 gmt revision:1 [0] [head]

PMID-8717039[0] Consolidation in human motor memory.

  • while practice produces speed and accuracy improvements, significant improvements - ~20% also occur 24hours later following a period of sleep. Why is this? We can answer it with the recording system!

____References____

[0] Brashers-Krug T, Shadmehr R, Bizzi E, Consolidation in human motor memory.Nature 382:6588, 252-5 (1996 Jul 18)

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ref: Debarnot-2009.03 tags: sleep motor imagery practice date: 03-24-2009 15:32 gmt revision:3 [2] [1] [0] [head]

PMID-18835655[0] Sleep-related improvements in motor learning following mental practice.

  • shows that after both physical practice and mental imagery on day 1, sleep improves test performance in both when testing on day 2.

____References____

[0] Debarnot U, Creveaux T, Collet C, Gemignani A, Massarelli R, Doyon J, Guillot A, Sleep-related improvements in motor learning following mental practice.Brain Cogn 69:2, 398-405 (2009 Mar)

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ref: Rasch-2009.04 tags: REM learning procedural memory sleep spindles date: 03-23-2009 18:32 gmt revision:3 [2] [1] [0] [head]

PMID-18836440[0] Pharmacological REM sleep suppression paradoxically improves rather than impairs skill memory

  • surpressed REM sleep with SSRIs or norepinephrine reuptake inhibitor
    • yet tested the subjects after a long wash-out: 32 hours, including 2 nights sleep.
  • did not impair word-pair recognition, and improved finger tapping accuracy.
  • sleep spindles are a feature of non-REM sleep.
  • REM sleep is characterized by an abscence of serotonin and norepinephrine; SSRIs and SNRIs increase the levels of these two neurotransmitters, respectively, at the synaptic cleft.
  • clinical studies of depressed patients show no impairment of skill performance during long-term treatment with these drugs, despite marked REM supression
  • did mirror-tracing and finger-tapping tasks.
  • SSRI supressed REM sleep; SNRI almost completely removed REM.
  • treatment increased accuracy of finger tapping task! esp. for the SNRI.
    • increase in accuracy was positively correlated to the change in spindle density.
  • For the mirror task, there were notable improvements after sleep, but no significant difference between placebo, SSRI, and SNRI groups.
  • paired-word retention task has been shown dependent on SWS; it was not affected by pharmacology.
  • They suggest that perhaps SSRI /SNRI supressed simply the typical measures of REM sleep, and that other factors critical for the associated consolidation were unaffected (e.g. high cholinergic activity).
  • result is consistent with [1]

____References____

[0] Rasch B, Pommer J, Diekelmann S, Born J, Pharmacological REM sleep suppression paradoxically improves rather than impairs skill memory.Nat Neurosci no Volume no Issue no Pages (2008 Oct 5)
[1] Tamaki M, Matsuoka T, Nittono H, Hori T, Fast sleep spindle (13-15 hz) activity correlates with sleep-dependent improvement in visuomotor performance.Sleep 31:2, 204-11 (2008 Feb 1)

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ref: Wagner-2004.01 tags: sleep insight mental restructure integration synthesis consolidation date: 03-20-2009 21:31 gmt revision:1 [0] [head]

PMID-14737168[0] Sleep Inspires Insight.

  • Subjects performed a cognitive task requiring the learning of stimulus–response sequences, in which they improved gradually by increasing response speed across task blocks. However, they could also improve abruptly after gaining insight into a hidden abstract rule underlying all sequences.
    • number reduction task - three numbers 1, 4, 9, in short sequence, with a simple comparison rule to generate a derivative number sequence; task was to determine the last number in sequence; this number was always the same as the second number.
  • This abstract rule was more likely to be learned after 8 hours of sleep as compared to 8 hours of wakefulness.
  • My thoughts: replay during sleep allows synchronous replay of cortical activity seen during the day (presumably from the hippocampus to the neocortex), replay which is critical for linking the second number with the last (response) number. This is a process of integration: merging present memories with existing memories / structure. The difference in time here is not as long as it could be .. presumably it goes back to anything in your cortex that is activated buy the hippocampal memories. In this way we build up semi-consistent integrated maps of the world. Possibly these things occur during dreams, and the weird events/thoughts/sensations are your brain trying to smooth and merge/infer things about the world.

____References____

[0] Wagner U, Gais S, Haider H, Verleger R, Born J, Sleep inspires insight.Nature 427:6972, 352-5 (2004 Jan 22)

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ref: Maquet-2001.11 tags: sleep learning memory Maquet date: 03-20-2009 18:38 gmt revision:1 [0] [head]

PMID-11691982[0] The Role of Sleep in Learning and Memory

  • 8 years ago; presumably much has changed?
  • NREM = SWS; REM = PS (paradoxical sleep)
  • nice table in there! looks as though he was careful in background research on this one; plenty of references.
  • "indeed, stress can also lead to an increase in REM sleep." -- but this may only be related to the presence of new material.
    • however, there is no increase in REM sleep if there is no material to learn.
  • reminder that theta rhythm is seen in the hippocampus in both exploratory activity and in REM sleep.
    • anticipated the presence of replay in the hippocampus
  • spindles allow the entry of Ca+2, which facilitates LTP (?).
  • I should check up on songbird learning (mentioned in the review!).
    • Young zebra finches have to establish the correspondence between vocal production (motor output) and the resulting auditory feedback (sensory).
    • This cannot be done during waking because the bird song arises from tightly time-coded sequence of activity; during sleep, however, motor output can be compared to sensory feedback (so as to capture an inverse model?)
  • PGO (ponto-geniculo-occipital) waves occur immediately before REM sleep. PGO waves are more common in rats after aversive training.
  • ACh increases cortical plasticity in adult mammals; REM sleep is characterized by a high level of ACh and 5-HT (serotonin).
---
  • sleep may not be necessary for recall-based learning, it just may be a goot time for it. Sharp waves and ripples are observed in both quiet waking and SWS.
  • Learning to reach in a force field is consolidated in 5 hours after training. [1]
  • Again mentions the fact that antidipressant drugs, which drastically reduce the amount of REM sleep, do not aversely affect memory.

____References____

[0] Maquet P, The role of sleep in learning and memory.Science 294:5544, 1048-52 (2001 Nov 2)
[1] Shadmehr R, Brashers-Krug T, Functional stages in the formation of human long-term motor memory.J Neurosci 17:1, 409-19 (1997 Jan 1)

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ref: Tononi-2006.02 tags: sleep synaptic homeostasis plasticity date: 03-20-2009 15:45 gmt revision:1 [0] [head]

PMID-16376591[0] Sleep function and synaptic homeostasis.

  • Sleep keeps the neural network stable & the synaptic weights in check.
    • if you don't sleep do you get epilepsy?? don't have access to the article, would have to read it.

____References____

[0] Tononi G, Cirelli C, Sleep function and synaptic homeostasis.Sleep Med Rev 10:1, 49-62 (2006 Feb)

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ref: Eschenko-2006.12 tags: sleep spindle learning rats date: 03-20-2009 00:40 gmt revision:1 [0] [head]

PMID-17167082[0] Elevated sleep spindle density after learning or after retrieval in rats.

  • sleep spindles = 12–15 Hz oscillations superimposed on slow waves (<1 Hz)
    • they say these 'promote' but infact they may just be effects of some lower-level synchronization / ensemble depolarization.
  • used an odor-response-reward task.
  • spindles reliably appear 1 hour after sleep begins.
  • hippocampal ripples are temporally related to cortical spindles and both are grouped by slow oscillations.
  • showed that pure exploration of novel environments (without the odorant pairing) does not change sleep spindle occurence frequency.

____References____

[0] Eschenko O, Mölle M, Born J, Sara SJ, Elevated sleep spindle density after learning or after retrieval in rats.J Neurosci 26:50, 12914-20 (2006 Dec 13)

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ref: Stickgold-2001.11 tags: review dream sleep REM NREM SWS learning memory replay date: 03-19-2009 17:09 gmt revision:7 [6] [5] [4] [3] [2] [1] [head]

PMID-11691983[0] Sleep, Learning, and Dreams: Off-line Memory Reprocessing

  • sleep can be broadly divided into REM (rapid eye movement) and NREM (no rapid eye movement) sleep, with the REM-NREM cycle lasting 90 minutes in humans.
  • REM seems involved in proper binocular wiring in the visual cortex, development of problem solving skills, and discrimination tasks.
    • REM sleep seems as important as visual experience for wiring binocular vision.
  • REM seems critical for learning procedural memories, but not declarative (by the authors claim that the tasks used in declarative tests are too simple).
    • Depriving rats of REM sleep can impair procedural learning at test points up to a week later.
    • SWS may be better for consolidation of declarative memory.
  • Strongest evidence comes from a visual texture discrimination task, where improvements are only seen after REM sleep.
    • REM has also been shown to have an effect in learning of complex logic games, foreign language acquisition, and after intensive studying.
    • Solving anagrames stronger after being woken up from REM sleep. (!)
  • REM (hypothetically) involves NC -> hippocampus; SWS involves hippocampus -> NC (hence declarative memory). (Buzaki 1996).
    • This may use theta waves, which enhance LTP in the hippocampus; the slow large depolarizations in SWS may facilitate LTP in the cortex.
  • Replay in the rat hippocampus:
    • replay occurs within layer CA1 during SWS for a half hour or so after learning, and in REM after 24 hours.
    • replay shifts from being in-phase with the theta wave activity (e.g. helping LTP) to being out of phase (coinicident with troughs, possibly used to 'erase' memories from the hippocampus?); this is in accord with memories becoming hippocampally independent.
  • ACh levels are at waking levels or higher, and levels of NE (noradrenergic) & 5-HT go near zero.
  • DLPFC (dorsolateral prefrontal cortex) is inhibited during REM sleep - presumably, this results in an inability to allocate attentional resources.
  • ACC (anterior cingulate cortex), MFC (medial frontal cortex), and the amygdala are highly active in REM sleep.
  • if you block correlates of learning - PKA pathwat, zif-268 genes during REM, learning is impaired.
  • In the context of a multilevel system of sleep-dependent memory reprocessing, dreams represent the conscious awareness of complex brain systems involved in the reprocessing of emotions and memories during sleep.
    • the whole section on dreaming is really interesting!

____References____

[0] Stickgold R, Hobson JA, Fosse R, Fosse M, Sleep, learning, and dreams: off-line memory reprocessing.Science 294:5544, 1052-7 (2001 Nov 2)

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ref: Mehta-2007.01 tags: hippocampus visual cortex wilson replay sleep learning states date: 03-09-2009 18:53 gmt revision:1 [0] [head]

PMID-17189946[0] Cortico-hippocampal interaction during up-down states and memory consolidation.

  • (from the associated review) Good pictorial description of how the hippocampus may impinge order upon the cortex:
    • During sleep the cortex is spontaneously and randomly active. Hippocampal activity is similarly disorganized.
    • During waking, the mouse/rat moves about in the environment, activating a sequence of place cells. The weights of the associated place cells are modified to reflect this sequence.
    • When the rat falls back to sleep, the hippocampus is still not random, and replays a compressed copy of the day's events to the cortex, which can then (and with other help, eg. ACh), learn/consolidate it.
  • see [1].

____References____

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ref: Ji-2007.01 tags: hippocampus visual cortex wilson replay sleep date: 03-09-2009 18:48 gmt revision:3 [2] [1] [0] [head]

PMID-17173043[0] Coordinated memory replay in the visual cortex and hippocampus during sleep.

  • EEG from Layer 5 of the visual cortex.
  • used tetrodes.
  • rats were trained to alternate loops in a figure-8 maze to get at food.
  • the walls of the maze were lined with high-contrast cues.
  • data for correlated activity between ctx and hippocampus weak - they just show that the frame ('up' period in cellular activity) start & end between the two regions are correlated. No surprise - they are in the same brain after all!
  • Found that cells in the deep visual cortex (V1 & V2) had localized firing fields. Rat vision is geared for navigation? (mostly?)
  • From this, they could show offline replay of the same sequence; these offline sequences were compressed by about 5-10.
    • shuffle tests on the replayed frames look pretty good - respectable degree of significance here.
    • Aside: possibly some of the noise of the recordings is reflective not of the noise of the system, but the noise / high dimensionality of the sensory input driving the visual ctx.
  • Also found some visual and some hippocampal cells that replayed sequences simultaneously; shuffle test here looks ok too.
  • picture from associated review, {692}

____References____

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ref: Nishida-2007.04 tags: sleep spindle learning nap NREM date: 03-06-2009 17:56 gmt revision:1 [0] [head]

PMID-17406665[0] Daytime naps, motor memory consolidation and regionally specific sleep spindles.

  • asked subjects to learn a motor task with their non-dominant hand, and then tested them 8 hours later.
  • subjects that were allowed a 60-90 minute siesta improved their performance significantly relative to controls and relative to previous performance.
  • when they subtracted EEG activity of the non-learning hemisphere from the learning hemisphere, spindle activity was strongly correlated with offline memory improvement.

____References____

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ref: Tamaki-2008.02 tags: sleep spindle NREM motor learning date: 02-18-2009 17:44 gmt revision:0 [head]

PMID-18274267[0] Fast sleep spindle (13-15 hz) activity correlates with sleep-dependent improvement in visuomotor performance.

  • mirror-tracing task performance improves following a night's sleep.
  • the improvement is correlated with the fast-spindle activity.
  • spindles were detected from EEG recordings with a 10-16hz butterworth filter in matlab. Spindles had to be >= 15uv, >= 0.5s
    • slow spindles = 10-13Hz, predominant in the frontal regions.
    • fast spindles > 13hz, predominant in the parietal regions.

____References____

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ref: Morin-2008.08 tags: sleep spindles NREM motor learning date: 02-18-2009 17:35 gmt revision:2 [1] [0] [head]

PMID-18714787[0] Motor sequence learning increases sleep spindles and fast frequencies in post-training sleep.

  • as you can read in the title, it is the motor learning that increases the spindles. They did not look for causality in the opposite direction.
  • Task was finger-tap motor sequence learning, with control. Subjects had to type on a computer keyboard using the nondominant hand. No visual feedback was given during non-training performance (e.g. during practice).
  • Beta-frequencies are greater in sleep after motor learning. , though this is not correlated with actual consolidation.
  • Other studies have shown that spindles are also more frequent after spatial or verbal learning.
  • observed no effect of SWS on motor sequence learning.

____References____

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ref: Song-2009.01 tags: sleep motor learning consolidation attention date: 02-18-2009 17:28 gmt revision:1 [0] [head]

PMID-18951924[0] Consciousness and the consolidation of motor learning

  • Not all consolidation occurs during sleep; in some instances consolidation only occurs during the day; in other times, neither daytime or sleep consolidates a memory.
  • Attention is an important factor that may determine if sleep or daytime replay plays a role in consolidation.
  • In a tapping task, after a night of sleep performance is faster and more accurrate. Without the sleep, but with the same 12-hour interval, the same improvement is absent.
  • Evidence suggests though we experience the sensation of 'voluntary' movement, the conscious wish to move is more an afterthought than the cause.
    • Source: Libet et al 1983. (Subjects could accurately time events, and reported that the will to move preceded actual movement. However, the cortical potentials associated with movement preceded conscious awareness).
    • nonetheless, studies indicate that conscious awareness can affect movements, and how they are consolidated.
  • people with no declarative memory (like HR) can still remember procedural skills.
  • Consolidation = the process by which a fragile memory acquired via practice or exposure is consolidated into a more permanent, stable long-term form. If it occurs in the hours after practice, then it is 'off-line'; likewise for sleep.
    • Consolidation also includes stabilization, or making the memories robust to interference from new memories (retroactive interference).
    • This seems to be dependent on sleep, specifically NREM.
    • In studies where attention was broken using a tone counting task, neither over-night nor over-day enhancements were found to occur for motor sequence learning.
    • Another interesting effect is the development of explicit memory over the course of a night's sleep. Sleep seems to encourage conscious awareness of implicit patterns. -- probably through replay and integration.
  • Regarding "thinking too much" about sports: "As in the studies cited above, motor learning may initially rely on more explicit and prefrontal areas, but after extended practice and expertise, shift to more dorsal areas, but thinking about the movement can shift activity back to the less skilled explicit areas. Although many explanations may be derived, one could argue that these athletes show that even when years of practice has given the implicit system an exquisitely fine tuned memory for a movement, the explicit system can interfere at the time of performance and erase all evidence of implicit memory."
  • Well-written throughout, especially the conclusion paragraph.

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ref: Rasch-2009.06 tags: sleep cholinergic acetylcholine REM motor consolidation date: 02-18-2009 17:27 gmt revision:0 [head]

PMID-19194375[0] "Impaired Off-Line Consolidation of Motor Memories After Combined Blockade of Cholinergic Receptors During REM Sleep-Rich Sleep."

  • In REM sleep there is high, almost to wake-like, levels of ACh activity (in the cortex? they don't say).
  • Trained subjects on a motor task after a 3-hour period of slow wave sleep.
  • Then administered ACh (muscarinic + nicotinic) blockers or placebo
  • Subjects with blocked ACh reception showed less motor consolidation. So, ACh is needed! (This is consistent with Ach being an attentional / selective signal for activating the cortex).

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ref: Pearlmutter-2009.06 tags: sleep network stability learning memory date: 02-05-2009 19:21 gmt revision:1 [0] [head]

PMID-19191602 A New Hypothesis for Sleep: Tuning for Criticality.

  • Their hypothesis: in the course of learning, the brain's networks move closer to instability, as the process of learning and information storage requires that the network move closer to instability.
    • That is, a perfectly stable network stores no information: output is the same independent of input; a highly unstable network can potentially store a lot of information, or be a very selective or critical system: output is highly sensitive to input.
  • Sleep serves to restore the stability of the network by exposing it to a variety of inputs, checking for runaway activity, and adjusting accordingly. (inhibition / glia? how?)
  • Say that when sleep is not possible, an emergency mechanism must com into play, namely tiredness, to prevent runaway behavior.
  • (From wikipedia:) a potentially serious side-effect of many antipsychotics is that they tend to lower a individual's seizure threshold. Recall that removal of all dopamine can inhibit REM sleep; it's all somehow consistent, but unclear how maintaining network stability and being able to move are related.

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ref: Dzirasa-2006.1 tags: Kafui dopamine sleep REM state-diagram SCLin date: 10-05-2008 17:37 gmt revision:2 [1] [0] [head]

PMID-17035544[0] Dopaminergic control of sleep-wake states

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ref: Dzirasa-2006.1 tags: DAT-KO Kafui Nicolelis sleep wake dopamine tyrosine synthesis date: 03-12-2007 01:50 gmt revision:1 [0] [head]

PMID-17035544 Dopaminergic control of sleep-wake states.

  • dopmergic activity is high in REM sleep!! perhaps this is involved in learning?
  • they have a good description of the DAT-KO model, and why it is good for both exessive levels of synaptic dopamine as well as depressed/parkinsonian levels...
  • also at http://hardm.ath.cx:88/pdf/Kafui2006.pdf

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ref: GarciaRill-1991.01 tags: PPN pedunculopontine nucleus brainstem sleep locomotion consciousness 1991 date: 0-0-2007 0:0 revision:0 [head]

PMID-1887068 The Pedunculopontine nucleus

  • extensive review!