phenomenon · claim-type · cross-domain-transfer · mechanism · claim-relation · replication-status · limitation — grounded in the full text| phenomenon | dreaming as conscious experience during sleep— “Using high-density EEG, we contrasted the presence and absence of dreaming within NREM and REM sleep.” | |
| claim-type | existence— “In both NREM and REM sleep, the presence of dreaming was associated with a local decrease in low-frequency activity in posterior cortical regions.” | |
| method — evidence | — “They were performed using a 256-channel highdensity EEG (hd-EEG) system (Electrical Geodesics, Inc., Eugene, Ore.).” | |
| mechanism | Conscious experience during sleep requires local activation (loss of low-frequency, bistable mode) of the posterior hot zone, which is why dreaming can occur in NREM and REM alike regardless of the EEG in the rest of cortex— “The present results resolve these paradoxes by showing that in both REM and NREM sleep, dreaming, and more generally, conscious experience during sleep, requires a localized activation of a posterior hot zone, irrespective of the EEG in the rest of the cortex.” | mechanisms[0] |
| mechanism | Low-frequency (1-4 Hz) activity indexes neuronal down-states and bistability, which block stable causal interaction between cortical areas and so abolish experience— “EEG slow frequencies between 1 and 4 Hz during sleep are associated with neuronal down-states and bistability 12, which prevent the emergence of stable causal interactions among cortical areas 13, and have been linked to the loss of consciousness 14,15.” | mechanisms[1] |
| mechanism | Once the hot zone is out of its low-frequency mode, which specific neuronal groups fire strongly determines which contents are experienced, as in waking perception— “A plausible interpretation of this finding is that, as long as the posterior hot zone is not in a low-frequency mode that prevents experiences, the specific contents of experiences when dreaming are dictated by which specific groups of neurons fire strongly and which do not, just as in wake.” | mechanisms[2] |
| extends | the fMRI dream-content decoding study cited as ref. 43 (a wake-trained pattern classifier decoding content reported at the wake–sleep transition)— “Our results with high-density EEG extend these findings beyond falling asleep to periods of consolidated sleep, providing further evidence that dream reports reflect conscious experience during sleep rather than confabulations upon awakening 44,45.” | claim_relations[0] |
| contradicts | the influential neuroimaging-derived notion (ref. 54) that the neural correlates of consciousness correspond to a broad fronto-parietal network— “By exploiting a within state, no stimulus, no task paradigm, our findings indicate that the neural correlate of consciousness, rather than involving the broad lateral fronto-parietal network, is restricted to a posterior hot zone.” | claim_relations[1] |
| sense | absence of a dream report - AS NO EXPERIENCE (NE): the subject reports not experiencing anything— “or not experiencing anything (no experience, NE, see Online Methods).” | senses[0] |
| sense | absence of a dream report - AS EXPERIENCE WITHOUT RECALL (DEWR): the subject reports experiencing something but cannot remember the content, which is a different state from having had none— “experiencing something but could not remember the content (dreaming experience without recall of content, DEWR)” | senses[1] |
| sense | dreaming - traditionally IDENTIFIED WITH REM sleep and its wake-like high-frequency EEG, an identification the paper reports as broken because dreaming also occurs in NREM sleep— “Traditionally, dreaming has been identified with REM sleep, characterized by a wake-like, globally ‘activated’, high-frequency EEG. However, dreaming also occurs in NREM sleep, characterized by prominent low-frequency activity.” | senses[2] |
| control | a longer 20-second pre-awakening window used for the experience/no-experience contrast than the 0 to -8s windows used for content-specific contrasts — held — rules out a report being assigned to the wrong stretch of sleep - subjects could tie CONTENT to a moment but not the bare presence or absence of an experience, so that contrast is given more room— “Therefore, we opted to include slightly longer timeframes (20s before the awakening) to account for possible variability when comparing DE, DEWR and NCE.” | controls[0] |
| differs in | the influential neuroimaging-derived notion (ref. 54) that the neural correlates of consciousness correspond to a broad fronto-parietal network — THE AXIS IS THE PARADIGM, AND IT IS NAMED IN THE SAME SENTENCE AS THE CONCLUSION. 'By exploiting a within state, no stimulus, no task paradigm, our findings indicate that the neural correlate of consciousness, rather than involving the broad lateral fronto-parietal network, is restricted to a posterior hot zone.' The fronto-parietal result is not called wrong - it is attributed to paradigms that require a task and a report, which this one removes. A bare 'contradicts' records a dispute about ANATOMY; the parameter shows it is a dispute about METHOD.— “By exploiting a within state, no stimulus, no task paradigm, our findings indicate that the neural correlate of consciousness, rather than involving the broad lateral fronto-parietal network, is restricted to a posterior hot zone.”— “By exploiting a within state, no stimulus, no task paradigm” | claim_relations[1] |
| edge | dreaming —distinct-from→ REM sleep— “Traditionally, dreaming has been identified with REM sleep, characterized by a wake-like, globally ‘activated’, high-frequency EEG. However, dreaming also occurs in NREM sleep, characterized by prominent low-frequency activity.” | concept_edges[0] |
| outcome (stated by the tagger, no quotation) | control — held | controls[0] |
| for which use | limitation — the anatomical completeness of the hot zone: SINCE THE POSTERIOR HOT ZONE WAS HIGHLIGHTED BY AVERAGING EEG RECORDINGS PRECEDING MANY AWAKENINGS FROM MANY SUBJECTS, THE FULL NEURAL CORRELATES OF EXPERIENCES IN SLEEP COULD OCCASIONALLY INCLUDE ADDITIONAL BRAIN REGIONS— “Of course, since the posterior hot zone was highlighted by averaging EEG recordings preceding many awakenings from many subjects, the full neural correlates of experiences ins sleep could occasionally include additional brain regions.” | limitations[0] |
| for which use | limitation — the interpretation of the hot zone as supporting experience: WE CANNOT RULE OUT THAT [it] MAY INCLUDE ... AREAS THAT MIGHT SUPPORT UNCONSCIOUS ASPECTS OF DREAM GENERATION— “Conversely, we cannot rule out that the posterior hot zone may include, besides brain regions supporting experiences, areas that might support unconscious aspects of dream generation.” | limitations[1] |
| for which use | limitation — the absolute low-frequency power values: SOURCE MODELING STRONGLY REDUCES BUT DOES NOT COMPLETELY ELIMINATE THE EFFECTS OF VOLUME CONDUCTION— “Indeed, source modeling strongly reduces but does not completely eliminate the effects of volume conduction.” | limitations[2] |
| for which use | limitation — sleep stage as an indicator of whether a subject was having an experience: the paper states this cannot be determined from behavioural state, traditional EEG features or neuroimaging correlates— “Thus, whether one experiences something or not during sleep cannot be determined simply by assessing one’s behavioral state based on traditional EEG features or neuroimaging correlates” | limitations[3] |
| for which use | limitation — REM sleep as the state of dreaming: the paper reports a consistent minority of REM awakenings with no reported experience, and dreaming occurring in NREM sleep— “Conversely, in a small but consistent minority of cases, subjects deny having had any experience when awakened from REM sleep.” | limitations[4] |
| replication | untested | |
| limitation | The hot zone was identified by averaging across many awakenings and subjects, so individual episodes of experience may involve additional regions.— “Of course, since the posterior hot zone was highlighted by averaging EEG recordings preceding many awakenings from many subjects, the full neural correlates of experiences ins sleep could occasionally include additional brain regions.” | limitations[0] |
| limitation | Parts of the posterior hot zone may support unconscious dream-generating processes rather than experience itself.— “Conversely, we cannot rule out that the posterior hot zone may include, besides brain regions supporting experiences, areas that might support unconscious aspects of dream generation.” | limitations[1] |
| limitation | Source modelling does not fully remove volume conduction, which inflates absolute low-frequency power values.— “Indeed, source modeling strongly reduces but does not completely eliminate the effects of volume conduction.” | limitations[2] |
| limitation | The behavioural state does not settle whether there was an experience, and the paper says so of both the traditional EEG features and the neuroimaging correlates.— “Thus, whether one experiences something or not during sleep cannot be determined simply by assessing one’s behavioral state based on traditional EEG features or neuroimaging correlates” | limitations[3] |
| limitation | The identification the field worked with is reported as failing in both directions: dreams are absent from some REM awakenings and present in NREM sleep.— “Conversely, in a small but consistent minority of cases, subjects deny having had any experience when awakened from REM sleep.” | limitations[4] |
finding · quantity · variable · definition · key-term — grounded in the full text| finding | In both NREM and REM sleep, dreaming was associated with a local decrease in low-frequency activity in posterior cortical regions.— “In both NREM and REM sleep, the presence of dreaming was associated with a local decrease in low-frequency activity in posterior cortical regions.” | content_tags.findings[0] |
| finding | Reports of having experienced something without recalling its content also showed the posterior low-frequency decrease relative to no-experience reports, so the posterior marker tracks having an experience rather than remembering it.— “Thus, decreased low-frequency power in this posterior cortical zone was correlated with the occurrence of dreaming experiences, irrespective of the ability to remember the contents of the experience.” | content_tags.findings[1] |
| finding | Awakenings triggered in real time by a bispectral low/high-frequency threshold over the posterior hot zone predicted the presence or absence of dreaming in NREM sleep with 87% overall accuracy (91.6% for dreaming predictions, 80.7% for no-experience predictions).— “After removal of trials containing artifact (see Online Methods), there remained 36 awakenings initiated by the algorithm with a DE prediction, out of which 33 were accurate (DE mean accuracy = 91.6%, p=0.00001), and 26 awakenings with a NE prediction, out of which 21 were accurate (NE mean accuracy = 80.7%, p=0.0003); total prediction… | content_tags.findings[2] |
| finding | High-frequency activity correlated with the thinking dimension of dreams in frontal regions and with the perceiving dimension in parietal, occipital and temporal areas.— “We found that high-frequency activity correlated with the thinking dimension in frontal brain regions and with the perceiving dimension in parietal, occipital and temporal areas (r>0.14, Fig. 4A).” | content_tags.findings[3] |
| finding | Dreams containing faces were accompanied by increased high-frequency activity in a temporo-occipital region closely matching the fusiform face area.— “As shown in Fig. 4B, DEs containing faces, compared to DEs without faces, were associated with increased high-frequency activity in a circumscribed temporo-occipital region that closely matched the fusiform face area (FFA).” | content_tags.findings[4] |
| finding | Dreams with a definite spatial setting showed increased high-frequency activity in right posterior parietal cortex, an area supporting spatial perception and visuo-spatial attention in wakefulness.— “We found that DEs with a definite spatial setting were associated with increased high-frequency activity in the right posterior parietal cortex (rPPC) (Fig. 4C), an area involved in spatial perception and visuo-spatial attention 20, whose lesion can cause spatial… | content_tags.findings[5] |
| finding | Dreams containing speech showed increased high-frequency activity in a left posterior temporal region corresponding to Wernicke's area. | content_tags.findings[6] |
| finding | The results showed no reliable hemispheric asymmetry, apart from a borderline right-sided effect for the high-frequency dreaming-versus-no-experience contrast in REM sleep. | content_tags.findings[7] |
| finding | The low- and high-frequency effects on dreaming survived control for participant age, with a significant main effect of report type and no age effect. | content_tags.findings[8] |
| finding | Because the correlate of experience was confined to a posterior region rather than a lateral fronto-parietal network, the authors conclude the neural correlate of consciousness is posterior rather than fronto-parietal. Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[9] |
| quantity | 87% — Overall accuracy of real-time prediction of the presence or absence of dreaming in NREM sleep from posterior hot-zone EEG Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[0] |
| quantity | N=32, 233 awakenings; N=7, 815 awakenings — Sample sizes for experiment 1 (many naive subjects, few awakenings each) and experiment 2 (few trained subjects, many awakenings each) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[1] |
| quantity | 84 — Total number of algorithm-triggered awakenings in the real-time prediction experiment Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[2] |
| quantity | p=0.023 — Region-of-interest test showing higher high-frequency activity in the right fusiform face area for dreams containing faces Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[3] |
| quantity | r>0.14 — Correlation threshold at which high-frequency power tracked the thinking-versus-perceiving rating of REM dreams Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[4] |
| quantity | p=0.003 / p=0.005 — Main effect of report type on low-frequency and high-frequency activity after controlling for age Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[5] |
| quantity | p= 0.046 — The single borderline hemispheric lateralization effect, for high-frequency DE-vs-NE in REM sleep Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[6] |
| variable | type of report (independent) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[0] |
| variable | low-frequency power (dependent) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[1] |
| variable | high-frequency band power (dependent) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[2] |
| variable | hemisphere (moderator) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[3] |
| variable | age (covariate) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[4] |
| definition | posterior cortical 'hot zone' Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[1] |
| definition | bispectral threshold Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[2] |
| definition | EEG slow waves Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[3] |
| definition | dreaming experience Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[4] |
| definition | DEWR Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[5] |
| definition | no experience Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[6] |
| concept | dreaming Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[0] |
| concept | REM sleep Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[1] |
| concept | no experience Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[2] |
| repeated-measures ANOVA F | as written: repeated-measure-ANOVA Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[0] |
| ANCOVA | as written: repeated measures ANCOVA Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[1] |
| paired t-test p | as written: paired one-tailed t-test Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[2] |
| Spearman rank correlation r | as written: Spearman rank correlation coefficient Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[3] |
| permutation test | as written: a permutation-based approach Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[4] |
| nonparametric multiple-comparison correction | as written: Statistical nonparametric mapping (SnPM) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[5] |
| Kolmogorov-Smirnov normality test | as written: Lilliefors modification of the Kolmogorov-Smirnov test Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[6] |
| false discovery rate correction P | as written: topological FDR Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[7] |
| spectral power density estimation (Welch periodogram) | as written: Welch's modified periodogram method Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[8] |
| general linear model | as written: the GLM framework implemented in SPM12 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[9] |
| standard deviation SD | as written: mean ± SD Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[10] |
| F-test for interaction F | as written: F(1,6)=1.35, p=0.29 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[11] |
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