PreprintCited by 45Sleep and Wakefulness ResearchSleep and related disordersMemory Processes and Influences

Structural differences between REM and non-REM dream reports assessed by graph analysis

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Martin, Joshua M., Wainstein, Danyal, Mota, Natalia B., Mota-Rolim, Sergio A., Araújo, John Fontenele, Solms, Mark, Ribeiro, Sidarta·2020·PLoS ONE

Preprint — published as 10.1371/journal.pone.0228903

Abstract

Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural organization of dream reports is lacking, and traditional measures that distinguish REM and non-REM dreaming may be confounded by report length. This problem is amenable to the analysis of dream reports as non-semantic directed word graphs, which provide a structural assessment of oral reports, while controlling for individual differences in verbosity. Against this background, the present study had two main aims: Firstly, to investigate differences in graph structure between REM and non-REM dream reports, and secondly, to evaluate how non-semantic directed word graph analysis compares to the widely used measure of report length in dream analysis. To do this, we analyzed a set of 125 dream reports obtained from 19 participants in controlled laboratory awakenings from REM and N2 sleep. We found that: (1) graphs from REM sleep possess a larger connectedness compared to those from N2; (2) measures of graph structure can predict ratings of dream complexity, where increases in connectedness and decreases in randomness are observed in relation to increasing dream report complexity; and (3) measures of the Largest Connected Component of a graph can improve a model containing report length in predicting sleep stage and dream complexity. These results indicate that dream reports sampled after REM awakening have on average a larger connectedness compared to those sampled after N2 (i.e. words recur with a longer range), a difference which appears to be related to underlying differences in dream complexity. Altogether, graph analysis represents a promising method for dream research, due to its automated nature and potential to complement report length in dream analysis.

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  • REM dreams are more complex and have a larger connectedness (though graph-theoretically less random-like) than NREM dreams.

    “the analysis of dream protocols by non-semantic word graphs has shown that REM dreams are more complex and have a larger connectedness (although they are graph-theoretically less random-like) than NREM dreams [78].”

    From How Adversarial REM Dreams May Facilitate Creativity, and Why We Become Aware of Them (2024) · cites this paper as [78]

    The Discussion and Conclusions report larger graph connectedness in REM than N2 dream reports and associate more complex dreams with larger connectedness. But the section “REM Reports Are Longer and Have Larger Connectedness Compared to N2” explicitly says the study found no difference between REM and non-REM reports in random-likeness, contrary to the citing sentence’s comparative claim. (LLM, conf=0.92)

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  1. Nielsen TA, Kuiken DL, Moffitt A, Hoffman R, Newell R. Comparisons of the story structure of stage REM and stage 2 mentation reports. Sleep Research. 1983; 20: 181.

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Authors
Martin, J. M., Wainstein, D., Mota, N. B., Mota-Rolim, S. A., Araújo, J. F., Solms, M., & Ribeiro, S.
Affiliations
  • Universidade Federal do Rio Grande do Norte (BR)
  • University of Cape Town (ZA)
Corresponding author
Ribeiro, Sidarta
Venue
PLoS ONE
Publisher
openRxiv
Published
2020-01-28
Volume
15
Issue
7
Pages
e0228903-e0228903
ISSN
1932-6203 (ISSN-L)
OpenAlex
W3044697089
Cited by
45
References
45
Citations by year
2026: 7 · 2025: 8 · 2024: 13 · 2023: 6 · 2022: 8 · 2021: 3
FWCI
2.28
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • PLoS ONE (publishedVersion, cc-by)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, cc-by)
Funders
  • Fundação de Amparo à Pesquisa do Estado de São Paulo (2013-07699-0, 13/07699-0)
  • Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (2013/07699-0, 308775/2015-5, 408145/2016-1)
  • Governo Brasil
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico (2013/07699–0, 308775/2015­5, 408145/2016-1)
  • Financiadora de Estudos e Projetos (2013/07699-0)
  • Fundação de Apoio à Pesquisa do Rio Grande do Norte
  • University of Cape Town (457091)
  • Ministério da Ciência e Tecnologia
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Sleep and Wakefulness Research
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory Processes and Influences
Keywords
REM sleep, NREM sleep, dream narrative, graph structure, graph connectivity, largest connected component, report length, sleep stage classification, dream vividness, N2 sleep
MeSH terms
Adolescent, Adult, Dreams, Female, Humans, Male, Mental Recall, Sleep Stages, Sleep, REM, Time Factors, Linear Models, Young Adult

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