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. 2018 Jun 1;13(6):637-647.
doi: 10.1093/scan/nsy041.

Incorporation of Recent Waking-Life Experiences in Dreams Correlates With Frontal Theta Activity in REM Sleep

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Free PMC article

Incorporation of Recent Waking-Life Experiences in Dreams Correlates With Frontal Theta Activity in REM Sleep

Jean-Baptiste Eichenlaub et al. Soc Cogn Affect Neurosci. .
Free PMC article

Abstract

Rapid eye movement (REM) sleep and its main oscillatory feature, frontal theta, have been related to the processing of recent emotional memories. As memories constitute much of the source material for our dreams, we explored the link between REM frontal theta and the memory sources of dreaming, so as to elucidate the brain activities behind the formation of dream content. Twenty participants were woken for dream reports in REM and slow wave sleep (SWS) while monitored using electroencephalography. Eighteen participants reported at least one REM dream and 14 at least one SWS dream, and they, and independent judges, subsequently compared their dream reports with log records of their previous daily experiences. The number of references to recent waking-life experiences in REM dreams was positively correlated with frontal theta activity in the REM sleep period. No such correlation was observed for older memories, nor for SWS dreams. The emotional intensity of recent waking-life experiences incorporated into dreams was higher than the emotional intensity of experiences that were not incorporated. These results suggest that the formation of wakefulness-related dream content is associated with REM theta activity, and accords with theories that dreaming reflects emotional memory processing taking place in REM sleep.

Figures

Fig. 1.
Fig. 1.
(A) Schematic of the experiment. For 10 consecutive days participants were asked to complete a daily log. On the night of the 10th day, they slept in the sleep laboratory and were monitored using polysomnographic recordings. They were awoken after 10 min of REM or SWS sleep, and were asked to report their dreams. Approximately 4 weeks later they were asked to identify if parts of the dream reports collected in the sleep laboratory matched parts of the 10 daily logs (see Methods). (B) Mean number of waking-life experiences across the 10 daily log days identified by the participants as being incorporated in REM dreams. Per participant, the mean number of incorporations of recent (days 1/2) and older (days 3/4, 5/6, 7/8 and 9/10) waking experiences in REM dreams was calculated (for participants who had only one REM dreams, this unique value was used). The mean across participants was then calculated and is displayed in Figure 1B. Error bars represent s.d. Daily log number refers to the number of days between completing the log and going to the laboratory (e.g. items from daily log 7 occurred 7 days before the night in the laboratory). (C) Examples of 30 s-long recordings (F3, F4 and bipolar EOG) in REM sleep prior to an awakening with a dream report. Three examples from three different participants are displayed. In the dream reports following these REM sleep periods, participants identified 4, 2 and 0 recent incorporations, respectively (from top to bottom panels). EOG are from bipolar montage and the hatched areas characterize EOG events as automatically detected (see Methods).
Fig. 2.
Fig. 2.
Example of incorporations of daily life experiences into dreams. A daily log is displayed on the left side and a dream report on the right side. In this example, the participant identified three correspondences scored 4, 7 and 6, respectively (on a scale from 0 [none] to 8 [extremely strong] assessing the extent of correspondence between the part of the daily log and the part of the dream report).
Fig. 3.
Fig. 3.
Averaged power spectrum in REM and SWS sleep. Per electrode (F3 and F4), power spectrum of the 3 min of sleep preceding each awakening was computed (see Methods) and log-transformed (base 10) before being averaged across awakenings for REM and SWS separately.
Fig. 4.
Fig. 4.
Relationship between the number of incorporations of daily experiences in REM dreams and frontal theta activity in REM sleep. The two first panels display the relationship between the frontal theta power in REM sleep and the number of recent (from days 1/2, top panel) and older (from days 7/8, middle panel) experiences identified as being incorporated in REM dreams by the participants. The last panel displays the relationship when judges independently identified recent incorporations in REM dreams (from days 1/2, bottom panel). Higher frontal theta activity in REM sleep was associated with higher number of references to recent waking experiences in REM dreams as identified by the participants for the all REM (weighted correlation coefficient, in gray) and last/only REM (in red) samples (*P < 0.05, † P < 0.10; two-tailed) or by independent judges for the last/only REM samples (*P < 0.05, two-tailed). The sample of the final or only REM dream of each participant is highlighted in red. The data points for number of incorporations 0, 1 and 2 for participants’ scores (top and middle panels) were slightly spaced horizontally for display purposes.

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References

    1. Ambrosini M.V., Giuditta A. (2001). Learning and sleep: the sequential hypothesis. Sleep Medicine Reviews, 5(6), 477–90. - PubMed
    1. Antrobus J. (1983). REM and NREM sleep reports: comparison of word frequencies by cognitive classes. Psychophysiology, 20(5), 562–8. - PubMed
    1. Baran B., Pace-Schott E.F., Ericson C., Spencer R.M. (2012). Processing of emotional reactivity and emotional memory over sleep. Journal of Neuroscience, 32(3), 1035–42. - PMC - PubMed
    1. Blagrove M., Fouquet N.C., Henley-Einion J.A., et al. (2011a). Assessing the dream-lag effect for REM and NREM stage 2 dreams. PLoS One, 6(10), e26708.. - PMC - PubMed
    1. Blagrove M., Henley-Einion J., Barnett A., Edwards D., Heidi Seage C. (2011b). A replication of the 5-7 day dream-lag effect with comparison of dreams to future events as control for baseline matching. Consciousness and Cognition, 20(2), 384–91. - PubMed

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