PLoS One
March 22, 2022
Erin J. Wamsley
22 citations
The constructive episodic simulation hypothesis, which proposes that waking thought combines fragments of past episodes to imagine future events, may also explain dreaming. In a study of 48 college students who identified waking-life sources for 469 dreams, 53.5% of dreams were traced to at least one past episodic source and 25.7% to a future episodic source. 43.9% of dreams with content drew on multiple waking sources, incorporating memory fragments into scenarios anticipating future events. The phenomenology and distribution of dream sources across time and sleep stage provide evidence that dreams use memory to simulate potential futures, not merely reflect the past.
May 16, 2023
William Wong, Kátia C. Andrade, Thomas Andrillon et al.
21 citations
preprint
A new open-access database, DREAM, combines sleep magneto/electroencephalography (M/EEG) recordings with standardized dream reports to enable large-scale neurocognitive research on dreaming. The initial release includes 20 datasets from 561 participants and 2649 awakenings, each with at least 20 seconds of high-frequency M/EEG data and a classification of the subject's experience. Analyses demonstrate that features extracted from EEG can predict whether a person reports having had a conscious experience during both REM and NREM sleep. The database aims to overcome the limitations of small sample sizes and methodological variability in dream research, allowing new questions to be addressed at a scale unattainable by individual labs.
Nature Communications
August 13, 2025
William Wong, Rubén Herzog, Kátia Cristine Andrade et al.
10 citations
A new open database, the DREAM database, combines standardized sleep magneto/electroencephalography (M/EEG) recordings with dream reports from 505 participants across 20 datasets, totaling 2,643 awakenings. Each awakening includes at least 20 seconds of high-resolution sleep EEG (≥100 Hz, ≥2 electrodes) and a classification of the sleeper's reported experience. Analyses showed that reports of conscious experiences during sleep can be predicted from objective EEG features in both REM and NREM sleep. The database aims to overcome limitations of small sample sizes and methodological variability in dream research, enabling larger-scale investigations of the neurocognitive basis of dreaming.
SLEEP Advances
January 1, 2024
Erin J. Wamsley, Tempest Trost, Matthew A. Tucker
2 citations
Dreaming is influenced by the activation of newly formed memory traces in the sleeping brain, but how this happens is still being investigated. In a study testing whether people dream of recent experiences that overlap with well-established semantic networks, participants received new information about a favorite celebrity. Their dream content was tracked across three consecutive nights, and they were asked about recent and remote memory sources of their dreams. The celebrity manipulation did not affect dream content. However, the dataset offers rich descriptive information about how recent and remote memory fragments are incorporated into dreams and how multiple memory sources combine to create bizarre, imaginative scenarios. These observations are discussed in light of the proposed memory updating function of sleep-dependent memory consolidation and the NEXTUP model of dreaming.
SLEEP Advances
January 1, 2025
Chadwick C Frost, Erin J. Wamsley
1 citation
Activating a remote emotional memory just before sleep can induce dreams about that memory. In a study with 34 participants, those who recalled and wrote about an emotionally negative remote memory before a daytime nap later had dreams judged to contain content from that memory more than from a control task. Participants also rated their dreams as more emotionally negative after the memory task. The findings suggest that dream content can be experimentally influenced by reactivating older memories, possibly reflecting memory reconsolidation during sleep.
SLEEP Advances
January 1, 2026
Tony J. Cunningham, Erin J. Wamsley, JD Payne
A Festschrift honors Dr. Robert Stickgold's career, which transformed sleep from a passive state into an active component of memory consolidation, where reactivation and dreaming stabilize, abstract, and integrate waking experiences. His work established that sleep improves performance on visual discrimination and procedural memory, linked gains to Stage 2 sleep and spindles, and showed sleep extracts gist and transforms memories for future use. He developed the Nightcap device for at-home dream collection and the NEXTUP model of dreaming as creating novel meaning. Contributions from colleagues report that reactivation during wake fails to improve performance like sleep does, sleep restriction impairs memory discrimination in adolescents, total sleep deprivation impairs memory but recovery sleep enhances emotional content, and closed-loop auditory stimulation targets spindles without disrupting sleep.
Sleep
April 20, 2024
Chadwick C Frost, Taya Middleton, Erin J. Wamsley
Recalling a personal emotional memory before sleep did not make people dream about that memory more than writing about a neutral topic. However, dreams after recalling an angry memory were rated as more negative in emotion, especially the first dream reported. This suggests that while pre-sleep experiences rarely appear directly in dream content, emotional stimuli can influence the emotional tone of dreams, possibly reflecting emotional memory consolidation or a general effect of pre-sleep mood on dream emotion.
Sleep
December 11, 2023
Lauren Hudachek, Erin J. Wamsley
Dreaming about newly learned information is strongly associated with better memory after sleep, according to a meta-analysis of 16 studies. Across 45 reported effects, the association between task-related dreaming and memory performance was statistically significant. The relationship held for all types of learning tasks examined. Among studies using polysomnography, the association was significant for dreams collected during non-rapid eye movement (NREM) sleep but not for those from rapid eye movement (REM) sleep. These results suggest that dream content may reflect memory consolidation, with preliminary evidence that the link between dreaming and memory may be stronger in NREM sleep than in REM sleep.
Psychophysiology
July 1, 2019
Jing Zhang, Erin J. Wamsley
Dreaming is associated with distinct patterns of brain activity depending on the stage of sleep. During the transition into sleep, dream imagery emerges alongside increased low-frequency EEG power below 7 Hz. During later N2 sleep, dreaming occurs when low-frequency power below 1 Hz decreases and higher-frequency power above 4 Hz increases. No EEG predictors of dreaming were found during REM sleep. These patterns suggest an inverted-U relationship between dreaming and low-frequency EEG rhythms: dreaming first appears with EEG slowing during sleep onset, then fades as high-amplitude slow oscillations dominate N2 sleep.
Journal of Sleep Research
February 1, 2019
Erin J. Wamsley, Robert Stickgold
Dreaming about a spatial learning task during sleep predicts improved performance the next morning. In an overnight study, people trained on a virtual maze navigation task reported dreams from all sleep phases that reflected the task. Unambiguous representation of the task in dream content was associated with better next-morning performance. These findings align with models of memory consolidation that propose memory traces are reactivated during sleep, and replicate earlier work showing that dreaming about a learning task during a nap predicted performance gains.
Oxford Handbooks Online
April 5, 2018
Erin J. Wamsley
Dreams are not a mysterious experience separate from waking thought but arise from the same brain processes that produce spontaneous thoughts during wakefulness. New evidence indicates these processes involve the brain's memory systems, which support the consolidation of newly learned experiences. During both sleep and wakefulness, fragments of recent memories are recombined with related older memories and general knowledge to create novel scenarios. This adaptive process contributes to memory consolidation and is reflected in the phenomenology of both nightly dreams and waking daydreams.
Current Neurology and Neuroscience Reports
March 1, 2014
Erin J. Wamsley
Dreaming is shaped by the brain's consolidation of memories during sleep. After new information is learned, memory traces are gradually stabilized and reorganized for long-term storage. Sleep provides an ideal state for this process, allowing memory networks to be reactivated without new sensory input. This reactivation and consolidation influences conscious experience during sleep, contributing to dream content recalled upon waking. The article reviews evidence supporting this hypothesis and addresses common objections.
Sleep
February 1, 2014
Erin J. Wamsley, Claire E H M Donjacour, Thomas E Scammell et al.
A distinctive feature of narcolepsy, termed 'dream delusions,' occurs when patients mistake the memory of a vivid dream for a real experience and form sustained false beliefs that can persist for days or weeks. In interviews with 46 narcolepsy patients with cataplexy and 41 healthy controls at academic medical centers in Boston and Leiden, dream delusions were surprisingly common and often severe, differing from fleeting hypnagogic or hypnopompic hallucinations. These false memories suggest source memory deficits in narcolepsy that have not yet been fully characterized.
Sleep
January 1, 2010
Erin J. Wamsley, Karen Perry, Ina Djonlagic et al.
During light NREM sleep, people's dream reports often replay recent waking experiences. In a visuomotor learning task, 30% of verbal reports collected from sleeping participants related to the task. The replay became more abstracted from the original experience as sleep progressed. These findings suggest that memory reactivation during sleep is reflected in subjective dream content, offering a window into cognitive processing in the sleeping brain.