People who are asleep and having a lucid dream—aware that they are dreaming—can perceive questions from an experimenter and answer them in real time using eye movements and facial muscle contractions. In a study of 36 individuals during REM sleep, including frequent lucid dreamers, a novice, and a patient with narcolepsy, participants performed perceptual analysis of new information, held information in working memory, computed simple answers, and gave volitional replies. Correct answers occurred on 29 occasions across 6 individuals, documented by four independent laboratories. This two-way communication channel allows real-time interrogation of dream cognition and characteristics.
Dreams during REM sleep are emotionally fluid and fast-changing, with positive and negative emotions alternating frequently. In a study of 24 lucid dreamers with narcolepsy who reported emotional valence in real-time using facial codes during daytime naps monitored with polysomnography, 62 of 126 naps contained at least one emotional code during REM sleep, yielding 191 codes total. Positive and negative codes were evenly balanced per nap, and over half of naps with at least two codes showed opposite valences. The average duration of a given emotional valence was about one minute, with positive emotions emerging earlier than negative ones. These findings suggest that the emotional dynamics of REM sleep dreams may contribute to understanding how dreams help regulate emotions.
Patients with idiopathic hypersomnia more often report a night blackout—an absence of experiences or recall from sleep onset to offset—than patients with narcolepsy or healthy controls. In a questionnaire study of 133 idiopathic hypersomnia patients, 108 narcolepsy patients, and 128 controls, those with idiopathic hypersomnia and frequent night amnesia had lower dream recall, felt sleep as deeper and mind as blank, and showed a higher proportion of slow wave sleep on retrospectively collected recordings. The night blackout offers a model for studying loss of consciousness during sleep, experienced as contentless, selfless, and timeless upon awakening.
Only about 20% of people regularly experience lucid dreams, but induction techniques can increase their frequency. External stimulation aims to integrate cues into dreams to remind the sleeper they are dreaming. This project replicated such induction with low-cost, portable equipment: an OpenBCI Cyton EEG board for sleep scoring and a mask with two LEDs controlled by a microcontroller. Two volunteers slept for two hours in a lab. One reported that blue lights from the mask were incorporated into their dream; the other awoke during stimulation. These results align with prior work. Ongoing research includes automated online sleep scoring and testing vibro-tactile stimulation.