The relationship between dreams and subsequent morning mood using self-reports and text analysis

While material from waking life is often represented in dreams, it is less clear whether and how dreams impact waking life in return. Here, we assessed whether dream mood and content from home diaries predict subsequent waking mood using both subjective self-report and an objective automated word detection approach. Subjective ratings of dream and morning mood were highly correlated within participants for both negative and positive valence, suggesting that dream mood persists into waking. Text analyses revealed similar relationships between affect words in dreams and morning mood. Moreover, dreams referencing death or the body were related to worse morning mood, as was first-person singular pronoun usage (e.g., “I”). Dreams referencing leisure or ingestion, or including first-person plural pronouns (e.g., “we”), were related to better morning mood. Together, these results suggest that subjective experiences during sleep, while often overlooked, may be an important contributor to the emotion processing functions of sleep

Lucid dream induction with sleep EEG wearables

Lucid dreaming (LD) is defined as a state of awareness of the ongoing dream state while sleeping. Lucid dreaming is a rather rare phenomenon; however, it can be learned and trained, and various studies have proposed different techniques to ‘induce’ lucid dreams. Nonetheless, these studies either lacked physiological measurements and were therefore merely limited to self-reported questionnaires, or in the case of including physiological measurements, their generalizability was restricted mainly due to the exclusive recruitment of ‘experienced’ lucid dreamers. Only a few studies attempted to reliably induce lucid dreams in ‘naive’ participants, but they involved small sample sizes and have not yet been replicated. To overcome these limitations, we designed a multi-center study including three laboratories, in the Netherlands, Canada, and Italy respectively, with the aim of recruiting 60 participants overall (i.e. 20 participants per laboratory). This is the largest sample size for a lucid dreaming induction study with physiological measurements to date. We will test the applicability of a combination of two lucid dreaming induction techniques: targeted lucidity reactivation (TLR) and sense-initiated lucid dream (SSILD), which will be implemented by presenting perceptual cues (visual, auditory, and tactile) before and during REM sleep. To do so, we will employ minimal measurement modalities, i.e., an EEG headband and three additional chin EMG electrodes. We will also use this dataset to develop and validate the first open-source dream engineering toolbox, Dreamento (DREAM ENgineering TOolbox, Esfahani et al., 2022). Participants will visit the laboratory three times throughout an approximately two week period, including an intake session and two morning naps (stimulation and control, in counterbalanced order across subjects). During the intake session, participants will receive information about the study and complete preliminary screening questionnaires. Then, participants will complete daily dream diaries for the following two weeks. The morning nap sessions will be held at least one and two weeks after the intake session, respectively. Both nap sessions consist of the same cognitive training procedure during wakefulness, but differ in terms of the sensory stimulation procedure during sleep. Participants will receive sensory cues upon detection of REM sleep during the stimulation session, but not during the control session. They will be instructed to signal their lucidity using a predefined intentional eye movement pattern (left-right-left-right, LRLR) and will be awakened once the REM period ends to report any subjective experience and complete a lucidity questionnaire