Infant Sleep Actigraphy

This contains the files used in the two articles "Actimetry in infant sleep research: an approach to facilitate comparability" https://doi.org/10.1093/sleep/zsz083 and "Which are the Central Aspects of Infant Sleep? The Dynamics of Sleep Composites across Infancy" doi will be added. The first article compares to commonly used algorithms (Sadeh et al. 1994 and Oakley 1997) and shows that without adjustment the estimated sleep variables are quite different but by introducing a set of adjustments they become quite similar and also more similar to a parent-reported diary. The second article describes how you can extract sleep composites from the actigraphy data and how these sleep composites change across infancy

Memory reactivations during sleep: a neural basis of dream experiences?

Newly encoded memory traces are spontaneously reactivated during sleep. Since their discovery in the 1990s, these memory reactivations have been discussed as a potential neural basis for dream experiences. New results from animal and human research, as well as the rapidly growing field of sleep and dream engineering, provide essential insights into this question, revealing both strong parallels and disparities between the two phenomena. We suggest that while memory reactivations may contribute to subjective experiences across different states of consciousness, they are not likely to be experienced directly as dreams. We identify important limitations in current research paradigms and suggest novel strategies to address this question empirically

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