DOI: 10.6084/m9.figshare.24794952.v1
title: Kumral et al., 2023

description: Dream EEG and Mentation (DREAM) dataset<br>=======================================<br>Dataset information<br>-------------------- Common name: Kumral et al., 2023<br>- Full name: N/A<br>- Authors: Deniz Kumral, Jessica Palmieri, Steffen Gais, Monika Schönauer<br>- Location: Albert-Ludwigs-Universität Freiburg, Eberhard Karls Universität Tübingen, Ludwig-Maximilians-Universität München<br>- Year: 2013<br>- Set ID: 19<br>- Amendment: 0<br>- Corresponding author ID: 19Previous publications:<br>Kumral, D., Palmieri, J., Gais, S., & Schoenauer, M. (2023). Daytime experiences shape neural activity and dream content in the sleeping brain. bioRxiv, 2023-07.Correspondence:<br>M. Schönauer, Institute of Psychology, Neuropsychology, University of Freiburg; Freiburg im Breisgau, Germany, phone: +49 761 203 2463, Engelbergerstraße 41, Freiburg im Breisgau, 79106, Germany<br>Metadata<br>--------- Key ID: 21<br>- Date entered: 2024-01-22T05:30:40+00:00<br>- Number of samples: 66<br>- Number of subjects: 19<br>- Proportion REM: 0.136363636<br>- Proportion N1: 0.090909091<br>- Proportion N2: 0.636363636<br>- Proportion W: 0<br>- Proportion experience: 0.636363636<br>- Proportion no-experience: 0.363636364<br>- Proportion healthy: 1<br>- Provoked awakening: Yes<br>- Time of awakening: Mixed<br>- Form of response: Free<br>- Date approved: 2024-01-25T05:53:22+00:00<br>How to decode data files<br>------------------------* EEG files: All the EEG data are already transformed into ".edf" format from original Brainvision files. We extracted sleep data from the point after we stopped the audiobook (see: procedure) until the time right before awakening. Due to the resolution of sleep scoring for this dataset (30 secs), up to one minute of data before the actual point of waking up may thus have been cut from the files.* Dream Reports: Dream data is reported using Excel files in .csv (UTF-8) format.<br>### Treatment group codes ###N/A<br>Experimental description<br>------------------------Participants<br>20 participants (10 male) aged 20 – 30 years (25.5 ± 2.7) completed the study. They were healthy, nonsmokers, and did not ingest any alcohol, caffeine or medication other than oral contraceptives on the days of the experiment. The participants reported sleeping between 6 and 10 hours per night, had a regular circadian rhythm, and were neither extreme morning nor evening chronotypes, as measured by the Munich Chronotype Questionnaire. They had no shift work or long-distance flights during the six weeks preceding the experiment and did not have any sleep-related pathology. All participants were right-handed, confirmed by the Edinburgh Handedness Questionnaire. The experiment was approved by the local ethics committee (Department of Psychology, Ludwig-Maximilians-Universität München). Informed consent was obtained from all subjects. One participant had to be excluded because due to a technical problem with the audiobook.Procedure<br>All participants visited the sleep laboratory twice, once for an adaptation night to become familiar with the experimental procedure and environment (i.e., wearing an EEG cap), and again for the night of the main experiment. On the experimental night, participants fell asleep while listening to one of four randomly assigned audiobooks. Participants had not read the book or listened to the audiobook prior to the experiment. Participants were instructed to remember the content of the audiobook. The audiobook was turned off once they reached consolidated stage 2 sleep. Participants were awoken multiple times during the night, approximately every 90 minutes, to answer questions regarding their cognitive experiences during sleep (i.e. dreaming) and about the content of the audiobook passage they had listened to. After these tests, they continued listening to the same audiobook while falling asleep again. After each 90-min sleep cycle, participants were awoken and reported their cognitive experience (i.e., dreaming) in a standardized dream recall procedure. They were asked up to three times what was going through their minds immediately before waking up. If the participants were able to remember any dream, we instructed them that they should proceed to give a detailed report on who participated in the dream, where the dream was set, and what happened in the dream. We recorded their full dream report, asking up to three times “Can you recall more?”<br>### DREAM categorization procedure ###In this study, we define a “dream” as any mental experience recalled from sleep. We did not assess whether participants might have been dreaming, but failed to recall the dream. Therefore, the dream reports are coded as:<br>* 0 = no experience<br>* 2 = experience<br>Technical details<br>-----------------N/A<br>### Data acquisition ###Sleep EEG was recorded using an active 128 channel Ag/AgCl-electrode system (BrainAmp MR with ActiCap, Brain Products, Gilching, Germany) with a 1 kHz sampling frequency and a high-pass filter of 0.1 Hz. Electrodes were positioned according to the extended international 10–20 electrode system.<br>### Data preprocessing ###The EEG data is not preprocessed. As mentioned earlier, we extracted sleep data from the point after we stopped the audiobook (see: procedure) until the time right before awakening. Due to the resolution of sleep scoring for this dataset (30 secs), up to one minute of data before the actual point of waking up may thus have been cut from the files.