DOI: 10.6084/m9.figshare.22106123
title: TWC_USA

description: Dream EEG and Mentation (DREAM) data set ======================================== <br> <br> Data set information -------------------- <br> - Common name: TWC_USA - Full name: Two-way communicaton data from USA team - Authors: Karen R. Konkoly, Remington Mallett, Ken A. Paller - Location: Northwestern University - Year: 2021 - Set ID: 4 - Amendment: 1 - Corresponding author ID: 4 <br> Previous publications: Konkoly, K. R., Appel, K., Chabani, E., Mangiaruga, A., Gott, J., Mallett, R., ... & Paller, K. A. (2021). Real-time dialogue between experimenters and dreamers during REM sleep. Current Biology, 31(7), 1417-1427. <br> Correspondence: karenkonkoly2023@u.northwestern.edu <br> <br> Metadata -------- <br> - Key ID: 5 - Date entered: 2023-02-08T03:09:10+00:00 - Number of samples: 33 - Number of subjects: 19 - Proportion REM: 61% - Proportion N1: 18% - Proportion N2: 18% - Proportion W: 0% - Proportion experience: 82% - Proportion no-experience: 15% - Proportion healthy: 100% - Provoked awakening: Some - Time of awakening: Mixed - Form of response: Structured - Date approved: 2023-02-09T05:50:12+00:00 <br> <br> How to decode data files ------------------------ <br> * L-MSTD is an electrode on the left mastoid for if a back-up reference channel was needed. The EMG channel is on the chin, and channels 26 and 27 are back-up EMG electrodes located nearby on the chin. On some recordings EMG-2 is the back-up EMG channel instead, which is also located nearby on the chin. * The "status" channel was created when converting the data to EDF, and contains information about port codes in the data set. Disregard that the port codes are expressed in microvolts. More information about the meanings of the port codes below. * It may be that there is a second of flat EEG at the end of each recording which appears to be an artifact of converting the file type to .EDF and should be disregarded * The time of awakening column contains only approximated times based on experimenters' notes and the duration of files <br> * There are port codes in the data that have slightly meanings for some different participants (in the "status" channel). Here is a guide for their meanings: <br> - 32 just indicates that a new script was started (no sounds played) - 64 means the volume was turned down (no sounds played) - 65 means the volume was turned up (no sounds played) - 29 means a TLR auditory cue was presented - 23 means a TLR light cue was presented (but code and light cue are triggered manually, so time-locked analyses is not possible here) - Codes 1-20 correspond to math problems that were presented during sleep, and were changed after case 08. See below for guide <br> Cases 01-08 <br> - 1: 9-7 - 2: 3+2 - 3: 14-13 - 4: 6+1 - 5: 19-16 - 6: 1+1 - 7: 5-2 - 8: 1+4 - 9: 15-10 - 10: 3+3 - 11: 8-4 - 12: 2+2 - 13: 8-0 - 14: 4+1 - 15: 14-13 - 16: 2+4 - 17: 16-13 - 18: 3+1 - 19: 10-8 - 20: 1+0 <br> Cases 09-33 <br> - 1: 9-7 - 2: 3+1 - 3: 8-7 - 4: 1+2 - 5: 9-6 - 6: 1+1 - 7: 5-2 - 8: 4-1 - 9: 8-6 - 10: 8-5 - 11: 2+2 - 12: 2+1 - 13: 3+0 - 14: 1+0 - 15: 7-4 - 16: 2+0 - 17: 6-3 - 18: 3-1 - 19: 5-4 - 20: 1+0 <br> <br> ### Treatment group codes ### <br> N/A <br> <br> Experimental description ------------------------ <br> Methods: <br> Twenty-two participants (15 female, age range 18-33 years, M = 21.1 ± 4.3 years) who claimed to remember at least one dream per week were recruited by word of mouth, online forum, and the Northwestern University Psychology Department participant pool. They each participated in one or more nap sessions, which amounted to 27 nap sessions in total. <br> Procedure: <br> Participants visited the laboratory at Northwestern University at approximately their normal wake time and received guidance on identifying lucid dreams and instructions for the experiment for about 40 min during preparations for polysomnographic recordings, including EEG, EMG, and EOG, using a Neuroscan SynAmps system. Participants were instructed to signal with a prearranged number of LR eye movements if they became lucid in a dream. <br> Next, participants practiced making ocular signals and responding to questions using combinations of LR signals. Subsequently, participants completed the Targeted Lucidity Reactivation (TLR) procedure while lying in bed. This procedure was derived from the procedure developed by Carr and collegues. A method of reality checking to induce lucid dreaming was paired with sensory stimulation and accelerated in a single session immediately before sleep, and then cues were presented again during REM sleep. In this procedure, participants were trained to associate a novel cue sound with a lucid state of mind during wake. The sound consisted of three pure-tone beeps increasing in pitch (400, 600, and 800 Hz) at approximately 40-45 dB SPL and lasting approximately 650 ms. For one participant (ppt. 121) the pure-tone beeps had previously been associated with a different task in an unrelated study. Thus, for this participant, a 1000-ms violin sound and low-intensity flashing-red LED lights were used as cues. All participants were informed that this cue would be given during sleep to help promote a lucid dream. Over the next 15 min, the TLR sound was played up to 15 times. The first 4 times, it was followed by verbal guidance to enter a lucid state as follows. ‘‘As you notice the signal, you become lucid. Bring your attention to your thoughts and notice where your mind has wandered.[pause] Now observe your body, sensations, and feelings.[pause] Observe your breathing. [pause] Remain lucid, critically aware, and notice how aspects of this experience are in any way different from your normal waking experience.’’ <br> Participants often fell asleep before all 15 TLR cue presentations were completed. Standard polysomnographic methods were used to determine sleep state. Once participants entered REM sleep, TLR cues were presented again, at about 30-s intervals, as long as REM sleep remained stable. After participants responded to a cue with a lucid eye signal, or after approximately 10 cues were presented without response, we began the math problem portion of the experiment. <br> We devised the following task to engage auditory perception of math problems, working memory, and the ability to express the correct answer. We used simple addition and subtraction problems that could each be answered by a number between 1 and 4 (LR = 1, LRLR = 2, LRLRLR = 3, LRLRLRLR = 4), or between 1 and 6 for the first 5 participants. <br> From the above dataset, data was included in DREAM if there was a period of sleep on the EEG followed by a report of a dream (or a lack of dream). The EEG data includes the last period of continuous sleep before the dream report was collected, starting with the first epoch scored as wake, and ending at the last second before clear movement/alpha activity indicating wake. Also, there are a few instances, noted in the “Remarks” column in the “Records” file, where I included epochs that were scored as wake, when the wake seemed due to alpha from participants attempting to answer questions with eye movements (only one of these included wake in the last 20 seconds of the recording, case21_sub111). <br> EEG sleep data was NOT included if it was not followed by a verbal/written dream report or clear note on the experimenter’s log that there was no recall. Also not included is data where participants completed eye signals or answered questions, but it was not part of the continuous period of sleep before a dream report was given. Also excluded was a case in which a dream report was collected at the end of the nap but the participant had been in and out of sleep beforehand, so it was unclear which sleep period the report referred to. <br> <br> ### DREAM categorization procedure ### <br> Karen Konkoly rated reports according to the DREAM categorization. If the participant reported remembering any sort of mental content from sleep, it was rated “2”. If the participant reported remembering a dream but none of its content, it was rated “1”. If the participant reported not remembering anything, or not falling asleep, it was rated “0”.