Original Research ARTICLE
Assessing sleep consciousness within subjects using a serial awakening paradigm
- 1Department of Psychiatry, University of Wisconsin, Madison, WI, USA
- 2Medical Scientist Training Program and Neuroscience Training Program, University of Wisconsin, Madison, WI, USA
- 3Department of Psychology, University of Wisconsin, Madison, WI, USA
Dreaming—a particular form of consciousness that occurs during sleep—undergoes major changes in the course of the night. We aimed to outline state-dependent features of consciousness using a paradigm with multiple serial awakenings/questionings that allowed for within as well as between subject comparisons. Seven healthy participants who spent 44 experimental study nights in the laboratory were awakened by a computerized sound at 15–30 min intervals, regardless of sleep stage, and questioned for the presence or absence of sleep consciousness. Recall without content (“I was experiencing something but do not remember what”) was considered separately. Subjects had to indicate the content of the most recent conscious experience prior to the alarm sound and to estimate its duration and richness. We also assessed the degree of thinking and perceiving, self- and environment-relatedness and reflective consciousness of the experiences. Of the 778 questionings, 5% were performed during wakefulness, 2% in stage N1, 42% in N2, 33% in N3, and 17% in rapid eye movement (REM) sleep. Recall with content was reported in 34% of non-REM and in 77% of REM sleep awakenings. Sleep fragmentation inherent to the study design appeared to only minimally affect the recall of conscious experiences. Each stage displayed a unique combination of characteristic features of sleep consciousness. In conclusion, our serial awakening paradigm allowed us to collect a large and representative sample of conscious experiences across states of being. It represents a time-efficient method for the study of sleep consciousness that may prove particularly advantageous when combined with techniques such as functional MRI and high-density EEG.
Keywords: consciousness, sleep, dreaming, wakefulness, EEG
Citation: Siclari F, LaRocque JJ, Postle BR and Tononi G (2013) Assessing sleep consciousness within subjects using a serial awakening paradigm. Front. Psychol. 4:542. doi: 10.3389/fpsyg.2013.00542
Received: 06 May 2013; Accepted: 31 July 2013;
Published online: 20 August 2013.
Edited by:Jennifer M. Windt, Johannes Gutenberg-University of Mainz, Germany
Reviewed by:Tore Nielsen, Université de Montréal, Canada
Valdas Noreika, Medical Research Council, UK
Jean-Baptiste Eichenlaub, Swansea University Sleep Lab, UK
Copyright © 2013 Siclari, LaRocque, Postle and Tononi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Giulio Tononi, Department of Psychiatry, University of Wisconsin, 6001 Research Park Blvd, Madison, WI 53519, USA e-mail: email@example.com
† These authors have contributed equally to this work.