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Campillo-Ferrer T, Alcaraz-Sánchez A, Demšar E, Wu HP, Dresler M, Windt J, Blanke O. Out-of-body experiences in relation to lucid dreaming and sleep paralysis: a theoretical review and conceptual model. Neurosci Biobehav Rev 2024:105770. [PMID: 38880408 DOI: 10.1016/j.neubiorev.2024.105770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/31/2024] [Accepted: 06/11/2024] [Indexed: 06/18/2024]
Abstract
Out-of-body experiences (OBEs) are characterized by the subjective experience of being located outside the physical body. Little is known about the neurophysiology of spontaneous OBEs, which are often reported by healthy individuals as occurring during states of reduced vigilance, particularly in proximity to or during sleep (sleep-related OBEs). In this paper, we review the current state of research on sleep-related OBEs and hypothesize that maintaining consciousness during transitions from wakefulness to REM sleep (sleep-onset REM periods) may facilitate sleep-related OBEs. Based on this hypothesis, we propose a new conceptual model that potentially describes the relationship between OBEs and sleep states. The model sheds light on the phenomenological differences between sleep-related OBEs and similar states of consciousness, such as lucid dreaming (the realization of being in a dream state) and sleep paralysis (feeling paralyzed while falling asleep or waking up), and explores the potential polysomnographic features underlying sleep-related OBEs. Additionally, we apply the predictive coding framework and suggest a connecting link between sleep-related OBEs and OBEs reported during wakefulness.
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Affiliation(s)
- Teresa Campillo-Ferrer
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Neuropsychology, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany.
| | - Adriana Alcaraz-Sánchez
- Centre for Philosophical Psychology, Department of Philosophy, University of Antwerp, Antwerp, Belgium
| | - Ema Demšar
- Monash Centre for Consciousness and Contemplative Studies, Melbourne, Australia; Monash University, Department of Philosophy, Melbourne, Australia
| | - Hsin-Ping Wu
- Laboratory of Cognitive Neuroscience, Neuro-X Institute & Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Department of Clinical Neuroscience, Geneva University Hospital, Geneva, Switzerland
| | - Martin Dresler
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jennifer Windt
- Monash Centre for Consciousness and Contemplative Studies, Melbourne, Australia; Monash University, Department of Philosophy, Melbourne, Australia
| | - Olaf Blanke
- Laboratory of Cognitive Neuroscience, Neuro-X Institute & Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Department of Clinical Neuroscience, Geneva University Hospital, Geneva, Switzerland
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Kempe S, Köpp W, Wittmann L. Personality Functioning Improvement during Psychotherapy Is Associated with an Enhanced Capacity for Affect Regulation in Dreams: A Preliminary Study. Brain Sci 2024; 14:489. [PMID: 38790467 PMCID: PMC11118223 DOI: 10.3390/brainsci14050489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND Clinical case illustrations of patients with an impairment of personality functioning (IPF) have repeatedly reported that progress during psychotherapy is reflected by alterations in dream content. However, quantitative studies based on samples of psychotherapy patients are scarce. As a core component of both personality functioning and contemporary psychodynamic dream theory, the construct of affect regulation is of specific significance in this context. AIMS To test if improvement in personality functioning in the course of psychotherapy is associated with an increasing ability to regulate affects in dreams. METHOD In a longitudinal design, affect regulation was compared in N = 94 unsolicited dream reports from the first vs. last third of long term psychotherapy of ten patients with initial IPF. Dream reports were transcribed from recordings of the sessions. Expert ratings of the level of personality functioning were obtained using the Scales of Psychological Capacities. The capacity for affect regulation was assessed using the Zurich Dream Process Coding System. Group differences were assessed using linear mixed models, controlling for dream length as well as the nested structure of this data set. RESULTS Patients demonstrated an increased capacity for affect regulation in dreams that was primarily evident in three core features: the complexity of dream elements (cf., e.g., parameter attributes, p = 0.024); the extent of affective involvement in the dream ego (cf., e.g., parameter subject feeling, p = 0.014); and the flexibility to regulate the dynamics of safety/involvement processes (p ≤ 0.001). This pattern was especially prominent in a subgroup (n = 7) of patients with more pronounced improvements in personality functioning. CONCLUSION These findings support the hypotheses that decreasing IPF during psychotherapy is associated with increases in the capacity for affect regulation in dreams. Thus, researchers and therapists can utilize dream reports to illuminate the important aspects of treatment progress in clinical practice.
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Affiliation(s)
- Simon Kempe
- Department of Psychology, International Psychoanalytic University, Stromstraße 1, 10555 Berlin, Germany
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Sebastiani L, Barcaro U, Paradisi P, Frumento P, Faraguna U. Morning naps architecture and mentation recall complexity. J Sleep Res 2023; 32:e13915. [PMID: 37139546 DOI: 10.1111/jsr.13915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/05/2023]
Abstract
Mentation reports were collected after spontaneous awakenings from morning naps in 18 healthy participants, and associations between sleep stages duration and complexity of recalled mentation were investigated. Participants were continuously recorded with polysomnography and allowed to sleep for a maximum of 2 hr. Mentation reports were classified according to both their complexity (1-6 scale) and their perceived timing of occurrence (Recent or Previous Mentation with respect to the final awakening). The results showed a good level of mentation recall, including different types of mentation with lab-related stimuli. N1 + N2 duration was positively related to the complexity of Previous Mentation recall, while rapid eye movement sleep duration was negatively related. This suggests that the recall of complex mentation, such as dreaming with a plot, occurring far from awakening may depend on the length of N1 + N2. However, the duration of sleep stages did not predict the complexity of Recent Mentation recall. Nevertheless, 80% of participants who recalled Recent Mentation had a rapid eye movement sleep episode. Half of the participants reported incorporating lab-related stimuli in their mentation, which positively correlated with both N1 + N2 and rapid eye movement duration. In conclusion, nap sleep architecture is informative about the complexity of dreams perceived as having occurred early during the sleep episode, but not about those perceived as recent.
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Affiliation(s)
- Laura Sebastiani
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Institute of Information Science and Technologies "Alessandro Faedo" (ISTI-CNR), Pisa, Italy
| | - Umberto Barcaro
- Institute of Information Science and Technologies "Alessandro Faedo" (ISTI-CNR), Pisa, Italy
| | - Paolo Paradisi
- Institute of Information Science and Technologies "Alessandro Faedo" (ISTI-CNR), Pisa, Italy
- BCAM-Basque Center for Applied Mathematics, Bilbao, Spain
| | - Paolo Frumento
- Department of Political Sciences, University of Pisa, Pisa, Italy
| | - Ugo Faraguna
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Pisa, Italy
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Valli K, Radek L, Kallionpää RE, Scheinin A, Långsjö J, Kaisti K, Kantonen O, Korhonen J, Vahlberg T, Revonsuo A, Scheinin H. Subjective experiences during dexmedetomidine- or propofol-induced unresponsiveness and non-rapid eye movement sleep in healthy male subjects. Br J Anaesth 2023; 131:348-359. [PMID: 37268445 PMCID: PMC10375502 DOI: 10.1016/j.bja.2023.04.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Anaesthetic-induced unresponsiveness and non-rapid eye movement (NREM) sleep share common neural pathways and neurophysiological features. We hypothesised that these states bear resemblance also at the experiential level. METHODS We compared, in a within-subject design, the prevalence and content of experiences in reports obtained after anaesthetic-induced unresponsiveness and NREM sleep. Healthy males (N=39) received dexmedetomidine (n=20) or propofol (n=19) in stepwise doses to induce unresponsiveness. Those rousable were interviewed and left unstimulated, and the procedure was repeated. Finally, the anaesthetic dose was increased 50%, and the participants were interviewed after recovery. The same participants (N=37) were also later interviewed after NREM sleep awakenings. RESULTS Most subjects were rousable, with no difference between anaesthetic agents (P=0.480). Lower drug plasma concentrations were associated with being rousable for both dexmedetomidine (P=0.007) and propofol (P=0.002) but not with recall of experiences in either drug group (dexmedetomidine: P=0.543; propofol: P=0.460). Of the 76 and 73 interviews performed after anaesthetic-induced unresponsiveness and NREM sleep, 69.7% and 64.4% included experiences, respectively. Recall did not differ between anaesthetic-induced unresponsiveness and NREM sleep (P=0.581), or between dexmedetomidine and propofol in any of the three awakening rounds (P>0.05). Disconnected dream-like experiences (62.3% vs 51.1%; P=0.418) and memory incorporation of the research setting (88.7% vs 78.7%; P=0.204) were equally often present in anaesthesia and sleep interviews, respectively, whereas awareness, signifying connected consciousness, was rarely reported in either state. CONCLUSIONS Anaesthetic-induced unresponsiveness and NREM sleep are characterised by disconnected conscious experiences with corresponding recall frequencies and content. CLINICAL TRIAL REGISTRATION Clinical trial registration. This study was part of a larger study registered at ClinicalTrials.gov (NCT01889004).
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Affiliation(s)
- Katja Valli
- Department of Psychology and Speech-Language Pathology, Turku Brain and Mind Center, University of Turku, Turku, Finland; Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland; Department of Cognitive Neuroscience and Philosophy, School of Bioscience, University of Skövde, Skövde, Sweden.
| | - Linda Radek
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Roosa E Kallionpää
- Department of Psychology and Speech-Language Pathology, Turku Brain and Mind Center, University of Turku, Turku, Finland; Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland
| | - Annalotta Scheinin
- Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland; Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Jaakko Långsjö
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Department of Intensive Care, Tampere University Hospital, Tampere, Finland
| | - Kaike Kaisti
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Department of Anesthesiology and Intensive Care, Oulu University Hospital, Oulu, Finland
| | - Oskari Kantonen
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Jarno Korhonen
- Department of Psychology and Speech-Language Pathology, Turku Brain and Mind Center, University of Turku, Turku, Finland
| | - Tero Vahlberg
- Institute of Clinical Medicine, Biostatistics, University of Turku and Turku University Hospital, Turku, Finland
| | - Antti Revonsuo
- Department of Psychology and Speech-Language Pathology, Turku Brain and Mind Center, University of Turku, Turku, Finland; Department of Cognitive Neuroscience and Philosophy, School of Bioscience, University of Skövde, Skövde, Sweden
| | - Harry Scheinin
- Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland; Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Institute of Biomedicine and Unit of Clinical Pharmacology, University of Turku and Turku University Hospital, Turku, Finland
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Cunningham TJ. The next step in understanding the function of dreams. Sleep 2023; 46:zsad010. [PMID: 36656722 PMCID: PMC10091084 DOI: 10.1093/sleep/zsad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Indexed: 01/20/2023] Open
Affiliation(s)
- Tony J Cunningham
- Center for Sleep and Cognition, Psychiatry Department, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
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Picard-Deland C, Konkoly K, Raider R, Paller KA, Nielsen T, Pigeon WR, Carr M. The memory sources of dreams: serial awakenings across sleep stages and time of night. Sleep 2023; 46:zsac292. [PMID: 36462190 PMCID: PMC10091095 DOI: 10.1093/sleep/zsac292] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/27/2022] [Indexed: 12/05/2022] Open
Abstract
Memories of waking-life events are incorporated into dreams, but their incorporation is not uniform across a night of sleep. This study aimed to elucidate ways in which such memory sources vary by sleep stage and time of night. Twenty healthy participants (11 F; 24.1 ± 5.7 years) spent a night in the laboratory and were awakened for dream collection approximately 12 times spread across early, middle, and late periods of sleep, while covering all stages of sleep (N1, N2, N3, REM). In the morning, participants identified and dated associated memories of waking-life events for each dream report, when possible. The incorporation of recent memory sources in dreams was more frequent in N1 and REM than in other sleep stages. The incorporation of distant memories from over a week ago, semantic memories not traceable to a single event, and anticipated future events remained stable throughout sleep. In contrast, the relative proportions of recent versus distant memory sources changed across the night, independently of sleep stage, with late-night dreams in all stages having relatively less recent and more remote memory sources than dreams earlier in the night. Qualitatively, dreams tended to repeat similar themes across the night and in different sleep stages. The present findings clarify the temporal course of memory incorporations in dreams, highlighting a specific connection between time of night and the temporal remoteness of memories. We discuss how dream content may, at least in part, reflect the mechanisms of sleep-dependent memory consolidation.
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Affiliation(s)
| | - Karen Konkoly
- Department of Psychology, Northwestern University, Evanston, IL, USA
| | - Rachel Raider
- Department of Psychiatry, University of Rochester Medical Center, Rochester, NY, USA
| | - Ken A Paller
- Department of Psychology, Northwestern University, Evanston, IL, USA
| | - Tore Nielsen
- Department of Psychiatry and Addictology, University of Montreal, Montreal, Quebec, Canada
| | - Wilfred R Pigeon
- Department of Psychiatry, University of Rochester Medical Center, Rochester, NY, USA
| | - Michelle Carr
- Department of Psychiatry, University of Rochester Medical Center, Rochester, NY, USA
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Simor P, Peigneux P, Bódizs R. Sleep and dreaming in the light of reactive and predictive homeostasis. Neurosci Biobehav Rev 2023; 147:105104. [PMID: 36804397 DOI: 10.1016/j.neubiorev.2023.105104] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/07/2023] [Accepted: 02/16/2023] [Indexed: 02/19/2023]
Abstract
Dreams are often viewed as fascinating but irrelevant mental epihenomena of the sleeping mind with questionable functional relevance. Despite long hours of oneiric activity, and high individual differences in dream recall, dreams are lost into oblivion. Here, we conceptualize dreaming and dream amnesia as inherent aspects of the reactive and predictive homeostatic functions of sleep. Mental activity during sleep conforms to the interplay of restorative processes and future anticipation, and particularly during the second half of the night, it unfolds as a special form of non-constrained, self-referent, and future-oriented cognitive process. Awakening facilitates constrained, goal-directed prospection that competes for shared neural resources with dream production and dream recall, and contributes to dream amnesia. We present the neurophysiological aspects of reactive and predictive homeostasis during sleep, highlighting the putative role of cortisol in predictive homeostasis and forgetting dreams. The theoretical and methodological aspects of our proposal are discussed in relation to the study of dreaming, dream recall, and sleep-related cognitive processes.
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Affiliation(s)
- Péter Simor
- Institute of Psychology, ELTE, Eötvös Loránd University, Budapest, Hungary; UR2NF, Neuropsychology and Functional Neuroimaging Research Unit at CRCN - Center for Research in Cognition and Neurosciences and UNI - ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Philippe Peigneux
- UR2NF, Neuropsychology and Functional Neuroimaging Research Unit at CRCN - Center for Research in Cognition and Neurosciences and UNI - ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Róbert Bódizs
- Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary.
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Picard-Deland C, Bernardi G, Genzel L, Dresler M, Schoch SF. Memory reactivations during sleep: a neural basis of dream experiences? Trends Cogn Sci 2023; 27:568-582. [PMID: 36959079 DOI: 10.1016/j.tics.2023.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/18/2023] [Accepted: 02/28/2023] [Indexed: 03/25/2023]
Abstract
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 from the rapidly growing field of sleep and dream engineering, provide essential insights into this question, and reveal both strong parallels and disparities between the two phenomena. We suggest that, although memory reactivations may contribute to subjective experiences across different states of consciousness, they are not likely to be the primary neural basis of dreaming. We identify important limitations in current research paradigms and suggest novel strategies to address this question empirically.
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Affiliation(s)
- Claudia Picard-Deland
- Dream and Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, University of Montreal, Montreal, QC, Canada
| | - Giulio Bernardi
- Institutions, Markets, Technologies (IMT) School for Advanced Studies Lucca, Lucca, Italy
| | - Lisa Genzel
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Martin Dresler
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Sarah F Schoch
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands; Center of Competence Sleep and Health Zurich, University of Zurich, Zurich, Switzerland.
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Zhang Y, Song B, Zhu J. The relationship between different bispectral index and the occurrence of dreams in elective surgery under general anesthesia: protocol for a randomized controlled clinical trial. Trials 2023; 24:205. [PMID: 36941648 PMCID: PMC10026450 DOI: 10.1186/s13063-023-07222-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 03/06/2023] [Indexed: 03/22/2023] Open
Abstract
INTRODUCTION Dreaming reported after anesthesia remains a poorly understood phenomenon. At present, there is a hypothesis that dreaming occurs intraoperatively and is related to light or inadequate anesthesia; thus, in order to further verify the hypothesis, we choose elective surgery under general anesthesia to observe whether the generation of dreams is related to the dose of general anesthetics maintenance. METHODS AND ANALYSIS This randomized, double-blind controlled trial to observe whether the generation of dreams is related to the dose of general anesthetics maintenance in the elective surgery under general anesthesia. A total of 124 participants will be randomly allocated to a low bispectral index or high bispectral index group at a ratio of 1:1. The Hospital Anxiety and Depression Scale (HADS) is used to assess the anxiety and depression status of participants during the perioperative period. Ramsay score is used to assess patients' sedation level after surgery in the PACU. Modified Brice questionnaire and awareness classification are used to assess whether patients experienced dreaming during the surgery. ETHICS AND DISSEMINATION This randomized, double-blind controlled trial received prospective ethics committee approval at the Human Research Ethical Committee of Shengjing Hospital, Shenyang, Liaoning Province, China (Institutional Review Board registration number 2021PS664K), and was compliant with the Declaration of Helsinki. Written informed consent was obtained from all subjects participating in the trial.
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Affiliation(s)
- Yufei Zhang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China
| | - Bijia Song
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China
| | - Junchao Zhu
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China.
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