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Brouwer A, Carhart‐Harris RL, Raison CL. Psychotomimetic compensation versus sensitization. Pharmacol Res Perspect 2024; 12:e1217. [PMID: 38923845 PMCID: PMC11194300 DOI: 10.1002/prp2.1217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 05/08/2024] [Indexed: 06/28/2024] Open
Abstract
It is a paradox that psychotomimetic drugs can relieve symptoms that increase risk of and cooccur with psychosis, such as attention and motivational deficits (e.g., amphetamines), pain (e.g., cannabis) and symptoms of depression (e.g., psychedelics, dissociatives). We introduce the ideas of psychotomimetic compensation and psychotomimetic sensitization to explain this paradox. Psychotomimetic compensation refers to a short-term stressor or drug-induced compensation against stress that is facilitated by engagement of neurotransmitter/modulator systems (endocannabinoid, serotonergic, glutamatergic and dopaminergic) that mediate the effects of common psychotomimetic drugs. Psychotomimetic sensitization occurs after repeated exposure to stress and/or drugs and is evidenced by the gradual intensification and increase of psychotic-like experiences over time. Theoretical and practical implications of this model are discussed.
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Affiliation(s)
- Ari Brouwer
- Department of Human Development and Family Studies, School of Human EcologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Robin L. Carhart‐Harris
- Department of Neurology and PsychiatryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Charles L. Raison
- Department of Psychiatry, School of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- Vail Health Behavioral Health Innovation CenterVailColoradoUSA
- Center for the Study of Human HealthEmory UniversityAtlantaGeorgiaUSA
- Department of Spiritual HealthEmory University Woodruff Health Sciences CenterAtlantaGeorgiaUSA
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Cardone P, Alnagger N, Annen J, Bicego A, Gosseries O, Martial C. Psychedelics and disorders of consciousness: the current landscape and the path forward. Neurosci Conscious 2024; 2024:niae025. [PMID: 38881630 PMCID: PMC11179162 DOI: 10.1093/nc/niae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 02/16/2024] [Accepted: 05/20/2024] [Indexed: 06/18/2024] Open
Abstract
Modern medicine has been shaken by the surge of psychedelic science that proposes a new approach to mitigate mental disorders, such as depression and post-traumatic stress disorder. Clinical trials to investigate whether psychedelic substances can treat psychiatric conditions are now underway, yet less discussion gravitates around their use in neurological disorders due to brain injury. One suggested implementation of brain-complexity enhancing psychedelics is to treat people with post-comatose disorders of consciousness (DoC). In this article, we discuss the rationale of this endeavour, examining possible outcomes of such experiments by postulating the existence of an optimal level of complexity. We consider the possible counterintuitive effects of both psychedelics and DoC on the functional connectivity of the default mode network and its possible impact on selfhood. We also elaborate on the role of computational modelling in providing complementary information to experimental studies, both contributing to our understanding of the treatment mechanisms and providing a path towards personalized medicine. Finally, we update the discourse surrounding the ethical considerations, encompassing clinical and scientific values.
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Affiliation(s)
- Paolo Cardone
- Coma Science Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Centre du Cerveau2, University Hospital of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
| | - Naji Alnagger
- Coma Science Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Centre du Cerveau2, University Hospital of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
| | - Jitka Annen
- Coma Science Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Centre du Cerveau2, University Hospital of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Department of Data Analysis, University of Ghent, Henri Dunantlaan 1, Ghent 9000, Belgium
| | - Aminata Bicego
- Sensation and Perception Research Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Centre du Cerveau2, University Hospital of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Sensation and Perception Research Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
- Centre du Cerveau2, University Hospital of Liège, Avenue de l'hôpital 11, Liège 4000, Belgium
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3
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Mashour GA, Lee U, Pal D, Li D. Consciousness and the Dying Brain. Anesthesiology 2024; 140:1221-1231. [PMID: 38603803 PMCID: PMC11096058 DOI: 10.1097/aln.0000000000004970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/26/2024] [Indexed: 04/13/2024]
Abstract
The near-death experience has been reported since antiquity and is often characterized by the perception of light, interactions with other entities, and life recall. Near-death experiences can occur in a variety of situations, but they have been studied systematically after in-hospital cardiac arrest, with an incidence of 10 to 20%. Long attributed to metaphysical or supernatural causes, there have been recent advances in understanding the neurophysiologic basis of this unique category of conscious experience. This article reviews the epidemiology and neurobiology of near-death experiences, with a focus on clinical and laboratory evidence for a surge of neurophysiologic gamma oscillations and cortical connectivity after cardiac and respiratory arrest.
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Affiliation(s)
- George A. Mashour
- Department of Anesthesiology, Center for Consciousness Science, Neuroscience Graduate Program, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan
| | - UnCheol Lee
- Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan
| | - Dinesh Pal
- Department of Anesthesiology, Center for Consciousness Science and Neuroscience Graduate Program, Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Duan Li
- Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan
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Kovoor JG, Santhosh S, Stretton B, Tan S, Gouldooz H, Moorthy S, Pietris J, Hannemann C, Yu LK, Johnson R, Reddi BA, Gupta AK, Wagner M, Page GJ, Kovoor P, Bastiampillai T, Maddocks I, Perry SW, Wong ML, Licinio J, Bacchi S. Near-death experiences after cardiac arrest: a scoping review. DISCOVER MENTAL HEALTH 2024; 4:19. [PMID: 38806961 PMCID: PMC11133272 DOI: 10.1007/s44192-024-00072-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 05/24/2024] [Indexed: 05/30/2024]
Abstract
BACKGROUND This scoping review aimed to characterise near-death experiences in the setting of cardiac arrest, a phenomenon that is poorly understood and may have clinical consequences. METHOD PubMed/MEDLINE was searched to 23 July 2023 for prospective studies describing near-death experiences in cardiac arrest. PRISMA-ScR guidelines were adhered to. Qualitative and quantitative data were synthesised. Meta-analysis was precluded due to data heterogeneity. RESULTS 60 records were identified, of which 11 studies involving interviews were included from various countries. Sample size ranged from 28-344, and proportion of female patients (when reported) was 0-50%, with mean age (when reported) ranging 54-64 years. Comorbidities and reasons for cardiac arrest were heterogeneously reported. Incidence of near-death experiences in the included studies varied from 6.3% to 39.3%; with variation between in-hospital (6.3-39.3%) versus out-of-hospital (18.9-21.2%) cardiac arrest. Individual variables regarding patient characteristics demonstrated statistically significant association with propensity for near-death experiences. Reported content of near-death experiences tended to reflect the language of the questionnaires used, rather than the true language used by individual study participants. Three studies conducted follow-up, and all suggested a positive life attitude change, however one found significantly higher 30-day all-cause mortality in patients with near-death experiences versus those without, in non-controlled analysis. CONCLUSIONS From prospective studies that have investigated the phenomenon, near-death experiences may occur in as frequent as over one-third of patients with cardiac arrest. Lasting effects may follow these events, however these could also be confounded by clinical characteristics.
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Affiliation(s)
- Joshua G Kovoor
- University of Adelaide, Adelaide, South Australia, Australia
- Ballarat Base Hospital, Ballarat, VIC, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Health and Information, Adelaide, South Australia, Australia
- Heart of the Nation, Sydney, NSW, Australia
| | | | - Brandon Stretton
- University of Adelaide, Adelaide, South Australia, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Health and Information, Adelaide, South Australia, Australia
| | - Sheryn Tan
- University of Adelaide, Adelaide, South Australia, Australia
- Health and Information, Adelaide, South Australia, Australia
| | - Hasti Gouldooz
- Gold Coast University Hospital, Gold Coast, QLD, Australia
| | | | | | - Christopher Hannemann
- Ballarat Base Hospital, Ballarat, VIC, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Long Kiu Yu
- University of Adelaide, Adelaide, South Australia, Australia
| | - Rhys Johnson
- University of Adelaide, Adelaide, South Australia, Australia
| | - Benjamin A Reddi
- University of Adelaide, Adelaide, South Australia, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Aashray K Gupta
- University of Adelaide, Adelaide, South Australia, Australia
- Health and Information, Adelaide, South Australia, Australia
- Gold Coast University Hospital, Gold Coast, QLD, Australia
| | - Morganne Wagner
- State University of New York Upstate Medical University, Syracuse, NY, USA
| | | | - Pramesh Kovoor
- Heart of the Nation, Sydney, NSW, Australia
- Westmead Hospital, Sydney, NSW, Australia
- University of Sydney, Sydney, NSW, Australia
| | - Tarun Bastiampillai
- Flinders University, Adelaide, South Australia, Australia
- Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Ian Maddocks
- Australasian Chapter of Palliative Medicine, Royal Australasian College of Physicians, Adelaide, South Australia, Australia
| | - Seth W Perry
- State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Ma-Li Wong
- State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Julio Licinio
- State University of New York Upstate Medical University, Syracuse, NY, USA
- Flinders University, Adelaide, South Australia, Australia
| | - Stephen Bacchi
- Health and Information, Adelaide, South Australia, Australia.
- Flinders University, Adelaide, South Australia, Australia.
- Lyell McEwin Hospital, Adelaide, South Australia, Australia.
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Shinozuka K, Tabaac BJ, Arenas A, Beutler BD, Cherian K, Evans VD, Fasano C, Muir OS. Psychedelic Therapy: A Primer for Primary Care Clinicians-N,N-Dimethyltryptamine and Ayahuasca. Am J Ther 2024; 31:e112-e120. [PMID: 38518268 DOI: 10.1097/mjt.0000000000001725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND N,N-dimethyltryptamine (DMT) is a naturally occurring serotonergic psychedelic found in natural plants around the globe. As the main psychoactive component in ayahuasca, which also contains monoamine oxidase inhibitors, DMT has been consumed as plant-based brew by indigenous peoples for centuries. Further research is required to delineate the therapeutic utility of DMT. AREAS OF UNCERTAINTY Although previous research has shown that DMT is synthesized endogenously, it may not be produced at physiologically relevant concentrations. Additionally, the phenomenological similarities between the DMT-induced state and near-death experiences led to the popular hypothesis that endogenous DMT is released during the dying process. However, this hypothesis continues to be debated. Generally, DMT and ayahuasca seem to be physiologically and psychiatrically safe, although ayahuasca is known to cause transient vomiting. THERAPEUTIC ADVANCES A double-blind, randomized controlled trial showed that, within 1 week, ayahuasca causes remission in 36% of patients with treatment-resistant depression. According to top-line results from a recent phase IIa trial, 57% of patients with major depressive disorder experienced remission 12 weeks after receiving a single intravenous dose of DMT. LIMITATIONS There has only been a single published double-blind randomized controlled trial on ayahuasca and 2 on DMT. All clinical trials have had small sample sizes (≤34 participants). DMT requires further research to understand its therapeutic and clinical potential as a psychedelic. CONCLUSIONS Preliminary evidence indicates that ayahuasca and DMT may be more effective than existing antidepressants for treating major depressive disorder and treatment-resistant depression.
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Affiliation(s)
- Kenneth Shinozuka
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Burton J Tabaac
- University of Nevada, Reno School of Medicine, Reno, NV
- Department of Neurology, Carson Tahoe Health, Carson City, NV
| | - Alejandro Arenas
- Department of Anesthesiology, University of Washington School of Medicine, Seattle, WA
| | - Bryce D Beutler
- University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Kirsten Cherian
- Department of Psychiatry & Behavioral Sciences, Stanford University, Palo Alto, CA
| | - Viviana D Evans
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Owen S Muir
- Fermata Health, Brooklyn, New York, NY; and
- Acacia Clinics, Sunnyvale, CA
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6
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Acevedo EC, Uhler S, White KP, Al-Shawaf L. What Predicts Beneficial Outcomes in Psychedelic Use? A Quantitative Content Analysis of Psychedelic Health Outcomes. J Psychoactive Drugs 2024:1-10. [PMID: 38341606 DOI: 10.1080/02791072.2024.2314729] [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: 08/01/2023] [Accepted: 12/19/2023] [Indexed: 02/12/2024]
Abstract
Interest in psychedelics and their possible therapeutic potential has been growing. Metaphysical belief theory asserts that these benefits stem from the adoption of comforting supernatural beliefs following a mystical experience. By contrast, predictive self-binding theory suggests that the beneficial outcomes of psychedelics are primarily driven by psychological insights. The present study tests these competing models of psychedelic benefits. We conducted a quantitative content analysis on unsolicited self-reports of psychedelic users available on Erowid.org, to examine the potential relations between psychological insight, ego dissolution, therapeutic intent, altered metaphysical belief, and enduring health outcomes. We randomly selected, coded, and analyzed two hundred forty psychedelic experience reports from the website. Path analysis using structural equation modeling showed that psychological insight, not metaphysical beliefs, uniquely predicted beneficial outcomes. Moreover, beneficial outcomes' positive relation to ego dissolution and therapeutic intent was fully mediated by psychological insight. These findings support the predictive self-binding model over the metaphysical belief model.
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Affiliation(s)
- Elias C Acevedo
- Department of Psychology, University of Colorado, Colorado Springs, CO, USA
| | - Scott Uhler
- Department of Psychology, University of Colorado, Colorado Springs, CO, USA
| | - Kaitlyn P White
- Department of Psychology, University of Colorado, Colorado Springs, CO, USA
| | - Laith Al-Shawaf
- Department of Psychology, University of Colorado, Colorado Springs, CO, USA
- Lyda Hill Institute for Human Resilience, University of Colorado, Colorado Springs, USA
- Institute for Advanced Study, Toulouse, France
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McAlpine RG, Blackburne G, Kamboj SK. Development and psychometric validation of a novel scale for measuring 'psychedelic preparedness'. Sci Rep 2024; 14:3280. [PMID: 38332334 PMCID: PMC10853197 DOI: 10.1038/s41598-024-53829-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 02/05/2024] [Indexed: 02/10/2024] Open
Abstract
Preparing participants for psychedelic experiences is crucial for ensuring these experiences are safe and, potentially beneficial. However, there is currently no validated measure to assess the extent to which participants are well-prepared for such experiences. Our study aimed to address this gap by developing, validating, and testing the Psychedelic Preparedness Scale (PPS). Using a novel iterative Delphi-focus group methodology ('DelFo'), followed by qualitative pre-test interviews, we incorporated the perspectives of expert clinicians/researchers and of psychedelic users to generate items for the scale. Psychometric validation of the PPS was carried out in two large online samples of psychedelic users (N = 516; N = 716), and the scale was also administered to a group of participants before and after a 5-7-day psilocybin retreat (N = 46). Exploratory and confirmatory factor analysis identified four factors from the 20-item PPS: Knowledge-Expectations, Intention-Preparation, Psychophysical-Readiness, and Support-Planning. The PPS demonstrated excellent reliability (ω = 0.954) and evidence supporting convergent, divergent and discriminant validity was also obtained. Significant differences between those scoring high and low (on psychedelic preparedness) before the psychedelic experience were found on measures of mental health/wellbeing outcomes assessed after the experience, suggesting that the scale has predictive utility. By prospectively measuring modifiable pre-treatment preparatory behaviours and attitudes using the PPS, it may be possible to determine whether a participant has generated the appropriate mental 'set' and is therefore likely to benefit from a psychedelic experience, or at least, less likely to be harmed.
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Affiliation(s)
- Rosalind G McAlpine
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology, University College London, London, UK.
| | - George Blackburne
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology, University College London, London, UK
- Experimental Psychology, University College London, London, UK
| | - Sunjeev K Kamboj
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology, University College London, London, UK
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8
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David J, Bouso JC, Kohek M, Ona G, Tadmor N, Arnon T, Dor-Ziderman Y, Berkovich-Ohana A. Ayahuasca-induced personal death experiences: prevalence, characteristics, and impact on attitudes toward death, life, and the environment. Front Psychiatry 2023; 14:1287961. [PMID: 38169823 PMCID: PMC10758466 DOI: 10.3389/fpsyt.2023.1287961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/22/2023] [Indexed: 01/05/2024] Open
Abstract
Introduction Despite an emerging understanding regarding the pivotal mechanistic role of subjective experiences that unfold during acute psychedelic states, very little has been done in the direction of better characterizing such experiences and determining their long-term impact. The present paper utilizes two cross-sectional studies for spotlighting - for the first time in the literature - the characteristics and outcomes of self-reported past experiences related to one's subjective sense of death during ayahuasca ceremonies, termed here Ayahuasca-induced Personal Death (APD) experiences. Methods Study 1 (n = 54) reports the prevalence, demographics, intensity, and impact of APDs on attitudes toward death, explores whether APDs are related with psychopathology, and reveals their impact on environmental concerns. Study 2 is a larger study (n = 306) aiming at generalizing the basic study 1 results regarding APD experience, and in addition, examining whether APDs is associated with self-reported coping strategies and values in life. Results Our results indicate that APDs occur to more than half of those participating in ayahuasca ceremonies, typically manifest as strong and transformative experiences, and are associated with an increased sense of transcending death (study 1), as well as the certainty in the continuation of consciousness after death (study 2). No associations were found between having undergone APD experiences and participants' demographics, personality type, and psychopathology. However, APDs were associated with increased self-reported environmental concern (study 1). These experiences also impact life in profound ways. APDs were found to be associated with increases in one's self-reported ability to cope with distress-causing life problems and the sense of fulfillment in life (study 2). Discussion The study's findings highlight the prevalence, safety and potency of death experiences that occur during ayahuasca ceremonies, marking them as possible mechanisms for psychedelics' long-term salutatory effects in non-clinical populations. Thus, the present results join other efforts of tracking and characterizing the profound subjective experiences that occur during acute psychedelic states.
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Affiliation(s)
- Jonathan David
- Edmond J. Safra Brain Research Center, University of Haifa, Haifa, Israel
- Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, Israel
- Department of Counseling and Human Development, Faculty of Education, University of Haifa, Haifa, Israel
| | - José Carlos Bouso
- International Center for Ethnobotanical Education, Research & Service (ICEERS), Barcelona, Spain
- Medical Anthropology Research Center (MARC), Department of Anthropology, Philosophy and Social Work, Universitat Rovira i Virgili, Tarragona, Spain
- Department of Neurosciences and Behavior, University of São Paulo, São Paulo, Brazil
| | - Maja Kohek
- International Center for Ethnobotanical Education, Research & Service (ICEERS), Barcelona, Spain
- Medical Anthropology Research Center (MARC), Department of Anthropology, Philosophy and Social Work, Universitat Rovira i Virgili, Tarragona, Spain
| | - Genís Ona
- International Center for Ethnobotanical Education, Research & Service (ICEERS), Barcelona, Spain
- Medical Anthropology Research Center (MARC), Department of Anthropology, Philosophy and Social Work, Universitat Rovira i Virgili, Tarragona, Spain
| | - Nir Tadmor
- Department of Counseling and Human Development, Faculty of Education, University of Haifa, Haifa, Israel
| | - Tal Arnon
- Integral Transpersonal Psychology, California Institute of Integral Studies, San Francisco, CA, United States
| | - Yair Dor-Ziderman
- Edmond J. Safra Brain Research Center, University of Haifa, Haifa, Israel
- Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, Israel
- Department of Counseling and Human Development, Faculty of Education, University of Haifa, Haifa, Israel
| | - Aviva Berkovich-Ohana
- Edmond J. Safra Brain Research Center, University of Haifa, Haifa, Israel
- Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, Israel
- Department of Counseling and Human Development, Faculty of Education, University of Haifa, Haifa, Israel
- Department of Learning and Instructional Sciences, Faculty of Education, University of Haifa, Haifa, Israel
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Ruffell SGD, Crosland‐Wood M, Palmer R, Netzband N, Tsang W, Weiss B, Gandy S, Cowley‐Court T, Halman A, McHerron D, Jong A, Kennedy T, White E, Perkins D, Terhune DB, Sarris J. Ayahuasca: A review of historical, pharmacological, and therapeutic aspects. PCN REPORTS : PSYCHIATRY AND CLINICAL NEUROSCIENCES 2023; 2:e146. [PMID: 38868739 PMCID: PMC11114307 DOI: 10.1002/pcn5.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/13/2023] [Accepted: 08/30/2023] [Indexed: 06/14/2024]
Abstract
Ayahuasca is a psychedelic plant brew originating from the Amazon rainforest. It is formed from two basic components, the Banisteriopsis caapi vine and a plant containing the potent psychedelic dimethyltryptamine (DMT), usually Psychotria viridis. Here we review the history of ayahuasca and describe recent work on its pharmacology, phenomenological responses, and clinical applications. There has been a significant increase in interest in ayahuasca since the turn of the millennium. Anecdotal evidence varies significantly, ranging from evangelical accounts to horror stories involving physical and psychological harm. The effects of the brew on personality and mental health outcomes are discussed in this review. Furthermore, phenomenological analyses of the ayahuasca experience are explored. Ayahuasca is a promising psychedelic agent that warrants greater empirical attention regarding its basic neurochemical mechanisms of action and potential therapeutic application.
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Affiliation(s)
- Simon G. D. Ruffell
- Onaya ScienceIquitosPeru
- Psychae InstituteMelbourneVictoriaAustralia
- School of Population and Global HealthUniversity of MelbourneMelbourneAustralia
| | - Max Crosland‐Wood
- Onaya ScienceIquitosPeru
- Psychology and Psychotherapy departmentCentral and North West London NHS TrustLondonUK
| | - Rob Palmer
- Onaya ScienceIquitosPeru
- School of MedicineUniversity of YaleNew HavenConnecticutUSA
- Department of PsychologyUniversity of New MexicoAlbuquerqueNew MexicoUSA
| | | | - WaiFung Tsang
- Onaya ScienceIquitosPeru
- Institute of Psychology, Psychiatry and NeuroscienceSouth London and The Maudsley NHS TrustLondonUK
- Department of Psychology, Institute of Psychiatry, Psychology & NeuroscienceKing's College LondonLondonUK
| | - Brandon Weiss
- Onaya ScienceIquitosPeru
- Division of PsychiatryImperial College LondonLondonUK
| | | | - Tessa Cowley‐Court
- Psychae InstituteMelbourneVictoriaAustralia
- School of Population and Global HealthUniversity of MelbourneMelbourneAustralia
| | - Andreas Halman
- School of Population and Global HealthUniversity of MelbourneMelbourneAustralia
| | | | - Angelina Jong
- Institute of Psychology, Psychiatry and NeuroscienceSouth London and The Maudsley NHS TrustLondonUK
- Department of Psychology, Institute of Psychiatry, Psychology & NeuroscienceKing's College LondonLondonUK
| | | | | | - Daniel Perkins
- Psychae InstituteMelbourneVictoriaAustralia
- School of Population and Global HealthUniversity of MelbourneMelbourneAustralia
- Centre for Mental HealthSwinburne UniversityMelbourneAustralia
| | - Devin B. Terhune
- Psychology and Psychotherapy departmentCentral and North West London NHS TrustLondonUK
| | - Jerome Sarris
- Psychae InstituteMelbourneVictoriaAustralia
- NICM Health Research InstituteWestern Sydney UniversitySydneyAustralia
- Florey Institute for Neuroscience and Mental HealthUniversity of MelbourneMelbourneAustralia
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10
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Bottemanne H, Berkovitch L, Gauld C, Balcerac A, Schmidt L, Mouchabac S, Fossati P. Storm on predictive brain: A neurocomputational account of ketamine antidepressant effect. Neurosci Biobehav Rev 2023; 154:105410. [PMID: 37793581 DOI: 10.1016/j.neubiorev.2023.105410] [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: 04/22/2023] [Revised: 08/24/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
For the past decade, ketamine, an N-methyl-D-aspartate receptor (NMDAr) antagonist, has been considered a promising treatment for major depressive disorder (MDD). Unlike the delayed effect of monoaminergic treatment, ketamine may produce fast-acting antidepressant effects hours after a single administration at subanesthetic dose. Along with these antidepressant effects, it may also induce transient dissociative (disturbing of the sense of self and reality) symptoms during acute administration which resolve within hours. To understand ketamine's rapid-acting antidepressant effect, several biological hypotheses have been explored, but despite these promising avenues, there is a lack of model to understand the timeframe of antidepressant and dissociative effects of ketamine. In this article, we propose a neurocomputational account of ketamine's antidepressant and dissociative effects based on the Predictive Processing (PP) theory, a framework for cognitive and sensory processing. PP theory suggests that the brain produces top-down predictions to process incoming sensory signals, and generates bottom-up prediction errors (PEs) which are then used to update predictions. This iterative dynamic neural process would relies on N-methyl-D-aspartate (NMDAr) and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic receptors (AMPAr), two major component of the glutamatergic signaling. Furthermore, it has been suggested that MDD is characterized by over-rigid predictions which cannot be updated by the PEs, leading to miscalibration of hierarchical inference and self-reinforcing negative feedback loops. Based on former empirical studies using behavioral paradigms, neurophysiological recordings, and computational modeling, we suggest that ketamine impairs top-down predictions by blocking NMDA receptors, and enhances presynaptic glutamate release and PEs, producing transient dissociative symptoms and fast-acting antidepressant effect in hours following acute administration. Moreover, we present data showing that ketamine may enhance a delayed neural plasticity pathways through AMPAr potentiation, triggering a prolonged antidepressant effect up to seven days for unique administration. Taken together, the two sides of antidepressant effects with distinct timeframe could constitute the keystone of antidepressant properties of ketamine. These PP disturbances may also participate to a ketamine-induced time window of mental flexibility, which can be used to improve the psychotherapeutic process. Finally, these proposals could be used as a theoretical framework for future research into fast-acting antidepressants, and combination with existing antidepressant and psychotherapy.
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Affiliation(s)
- Hugo Bottemanne
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France; Sorbonne University, Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
| | - Lucie Berkovitch
- Saclay CEA Centre, Neurospin, Gif-Sur-Yvette Cedex, France; Department of Psychiatry, GHU Paris Psychiatrie et Neurosciences, Service Hospitalo-Universitaire, Paris, France
| | - Christophe Gauld
- Department of Child Psychiatry, CHU de Lyon, F-69000 Lyon, France; Institut des Sciences Cognitives Marc Jeannerod, UMR 5229 CNRS & Université Claude Bernard Lyon 1, F-69000 Lyon, France
| | - Alexander Balcerac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Neurology, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Liane Schmidt
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France
| | - Stephane Mouchabac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Psychiatry, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Philippe Fossati
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France
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Garel N, Drury J, Thibault Lévesque J, Goyette N, Lehmann A, Looper K, Erritzoe D, Dames S, Turecki G, Rej S, Richard-Devantoy S, Greenway KT. The Montreal model: an integrative biomedical-psychedelic approach to ketamine for severe treatment-resistant depression. Front Psychiatry 2023; 14:1268832. [PMID: 37795512 PMCID: PMC10546328 DOI: 10.3389/fpsyt.2023.1268832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 08/30/2023] [Indexed: 10/06/2023] Open
Abstract
Background Subanesthetic ketamine has accumulated meta-analytic evidence for rapid antidepressant effects in treatment-resistant depression (TRD), resulting in both excitement and debate. Many unanswered questions surround ketamine's mechanisms of action and its integration into real-world psychiatric care, resulting in diverse utilizations that variously resemble electroconvulsive therapy, conventional antidepressants, or serotonergic psychedelics. There is thus an unmet need for clinical approaches to ketamine that are tailored to its unique therapeutic properties. Methods This article presents the Montreal model, a comprehensive biopsychosocial approach to ketamine for severe TRD refined over 6 years in public healthcare settings. To contextualize its development, we review the evidence for ketamine as a biomedical and as a psychedelic treatment of depression, emphasizing each perspectives' strengths, weaknesses, and distinct methods of utilization. We then describe the key clinical experiences and research findings that shaped the model's various components, which are presented in detail. Results The Montreal model, as implemented in a recent randomized clinical trial, aims to synergistically pair ketamine infusions with conventional and psychedelic biopsychosocial care. Ketamine is broadly conceptualized as a brief intervention that can produce windows of opportunity for enhanced psychiatric care, as well as powerful occasions for psychological growth. The model combines structured psychiatric care and concomitant psychotherapy with six ketamine infusions, administered with psychedelic-inspired nonpharmacological adjuncts including rolling preparative and integrative psychological support. Discussion Our integrative model aims to bridge the biomedical-psychedelic divide to offer a feasible, flexible, and standardized approach to ketamine for TRD. Our learnings from developing and implementing this psychedelic-inspired model for severe, real-world patients in two academic hospitals may offer valuable insights for the ongoing roll-out of a range of psychedelic therapies. Further research is needed to assess the Montreal model's effectiveness and hypothesized psychological mechanisms.
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Affiliation(s)
- Nicolas Garel
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
| | - Jessica Drury
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
| | | | - Nathalie Goyette
- McGill Group for Suicide Studies, Douglas Mental Health Research Institute, Montreal, QC, Canada
| | - Alexandre Lehmann
- International Laboratory for Brain, Music and Sound Research, Montreal, QC, Canada
- Department of Otolaryngology, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Karl Looper
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
- Jewish General Hospital, Lady Davis Institute for Medical Research, Montreal, QC, Canada
| | - David Erritzoe
- Division of Psychiatry, Department of Brain Sciences, Centres for Neuropsychopharmacology and Psychedelic Research, Imperial College London, London, United Kingdom
| | - Shannon Dames
- Health Sciences and Human Services, Vancouver Island University, Nanaimo, BC, Canada
| | - Gustavo Turecki
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
- McGill Group for Suicide Studies, Douglas Mental Health Research Institute, Montreal, QC, Canada
| | - Soham Rej
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
- Jewish General Hospital, Lady Davis Institute for Medical Research, Montreal, QC, Canada
- Geri-PARTy Research Group, Jewish General Hospital, Montreal, QC, Canada
| | - Stephane Richard-Devantoy
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
- McGill Group for Suicide Studies, Douglas Mental Health Research Institute, Montreal, QC, Canada
| | - Kyle T. Greenway
- Department of Psychiatry, Faculty of Medicine, McGill University, Montréal, QC, Canada
- Jewish General Hospital, Lady Davis Institute for Medical Research, Montreal, QC, Canada
- Division of Psychiatry, Department of Brain Sciences, Centres for Neuropsychopharmacology and Psychedelic Research, Imperial College London, London, United Kingdom
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Michael P, Luke D, Robinson O. This is your brain on death: a comparative analysis of a near-death experience and subsequent 5-Methoxy-DMT experience. Front Psychol 2023; 14:1083361. [PMID: 37457069 PMCID: PMC10345338 DOI: 10.3389/fpsyg.2023.1083361] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/02/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction Much research has focused on the modeling of the near-death experience (NDE) by classical and atypical psychedelics; however, to date, no study has reported on the relationship between the NDE and the experience induced by the highly potent, endogenous psychedelic drug 5-Methoxy-DMT (5MeO-DMT). This article presents a case study of an individual who is popularly documented to have had a profound near-death experience while in a coma caused by bacterial meningoencephalitis. Additionally, the individual also subsequently underwent an experience with 5MeO-DMT. Methods A semi-structured interview was conducted with the subject concerning his experiences with both the NDE and 5MeO-DMT. A basic thematic analysis was performed on both the original text describing the NDE as well as the interview itself, which mainly focused on the subject's experience with 5MeO-DMT. This analysis was organized to identify both the similar and different emergent themes between the two states, with a particular emphasis on the subject's perceptions of the similarities and differences between the experiences. Results There is a very high level of comparability between the original NDE and psychedelic experiences in general, including shared characteristics such as entering other worlds, meeting menacing or benevolent entities, experiencing synesthesia, perinatal regression, and lucid dreamlike properties. Much comparability was also identified with the 5MeO-DMT experience, in particular the major mystical experiential domains, such as ego dissolution, but especially transcendence of time and space. However, there were also a few unique themes (life review, the deceased, and the threshold) that emerged in the NDE that were not present in the 5MeO-DMT experience or other psychedelic experience studies, suggesting that these themes may be more unique to the NDE. Discussion Despite such similarities, the participant asserted that his NDE and psychedelic experiences were not similar enough to be attributed to endogenous psychedelics. In this study, we discussed several mechanisms that could potentially account for the NDE, including lucid dreams and perinatal regression. However, the study also explored the possibility that the unique etiology of the participant's NDE, bacterial meningoencephalitis affecting the neocortex, may have triggered similar downstream neural activity as that initiated by psychedelic agents through pyramidal neuronal activation. This hypothesis is presented with appropriate caveats and acknowledged as speculative.
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Affiliation(s)
- Pascal Michael
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
| | - David Luke
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Oliver Robinson
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
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Charpier S. Between life and death: the brain twilight zones. Front Neurosci 2023; 17:1156368. [PMID: 37260843 PMCID: PMC10227869 DOI: 10.3389/fnins.2023.1156368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/24/2023] [Indexed: 06/02/2023] Open
Abstract
Clinically, and legally, death is considered a well-defined state of the organism characterized, at least, by a complete and irreversible cessation of brain activities and functions. According to this pragmatic approach, the moment of death is implicitly represented by a discrete event from which all cerebral processes abruptly cease. However, a growing body of experimental and clinical evidence has demonstrated that cardiorespiratory failure, the leading cause of death, causes complex time-dependent changes in neuronal activity that can lead to death but also be reversed with successful resuscitation. This review synthesizes our current knowledge of the succeeding alterations in brain activities that accompany the dying and resuscitation processes. The anoxia-dependent brain defects that usher in a process of potential death successively include: (1) a set of changes in electroencephalographic (EEG) and neuronal activities, (2) a cessation of brain spontaneous electrical activity (isoelectric state), (3) a loss of consciousness whose timing in relation to EEG changes remains unclear, (4) an increase in brain resistivity, caused by neuronal swelling, concomitant with the occurrence of an EEG deviation reflecting the neuronal anoxic insult (the so-called "wave of death," or "terminal spreading depolarization"), followed by, (5) a terminal isoelectric brain state leading to death. However, a timely restoration of brain oxygen supply-or cerebral blood flow-can initiate a mirrored sequence of events: a repolarization of neurons followed by a re-emergence of neuronal, synaptic, and EEG activities from the electrocerebral silence. Accordingly, a recent study has revealed a new death-related brain wave: the "wave of resuscitation," which is a marker of the collective recovery of electrical properties of neurons at the beginning of the brain's reoxygenation phase. The slow process of dying still represents a terra incognita, during which neurons and neural networks evolve in uncertain states that remain to be fully understood. As current event-based models of death have become neurophysiologically inadequate, I propose a new mixed (event-process) model of death and resuscitation. It is based on a detailed description of the different phases that succeed each other in a dying brain, which are generally described separately and without mechanistic linkage, in order to integrate them into a continuum of declining brain activity. The model incorporates cerebral twilight zones (with still unknown neuronal and synaptic processes) punctuated by two characteristic cortical waves providing real-time biomarkers of death- and resuscitation.
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Affiliation(s)
- Stéphane Charpier
- Sorbonne Université, Institut du Cerveau – Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtriére, Paris, France
- Sorbonne University, UPMC Université Paris, Paris, France
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Coliță CI, Olaru DG, Coliță D, Hermann DM, Coliță E, Glavan D, Popa-Wagner A. Induced Coma, Death, and Organ Transplantation: A Physiologic, Genetic, and Theological Perspective. Int J Mol Sci 2023; 24:ijms24065744. [PMID: 36982814 PMCID: PMC10059721 DOI: 10.3390/ijms24065744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
In the clinic, the death certificate is issued if brain electrical activity is no longer detectable. However, recent research has shown that in model organisms and humans, gene activity continues for at least 96 h postmortem. The discovery that many genes are still working up to 48 h after death questions our definition of death and has implications for organ transplants and forensics. If genes can be active up to 48 h after death, is the person technically still alive at that point? We discovered a very interesting parallel between genes that were upregulated in the brain after death and genes upregulated in the brains that were subjected to medically-induced coma, including transcripts involved in neurotransmission, proteasomal degradation, apoptosis, inflammation, and most interestingly, cancer. Since these genes are involved in cellular proliferation, their activation after death could represent the cellular reaction to escape mortality and raises the question of organ viability and genetics used for transplantation after death. One factor limiting the organ availability for transplantation is religious belief. However, more recently, organ donation for the benefit of humans in need has been seen as “posthumous giving of organs and tissues can be a manifestation of love spreading also to the other side of death”.
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Affiliation(s)
- Cezar-Ivan Coliță
- Doctoral School, University of Medicine and Pharmacy Carol Davila, 020276 Bucharest, Romania; (C.-I.C.)
| | - Denissa-Greta Olaru
- Department of Psychiatry, University for Medicine and Pharmacy Craiova, 200349 Craiova, Romania;
| | - Daniela Coliță
- Doctoral School, University of Medicine and Pharmacy Carol Davila, 020276 Bucharest, Romania; (C.-I.C.)
| | - Dirk M. Hermann
- Chair of Vascular Neurology, Dementia and Ageing, Department of Neurology, University Hospital Essen, 45147 Essen, Germany
| | - Eugen Coliță
- Doctoral School, University of Medicine and Pharmacy Carol Davila, 020276 Bucharest, Romania; (C.-I.C.)
| | - Daniela Glavan
- Department of Psychiatry, University for Medicine and Pharmacy Craiova, 200349 Craiova, Romania;
- Correspondence: (D.G.); (A.P.-W.)
| | - Aurel Popa-Wagner
- Department of Psychiatry, University for Medicine and Pharmacy Craiova, 200349 Craiova, Romania;
- Chair of Vascular Neurology, Dementia and Ageing, Department of Neurology, University Hospital Essen, 45147 Essen, Germany
- Correspondence: (D.G.); (A.P.-W.)
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Romand R, Ehret G. Neuro-functional modeling of near-death experiences in contexts of altered states of consciousness. Front Psychol 2023; 13:846159. [PMID: 36743633 PMCID: PMC9891231 DOI: 10.3389/fpsyg.2022.846159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 11/23/2022] [Indexed: 01/19/2023] Open
Abstract
Near-death experiences (NDEs) including out-of-body experiences (OBEs) have been fascinating phenomena of perception both for affected persons and for communities in science and medicine. Modern progress in the recording of changing brain functions during the time between clinical death and brain death opened the perspective to address and understand the generation of NDEs in brain states of altered consciousness. Changes of consciousness can experimentally be induced in well-controlled clinical or laboratory settings. Reports of the persons having experienced the changes can inform about the similarity of the experiences with those from original NDEs. Thus, we collected neuro-functional models of NDEs including OBEs with experimental backgrounds of drug consumption, epilepsy, brain stimulation, and ischemic stress, and included so far largely unappreciated data from fighter pilot tests under gravitational stress generating cephalic nervous system ischemia. Since we found a large overlap of NDE themes or topics from original NDE reports with those from neuro-functional NDE models, we can state that, collectively, the models offer scientifically appropriate causal explanations for the occurrence of NDEs. The generation of OBEs, one of the NDE themes, can be localized in the temporo-parietal junction (TPJ) of the brain, a multimodal association area. The evaluated literature suggests that NDEs may emerge as hallucination-like phenomena from a brain in altered states of consciousness (ASCs).
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Affiliation(s)
- Raymond Romand
- Faculty of Medicine, University of Strasbourg, Strasbourg, France,*Correspondence: Raymond Romand,
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany,Günter Ehret,
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Bicego A, Cassol H, Simon J, Fritz P, Abagnale S, Vanhaudenhuyse A, Laureys S, Martial C. Personality traits and pattern of beliefs of near-death(-like) experiencers. Front Hum Neurosci 2023; 17:1124739. [PMID: 37187942 PMCID: PMC10175626 DOI: 10.3389/fnhum.2023.1124739] [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: 12/15/2022] [Accepted: 03/17/2023] [Indexed: 05/17/2023] Open
Abstract
Introduction Little is known about the potential personality and psychological predictors of near-death experiences (NDEs), and fewer yet those of near-death-like experiences (NDEs-like; similar phenomenology reported after a non-life-threatening context). This study investigated whether personality traits (Openness, Extraversion, Pleasantness, Conscientiousness, and Neuroticism), dissociative experiences, Fantasy proneness, disposition toward auditory hallucinations, absorption trait, and endorsement of paranormal and spiritual beliefs could be associated with the recall of NDEs(-like). Methods To this aim, we invited four groups of people to retrospectively fill in questionnaires assessing the following factors: NDE experiencers (n = 63), NDE(-like) experiencers (n = 31), controls with a life-threatening situation but no NDE(-like) (n = 43), and controls without a life-threatening situation or an NDE(-like) (n = 44). We carried out univariate analyses for each factor and then performed a multiple regression analysis and a discriminant analysis. Results The multivariate logistic regression analysis revealed that the endorsement of spiritual beliefs was associated with the recall of NDEs-like while Openness and Fantasy proneness were associated with the recall of NDEs. The discriminant analysis showed that these variables produce 35% of correct classification. Discussion Albeit retrospective, these results pave the way for future research on psychological predictors of NDEs(-like) by highlighting the influence of Spirituality, Openness, and Fantasy proneness on these phenomena.
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Affiliation(s)
- Aminata Bicego
- Sensation and Perception Research Group, GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Héléna Cassol
- Neurological and Functional Rehabilitation Center, University Hospital of Liège, Fraiture, Belgium
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Jessica Simon
- Psychology and Neuroscience of Cognition Research Unit (PsyNCog), University of Liège, Liège, Belgium
| | - Pauline Fritz
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau, University Hospital of Liège, Liège, Belgium
| | - Simona Abagnale
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Audrey Vanhaudenhuyse
- Sensation and Perception Research Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Interdisciplinary Algology Centre, University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau, University Hospital of Liège, Liège, Belgium
- CERVO Brain Research Center, University of Laval, Québec, QC, Canada
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau, University Hospital of Liège, Liège, Belgium
- *Correspondence: Charlotte Martial
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Martial C, Gosseries O, Cassol H, Kondziella D. Studying death and near-death experiences requires neuroscientific expertise. Ann N Y Acad Sci 2022; 1517:11-14. [PMID: 36017883 DOI: 10.1111/nyas.14888] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Parnia et al. recently published suggestions for the study of death and experiences recalled in a near-death context. We have serious reservations about the authors' statements. In this commentary, we discuss the omissions and knowledge gaps inherent to the authors' paper, which among others include incorrect neurological claims about brain death and misunderstandings regarding the terminology of consciousness. Although we believe that (near-)death research deserves a framework guideline, the paper by Parnia and colleagues is misleading and, contrary to the authors' intention, hinders the scientific understanding of near-death experiences and the neural mechanisms occurring in the dying brain.
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Affiliation(s)
- Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau2, University Hospital of Liège, Liège, Belgium
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
- Centre du Cerveau2, University Hospital of Liège, Liège, Belgium
| | - Héléna Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Sweeney MM, Nayak S, Hurwitz ES, Mitchell LN, Swift TC, Griffiths RR. Comparison of psychedelic and near-death or other non-ordinary experiences in changing attitudes about death and dying. PLoS One 2022; 17:e0271926. [PMID: 36001643 PMCID: PMC9401141 DOI: 10.1371/journal.pone.0271926] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 07/08/2022] [Indexed: 11/18/2022] Open
Abstract
Both psychedelic drug experiences and near-death experiences can occasion changes in perspectives on death and dying, but there have been few direct comparisons of these phenomena. This study directly compared psychedelic occasioned and non-drug experiences which altered individuals’ beliefs about death. Individuals who reported an experience that altered their beliefs about death occasioned by either a psychedelic drug or a near-death or other non-ordinary experience completed an online survey. Circumstances of the experience, mystical and near-death subjective features, changes in attitudes about death, and other persisting effects were evaluated. The study sample (n = 3192) included five groups: non-drug near-death or other non-ordinary experiences (n = 933), and drug experiences occasioned by lysergic acid diethylamide (LSD) (n = 904), psilocybin (n = 766), ayahuasca (n = 282), or N,N-dimethyltryptamine (DMT) (n = 307). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. Compared to the psychedelic groups, the non-drug group was more likely to report being unconscious, clinically dead, and that their life was in imminent danger. The groups were remarkably similar in the reported changes in death attitudes attributed to the experience, including a reduced fear of death and high ratings of positive persisting effects and personal meaning, spiritual significance, and psychological insight. Although both psychedelic and non-drug participants showed robust increases on standardized measures of mystical and near-death experiences, these measures were significantly greater in the psychedelic participants. Non-drug participants were more likely to rate their experiences as the single most meaningful of their lives. Comparing across psychedelic substances, ayahuasca and DMT groups tended report stronger and more positive enduring consequences of the experience than the psilocybin and LSD groups, which were largely indistinguishable. These data provide a detailed characterization and comparison of psychedelic occasioned and non-drug experiences that changed attitudes about death and suggest the importance of future prospective psychedelic administration studies.
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Affiliation(s)
- Mary M. Sweeney
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (MMS); (RRG)
| | - Sandeep Nayak
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ethan S. Hurwitz
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Lisa N. Mitchell
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - T. Cody Swift
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Roland R. Griffiths
- Department of Psychiatry and Behavioral Sciences, Behavioral Pharmacology Research Unit, Center for Psychedelics and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurosciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (MMS); (RRG)
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James E, Keppler J, L Robertshaw T, Sessa B. N,N-dimethyltryptamine and Amazonian ayahuasca plant medicine. Hum Psychopharmacol 2022; 37:e2835. [PMID: 35175662 PMCID: PMC9286861 DOI: 10.1002/hup.2835] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/13/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Reports have indicated possible uses of ayahuasca for the treatment of conditions including depression, addictions, post-traumatic stress disorder, anxiety and specific psychoneuroendocrine immune system pathologies. The article assesses potential ayahuasca and N,N-dimethyltryptamine (DMT) integration with contemporary healthcare. The review also seeks to provide a summary of selected literature regarding the mechanisms of action of DMT and ayahuasca; and assess to what extent the state of research can explain reports of unusual phenomenology. DESIGN A narrative review. RESULTS Compounds in ayahuasca have been found to bind to serotonergic receptors, glutaminergic receptors, sigma-1 receptors, trace amine-associated receptors, and modulate BDNF expression and the dopaminergic system. Subjective effects are associated with increased delta and theta oscillations in amygdala and hippocampal regions, decreased alpha wave activity in the default mode network, and stimulations of vision-related brain regions particularly in the visual association cortex. Both biological processes and field of consciousness models have been proposed to explain subjective effects of DMT and ayahuasca, however, the evidence supporting the proposed models is not sufficient to make confident conclusions. Ayahuasca plant medicine and DMT represent potentially novel treatment modalities. CONCLUSIONS Further research is required to clarify the mechanisms of action and develop treatments which can be made available to the general public. Integration between healthcare research institutions and reputable practitioners in the Amazon is recommended.
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Affiliation(s)
- Edward James
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffUK
| | | | | | - Ben Sessa
- Centre for NeuropsychopharmacologyDivision of Brain SciencesFaculty of MedicineImperial College LondonLondonUK
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Tagliazucchi E. Language as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs. Front Pharmacol 2022; 13:812227. [PMID: 35392561 PMCID: PMC8980225 DOI: 10.3389/fphar.2022.812227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/01/2022] [Indexed: 11/22/2022] Open
Abstract
Psychedelics are drugs capable of eliciting profound alterations in the subjective experience of the users, sometimes with long-lasting consequences. Because of this, psychedelic research tends to focus on human subjects, given their capacity to construct detailed narratives about the contents of their consciousness experiences. In spite of its relevance, the interaction between serotonergic psychedelics and language production is comparatively understudied in the recent literature. This review is focused on two aspects of this interaction: how the acute effects of psychedelic drugs impact on speech organization regardless of its semantic content, and how to characterize the subjective effects of psychedelic drugs by analyzing the semantic content of written retrospective reports. We show that the computational characterization of language production is capable of partially predicting the therapeutic outcome of individual experiences, relate the effects elicited by psychedelics with those associated with other altered states of consciousness, draw comparisons between the psychedelic state and the symptomatology of certain psychiatric disorders, and investigate the neurochemical profile and mechanism of action of different psychedelic drugs. We conclude that researchers studying psychedelics can considerably expand the range of their potential scientific conclusions by analyzing brief interviews obtained before, during and after the acute effects. Finally, we list a series of questions and open problems that should be addressed to further consolidate this approach.
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Affiliation(s)
- Enzo Tagliazucchi
- Latin American Brain Health Institute (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile.,Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA, CONICET), Pabellón I, Ciudad Universitaria (1428), Buenos Aires, Argentina
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21
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The use patterns of novel psychedelics: experiential fingerprints of substituted phenethylamines, tryptamines and lysergamides. Psychopharmacology (Berl) 2022; 239:1783-1796. [PMID: 35487983 PMCID: PMC9166850 DOI: 10.1007/s00213-022-06142-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 04/06/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Novel psychedelics (NPs) are an expanding set of compounds, presenting new challenges for drug policy and opportunities for clinical research. Unlike their classical derivatives, little is known regarding their use profiles or their subjective effects. AIMS The purpose of this study was to compile usage patterns and adverse event rates for individual NPs belonging to each of three main psychedelic structural families. Targeting the most widely used representatives for each class, we expanded on their phenomenological distinctions. METHODS A two-part survey was employed. We investigated the prevalence of novel phenethylamines, tryptamine and lysergamides in NP users (N = 1180), contrasting the type and incidence of adverse events (AEs) using a set of logistic regressions. Honing in on 2-4-Bromo-2,5-dimethoxyphenyl)ethanamine (2C-B) (48.6%), 1-propionyl-lysergic acid diethylamide (1P-LSD) (34.2%) and 4-Acetoxy-N,N-dimethyltryptamine (4-AcO-DMT) (23.1%), we examined their phenomenological separability using a gradient boosting (XGBoost) supervised classifier. RESULTS Novel phenethylamines had the highest prevalence of use (61.5%) seconded by tryptamines (43.8%) and lysergamides (42.9%). Usage patterns were identified for 32 different compounds, demonstrating variable dosages, durations and a common oral route of administration. Compared to phenethylamines, the odds for tryptamines and lysergamides users were significantly less for overall physical AEs. No significant differences in overall psychological AEs were found. Overall model area under the curve (AUC) stood at 0.79 with sensitivity (50.0%) and specificity (60.0%) for 2C-B ranking lowest. CONCLUSION NP classes may hold distinct AE rates and phenomenology, the latter potentially clouded by the subjective nature of these experiences. Further targeted research is warranted.
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22
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Hase A, Erdmann M, Limbach V, Hasler G. Analysis of recreational psychedelic substance use experiences classified by substance. Psychopharmacology (Berl) 2022; 239:643-659. [PMID: 35031816 PMCID: PMC8799548 DOI: 10.1007/s00213-022-06062-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 01/06/2022] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES Differences among psychedelic substances regarding their subjective experiences are clinically and scientifically interesting. Quantitative linguistic analysis is a powerful tool to examine such differences. This study compared five psychedelic substance report groups and a non-psychedelic report group on quantitative linguistic markers of psychological states and processes derived from recreational use-based online experience reports. METHODS Using 2947 publicly available online reports, we compared Ayahuasca and N,N-dimethyltryptamine (DMT, analyzed together), ketamine, lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), psilocybin (mushroom), and antidepressant drug use experiences. We examined word frequencies related to various psychological states and processes and semantic proximity to psychedelic and mystical experience scales. RESULTS Linguistic markers of psychological function indicated distinct effect profiles. For example, MDMA experience reports featured an emotionally intensifying profile accompanied by many cognitive process words and dynamic-personal language. In contrast, Ayahuasca and DMT experience reports involved relatively little emotional language, few cognitive process words, increased analytical thinking-associated language, and the most semantic similarity with psychedelic and mystical experience descriptions. LSD, psilocybin mushroom, and ketamine reports showed only small differences on the emotion-, analytical thinking-, psychedelic, and mystical experience-related language outcomes. Antidepressant reports featured more negative emotional and cognitive process-related words, fewer positive emotional and analytical thinking-related words, and were generally not similar to mystical and psychedelic language. CONCLUSION This article addresses an existing research gap regarding the comparison of different psychedelic drugs on linguistic profiles of psychological states, processes, and experiences. The large sample of experience reports involving multiple psychedelic drugs provides valuable information that would otherwise be difficult to obtain. The results could inform experimental research into psychedelic drug effects in healthy populations and clinical trials for psychedelic treatments of psychiatric problems.
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Affiliation(s)
- Adrian Hase
- Department of Medicine, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
| | - Max Erdmann
- grid.10493.3f0000000121858338Faculty of Medicine, University of Rostock, Rostock, Germany
| | - Verena Limbach
- grid.6612.30000 0004 1937 0642Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Gregor Hasler
- grid.8534.a0000 0004 0478 1713Department of Medicine, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
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Losing the Self in Near-Death Experiences: The Experience of Ego-Dissolution. Brain Sci 2021; 11:brainsci11070929. [PMID: 34356163 PMCID: PMC8307473 DOI: 10.3390/brainsci11070929] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/30/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
Many people who have had a near-death experience (NDE) describe, as part of it, a disturbed sense of having a “distinct self”. However, no empirical studies have been conducted to explore the frequency or intensity of these effects. We surveyed 100 NDE experiencers (Near-Death-Experience Content [NDE-C] scale total score ≥27/80). Eighty participants had their NDEs in life-threatening situations and 20 had theirs not related to life-threatening situations. Participants completed the Ego-Dissolution Inventory (EDI) and the Ego-Inflation Inventory (EII) to assess the experience of ego dissolution and inflation potentially experienced during their NDE, respectively. They also completed the Nature-Relatedness Scale (NR-6) which measures the trait-like construct of one’s self-identification with nature. Based on prior hypotheses, ratings of specific NDE-C items pertaining to out-of-body experiences and a sense of unity were used for correlational analyses. We found higher EDI total scores compared with EII total scores in our sample. Total scores of the NDE-C scale were positively correlated with EDI total scores and, although less strongly, the EII and NR-6 scores. EDI total scores were also positively correlated with the intensity of OBE and a sense of unity. This study suggests that the experience of dissolved ego-boundaries is a common feature of NDEs.
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Peinkhofer C, Martial C, Cassol H, Laureys S, Kondziella D. The evolutionary origin of near-death experiences: a systematic investigation. Brain Commun 2021; 3:fcab132. [PMID: 34240053 PMCID: PMC8260963 DOI: 10.1093/braincomms/fcab132] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/18/2021] [Accepted: 05/05/2021] [Indexed: 11/28/2022] Open
Abstract
Near-death experiences are known from all parts of the world, various times and
numerous cultural backgrounds. This universality suggests that near-death
experiences may have a biological origin and purpose. Adhering to a
preregistered protocol, we investigate the hypothesis that thanatosis, aka
death-feigning, a last-resort defense mechanism in animals, is the evolutionary
origin of near-death experiences. We first show that thanatosis is a highly
preserved survival strategy occurring at all major nodes in a cladogram ranging
from insects to humans. We then show that humans under attack by animal, human
and ‘modern’ predators can experience both thanatosis and
near-death experiences, and we further show that the phenomenology and the
effects of the two overlap. In summary, we build a line of evidence suggesting
that thanatosis is the evolutionary foundation of near-death experiences and
that their shared biological purpose is the benefit of survival. We propose that
the acquisition of language enabled humans to transform these events from
relatively stereotyped death-feigning under predatory attacks into the rich
perceptions that form near-death experiences and extend to non-predatory
situations.
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Affiliation(s)
- Costanza Peinkhofer
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen 2100, Denmark
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Helena Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen 2100, Denmark
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25
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Pan CX, Thomson K, Costa BA, Morris J. Questioning Capacity in an Elderly Jamaican Man with Terminal Cancer Exhibiting Near-Death Awareness: A Case Report and Review of Literature. J Palliat Med 2021; 24:1413-1417. [PMID: 33970707 DOI: 10.1089/jpm.2020.0785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Near-death awareness (NDA) refers to visions and dreams commonly experienced by terminally ill individuals within months to hours before death. Methods: A case report of a 68-year-old Jamaican male diagnosed with advanced cholangiocarcinoma, who experienced visions of his deceased mother during hospitalization. Results: This article discusses how to differentiate NDA from delirium, core components for determining decisional capacity, and how clinicians can use a cultural guide to optimize patient-centered care. Conclusion: Improved recognition of NDA may promote cultural humility/competency and help to differentiate NDA from an underlying medical/psychiatric condition. It may assist the clinician in understanding the significance of NDA and the comfort and meaning these experiences may hold for both the individual and their family.
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Affiliation(s)
- Cynthia X Pan
- Division of Geriatrics and Palliative Care Medicine, NewYork-Presbyterian Queens, Flushing, New York, USA
| | - Kelly Thomson
- Division of General Internal Medicine, NewYork-Presbyterian Queens, Flushing, New York, USA
| | - Bruno A Costa
- Department of Internal Medicine, Walter Cantidio University Hospital, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Jane Morris
- Department of Internal Medicine, Walter Cantidio University Hospital, Federal University of Ceará, Fortaleza, Ceará, Brazil
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26
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Pallavicini C, Cavanna F, Zamberlan F, de la Fuente LA, Ilksoy Y, Perl YS, Arias M, Romero C, Carhart-Harris R, Timmermann C, Tagliazucchi E. Neural and subjective effects of inhaled N,N-dimethyltryptamine in natural settings. J Psychopharmacol 2021; 35:406-420. [PMID: 33567945 DOI: 10.1177/0269881120981384] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND N,N-dimethyltryptamine is a short-acting psychedelic tryptamine found naturally in many plants and animals. Few studies to date have addressed the neural and psychological effects of N,N-dimethyltryptamine alone, either administered intravenously or inhaled in freebase form, and none have been conducted in natural settings. AIMS Our primary aim was to study the acute effects of inhaled N,N-dimethyltryptamine in natural settings, focusing on questions tuned to the advantages of conducting field research, including the effects of contextual factors (i.e. "set" and "setting"), the possibility of studying a comparatively large number of subjects, and the relaxed mental state of participants consuming N,N-dimethyltryptamine in familiar and comfortable settings. METHODS We combined state-of-the-art wireless electroencephalography with psychometric questionnaires to study the neural and subjective effects of naturalistic N,N-dimethyltryptamine use in 35 healthy and experienced participants. RESULTS We observed that N,N-dimethyltryptamine significantly decreased the power of alpha (8-12 Hz) oscillations throughout all scalp locations, while simultaneously increasing power of delta (1-4 Hz) and gamma (30-40 Hz) oscillations. Gamma power increases correlated with subjective reports indicative of some features of mystical-type experiences. N,N-dimethyltryptamine also increased global synchrony and metastability in the gamma band while decreasing those measures in the alpha band. CONCLUSIONS Our results are consistent with previous studies of psychedelic action in the human brain, while at the same time the results suggest potential electroencephalography markers of mystical-type experiences in natural settings, thus highlighting the importance of investigating these compounds in the contexts where they are naturally consumed.
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Affiliation(s)
- Carla Pallavicini
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina.,Fundación para la lucha contra las enfermedades neurológicas de la infancia (FLENI), Buenos Aires, Argentina
| | - Federico Cavanna
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina.,Fundación para la lucha contra las enfermedades neurológicas de la infancia (FLENI), Buenos Aires, Argentina
| | - Federico Zamberlan
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina
| | - Laura A de la Fuente
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina
| | - Yayla Ilksoy
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina
| | - Yonatan S Perl
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina
| | - Mauricio Arias
- Hospital General de Agudos Donación Francisco Santojanni, Buenos Aires, Argentina
| | - Celeste Romero
- Centro de Estudios de la Cultura Cannábica (CECCa), Buenos Aires, Argentina
| | | | | | - Enzo Tagliazucchi
- Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA - CONICET), Buenos Aires, Argentina
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Komagamine T, Kokubun N, Hirata K. Hystero-epilepsy in the Tuesday Lessons and NMDA receptor function: A hypothesis for dissociative disorder. Med Hypotheses 2021; 150:110567. [PMID: 33799161 DOI: 10.1016/j.mehy.2021.110567] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/16/2021] [Accepted: 03/09/2021] [Indexed: 11/30/2022]
Abstract
Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients demonstrate characteristic multistage progression and movement disorders, which are analogous to hystero-epilepsy in Jean-Martin Charcot's Tuesday Lessons. First, based on a review of the Tuesday Lessons recorded by Charcot's pupils, we hypothesized that there were patients with anti-NMDAR encephalitis among those diagnosed with hystero-epilepsy in the nineteenth century. We found acute-onset multiple neuropsychiatric manifestations resembling anti-NMDAR encephalitis among patients with hystero-epilepsy. Patients with drug withdrawal syndrome, dissociative and conversion disorders and patients under hypnosis from the modern point of view were also identified. These results suggested that hystero-epilepsy in the Tuesday Lessons could encompass dissociative and conversion disorders, hypnosis, drug withdrawal syndrome, and anti-NMDAR encephalitis-like manifestations. Based on Charcot's observations and current progress in molecular biology, such as the identification of glutamate/NMDAR system dysfunction in drug withdrawal syndrome, we then hypothesized that patients with dissociative and conversion disorders and those under hypnosis could also have hypofunction of the glutamatergic system. The NMDAR hypofunction hypothesis is emerging as a pathogenesis of schizophrenia. NMDAR antagonists are known to evoke symptoms similar to schizophrenia, anti-NMDAR encephalitis and near-death experiences. In current clinical reports, spectrum disorders such as dissociative disorder and conversion disorder have been observed in patients with anti-NMDAR encephalitis. Our hypothesis will offer an expansion of the NMDAR hypofunction hypothesis from psychosis to functional neurological disorders and normal specific situations, such as hypnosis, thanatosis, and near-death experiences.
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Affiliation(s)
| | - Norito Kokubun
- Department of Neurology, Dokkyo Medical University, Japan.
| | - Koichi Hirata
- Department of Neurology, Dokkyo Medical University, Japan.
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28
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Frohlich J, Toker D, Monti MM. Consciousness among delta waves: a paradox? Brain 2021; 144:2257-2277. [PMID: 33693596 DOI: 10.1093/brain/awab095] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/12/2021] [Accepted: 02/25/2021] [Indexed: 01/29/2023] Open
Abstract
A common observation in EEG research is that consciousness vanishes with the appearance of delta (1 - 4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are very frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalised epileptic seizures, and disorders of consciousness such as coma and vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the "down states" or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and nonconvulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalogram or MEG signals strongly relates to an individual's level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.
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Affiliation(s)
- Joel Frohlich
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Daniel Toker
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Martin M Monti
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA.,Department of Neurosurgery, UCLA Brain Injury Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
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29
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The Near-Death Experience Content (NDE-C) scale: Development and psychometric validation. Conscious Cogn 2020; 86:103049. [PMID: 33227590 DOI: 10.1016/j.concog.2020.103049] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023]
Abstract
As interest grows in near-death experiences (NDEs), it is increasingly important to accurately identify them to facilitate empirical research and reproducibility among assessors. We aimed (1) to reassess the psychometric properties of the NDE scale developed by Greyson (1983) and (2) to validate the Near-Death Experience Content (NDE-C) scale that quantifies NDEs in a more complete way. Internal consistency, construct and concurrent validity analyses were performed on the NDE scale. Based on those results and the most recent empirical evidence, we then developed a new 20-item scale. Internal consistency, explanatory and confirmatory factor, concurrent and discriminant validity analyses were conducted. Results revealed (1) a series of weaknesses in the NDE scale, (2) a 5-factor structure covering relevant dimensions and the very good psychometric properties of the NDE-C scale, including very good internal consistency (Cronbach α = 0.85) and concurrent validity (correlations above 0.76). This new reliable scale should facilitate future research.
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30
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Ruffell S, Netzband N, Bird C, Young AH, Juruena MF. The pharmacological interaction of compounds in ayahuasca: a systematic review. REVISTA BRASILEIRA DE PSIQUIATRIA (SAO PAULO, BRAZIL : 1999) 2020; 42:646-656. [PMID: 32638916 PMCID: PMC7678905 DOI: 10.1590/1516-4446-2020-0884] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/06/2020] [Indexed: 02/08/2023]
Abstract
Ayahuasca is a South American psychoactive plant brew used as traditional medicine in spiritual and in cultural rituals. This is a review of the current understanding about the pharmacological mechanisms that may be interacting in ayahuasca. Searches were performed using PubMed, PsycINFO, and Web of Science databases and 16 papers were selected. As hypothesized, the primary narrative in existing research revolved around prevention of deamination of N,N-dimethyltryptamine (N,N-DMT, also referred to as DMT) by monoamine oxidase inhibitors (MAOIs) in ayahuasca. Two of the constituents, DMT and harmine, have been studied more than the secondary harmala alkaloids. At present, it is unclear whether the pharmacological interactions in ayahuasca act synergistically or additively to produce psychoactive drug effects. The included studies suggest that our current understanding of the preparation's synergistic mechanisms is limited and that more complex processes may be involved; there is not yet enough data to determine any potential synergistic interaction between the known compounds in ayahuasca. Our pharmacological understanding of its compounds must be increased to avoid the potential risks of ayahuasca use.
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Affiliation(s)
- Simon Ruffell
- Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- Correspondence: Mario F. Juruena, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Room M3.24, PO72 De Crespigny Park, Denmark Hill, London SE5 8AF, UK. E-mail:
| | - Nige Netzband
- University of the West of England, Bristol, UK
- Correspondence: Mario F. Juruena, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Room M3.24, PO72 De Crespigny Park, Denmark Hill, London SE5 8AF, UK. E-mail:
| | - Catherine Bird
- Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Allan H. Young
- Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Mario F. Juruena
- Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- Correspondence: Mario F. Juruena, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Room M3.24, PO72 De Crespigny Park, Denmark Hill, London SE5 8AF, UK. E-mail:
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31
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Doss MK, May DG, Johnson MW, Clifton JM, Hedrick SL, Prisinzano TE, Griffiths RR, Barrett FS. The Acute Effects of the Atypical Dissociative Hallucinogen Salvinorin A on Functional Connectivity in the Human Brain. Sci Rep 2020; 10:16392. [PMID: 33009457 PMCID: PMC7532139 DOI: 10.1038/s41598-020-73216-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 09/11/2020] [Indexed: 12/23/2022] Open
Abstract
Salvinorin A (SA) is a κ-opioid receptor agonist and atypical dissociative hallucinogen found in Salvia divinorum. Despite the resurgence of hallucinogen studies, the effects of κ-opioid agonists on human brain function are not well-understood. This placebo-controlled, within-subject study used functional magnetic resonance imaging for the first time to explore the effects of inhaled SA on strength, variability, and entropy of functional connectivity (static, dynamic, and entropic functional connectivity, respectively, or sFC, dFC, and eFC). SA tended to decrease within-network sFC but increase between-network sFC, with the most prominent effect being attenuation of the default mode network (DMN) during the first half of a 20-min scan (i.e., during peak effects). SA reduced brainwide dFC but increased brainwide eFC, though only the former effect survived multiple comparison corrections. Finally, using connectome-based classification, most models trained on dFC network interactions could accurately classify the first half of SA scans. In contrast, few models trained on within- or between-network sFC and eFC performed above chance. Notably, models trained on within-DMN sFC and eFC performed better than models trained on other network interactions. This pattern of SA effects on human brain function is strikingly similar to that of other hallucinogens, necessitating studies of direct comparisons.
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Affiliation(s)
- Manoj K Doss
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA.
| | - Darrick G May
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Matthew W Johnson
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - John M Clifton
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Sidnee L Hedrick
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, USA
| | - Thomas E Prisinzano
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, USA
| | - Roland R Griffiths
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Frederick S Barrett
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA
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Kondziella D. The Neurology of Death and the Dying Brain: A Pictorial Essay. Front Neurol 2020; 11:736. [PMID: 32793105 PMCID: PMC7385288 DOI: 10.3389/fneur.2020.00736] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/15/2020] [Indexed: 01/18/2023] Open
Abstract
As neurologists earn their living with the preservation and restoration of brain function, they are also well-positioned to address the science behind the transition from life to death. This essay in pictures highlights areas of neurological expertise needed for brain death determination; shows pitfalls to avoid during the clinical examination and interpretation of confirmatory laboratory tests in brain death protocols; illustrates the great variability of brain death legislations around the world; discusses arguments for the implementation of donation after circulatory death (DCD); points to unresolved questions related to DCD and the time between cardiac standstill and organ procurement (“hands-off period”); provides an overview of the epidemiology and semiology of near-death experiences, including their importance for religion, literature, and the visual arts; suggests biological mechanisms for near-death experiences such as dysfunction of temporoparietal cortex, N-methyl-D-aspartate receptor antagonism, migraine aura, and rapid eye movement sleep; hypothesizes that thanatosis (aka. death-feigning, a common behavioral trait in the animal kingdom) represents the evolutionary origin of near-death experiences; and speculates about the future implications of recent attempts of brain resuscitation in an animal model. The aim is to provide the reader with a thorough understanding that the boundaries within the neurology of death and the dying brain are being pushed just like everywhere else in the clinical neurosciences.
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Affiliation(s)
- Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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de la Fuente A, Zamberlan F, Sánchez Ferrán A, Carrillo F, Tagliazucchi E, Pallavicini C. Relationship among subjective responses, flavor, and chemical composition across more than 800 commercial cannabis varieties. J Cannabis Res 2020; 2:21. [PMID: 33526118 PMCID: PMC7819481 DOI: 10.1186/s42238-020-00028-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 07/10/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Widespread commercialization of cannabis has led to the introduction of brand names based on users' subjective experience of psychological effects and flavors, but this process has occurred in the absence of agreed standards. The objective of this work was to leverage information extracted from large databases to evaluate the consistency and validity of these subjective reports, and to determine their correlation with the reported cultivars and with estimates of their chemical composition (delta-9-THC, CBD, terpenes). METHODS We analyzed a large publicly available dataset extracted from Leafly.com where users freely reported their experiences with cannabis cultivars, including different subjective effects and flavour associations. This analysis was complemented with information on the chemical composition of a subset of the cultivars extracted from Psilabs.org . The structure of this dataset was investigated using network analysis applied to the pairwise similarities between reported subjective effects and/or chemical compositions. Random forest classifiers were used to evaluate whether reports of flavours and subjective effects could identify the labelled species cultivar. We applied Natural Language Processing (NLP) tools to free narratives written by the users to validate the subjective effect and flavour tags. Finally, we explored the relationship between terpenoid content, cannabinoid composition and subjective reports in a subset of the cultivars. RESULTS Machine learning classifiers distinguished between species tags given by "Cannabis sativa" and "Cannabis indica" based on the reported flavours: = 0.828 ± 0.002 (p < 0.001); and effects: = 0.9965 ± 0.0002 (p < 0.001). A significant relationship between terpene and cannabinoid content was suggested by positive correlations between subjective effect and flavour tags (p < 0.05, False-Discovery-rate (FDR)-corrected); these correlations clustered the reported effects into three groups that represented unpleasant, stimulant and soothing effects. The use of predefined tags was validated by applying latent semantic analysis tools to unstructured written reviews, also providing breed-specific topics consistent with their purported subjective effects. Terpene profiles matched the perceptual characterizations made by the users, particularly for the terpene-flavours graph (Q = 0.324). CONCLUSIONS Our work represents the first data-driven synthesis of self-reported and chemical information in a large number of cannabis cultivars. Since terpene content is robustly inherited and less influenced by environmental factors, flavour perception could represent a reliable marker to indirectly characterize the psychoactive effects of cannabis. Our novel methodology helps meet demands for reliable cultivar characterization in the context of an ever-growing market for medicinal and recreational cannabis.
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Affiliation(s)
- Alethia de la Fuente
- Buenos Aires Physics Institute (IFIBA) and Physics Department, University of Buenos Aires, Buenos Aires, Argentina
- Institute of Cognitive and Translational Neuroscience (INCYT), INECO Foundation, Favaloro University, Buenos Aires, Argentina
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Federico Zamberlan
- Buenos Aires Physics Institute (IFIBA) and Physics Department, University of Buenos Aires, Buenos Aires, Argentina
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | | | - Facundo Carrillo
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Applied Artificial Intelligence Lab, ICC, CONICET, Buenos Aires, Argentina
| | - Enzo Tagliazucchi
- Buenos Aires Physics Institute (IFIBA) and Physics Department, University of Buenos Aires, Buenos Aires, Argentina
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Carla Pallavicini
- Buenos Aires Physics Institute (IFIBA) and Physics Department, University of Buenos Aires, Buenos Aires, Argentina.
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina.
- Grupo de Investigación en Neurociencias Aplicadas a las Alteraciones de la Conducta, FLENI-CONICET, Buenos Aires, Argentina.
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Cassol H, Bonin EAC, Bastin C, Puttaert N, Charland-Verville V, Laureys S, Martial C. Near-Death Experience Memories Include More Episodic Components Than Flashbulb Memories. Front Psychol 2020; 11:888. [PMID: 32528353 PMCID: PMC7247850 DOI: 10.3389/fpsyg.2020.00888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/09/2020] [Indexed: 11/13/2022] Open
Abstract
Memories of near-death experiences (NDEs) are recalled as "realer" than memories of other real or imagined events. Given their rich phenomenology, emotionality and consequentiality, it was hypothesized that they could meet some aspects of the definition of flashbulb memories. We aimed to identify and compare the episodic and non-episodic information provided in verbal recollections of NDE, flashbulb, and control autobiographical memories. The phenomenological characteristics and centrality of the memories were also compared. Twenty-five participants who had lived a NDE in a life-threatening situation were interviewed and completed the Memory Characteristics Questionnaires as well as the Centrality of Event Scale for their NDE, a flashbulb and another autobiographical memory used as control. Overall, transcribed NDE verbal recollections included a higher overall amount of details and more internal/episodic information than control autobiographical and flashbulb memories. Moreover, flashbulb memories were associated to a lower intensity of feelings while remembering and a lower personal importance, and are less reactivated and less susceptible to be remembered from a first person perspective compared to NDE and control autobiographical memories. Finally, NDE memories are the most central memories to experiencers' identity, followed by control autobiographical and then by flashbulb memories. These findings corroborate previous studies highlighting the impact and uniqueness of NDE memories.
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Affiliation(s)
- Helena Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau2 (Centre Intégré Pluridisciplinaire de l'Étude du Cerveau, de la Cognition et de la Conscience), University of Liège, Liège, Belgium
| | - Estelle A C Bonin
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau2 (Centre Intégré Pluridisciplinaire de l'Étude du Cerveau, de la Cognition et de la Conscience), University of Liège, Liège, Belgium
| | | | - Ninon Puttaert
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Vanessa Charland-Verville
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau2 (Centre Intégré Pluridisciplinaire de l'Étude du Cerveau, de la Cognition et de la Conscience), University of Liège, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau2 (Centre Intégré Pluridisciplinaire de l'Étude du Cerveau, de la Cognition et de la Conscience), University of Liège, Liège, Belgium
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau2 (Centre Intégré Pluridisciplinaire de l'Étude du Cerveau, de la Cognition et de la Conscience), University of Liège, Liège, Belgium
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Luke D. Anomalous Psychedelic Experiences: At the Neurochemical Juncture of the Humanistic and Parapsychological. JOURNAL OF HUMANISTIC PSYCHOLOGY 2020. [DOI: 10.1177/0022167820917767] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This article explores the nature of psychedelically induced anomalous experiences for what they reveal regarding the nature of “expanded consciousness” and its implications for humanistic and transpersonal psychology, parapsychology, and the psychology and underlying neuroscience of such experiences. Taking a multidisciplinary approach, this essay reviews the nature of 10 transpersonal or parapsychological experiences that commonly occur spontaneously and in relation to the use of psychedelic substances, namely synesthesia, extradimensional percepts, out-of-body experiences, near-death experiences, entity encounters, alien abduction, sleep paralysis, interspecies communication, possession, and psi (telepathy, precognition, and clairvoyance and psychokinesis).
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Nourkova VV. Compressed Life Review: Extreme Manifestation of Autobiographical Memory in Eye-Tracker. Behav Sci (Basel) 2020; 10:E60. [PMID: 32110854 PMCID: PMC7139868 DOI: 10.3390/bs10030060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/03/2020] [Accepted: 02/21/2020] [Indexed: 11/16/2022] Open
Abstract
The compressed life review (CLR) is a mnemonic illusion of having "your entire life flashing before your eyes". This research was guided by concerns over the retrospective methodology used in CLR studies. To depart from this methodology, I considered the long-term working memory (WM), "concentric", and "activation-based" models of memory. A novel theoretically rooted laboratory-based experimental technique aimed to elicit the CLR-like experience with no risk to healthy participants was developed. It consists of listening to superimposed audio recordings of previously trained verbal cues to an individually composed set of self-defining memories (SDMs). The technique evoked a self-reported CLR-like experience in 10 out of 20 participants. A significant similarity in eye movement patterns between a single SDM condition and a choir of SDM conditions in self-reported CLR experiencers was confirmed. In both conditions, stimuli caused relative visual immobilization, in contrast to listening to a single neutral phrase, and a choir of neutral phrases that led to active visual exploration. The data suggest that CLR-like phenomenology may be successfully induced by triggering short-term access to the verbally cued SDMs and may be associated with specific patterns of visual activity that are not reportedly involved with deliberate autobiographical retrieval.
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Affiliation(s)
- Veronika V Nourkova
- Department of psychology, Lomonosov Moscow State University, Moscow 125009, Russia
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Characterization of near death experiences using text mining analyses: A preliminary study. PLoS One 2020; 15:e0227402. [PMID: 31999716 PMCID: PMC6992169 DOI: 10.1371/journal.pone.0227402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 12/18/2019] [Indexed: 01/04/2023] Open
Abstract
The notion that death represents a passing to an afterlife, where we are reunited with loved ones and live eternally in a utopian paradise, is common in the reports of people who have encountered a “Near-Death Experience” (NDE). NDEs are thoroughly portrayed by the media but empirical studies are rather recent. The definition of the phenomenon as well as the identification of NDE experiencers is still a matter of debate. To date, NDEs’ identification and description in studies have mostly derived from answered items in questionnaires. However, questionnaires’ content could be restricting and subject to personal interpretation. We believe that in addition to their use, user-independent statistical text examination of freely expressed NDEs narratives is of prior importance to help capture the phenomenology of such a subjective and complex phenomenon. Towards that aim, we included 158 participants with a firsthand retrospective narrative of their self-reported NDE that we analyzed using an automated text-mining method. The output revealed the top words expressed by experiencers. In a second step, a hierarchical clustering analysis was conducted to visualize the relationships between these words. It revealed three main clusters of features: visual perceptions, emotions and spatial components. We believe the user-independent and data-driven text mining approach used in this study is promising by contributing to the building a rigorous description and definition of NDEs.
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Martial C, Cassol H, Laureys S, Gosseries O. Near-Death Experience as a Probe to Explore (Disconnected) Consciousness. Trends Cogn Sci 2020; 24:173-183. [PMID: 31982302 DOI: 10.1016/j.tics.2019.12.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 12/15/2022]
Abstract
Forty-five years ago, the first evidence of near-death experience (NDE) during comatose state was provided, setting the stage for a new paradigm for studying the neural basis of consciousness in unresponsive states. At present, the state of consciousness associated with NDEs remains an open question. In the common view, consciousness is said to disappear in a coma with the brain shutting down, but this is an oversimplification. We argue that a novel framework distinguishing awareness, wakefulness, and connectedness is needed to comprehend the phenomenon. Classical NDEs correspond to internal awareness experienced in unresponsive conditions, thereby corresponding to an episode of disconnected consciousness. Our proposal suggests new directions for NDE research, and more broadly, consciousness science.
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Affiliation(s)
- Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium; Centre du Cerveau (Centre intégré pluridisciplinaire de l'étude du cerveau, de la cognition et de la conscience), University Hospital of Liège, Liège, Belgium.
| | - Héléna Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium; Centre du Cerveau (Centre intégré pluridisciplinaire de l'étude du cerveau, de la cognition et de la conscience), University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium; Centre du Cerveau (Centre intégré pluridisciplinaire de l'étude du cerveau, de la cognition et de la conscience), University Hospital of Liège, Liège, Belgium
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium; Centre du Cerveau (Centre intégré pluridisciplinaire de l'étude du cerveau, de la cognition et de la conscience), University Hospital of Liège, Liège, Belgium
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Kondziella D, Olsen MH, Lemale CL, Dreier JP. Migraine aura, a predictor of near-death experiences in a crowdsourced study. PeerJ 2019; 7:e8202. [PMID: 31824781 PMCID: PMC6898989 DOI: 10.7717/peerj.8202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/13/2019] [Indexed: 12/20/2022] Open
Abstract
Background Near-death experiences (NDE) occur with imminent death and in situations of stress and danger but are poorly understood. Evidence suggests that NDE are associated with rapid eye movement (REM) sleep intrusion, a feature of narcolepsy. Previous studies further found REM abnormalities and an increased frequency of dream-enacting behavior in migraine patients, as well as an association between migraine with aura and narcolepsy. We therefore investigated if NDE are more common in people with migraine aura. Methods We recruited 1,037 laypeople from 35 countries and five continents, without any filters except for English language and age ≥18 years, via a crowdsourcing platform. Reports were validated using the Greyson NDE Scale. Results Eighty-one of 1,037 participants had NDE (7.8%; CI [6.3-9.7%]). There were no significant associations between NDE and age (p > 0.6, t-test independent samples) or gender (p > 0.9, Chi-square test). The only significant association was between NDE and migraine aura: 48 (6.1%) of 783 subjects without migraine aura and 33 (13.0%) of 254 subjects with migraine aura had NDE (p < 0.001, odds ratio (OR) = 2.29). In multiple logistic regression analysis, migraine aura remained significant after adjustment for age (p < 0.001, OR = 2.31), gender (p < 0.001, OR = 2.33), or both (p < 0.001, OR = 2.33). Conclusions In our sample, migraine aura was a predictor of NDE. This indirectly supports the association between NDE and REM intrusion and might have implications for the understanding of NDE, because a variant of spreading depolarization (SD), terminal SD, occurs in humans at the end of life, while a short-lasting variant of SD is considered the pathophysiological correlate of migraine aura.
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Affiliation(s)
- Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Markus Harboe Olsen
- Department of Neuroanesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Coline L Lemale
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Jens P Dreier
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
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40
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Martial C, Mensen A, Charland-Verville V, Vanhaudenhuyse A, Rentmeister D, Bahri MA, Cassol H, Englebert J, Gosseries O, Laureys S, Faymonville ME. Neurophenomenology of near-death experience memory in hypnotic recall: a within-subject EEG study. Sci Rep 2019; 9:14047. [PMID: 31575924 PMCID: PMC6773844 DOI: 10.1038/s41598-019-50601-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/12/2019] [Indexed: 12/30/2022] Open
Abstract
The neurobiological basis of near-death experiences (NDEs) is unknown, but a few studies attempted to investigate it by reproducing in laboratory settings phenomenological experiences that seem to closely resemble NDEs. So far, no study has induced NDE-like features via hypnotic modulation while simultaneously measuring changes in brain activity using high-density EEG. Five volunteers who previously had experienced a pleasant NDE were invited to re-experience the NDE memory and another pleasant autobiographical memory (dating to the same time period), in normal consciousness and with hypnosis. We compared the hypnosis-induced subjective experience with the one of the genuine experience memory. Continuous high-density EEG was recorded throughout. At a phenomenological level, we succeeded in recreating NDE-like features without any adverse effects. Absorption and dissociation levels were reported as higher during all hypnosis conditions as compared to normal consciousness conditions, suggesting that our hypnosis-based protocol increased the felt subjective experience in the recall of both memories. The recall of a NDE phenomenology was related to an increase of alpha activity in frontal and posterior regions. This study provides a proof-of-concept methodology for studying the phenomenon, enabling to prospectively explore the NDE-like features and associated EEG changes in controlled settings.
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Affiliation(s)
- Charlotte Martial
- GIGA-Consciousness, University of Liège, Liège, Belgium. .,Centre du Cerveau², University Hospital of Liège, Liège, Belgium.
| | - Armand Mensen
- GIGA-Consciousness, University of Liège, Liège, Belgium
| | - Vanessa Charland-Verville
- GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau², University Hospital of Liège, Liège, Belgium
| | - Audrey Vanhaudenhuyse
- GIGA-Sensation & Perception Research Group, University of Liège, Liège, Belgium.,Department of Algology, University Hospital of Liège, Liège, Belgium
| | | | - Mohamed Ali Bahri
- GIGA-Cyclotron Research Centre In Vivo Imaging, University of Liège, Liège, Belgium
| | - Héléna Cassol
- GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau², University Hospital of Liège, Liège, Belgium
| | | | - Olivia Gosseries
- GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau², University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- GIGA-Consciousness, University of Liège, Liège, Belgium.,Centre du Cerveau², University Hospital of Liège, Liège, Belgium
| | - Marie-Elisabeth Faymonville
- GIGA-Sensation & Perception Research Group, University of Liège, Liège, Belgium.,Department of Algology, University Hospital of Liège, Liège, Belgium
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Peinkhofer C, Dreier JP, Kondziella D. Semiology and Mechanisms of Near-Death Experiences. Curr Neurol Neurosci Rep 2019; 19:62. [PMID: 31352520 DOI: 10.1007/s11910-019-0983-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE OF REVIEW Near-death experiences (NDEs) are conscious perceptual experiences, including self-related emotional, spiritual, and mystical experiences, occurring in close encounters with death or in non-life-threatening situations. The origin of NDEs remains unknown. Here, we review recent advances in the understanding of NDE semiology and pathophysiology. RECENT FINDINGS Recent prospective studies confirm that NDEs reflect a spectrum of highly distinctive memories which are associated with negative or positive emotions and can be influenced by the nature of the causal event, but the temporal sequence with which these images unfold is variable. Some drugs, notably ketamine, may lead to experiences that are similar or even identical to NDEs. New models extend previous neural network theories and include aspects of evolutionary and quantum theories. Although the factual existence of NDEs is no longer doubted and the semiology well-described, a pathophysiological model that includes all aspects of NDEs is still lacking.
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Affiliation(s)
- Costanza Peinkhofer
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, 2100, Copenhagen, Denmark.,Medical Faculty, University of Trieste, Trieste, Italy
| | - Jens P Dreier
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, 2100, Copenhagen, Denmark. .,Department of Neuroscience, Norwegian University of Technology and Science, Trondheim, Norway. .,Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen, Denmark.
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Lake J. The near-death experience (NDE) as an inherited predisposition: Possible genetic, epigenetic, neural and symbolic mechanisms. Med Hypotheses 2019; 126:135-148. [PMID: 31010490 DOI: 10.1016/j.mehy.2019.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/24/2019] [Accepted: 03/21/2019] [Indexed: 12/21/2022]
Affiliation(s)
- James Lake
- Center for Integrative Medicine, University of Arizona College of Medicine, Tucson, AZ, United States.
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