Frontiers in Human Neuroscience
June 13, 2017
Charlotte Martial, Héléna Cassol, Georgios Antonopoulos et al.
85 citations
Near-death experiences (NDEs) often follow a common sequence: an out-of-body experience, moving through a tunnel, seeing a bright light, then feeling peace. However, this sequence occurred in only a small number of experiencers, suggesting that the order of NDE features varies widely among individuals. The study analyzed 154 written NDE narratives from French speakers, using text analysis to infer the timing and frequency of core features. The findings indicate that while a typical pattern exists, it is not universal, and understanding the relationships between features may improve scientific definitions of NDEs.
Physical review. E
July 28, 2021
Yonatan Sanz Perl, Hernan Bocaccio, Carla Pallavicini et al.
82 citations
Conscious wakefulness is characterized by brain dynamics far from thermodynamic equilibrium, while states of reduced consciousness—such as deep sleep and anesthesia induced by propofol, ketamine, or ketamine plus medetomidine—operate closer to equilibrium. This conclusion comes from analyzing electrocorticography data from nonhuman primates and functional magnetic resonance imaging data from humans. Entropy production and the curl of probability flux in phase space reliably distinguished conscious from unconscious states. The findings establish nonequilibrium macroscopic brain dynamics as a robust signature of consciousness and offer a statistical mechanics framework for studying cognition and awareness.
Journal of Neuroscience
March 23, 2021
Diego Candia‐rivera, Jitka Annen, Olivia Gosseries et al.
81 citations
Heartbeat-evoked responses (HERs) in resting-state EEG can distinguish between postcomatose patients who are unresponsive and those in a minimally conscious state with 87% accuracy, 96% sensitivity, and 50% specificity. HERs provide more accurate classification than random EEG segments not locked to heartbeats or heart rate variability. HER-based consciousness scores correlate with glucose metabolism in the right superior temporal sulcus and right ventral occipitotemporal cortex. HERs reflect consciousness diagnosis based on brain metabolism better than behavior-based diagnosis (77% validation accuracy). These findings suggest HERs capture a capacity for consciousness that does not necessarily translate into intentional overt behavior.
Human Brain Mapping
May 8, 2008
Melanie Boly, Christophe Phillips, Evelyne Balteau et al.
73 citations
Variability in how people perceive the same sensory stimulus from one moment to the next may stem from ongoing fluctuations in baseline brain activity. This review examines evidence that activity levels in sensory brain areas before a stimulus predict whether that stimulus will be consciously perceived. The findings are discussed in the context of recent discoveries about the structure of spontaneous BOLD signal fluctuations in the awake human brain, and possible sources of these baseline fluctuations are considered.
Science
March 2, 2007
Adrian M. Owen, Martin R. Coleman, Melanie Boly et al.
72 citations
Functional neuroimaging data indicate that brain activity patterns in a patient diagnosed as vegetative could not have occurred automatically without conscious awareness. The most straightforward explanation is that the patient was consciously aware despite the vegetative state diagnosis.
February 26, 2013
Vincent Bonhomme, P Boveroux, J. F. Brichant et al.
71 citations
Hypnotic anesthetic agents alter consciousness by targeting specific brain networks in a dose-dependent manner. Higher-order networks involved in mental content and sub-cortical networks regulating thalamic activity are affected first as concentrations increase and inhibitory neurotransmission is enhanced. Lower-order sensory networks, including thalamo-cortical connectivity within them, are preserved even at concentrations that suppress responsiveness, though cross-modal sensory interactions are inhibited. Thalamo-cortical connectivity into consciousness networks decreases with higher concentrations and becomes anti-correlated between thalamus and cortex at the deepest sedation levels when the subject is non-responsive. Whether these changes occur with agents that inhibit excitatory neurotransmission remains unknown, and the link between fMRI observations and biochemical targets is still unidentified.
Frontiers in Psychiatry
June 7, 2018
Charlotte Martial, Héléna Cassol, Vanessa Charland-Verville et al.
70 citations
People who report near-death experiences (NDEs) without facing a life-threatening situation score higher on fantasy proneness than those who have NDEs during actual danger, those whose experiences do not meet NDE criteria, and healthy controls. In contrast, individuals who have classical NDEs (during a life-threatening event) show no difference in fantasy proneness compared to matched controls. The intensity of the reported experience correlates positively with engagement in fantasy. These findings suggest that strong fantasy proneness may make some individuals more likely to report NDE-like experiences under suitable physiological or psychological conditions, such as meditation or syncope.
Consciousness and Cognition
November 1, 2020
Charlotte Martial, Jessica Simon, Ninon Puttaert et al.
69 citations
Two scales for measuring near-death experiences (NDEs) were evaluated. The original NDE scale showed several weaknesses. A new 20-item Near-Death Experience Content (NDE-C) scale was developed and validated, revealing a five-factor structure covering relevant dimensions. The NDE-C scale demonstrated very good internal consistency (Cronbach α = 0.85) and concurrent validity (correlations above 0.76). This new reliable scale should facilitate future research on NDEs.
Communications Biology
June 29, 2022
Anira Escrichs, Yonatan Sanz Perl, Carme Uribe et al.
67 citations
Different brain states—resting, meditating, deep sleep, and disorders of consciousness after coma—are underpinned by distinct spatiotemporal dynamics that can be characterized using turbulence theory. Non-conscious states tend to be more synchronous, while conscious states are more asynchronous, but the work goes beyond this simple dichotomy. A model-free analysis of human neuroimaging data applied Kuramoto's turbulence framework with coupled oscillators and measured information cascades across spatial scales. A complementary model-based approach used exhaustive computer simulations of whole-brain models fitted to those measures to study information encoding. The framework shows that turbulence theory provides excellent tools for describing and differentiating between brain states.
Memory
June 12, 2019
Héléna Cassol, Charlotte Martial, Jitka Annen et al.
60 citations
Near-death experiences (NDEs) are typically positive, but about 14% of 123 NDE accounts were distressing. These distressing NDEs included inverse, hellish, or void types, with inverse and hellish each appearing 8 times and void once. A higher proportion of suicide survivors reported distressing NDEs compared to classical ones. Memories of distressing NDEs were as phenomenologically detailed as those of classical NDEs. The findings suggest distressing NDEs require careful attention to help experiencers integrate them into their identity.
Communications biology
August 5, 2024
Charlotte Maschke, Jordan O'Byrne, Michele Angelo Colombo et al.
50 citations
Consciousness may depend on brain activity poised at criticality—a state with complex patterns and high sensitivity to disruption. Analyzing resting-state EEG from healthy volunteers under propofol, xenon, or ketamine anesthesia, the study found that unconsciousness (from propofol or xenon) shifted brain dynamics away from avalanche criticality and the edge of chaos. Ketamine anesthesia preserved consciousness (vivid dreams) and criticality. Dynamical properties from resting EEG accurately predicted individual values of the perturbational complexity index (PCI), a TMS-based consciousness measure. The findings link perturbational complexity to criticality and suggest criticality is necessary for consciousness.
Brain Communications
June 22, 2021
C. Peinkhofer, C. Martial, H. Cassol et al.
49 citations
Near-death experiences occur across cultures, suggesting a biological basis. This work tests the hypothesis that thanatosis, or death-feigning—a last-resort defense seen in animals from insects to humans—is the evolutionary origin of near-death experiences. Thanatosis is a highly preserved survival strategy. Humans attacked by animal, human, or modern predators can exhibit both thanatosis and near-death experiences, and their phenomenology and effects overlap. The evidence indicates thanatosis is the evolutionary foundation of near-death experiences, with the shared biological purpose of survival. Language may have transformed these stereotyped death-feigning events into the rich perceptions of near-death experiences, extending them to non-predatory situations.
Scientific Reports
November 5, 2018
Matthieu Darracq, Chadd M. Funk, Daniel Polyakov et al.
49 citations
Sleep and anesthesia alter conscious experience, which can be absent (unconsciousness) or take the form of dreaming where sensory stimuli are not incorporated (disconnected consciousness). Using transcranial magnetic stimulation-electroencephalography over parietal regions, evoked alpha power (8-12 Hz) decreased during disconnected consciousness in rapid eye movement sleep and ketamine anesthesia compared to wakefulness. In unconscious states of propofol anesthesia and non-rapid eye movement sleep, evoked low-gamma power (30-40 Hz) decreased compared to wakefulness or disconnected consciousness. These findings, confirmed with dream reports from serial awakenings, suggest suppression of evoked alpha activity may mark sensory disconnection.
Brain Injury
August 1, 2014
Martino Napolitani, Olivier Bodart, Paola Canali et al.
44 citations
Transcranial magnetic stimulation combined with high-density electroencephalography (TMS-hdEEG) offers advantages over other brain imaging techniques for assessing consciousness. A key requirement for consciousness is the brain's capacity to rapidly integrate information across specialized cortical areas. TMS-EEG stimulates any cortical area and records immediate electrical responses, successfully measuring changes in brain complexity under physiological, pharmacological, and pathological conditions. This technique reliably discriminates between conscious and unconscious patients at the single subject level, though further validation as a clinical tool is needed.
International Anesthesiology Clinics
January 1, 2008
Pierre Boveroux, Vincent Bonhomme, Melanie Boly et al.
44 citations
A peer-reviewed article examines the intersection of medicine, consciousness, and brain function, focusing on altered states such as those arising from cardiovascular syncope, autonomic disorders, hallucinations in medical conditions, and traumatic brain injury with neurovascular disturbances. The work discusses how these conditions affect cognitive science, psychology, and legal implications, without presenting a single empirical finding or specific numerical data. The argument integrates neuroscience and philately as a metaphor for collecting insights, suggesting that altered states of consciousness can inform understanding of brain function and autonomic regulation.
Brain sciences
July 14, 2021
Charlotte Martial, Géraldine Fontaine, Olivia Gosseries et al.
37 citations
People who have had a near-death experience often report a disturbed sense of having a distinct self. In a survey of 100 individuals who scored 27 or higher out of 80 on the Near-Death-Experience Content scale, 80 had their experience in a life-threatening situation and 20 did not. Participants completed inventories measuring ego dissolution and ego inflation during their NDE, as well as a scale of nature-relatedness. Ego-dissolution scores were higher than ego-inflation scores. Total NDE intensity positively correlated with ego dissolution and, more weakly, with ego inflation and nature-relatedness. Ego dissolution also correlated with the intensity of out-of-body experiences and a sense of unity. The findings suggest that dissolved ego-boundaries are a common feature of NDEs.
Scientific reports
October 1, 2019
Charlotte Martial, Armand Mensen, Vanessa Charland-Verville et al.
36 citations
A proof-of-concept study induced near-death experience (NDE)-like features in five volunteers who had previously had a pleasant NDE by having them recall the memory under hypnosis while their brain activity was recorded with high-density EEG. The hypnosis protocol recreated NDE-like features without adverse effects and increased absorption and dissociation compared to normal consciousness recall. Recalling the NDE phenomenology was associated with increased alpha brain activity in frontal and posterior regions. The methodology offers a controlled way to prospectively study NDE-like features and their EEG correlates.
NeuroImage
February 9, 2021
Riku Ihalainen, Olivia Gosseries, Frederik van de Steen et al.
30 citations
Using dynamic causal modelling of high-density EEG recordings from 10 people during propofol anaesthesia, the study evaluated how three resting state networks—the default mode network, the salience network, and the central executive network—contribute to consciousness. Loss of consciousness reduced inter-network connectivity in the parietal cortex, especially feed-forward frontoparietal and parietal connections at the precuneus node within the default mode network. Within the salience and central executive networks, unconsciousness generated small increases in bidirectional connectivity. The most consistent predictions of consciousness came from a key set of frontoparietal connections, supporting the importance of the posterior hot zone in explaining loss of consciousness.
Scientific Reports
September 22, 2023
Victor Oswald, Audrey Vanhaudenhuyse, Jitka Annen et al.
24 citations
Self-induced cognitive trance (SICT) is a voluntary non-ordinary state of consciousness involving narrowed awareness, hyper-focused immersion, and altered perception. This study examined autonomic nervous system changes during SICT by measuring heart rate variability and respiration rate variability in 25 proficient participants across three conditions: resting state, SICT, and a mental imagery task. During SICT, participants showed increased heart rate, decreased high-frequency heart rate variability, and specific increases in respiratory amplitude, phase ratio, and respiration rate variability compared to control conditions. These findings suggest SICT is associated with reduced parasympathetic activity, indicating a hyperarousal state of the autonomic nervous system.
Consciousness and Cognition
July 8, 2017
Charlotte Martial, Vanessa Charland-Verville, Héléna Cassol et al.
24 citations
Memories of near-death experiences (NDEs) are detailed and stable over time, yet their rich phenomenology lacks a satisfactory explanation. In 152 individuals who reported a classical NDE during life-threatening conditions, the intensity of the NDE was positively correlated with phenomenological characteristics of the memory, such as sensory details, personal importance, and frequency of reactivation. Those who described more intense NDEs also reported more vivid and detailed memories of the event.
NeuroImage
June 1, 2024
Pradeep Kumar G, Rajanikant Panda, Kanishka Sharma et al.
20 citations
High-order interactions between brain regions, measured as synergistic and redundant information, change differently across three non-ordinary states of consciousness. During Rajyoga meditation, synergy increased across the whole brain in delta and theta brainwave bands, while redundancy decreased in frontal, central, and posterior electrodes in delta and beta bands. During hypnosis, synergy decreased in mid-frontal, temporal, and mid-centro-parietal electrodes in the delta band, and in left frontal and right parietal electrodes in the beta2 band. During auto-induced cognitive trance, synergy decreased in delta and theta bands in left-frontal, right-frontocentral, and posterior electrodes, and at the whole brain level in the alpha band. Redundancy changes during hypnosis and auto-induced cognitive trance were not significant. Subjective reports of absorption, dissociation, and mystical experience did not correlate with the high-order measures.
Frontiers in psychology
January 1, 2022
Charlotte Grégoire, Nolwenn Marie, Corine Sombrun et al.
20 citations
A protocol describes a planned trial comparing three group interventions—hypnosis, mindful self-compassion meditation, and self-induced cognitive trance (SICT)—against a no-intervention control for improving quality of life in cancer patients who have completed active treatment within the past year. The study targets cancer-related fatigue, emotional distress, sleep difficulties, pain, and cognitive problems. Each participant chooses their preferred arm. Data from questionnaires, neurobiological measures, and medical records are collected at baseline, immediately after the intervention, and at 3- and 12-month follow-ups. The trial aims to enroll 160 patients and will assess short- and long-term effectiveness.
Neuroscience of Consciousness
January 1, 2019
Héléna Cassol, Arnaud D’Argembeau, Vanessa Charland‐verville et al.
16 citations
People who report near-death experiences (NDEs) often consider those memories central to their identity, regardless of whether the experience occurred during actual physical danger. Among 71 participants screened with the Greyson NDE scale, 48 had real NDEs and 23 had NDE-like experiences without life threat. Those who recalled their NDE (41 total) rated it as more central to their identity than other self-defining memories. Richer NDE memories were associated with greater centrality. The findings suggest that the self-defining nature of NDEs relates more to their phenomenological content than to the circumstances of occurrence, highlighting the importance of integrating these memories into personal identity.
Journal of Cognitive Neuroscience
January 1, 2023
Rajanikant Panda, Audrey Vanhaudenhuyse, Andrea Piarulli et al.
15 citations
During hypnosis, brain connectivity changes in ways that suggest more efficient cognitive processing and less mind-wandering. In nine healthy participants, hypnosis increased delta-wave connections between frontal brain regions and between frontal and parietal regions. It decreased alpha and beta-2 connections among frontal, parietal, and midline areas. Network analysis showed greater segregation of short-range connections in delta and alpha bands and greater integration of long-range connections in beta-2 bands. Frontal and right parietal electrodes became central hubs. These altered dynamics may reflect a modified balance between internal and external awareness networks.
Brain Structure and Function
January 1, 2021
Jitka Annen, Rajanikant Panda, Charlotte Martial et al.
15 citations
A world champion free diver's brain activity and connectivity shift markedly during a 6.5-minute breath-hold. EEG shows increased alpha wave power and connectivity, with decreased delta band connectivity. fMRI reveals heightened connectivity within the default mode network and visual areas, but reduced connectivity in sensorimotor cortices. These changes overlap with some meditation-related brain signatures but also include unique features suggesting altered somatosensory integration. Self-reports indicate that elite free divers may achieve a state of sensory dissociation during prolonged apnea, reflecting their ability to adapt psychologically and physiologically to extreme breath-holding.