NeuroImage
January 11, 2019
Michele Colombo, Martino Napolitani, Mélanie Boly et al.
359 citations
During anesthesia, people may still be conscious even though they do not respond. A marker of consciousness based on the decay rate of the power spectral density (PSD) of resting EEG—measured by the spectral exponent β—was tested in healthy participants under xenon, propofol, or ketamine anesthesia (n=5 per group). Delayed reports indicated whether consciousness was present or absent. Xenon and propofol, which abolish consciousness, caused a steeper PSD decay (more negative β) compared to wakefulness. Ketamine, which preserves consciousness, showed a PSD decay similar to wakefulness overall but a flattening in high frequencies (20–40 Hz). The spectral exponent correlated strongly with the Perturbational Complexity Index (PCI), supporting its use as a marker of consciousness.
Frontiers in Psychology
August 15, 2018
Christopher Timmermann, Leor Roseman, L. Williams et al.
228 citations
Near-death experiences (NDEs) share striking phenomenological similarities with the effects of the psychedelic drug DMT. In a placebo-controlled, within-subjects study, 13 healthy participants received DMT and placebo, then completed a standard NDE measure. DMT significantly increased NDE-like features compared to placebo. NDE scores were linked to DMT-induced ego-dissolution and mystical experiences, as well as baseline traits of absorption and delusional ideation. Nearly all NDE features overlapped between DMT-induced experiences and a matched group of actual NDE experiencers. These results indicate a remarkable similarity between the DMT state and NDEs, warranting further research.
Nature Communications
February 25, 2022
Minji Lee, Leandro Sanz, Alice Barra et al.
120 citations
A deep-learning-based explainable consciousness indicator (ECI) uses EEG responses to transcranial magnetic stimulation and resting-state EEG to separately quantify arousal and awareness. Tested during sleep (n=6), general anesthesia (n=16), and severe brain injury (n=34), ECI distinguishes states such as ketamine-induced anesthesia and rapid eye movement sleep, which combine low arousal with high awareness. Parietal brain regions are most relevant for these measurements. The indicator offers a way to disentangle the two components of consciousness across physiological, pharmacological, and pathological conditions.
Consciousness and cognition
March 1, 2019
Charlotte Martial, Héléna Cassol, Vanessa Charland-Verville et al.
98 citations
Near-death experiences (NDEs) share consistent features across cultures, suggesting a common neurobiological basis. Analyzing semantic similarity between about 15,000 reports from 165 psychoactive substances and 625 NDE narratives, the NMDA receptor antagonist ketamine produced reports most similar to NDEs, followed by Salvia divinorum and serotonergic psychedelics like DMT. The similarity was driven by concepts of self and environmental consciousness, as well as therapeutic, ceremonial, and religious aspects of drug use. Ketamine may serve as a safe experimental model for NDE phenomenology, and endogenous NMDA antagonists might be released near death.
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.
International Anesthesiology Clinics
January 1, 2008
Pierre Boveroux, Vincent Bonhomme, Mélanie 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
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.
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.
Journal of cognitive neuroscience
September 1, 2023
Charlotte Martial, Helena Cassol, Mel Slater et al.
13 citations
Out-of-body experiences (OBEs) can be partially induced in a virtual reality setup. Seven healthy participants wore a VR headset and saw their virtual body from a ceiling viewpoint; in one condition their real movements were mirrored onto the virtual body, in the other they were not. Participants reported strong sensations of floating and being high up, but only weak to moderate feelings of being out of their body. Brain activity recorded with 128 electrodes showed that these subjective experiences were linked to increased delta and decreased alpha power, reduced theta complexity, and increased beta-2 connectivity, supporting the idea that delta activity plays a prominent role in certain conscious states.
Frontiers in Human Neuroscience
April 28, 2023
Aminata Bicego, Héléna Cassol, Jessica Simon et al.
13 citations
Spiritual beliefs, Openness to experience, and Fantasy proneness are associated with recalling a near-death experience (NDE) or an NDE-like experience (similar phenomenology without a life-threatening context). In a retrospective study of 181 people divided into four groups—NDE experiencers, NDE-like experiencers, controls who faced a life-threatening situation without an NDE, and controls with neither—multivariate logistic regression showed that spiritual beliefs predicted NDE-like recall, while Openness and Fantasy proneness predicted NDE recall. A discriminant analysis using these variables correctly classified only 35% of cases, indicating other factors also play a role.
Psychology of Consciousness Theory Research and Practice
June 12, 2025
Etzel Cardeña, Aviva Berkovich‐ohana, Katja Valli et al.
11 citations
A multidisciplinary, international group used taxonomic principles and a modified Delphi method to create a taxonomy of altered states of consciousness based on central phenomenological features. They identified eight distinct states, some with subcategories: proto and transitional, delirium, minimal to no awareness, experiential detachment, enhanced physicality, altered identity, imaginary/fantasy/visionary, and unity/mystical. The authors hope this taxonomy will foster conceptual clarity and stimulate research across specializations, helping reveal what is common and different across triggers and antecedents of altered states, and encouraging phenomenological, psychological, cultural, and neuroscientific understanding.
NeuroImage
September 1, 2024
Charlotte Martial, Andrea Piarulli, Olivia Gosseries et al.
10 citations
During fainting, some people have dream-like experiences with extraordinary, mystical features similar to near-death experiences. In 22 healthy volunteers who fainted under controlled conditions, eight reported such near-death-like features. Their brain activity showed higher electrical activity in delta, theta, and beta2 frequency bands in temporal and frontal regions, including the insula, right temporoparietal junction, and cingulate cortex. The richer the experience, the stronger the activity in these areas. The brains of those with near-death-like experiences also showed more complex, more connected, and more integrated neural networks compared to those without such experiences. These surges of neural activity may mark disconnected consciousness during fainting.
bioRxiv : the preprint server for biology
October 31, 2023
Charlotte Maschke, Jordan O'Byrne, Michele Angelo Colombo et al.
7 citations
preprint
Consciousness may depend on brain activity poised at criticality, a state with optimal computational properties. Electroencephalograms were recorded from healthy, unresponsive volunteers under propofol, xenon, or ketamine anesthesia. Ketamine spared consciousness (vivid dreams), allowing separation of unresponsiveness from unconsciousness. Unconscious states showed a departure from both the edge of activity propagation and the edge of chaos. The perturbational complexity index (PCI), a sensitive consciousness measure, was predicted from these dynamical properties with a mean absolute error below 7%. Results link PCI to criticality and support criticality's role in consciousness.
Brain sciences
April 4, 2025
Ying Zhao, Anqi Wang, Weiqiao Zhao et al.
5 citations
A neurophysiological biomarker called the spectral exponent (SE), which measures the steepness of the aperiodic (1/f) slope of EEG activity, can help distinguish levels of consciousness in patients with disorders of consciousness (DoC). In a study of 15 DoC patients, 9 conscious brain-injured controls, and 23 healthy controls, narrowband SE (1-20 Hz) differentiated DoC patients from controls and minimally conscious from vegetative/unresponsive states. SE correlated positively with behavioral scores on the CRS-R, particularly the visual subscale. Longitudinal tracking in one patient showed a reduction in SE negativity, flattening of the 1/f slope, and parallel behavioral recovery. The SE offers an objective complement to subjective behavioral assessments.
Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics
April 18, 2025
Alice Barra, Rodrigo Huerta-Gutierrez, Jitka Annen et al.
3 citations
A subset of patients in a minimally conscious state show improved behavioral responsiveness after transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex, while those who are unresponsive show limited benefit. Among 131 patients, 32% of minimally conscious patients responded to tDCS, compared to 10% of unresponsive patients. A regression model using baseline diagnosis, Coma Recovery Scale-Revised Index, age, sex, and time since injury correctly identified responders 77% of the time. Patients in a minimally conscious state with better cognitive profiles and longer time since injury appear to respond better to tDCS, suggesting they are better candidates for this treatment.
bioRxiv (Cold Spring Harbor Laboratory)
August 19, 2024
Naji Alnagger, Paolo Cardone, Charlotte Martial et al.
3 citations
preprint
Disorders of consciousness, such as unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), have few treatments. Using whole-brain computational models built from individual patients' fMRI and diffusion-weighted imaging data, this virtual clinical trial simulated the effects of LSD and psilocybin. The psychedelics shifted the brains of patients with disorders of consciousness closer to a critical dynamical state, with a larger effect in MCS patients. In UWS patients, the treatment response depended on structural connectivity, whereas in MCS patients it aligned with baseline functional connectivity. These results provide a computational foundation for considering psychedelics in treating disorders of consciousness and highlight the role of computational modeling in drug discovery and personalized medicine.
Advanced Science
November 20, 2025
Paolo Cardone, Charlotte Martial, Yonatan Sanz Perl et al.
2 citations
Simulated administration of LSD and psilocybin in computational models of patients with disorders of consciousness (DoC), including unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), shifted brain activity closer to criticality—the phase transition between order and chaos. The effect was greater in MCS patients. In UWS patients, the treatment response correlated with structural connectivity, while in MCS patients it aligned with baseline functional connectivity. These results provide a computational foundation for using psychedelics in DoC treatment and highlight the potential role of computational modeling in drug discovery and personalized medicine.
bioRxiv Preprint Server
February 11, 2025
Saketh Malipeddi, Arun Sasidharan, Rahul Venugopal et al.
2 citations
preprint
Meditation alters brain activity, particularly in alpha and theta frequency bands, but most research has focused on average power changes from rest to meditation rather than how quickly these changes emerge. This gap means little is known about the time-to-onset and temporal dynamics of neural shifts during meditation practice.
PloS one
January 1, 2023
Justine Van de Velde, Katia Levecque, Bert Weijters et al.
1 citation
A six-month meditation practice of five to ten minutes daily improved emotional and physical well-being and prevented the development of cognitive well-being problems among 199 teachers who meditated with their pupils. A control group of 42 teachers showed worsening cognitive well-being over the same period. The effects were strongest for emotional and cognitive well-being and followed a linear trend. The findings suggest that focused attention meditation, a technique used in many mindfulness-based interventions, contributes to the well-being benefits of those interventions. Occupational groups facing emotional, cognitive, or physical well-being issues may benefit from a few minutes of this practice per day.
Communications Biology
June 12, 2026
Saketh Malipeddi, Arun Sasidharan, Bianca Ventura et al.
Advanced meditators from the Isha Yoga tradition report stronger non-dual experiences—where the boundary between self and environment dissolves—during breath-watching meditation compared to novices and meditation-naïve controls. Using EEG-based intrinsic neural timescales (INT), researchers found that across all participants, INTs are longer during internal attention (breath-watching) than during an external cognitive task. However, advanced meditators show similar INT durations between internal and external attention, and this reduced difference correlates with stronger reported non-dual experiences. The findings suggest that similar intrinsic neural timescale durations across internal and external attention may be a neural signature of non-duality.