Anesthesiology
September 30, 2010
Pierre Boveroux, Audrey Vanhaudenhuyse, Marie‐Aurélie Bruno et al.
645 citations
Propofol-induced unconsciousness is linked to decreased connectivity within frontoparietal networks (the default-mode and executive-control networks) and between the thalamus and these networks, with a negative correlation between thalamic and cortical activity emerging during unconsciousness. In contrast, connectivity in low-level sensory cortices (auditory and visual networks) is preserved, including their thalamocortical connections. Loss of consciousness is associated with a breakdown of cross-modal interactions between visual and auditory networks. These findings suggest that unconsciousness results from disrupted communication between sensory and higher-order frontoparietal cortices, preventing conscious perception.
Journal of Cognitive Neuroscience
June 1, 2010
Audrey Vanhaudenhuyse, Athena Demertzi, Manuel Schabus et al.
460 citations
Resting brain activity reveals two anticorrelated cortical systems linked to conscious awareness: an extrinsic system (lateral fronto-parietal areas) associated with external awareness and an intrinsic system (medial brain areas) associated with internal awareness. In 31 healthy volunteers, external and internal awareness were significantly anticorrelated, with a mean switching frequency of 0.05 Hz, similar to BOLD fMRI slow oscillations. In 22 volunteers, fMRI showed that precuneus/posterior cingulate, anterior cingulate/mesiofrontal cortices, and parahippocampal areas (intrinsic system) correlated with internal awareness, while lateral fronto-parietal cortices (extrinsic system) correlated with external awareness.
Anesthesiology
August 9, 2016
Vincent Bonhomme, Audrey Vanhaudenhuyse, Athena Demertzi et al.
206 citations
Ketamine alters consciousness by disrupting connectivity within and between specific resting-state brain networks, particularly the default mode network (DMn) and salience network (SALn), while leaving sensory and motor networks largely intact. In healthy volunteers given stepwise ketamine infusions until they lost responsiveness, DMn connectivity between the medial prefrontal cortex and other network regions decreased (from 0.20 to 0.07), and the normal anticorrelated activity between the DMn and sensory regions reversed (e.g., right sensory cortex shifted from -0.07 to 0.04). SALn connectivity was also suppressed but nonuniformly. These specific changes, including preserved sensory network connectivity, are shared with propofol-induced unconsciousness.
Trends in Cognitive Sciences
December 22, 2022
Christopher Timmermann, Prisca R. Bauer, Olivia Gosseries et al.
145 citations
A neurophenomenological framework is proposed for studying non-ordinary states of consciousness (NSCs) such as hypnosis, meditation, and psychedelics. NSCs involve shifts in what appears to the experiencer or how it appears, enabling investigation of the plastic and dynamic nature of experience across mind, brain, body, and context. The approach highlights NSCs as catalysts of transformation in clinical practice by refining understanding of relationships between subjective experience and neural dynamics. Ethical implications for standard conceptions of health and pathology are outlined, along with the crucial role of experience-based know-how in NSC research and application.
PLoS ONE
March 27, 2013
Marie Thonnard, Vanessa Charland-Verville, Serge Brédart et al.
140 citations
Near-Death Experiences (NDEs) are not well explained. Because NDEs are sometimes considered imagined, researchers compared the phenomenological characteristics of NDE memories with memories of real and imagined events. Coma survivors with NDEs (8), with coma memories but no NDE (6), and without coma memories (7), plus 18 healthy volunteers, completed the Memory Characteristics Questionnaire. NDE memories had more characteristics than memories of imagined or real events, and more self-referential and emotional information and better clarity than coma memories. These findings suggest NDE memories cannot be considered imagined events; they may be perceived as real despite not being lived in physical reality.
PLoS ONE
June 30, 2014
Enrico Amico, Francisco Gómez, Carol di Perri et al.
115 citations
Functional connectivity of brain areas fluctuates over time, even during anesthesia. By applying point process analysis to resting-state fMRI data from 18 healthy subjects during propofol-induced wakefulness, sedation, unconsciousness, and recovery, the study identified eight distinct co-activation patterns centered on the posterior cingulate cortex (PCC). The core of these patterns remained stable across consciousness levels, but propofol caused region-specific reductions in co-activation, including disconnections of the prefrontal cortex, thalamus, auditory cortex, motor cortex, and visual area. The methodology helps refine characterization of local functional brain changes associated with propofol-induced modulation of consciousness.
Frontiers in Systems Neuroscience
August 14, 2019
Vincent Bonhomme, Cécile Staquet, Javier Montupil et al.
109 citations
General anesthesia reversibly alters consciousness without globally shutting down the brain. Depending on the agent and dose, it can produce a complete absence of subjective experience (unconsciousness), a conscious experience without environmental perception (disconnected consciousness, like during dreaming), or oriented consciousness with environmental awareness (connected consciousness). Each state may be followed by explicit or implicit memories. Progress in brain function exploration has improved understanding of neural correlates of consciousness and their alterations during anesthesia, including changes in functional and effective brain connectivity, consciousness network topology, and spatio-temporal dynamics.
Science Advances
June 14, 2023
Leor Roseman, Christopher Timmermann, Daniel Golkowski et al.
65 citations
The effects of mind-altering drugs on brain function arise from complex interactions with multiple neurotransmitter systems, not just one. By linking the distribution of 19 neurotransmitter receptors and transporters (measured with PET) to changes in functional connectivity (measured with fMRI) caused by 10 drugs—anesthetics (propofol, sevoflurane, ketamine), psychedelics (LSD, psilocybin, DMT, ayahuasca), and others (MDMA, modafinil, methylphenidate)—the work shows a many-to-many mapping between drug effects and neurotransmitter systems. The drugs' impacts follow hierarchical gradients of brain structure and function, and regional susceptibility to drug-induced changes mirrors susceptibility to structural alterations from brain disorders.
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.
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.
Quality of Life Research
October 6, 2020
Charlotte Grégoire, Marie-Elisabeth Faymonville, Audrey Vanhaudenhuyse et al.
25 citations
A group intervention combining self-hypnosis and self-care improved self-esteem, reduced emotional distress, decreased maladaptive emotion regulation strategies, and increased mindfulness abilities in post-treatment cancer patients. Mindfulness gains accounted for 33% of the improvement in self-esteem and 41.6% of the reduction in emotional distress. The study included 95 women with cancer, with the intervention group showing significant benefits compared to a wait-list control group.
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.
OBM Integrative and Complementary Medicine
May 9, 2020
Audrey Vanhaudenhuyse, Anne‐Sophie Nyssen, Marie-Elisabeth Faymonville
22 citations
Hypnosis, a modified state of consciousness, reduces pain perception by re-engaging patients' resources to modulate pain and emotional distress, improving treatment and well-being. Neuroimaging shows hypnosis influences self and environmental consciousness networks, attentional and somatosensorial networks, disengaging subjects from external surroundings and altering body sensations and spontaneous thoughts. This review articulates clinical and neuroimaging findings on hypnosis for external pain stimuli, aiming to clarify mechanisms to guide future randomized controlled studies.
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.
Current Opinion in Behavioral Sciences
May 9, 2024
Olivia Gosseries, Nolwenn Marie, Yannick Lafon et al.
16 citations
Trance states, found across cultures from shamanic rituals to contemporary practices, are increasingly studied by researchers and clinicians. This review describes their common phenomenological features, such as altered awareness and perception. Using advanced neuroscientific techniques, it reports on the neural mechanisms underlying these states, including changes in brain connectivity and dynamics. The review also examines clinical applications, suggesting that trance states may be useful in therapeutic settings. By connecting subjective experience, brain function, and practical use, it advances understanding of trance and its potential benefits.
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.
BMC complementary medicine and therapies
November 4, 2024
Nolwenn Marie, Yannick Lafon, Aminata Bicego et al.
13 citations
Shamanic trances are non-pathological altered states of consciousness that differ from normal waking states in phenomenology and neurophysiology. A review of 27 studies classified findings into four dimensions: phenomenology, psychology, neuro-physiological functions, and clinical applications. The trances are influenced by multiple personal and environmental variables and may offer therapeutic potential, but the evidence is preliminary and requires rigorous studies to assess effectiveness for complementary therapies. The review highlights shamanic trance as a multifaceted area of study at the intersections of consciousness, spirituality, and therapy.
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.
Neuroscience of consciousness
January 1, 2024
Charlotte Grégoire, Corine Sombrun, Philippe Lenaif et al.
10 citations
Two Western trance practices, auto-induced cognitive trance (AICT) and Mahorikatan® trance (MT), both derived from traditional shamanic training, share core phenomenological features such as emotional expression, perceptual changes, a feeling of unicity, and expanded consciousness. AICT participants commonly reported body movements, vocalizations, increased creativity, visions of entities or places, and interaction with the environment, while MT participants commonly reported body dissolution. Most participants in both groups reported positive effects on personal life. The findings characterize the similarities and differences between these trance states and suggest further research into their potential clinical applications.
The International journal of clinical and experimental hypnosis
January 1, 2024
Mélanie Louras, Audrey Vanhaudenhuyse, Rajanikant Panda et al.
8 citations
Combining virtual reality with mind-body therapies such as meditation, mindfulness, relaxation, and hypnosis can reduce pain in both healthy volunteers and patients. A scoping review of 43 studies found that the combination is feasible, well-tolerated, and potentially useful for decreasing pain, and also improves anxiety, mood, and relaxation. However, insufficient research and a lack of multidimensional studies limit full understanding of their potential. More randomized controlled trials with usability evaluations are needed to incorporate these approaches into routine clinical practice.
Neuroscience of consciousness
January 1, 2024
Audrey Vanhaudenhuyse, Marie-Carmen Castillo, Charlotte Martial et al.
7 citations
Auto-induced cognitive trance (AICT) produces richer and more distinct subjective experiences than ordinary rest, auditory stimulation, or imagination. In 27 trained participants, free recalls of experiences were longer during AICT than in other conditions. Text mining identified four distinct classes of discourse, with AICT forming its own class clearly separate from ordinary conscious states. Nine content categories emerged, including nature, animals, body modifications, and difficulty describing thoughts. AICT was specifically characterized by reports of nature, animals, body modifications, and difficulty describing thoughts. These findings indicate that AICT generates a unique and richer phenomenology compared to other conscious states.
bioRxiv (Cold Spring Harbor Laboratory)
July 13, 2022
Andrea I. Luppi, Justine Y. Hansen, R. Adapa et al.
5 citations
preprint
Psychoactive drugs reshape brain function by engaging multiple neurotransmitter systems simultaneously. By mapping the distribution of 19 neurotransmitter receptors and transporters (via PET) and the connectivity changes caused by 10 drugs (anesthetics, psychedelics, and stimulants), the study shows that drug effects are organized along hierarchical gradients of brain structure and function. Additionally, brain regions susceptible to drug-induced changes are also vulnerable to structural alterations from brain disorders. These findings reveal systematic links between molecular neurochemistry and large-scale functional reorganization.
Int J Clin Health Psychol
January 1, 2025
Victor Oswald, Karim Jerbi, Corine Sombrun et al.
4 citations
People vary widely in their experiences during non-ordinary states of consciousness, and this variation is linked to measurable differences in the autonomic nervous system. The study shows that subjective experiences—such as changes in perception, emotion, or sense of self—correspond with distinct patterns of physiological responses, like heart rate or skin conductance. These findings suggest that the body's nervous system plays a key role in shaping how individuals experience altered states, highlighting a direct connection between inner, subjective phenomena and physiological processes.
British journal of anaesthesia
April 1, 2025
Milan Van Maldegem, Jakub Vohryzek, Selen Atasoy et al.
3 citations
Ketamine, at anesthetic doses, produces a state where people are unresponsive yet often report vivid inner experiences, separating conscious awareness from behavioral responsiveness. Using connectome harmonic decomposition on fMRI data, researchers found that brain signals during ketamine-induced unresponsiveness show increased fine-grained spatial patterns, indicating higher neural granularity. This harmonic signature aligned with those of LSD-induced and ketamine-induced psychedelic states, but misaligned with signatures from unconscious individuals due to propofol sedation or brain injury. The method can track changes in conscious awareness even when behavior is absent, offering a tool for consciousness and anesthesia research.