PLoS ONE
February 14, 2018
Héléna Cassol, Benoît Pétré, Sophie Degrange et al.
131 citations
Near-death experiences (NDEs) are profound psychological events that can significantly affect experiencers' lives. Previous research shows NDE memories are phenomenologically rich. This study analyzed the narratives of 34 cardiac arrest survivors to extract common themes. A qualitative thematic analysis identified 10 'time-bounded' themes—isolated events during the NDE—and 1 'transversal' theme that characterizes the entire narrative, often as a retrospective self-reflective comment. The division into themes provides detailed vocabulary used by experiencers and enables a rigorous description of the phenomenon, ensuring all self-reported manifestations are included.
PLoS ONE
March 17, 2021
Marcel O. Bonn‐Miller, Sue Sisley, Paula Riggs et al.
129 citations
A randomized placebo-controlled trial tested three concentrations of smoked cannabis (high THC, high CBD, THC+CBD) against placebo in military veterans with PTSD. Over three weeks, all groups including placebo showed significant improvements in PTSD symptom severity, but none of the active cannabis concentrations outperformed placebo statistically. The treatments were generally well tolerated. This preliminary trial did not find evidence that smoked cannabis is more effective than placebo for PTSD symptoms in the short term, highlighting the need for further well-powered studies.
PLoS ONE
August 28, 2013
Fabio Ferrarelli, Richard Smith, Daniela Dentico et al.
125 citations
Long-term Buddhist meditators with about 8,700 mean lifetime hours of practice show increased gamma power (25-40 Hz) in parietal-occipital regions during non-rapid eye movement sleep compared to meditation-naive individuals. This increase is specific to gamma frequencies, unrelated to spontaneous arousal levels during NREM sleep, and positively correlated with the length of lifetime daily meditation practice. The findings indicate that meditation practice produces measurable changes in spontaneous brain activity and suggest that EEG gamma activity during sleep may serve as a sensitive marker of long-lasting plastic effects of meditative training on brain function.
PLoS ONE
November 7, 2018
Cassandra Vieten, Helané Wahbeh, B Rael Cahn et al.
124 citations
A survey of 1120 meditators found that most report having had anomalous and extraordinary experiences during meditation, such as mystical, transpersonal, or difficult phenomena. While meditation research has largely focused on clinical effectiveness and neural correlates, these less-studied experiences may be crucial for psychological and spiritual development, act as mediators of meditation's benefits, or be important outcomes themselves. A task force of researchers and teachers developed recommendations to expand research into these areas, which represent largely uncharted scientific terrain suitable for rigorous investigation.
PLoS ONE
July 10, 2012
Janelle H. P. van Wel, Kim P. C. Kuypers, Eef L. Theunissen et al.
121 citations
MDMA increases both positive moods (vigor, arousal, friendliness, elation) and negative moods (anxiety, confusion) while also slowing reaction times on impulsivity tasks, indicating greater impulse control. Blocking 5-HT(2) receptors with ketanserin prevented the positive mood effects but not the negative mood or impulsivity changes. Blocking 5-HT(1) receptors with pindolol had no effect on any MDMA-related mood or impulse measures. Thus, 5-HT(2) receptors are specifically involved in MDMA's positive mood enhancement, while 5-HT(1) receptors do not appear to play a role in these effects.
PLoS ONE
January 9, 2017
Pierre Bourdin, Itxaso Barberia, Ramon Oliva et al.
120 citations
An out-of-body illusion induced by virtual reality reduced fear of death compared to a control condition where the illusion was weaker. Sixteen women per group experienced a virtual body from a first-person perspective with synchronized touch and movement, then viewed it from above. In the experimental group, the connection to the virtual body was cut, producing a stronger feeling of disownership; in the control group, synchrony continued. The experimental group reported lower fear of death, consistent with reports that naturally occurring out-of-body experiences are often linked to greater belief in life after death.
PLoS ONE
September 30, 2015
Eduardo Ekman Schenberg, João Felipe Morel Alexandre, Renato Filev et al.
115 citations
Ayahuasca, an Amazonian plant-based brew used ritually in Brazil and increasingly worldwide, produces a two-phase brain effect. Electroencephalogram recordings and blood measurements of the brew's compounds (DMT, harmine, harmaline, tetrahydroharmine, and their metabolites) showed that 50 minutes after ingestion, alpha brainwave power (8–13 Hz) decreased, mostly in the left parieto-occipital cortex. Between 75 and 125 minutes, slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) increased across multiple cortical regions, including left centro-parieto-occipital, left fronto-temporal, and right frontal areas. These brain changes were significantly linked to circulating levels of ayahuasca's active chemicals. The authors interpret these effects within cognitive and emotional frameworks relevant to ritual use and potential therapeutic applications.
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.
PLoS ONE
February 4, 2013
Xiancang Ma, Yonghui Dang, Min Jia et al.
115 citations
A single dose of the NMDA receptor antagonist ketamine, but not the GSK-3 inhibitor SB216763, produced long-lasting antidepressant effects in a mouse model of chronic mild stress (CMS). In CMS mice, ketamine reversed the drop in sucrose intake and reduced immobility in the tail suspension and forced swimming tests, effects that persisted for 8 days after a single dose. The GSK-3 inhibitor did not produce these effects. Ketamine also reduced immobility in non-stressed control mice. These results suggest that ketamine's rapid and sustained antidepressant action may not depend on GSK-3 inhibition.
PLoS ONE
February 10, 2023
Lucia Melloni, Liad Mudrik, Michael Pitts et al.
106 citations
An adversarial collaboration between proponents of Global Neuronal Workspace and Integrated Information Theory devised and preregistered two experiments that test contrasting predictions about the location and timing of correlates of visual consciousness. Six theory-impartial laboratories will follow the study protocol using fMRI, M-EEG, and intracranial EEG, with built-in replications between labs and within datasets. The project aims to provide decisive evidence for or against the two theories and clarify the neural footprints of conscious visual perception, while modeling large-scale, collaborative, and open science practice.
PLoS ONE
June 12, 2013
Philip R. Corlett, Victoria C. Cambridge, Jennifer M. Gardner et al.
104 citations
Delusions, the persistent bizarre beliefs characteristic of psychosis, may arise from disturbances in prediction error-dependent learning. In a placebo-controlled study with 18 human subjects, ketamine—an NMDA receptor antagonist that induces aberrant prediction error signals—was administered during re-exposure to a conditioned fear stimulus. This led to stronger subsequent fear memory compared to placebo, with the degree of strengthening correlating with individual vulnerability to ketamine's psychotogenic effects and with prediction error brain signals. A partial replication in an independent sample with an appetitive learning procedure (8 subjects) supported these findings. The results suggest a link between altered prediction error, memory strength, and psychosis, potentially explaining both the emergence and persistence of delusional beliefs.
PLoS ONE
June 27, 2014
Kim P. C. Kuypers, Rafael de la Torre, Magı́ Farré et al.
88 citations
A single 75 mg dose of MDMA selectively enhances emotional empathy—the ability to share and understand others' feelings—without affecting cognitive empathy (understanding others' mental states), trust, or reciprocity in social interactions. This effect was not altered by adding pindolol, a drug that blocks the 5-HT1A serotonin receptor. Oxytocin nasal spray, a hormone often linked to social bonding, had no effect on any empathy or social interaction measure. Changes in emotional empathy were unrelated to oxytocin levels in the blood. The findings suggest that MDMA's empathy-enhancing effects do not depend on peripheral oxytocin and may instead involve other receptors such as serotonin 2A or vasopressin 1A.
PLoS ONE
February 21, 2020
Bheatrix Bienemann, Nina Stamato Ruschel, Maria Luiza Pesse Campos et al.
81 citations
Psilocybin, found in psilocybe mushrooms, has low toxicity and addiction risk, but negative outcomes from its use are not well understood. Analyzing 346 self-reports from an online platform using textual analysis software, the study identified four main clusters: thinking distortions, emergencies, perceptual alterations, and substance administration. Bad trips were more frequent among female users and linked to thinking distortions. Using multiple doses in one session or combining psilocybin with other substances was associated with long-term negative outcomes, while single high doses of mushrooms were linked to medical emergencies. These findings can inform harm-reduction efforts.
PLoS ONE
November 20, 2009
Stéphane Doly, Jesus Bertran‐gonzalez, Jacques Callebert et al.
80 citations
The drug MDMA (ecstasy) produces its rewarding effects by causing the release of serotonin and dopamine in brain regions linked to reward. This study shows that the 5-HT(2B) receptor, a type of serotonin receptor, is essential for MDMA's reinforcing properties. Mice lacking the 5-HT(2B) receptor did not develop a preference for the location where they received MDMA (10 mg/kg) nor did they show behavioral sensitization. Blocking this receptor with an antagonist also prevented these effects in normal mice. However, at a higher dose (30 mg/kg), MDMA's effects were independent of serotonin and the 5-HT(2B) receptor, relying instead on dopamine. These findings highlight the dose-dependent role of serotonin-dopamine interactions in MDMA's addictive potential.
PLoS ONE
May 23, 2013
Pawel Z. Kosentka, Sarah L. Sprague, Martin Ryberg et al.
79 citations
Mushroom-forming fungi produce many toxic alkaloids, but the evolution of muscarine (a toxin that stimulates the parasympathetic nervous system) and psilocybin (a hallucinogen) had not been studied. This review and new chemical assays of 30 Inocybaceae samples, including tropical and southern-hemisphere species, tested whether muscarine is ancestral in the family. The results show muscarine evolved independently multiple times, with several losses, and is not ancestral for the whole family. It is a shared derived trait for a clade containing three major lineages (Inocybe, Nothocybe, Pseudosperma) whose common ancestor lived about 60 million years ago. Transitions from muscarine-producing ancestors to psilocybin occurred more recently, 10–20 million years ago, after muscarine loss in two separate lineages. Statistical analyses reject a single origin of muscarine-producing taxa.
PLoS ONE
June 17, 2016
Jason Wallach, Heather Kang, Tristan Colestock et al.
73 citations
1,2-Diarylethylamines such as diphenidine (DPH) and 2-methoxy-diphenidine (2-MXP) are sold as 'legal highs' and have been linked to fatal and non-fatal overdoses. Binding studies at 46 central nervous system receptors show these compounds are relatively selective N-methyl-D-aspartate receptor (NMDAR) antagonists with weak off-target inhibition of dopamine and norepinephrine reuptake. In rats, DPH and 2-MXP significantly reduced prepulse inhibition of startle (PPI), an effect seen with dissociative drugs like phencyclidine (PCP) and ketamine. DPH acted with a median effective dose (ED50) of 9.5 mg/kg, less potent than PCP and ketamine.
PLoS ONE
June 29, 2012
Laura Moreno-López, Emmanuel A. Stamatakis, María José Fernández-serrano et al.
73 citations
In a sample of 49 polysubstance users in residential treatment who had been abstinent for a prolonged period, the severity of use of heroin, alcohol, MDMA, and cannabis each showed negative correlations with brain metabolism in the dorsolateral prefrontal cortex and temporal cortex. Alcohol use was additionally linked to lower metabolism in the frontal premotor cortex and putamen, while stimulant use was associated with lower metabolism in the parietal cortex. These findings suggest that different drugs of abuse may produce overlapping and distinct patterns of brain dysfunction even after extended abstinence, which could inform targeted rehabilitation strategies.
PLoS ONE
November 30, 2020
Natália Bezerra Mota, Janaína Weissheimer, Marina Ribeiro et al.
71 citations
Dreams during the 2019-20 coronavirus outbreak reveal psychological distress. Analyzing 239 dream reports from 67 individuals, dreams during the Coronavirus disease 2019 (COVID-19) Pandemic showed more anger and sadness words. These dreams also linked to "contamination" and "cleanness." Intriguingly, these dream characteristics explained 40% of the variation in psychological suffering related to social isolation, relevant for Psychiatry and Medicine. This underscores how the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) crisis impacts Sleep and Wakefulness Research, including mind wandering and attention, reflecting widespread Coronavirus Infections' effects.
PLoS ONE
November 5, 2018
Itxaso Barberia, Ramon Oliva, Pierre Bourdin et al.
71 citations
Immersive virtual reality can simulate death and near-death experiences, offering a new way to study their psychological impact. Participants embodied in virtual bodies on an island witnessed companions' deaths and their own death, including out-of-body experience, life review, and tunnel leading to white light. Fifteen female participants experienced six sessions from childhood to death; sixteen controls formed a waiting group. Those who underwent the simulation reported life attitude changes, becoming more concerned with others and more interested in global rather than material issues compared to the control group. The small sample size means results are indicative rather than conclusive.
PLoS ONE
May 13, 2015
Melanie Boly, Shuntaro Sasai, Olivia Gosseries et al.
69 citations
A meaningful sequence of stimuli, like movie frames, triggers varied experiences, while meaningless stimuli, like TV noise, produce a uniform experience despite physical differences. The differentiation of cortical responses, measured by Lempel-Ziv complexity of functional MRI images, reflects the overall meaningfulness of a stimulus set rather than differences among stimuli. Brain activity patterns showed highest differentiation during a movie, intermediate for a temporally scrambled movie, and minimal for spatially scrambled TV noise, even though overall cortical activation was strong and widespread in all conditions. Meaningfulness also correlated with higher information integration among cortical regions. This approach can assess stimulus meaningfulness without identifying relevant features or neural locations.
PLoS ONE
March 8, 2019
Bernard J. Crespi, Natalie L. Dinsdale, Silven Read et al.
68 citations
Spirituality relates differently to autism spectrum and schizotypal spectrum traits in a large sample of undergraduates. Total spirituality was negatively correlated with autism traits and positively correlated with positive schizotypal traits, supporting the diametrical model of autism and psychosis. These opposing associations were driven mainly by the Search for Meaning subscale, which was the only spirituality dimension significantly negatively linked to autism and positively linked to positive schizotypal traits. Belief in God was positively correlated with positive schizotypal traits but showed no correlation with autism traits. The opposite patterns for Search for Meaning align with cognitive models: weak central coherence in autism and enhanced salience in positive schizotypy.
PLoS ONE
October 24, 2012
Ricardo Pardo-Lozano, M. Farré, Samanta Yubero-Lahoz et al.
67 citations
A single oral weight-adjusted dose of MDMA (1.4 mg/kg) produced similar plasma concentrations and positive subjective effects in healthy recreational users regardless of gender or CYP2D6 and COMT genotypes. Female subjects experienced more intense physiological effects (increased heart rate and oral temperature) and negative effects (dizziness, sedation, depression, psychotic symptoms). Genotypes of COMT val158met or 5-HTTLPR with high functionality led to greater cardiovascular effects, while low-functionality genotypes were linked to negative subjective effects. The contribution of MDMA pharmacokinetics to gender differences in drug effects appears negligible; instead, 5-HTTLPR and COMT val158met genotypes play a major role.
PLoS ONE
March 14, 2024
Adam W Levin, Rafaelle Lancelotta, Nathan D Sepeda et al.
65 citations
In a small randomized trial of psilocybin-assisted therapy for adults with major depressive disorder, the therapeutic alliance between participants and facilitators strengthened from the final preparation session to one week after the intervention. A stronger alliance before the psilocybin sessions predicted lower depression scores at 4 weeks, 6 months, and 12 months afterward. Stronger alliance also correlated with more intense mystical experiences and psychological insight during the drug sessions, which in turn predicted better depression outcomes. The findings suggest the therapeutic relationship is important for treatment success.
PLoS ONE
September 7, 2022
Geissy Lainny de Lima-Araújo, Geovan Menezes de Sousa, Thatiane Aparecida Mendes et al.
64 citations
A brief three-day mindfulness training increased interoceptive sensibility—the self-reported tendency to notice and attend to body signals—in 40 healthy young adults naive to meditation, compared with an active control group. Five of eight subdomains of interoceptive sensibility improved after the training, but interoceptive accuracy (objective performance on a heartbeat-detection task) did not change. The increase in interoceptive sensibility statistically mediated reductions in state anxiety, suggesting a plausible mechanism for the anxiolytic effects of brief mindfulness practices.
PLoS ONE
August 24, 2022
Mary M. Sweeney, Sandeep M. Nayak, Ethan Hurwitz et al.
60 citations
Psychedelic drug experiences and near-death or other non-ordinary experiences both change people's beliefs about death, but direct comparisons are rare. In a survey of 3,192 individuals who reported such experiences, those from non-drug causes (e.g., near-death) were more likely to involve unconsciousness, clinical death, or imminent danger. Both groups reported similar reductions in fear of death, high personal meaning, spiritual significance, and psychological insight. However, psychedelic participants scored higher on standardized measures of mystical and near-death features, while non-drug participants more often rated their experience as the single most meaningful of their lives. Among psychedelics, ayahuasca and DMT produced stronger positive enduring effects than psilocybin and LSD.