Frontiers in Human Neuroscience
June 12, 2015
Andrew R. Gallimore
52 citations
Classic psychedelics like LSD and psilocybin produce a fascinating but poorly understood state of consciousness. Modern functional neuroimaging has revealed some of their neural effects, but many phenomenological features remain unexplained. Integrated information theory (IIT), a leading mathematical theory of consciousness, can account for both the quantity and quality of conscious experience. Applying IIT to neuroimaging data on the psychedelic state yields a model that explains unconstrained cognition, altered concept structure and meaning, and expanded awareness. The model suggests that while cognitive flexibility, creativity, and imagination increase, this comes at the cost of cause-effect information and the brain's ability to organize, categorize, and differentiate conscious experience. It generates testable predictions using functional imaging, similar to studies of anesthesia and brain injury.
Frontiers in Human Neuroscience
March 18, 2021
Emma R. Huels, Hyoungkyu Kim, UnCheol Lee et al.
51 citations
Shamanic practitioners in trance show brain changes that overlap with but are distinct from those caused by psychedelic drugs. In 24 practitioners and 24 controls, EEG recordings during shamanic drumming revealed increased gamma power linked to visual changes, decreased low alpha and increased low beta connectivity, reduced gamma-band signal diversity tied to insightfulness, and increased criticality in beta and gamma bands correlating with complex imagery. Practitioners' altered-state scores matched or exceeded those of people on psychedelics. The findings indicate that shamanic trance and psychedelic states share some phenomenal features but produce unique neural signatures.
Frontiers in Human Neuroscience
June 19, 2014
Arianna Palmieri, Vincenzo Calvo, Johann Roland Kleinbub et al.
51 citations
Near-death experiences (NDEs) produce memories that are phenomenologically and neurally similar to memories of real events, not imagined ones. In a study of 10 people who had NDEs and 10 controls, a hypnosis-based protocol improved recall detail for all memory types. NDE memories matched real-event memories in richness, self-reference, and emotion, and differed significantly from imagined-event memories. Electroencephalography showed that real-memory recall correlated with high alpha and gamma brain rhythms, while NDE memory recall correlated with theta and delta bands—theta being a marker of episodic memory and delta linked to recollection, trance states, and transpersonal experience. The findings indicate NDE memories are stored as episodic memories of events experienced in a distinct state of consciousness.
Frontiers in Human Neuroscience
January 1, 2014
Andra Smith, Claude Messier
48 citations
A participant who can voluntarily produce sensations of her body moving outside its physical boundaries, while knowing her body is still, showed distinct brain activity patterns during these extra-corporeal experiences (ECEs) compared to motor imagery. Brain scans revealed left-sided activations in the supplementary motor area, supramarginal gyrus, posterior superior temporal gyrus (overlapping the temporoparietal junction linked to out-of-body experiences), and cerebellum, consistent with the impression of movement. Additional activity in the left middle and superior orbital frontal gyri, regions tied to action monitoring, suggests this ECE is an unusual form of kinesthetic imagery.
Frontiers in Human Neuroscience
January 1, 2013
Berit Brogaard
46 citations
Synesthesia—a blending of the senses—can arise developmentally, after brain injury, or from psychedelic drugs. While research has linked synesthesia to atypical brain connectivity and genetic factors, the underlying trigger remains unclear. This theoretical review proposes that excessive serotonin may be a common thread. Psychedelics like psilocybin and LSD increase serotonin, inducing synesthesia. After brain injury, cell death floods nearby regions with serotonin and glutamate, potentially causing unusual sensory binding. In autism, altered serotonin function may block normal gating mechanisms, contributing to developmental synesthesia. The author concludes that elevated serotonin levels, heightening sensory brain region excitability and connectivity, could unify at least some cases across these types.
Frontiers in Human Neuroscience
March 17, 2017
Michael Schaefer, Georg Northoff
43 citations
The self has two facets: a conscious self generated by cortical midline structures in the brain, and an unconscious self linked to embodied cognition via somatosensory cortices. This model draws on neuroscience imaging studies and theories of embodied cognition. The article describes problems with this dual-self model and discusses possible theoretical solutions.
Frontiers in Human Neuroscience
January 1, 2013
Sérgio A. Mota-Rolim, Zé H. Targino, Bryan C. Souza et al.
42 citations
Dreams typically involve actions, known people, sounds, and colors, and often relate to upcoming plans or recent memories. Nightmares frequently feature anxiety, being stalked, or other unpleasant sensations. Lucid dreaming—knowing one is dreaming—was experienced at least once by 77% of a Brazilian sample of 3,427 people, but episodes were brief (under one minute for 48%) and control was rare (29%). Lucid dreaming was more common when people did not need to wake early or were under stress, conditions that increase REM sleep. These findings suggest lucid dreaming is a widespread but unstable human experience, consistent with data from other continents.
Frontiers in Human Neuroscience
January 1, 2013
István Bókkon, Birendra N. Mallick, Jack A. Tuszynski
42 citations
Seeing brilliant lights during near-death experiences may arise from a surge of bioluminescent biophotons in the brain when blood flow returns after oxygen deprivation. The authors propose that reperfusion triggers an overproduction of free radicals and excited molecules, leading to a transient increase in biophoton emission within retinotopic visual areas. If this emission exceeds a threshold, the brain interprets the intrinsic photons as external light, creating the perception of brilliant lights. The article reviews experimental studies that support this concept and links the idea to phosphenes, dream-like imagery during REM sleep, and self-consciousness possibly involving low-energy quantum entanglements. It is presented as a discussion piece, not a definitive explanation.
Frontiers in Human Neuroscience
January 1, 2008
Lars Schwabe
41 citations
Out-of-body experiences (OBEs) may arise from disrupted vestibular processing in the brain. Using Bayesian modeling, the authors show that OBEs and associated illusory changes in self-location and movement can be explained as a misled inference: ambiguous signals from the vestibular otoliths in a supine position are integrated with a prior expectation for an upright body position, measured during natural head movements. This suggests that the brain's normal mechanisms for locating the self in space can be tricked by conflicting sensory and prior information. The findings point to ways to induce and study self-location and bodily self-consciousness experimentally in healthy individuals.
Frontiers in Human Neuroscience
October 6, 2017
Joseph Glicksohn, Aviva Berkovich‐ohana, Federica Mauro et al.
38 citations
Exposure to a monotonous sensory environment can alter time perception and subjective experience. Participants spent 20 minutes in a whole-body altered sensory chamber with white and colored light, relaxing with eyes closed. Before entering, they completed a time-production task; one group repeated it inside the chamber, another after exiting. The main effect of the sensory environment was a change in the intercept of the psychophysical function when produced time was plotted against target duration on a log-log scale. For participants reporting a marked change in time experience, such as the sensation of time disappearing, their time-production data could not be linearized on a log-log plot, suggesting a possible break in the psychophysical function.
Frontiers in Human Neuroscience
February 27, 2017
Baland Jalal, Vilayanur S. Ramachandran
38 citations
This opinion article argues that the concept of brain health should be expanded beyond the absence of disease to include optimal cognitive and emotional functioning across the lifespan. The authors propose a framework that integrates neuroscience, psychology, and public health to promote resilience and well-being. They suggest that lifestyle factors, such as diet, exercise, and social engagement, can enhance brain health and reduce the risk of neurodegenerative conditions. The piece calls for a shift in research and clinical practice toward proactive, preventive approaches that empower individuals to maintain brain health throughout life.
Frontiers in Human Neuroscience
January 1, 2014
Bruce Greyson, Nathan B. Fountain, Lori L. Derr et al.
35 citations
Out-of-body experiences are rare but real sensations reported by some people with epilepsy during seizures. In a group of 100 patients, 55% recalled some subjective experience with their seizures, and 7 reported out-of-body experiences. No demographic, medical, or seizure-related traits distinguished those who had out-of-body experiences from those who did not. These experiences did not affect epilepsy-related quality of life. Even among those who reported them, out-of-body sensations were extremely infrequent, often occurring only once or twice many years ago, making it impossible to link them to specific seizure characteristics or medications.
Frontiers in Human Neuroscience
February 16, 2022
Asa Young, Tam Hunt, Marissa Ericson
34 citations
Brain-generated electromagnetic field oscillations are increasingly seen as causal drivers of consciousness. Recent work highlights how the body's endogenous rhythms organize these fields through entrainment. This paper examines evidence of shared oscillations between the brain and other body parts in humans and animals, testing the Slowest Shared Resonance (SSR) principle of General Resonance Theory. The SSR principle states that macro-consciousness in coupled field systems depends on the slowest common denominator frequency. It predicts that a system's SSR decreases with distance between the brain and resonating structures. Observed resonance relationships—between brain and gastric neurons, sensory organs, and spinal cord—generally match these predictions, empirically supporting the SSR principle.
Frontiers in Human Neuroscience
July 18, 2023
Nicolas Garel, Julien Thibault Lévesque, Dasha A. Sandra et al.
29 citations
Past environmental exposures can significantly shape psychedelic drug experiences and their therapeutic outcomes, a concept the authors call 'imprinting.' In a clinical trial of ketamine for treatment-resistant depression, two patients' subjective experiences were altered by the type and amount of digital media they consumed in the days before treatment: higher media exposure reduced mystical and emotional qualities of the ketamine experience, overriding standard intention-setting practices and changing therapeutic results. Eight additional patients spontaneously reported past environmental exposures manifesting as visual hallucinations during ketamine sessions. Similar imprinting effects appear in historical reports of other psychedelic drugs and in dreaming. The authors propose expanding the contextual model of psychedelic action to include imprinting, which may help clinicians and researchers better understand these drug effects.
Frontiers in Human Neuroscience
July 3, 2014
Cassandra Gould van Praag, Tom Froese, Adam B. Barrett et al.
29 citations
A detailed phenomenological investigation of sequence-space synesthesia in a single adult (AB) reveals that synesthetic experiences occur within a specific spatial reference frame, a 'mental room' that overlays perception of the physical world, and that AB can voluntarily switch attention between these two rooms. Using the Elicitation Interview method across 9 hours of transcripts, the study found that, contrary to AB's initial report, the synesthetic concurrents usually followed an internal verbalization of the inducer rather than visual presentation, indicating an auditory component. This suggests cross-modal interactions between auditory and visual systems in the development of this synesthetic form.
Frontiers in Human Neuroscience
June 2, 2016
Fabiana M. Carvalho, Khallil Taverna Chaim, Tiago Arruda Sanchez et al.
26 citations
Updating internal models to predict future events relies on both frontal and parietal brain regions involved in uncertainty-driven updating and a separate network for temporal attention. Using fMRI, this study examined how continuous manipulation of temporal prediction engages these networks. Participants viewed periodic (simple harmonic oscillation) and non-periodic (variable acceleration) motion patterns. Non-periodic motion activated the exogenous temporal orienting network, including ventral premotor and inferior parietal cortices, cerebellum, presupplementary motor area, and motion-sensitive area MT+, with a right-hemisphere bias suggesting explicit timing. Periodic motion activated default-mode network midline areas (left DMPFC, ACC, bilateral PCC/PC), indicating the DMN may process contextually expected information and validate prospective internal models. Findings show continuous temporal prediction engages both temporal expectation representations and task-independent internal model updating.
Frontiers in Human Neuroscience
January 3, 2024
Keisuke Suzuki, Anil K. Seth, David J. Schwartzman
20 citations
Visual hallucinations differ substantially depending on their cause, such as neurodegenerative disease, visual loss, or psychedelic drugs. Using a deep neural network approach called computational (neuro)phenomenology, researchers identified three key dimensions that distinguish these hallucinations: realism (how true-to-life they seem), spontaneity (how much they depend on sensory input), and complexity. By tuning the network along these dimensions, they generated synthetic hallucinations characteristic of each cause. Two studies with patients having Parkinson's disease, Lewy body dementia, or Charles Bonnet syndrome, and people with recent psychedelic experience, confirmed that these synthetic images matched the phenomenology reported by each group. The findings show that a neural network model can capture the distinctive visual features of hallucinations from different origins.
Frontiers in Human Neuroscience
August 30, 2016
David Papo
19 citations
The entropic brain hypothesis proposes that conscious states are linked to the brain's entropy, with psychedelic states exemplifying primary states where brain activity becomes more random and harder to predict than in normal wakeful consciousness. This suggests psychedelic-induced brain activity exhibits criticality, while normal wakefulness is subcritical. However, the text questions whether entropy can uniquely indicate the quality of consciousness and raises doubts about whether psychedelic-induced activity is truly critical.
Frontiers in Human Neuroscience
April 26, 2016
Laura Schmalzl, C. Kerr
18 citations
Movement-based contemplative practices such as yoga, tai chi, the Feldenkrais Method, and dance have been shown to relieve symptoms of cancer, Parkinson's disease, chronic pain, fibromyalgia, PTSD, ADHD, depression, and anxiety, and to improve stress, cognition, physical function, and emotional states in healthy individuals. Despite these benefits, their neural mechanisms remain less studied than those of seated meditation, largely due to the challenge of investigating their combined movement, breath, and attention components. This Research Topic presents empirical data, theoretical frameworks, and clinical implications to advance understanding of the neurophysiological and neurocognitive mechanisms underlying these practices.
Frontiers in Human Neuroscience
August 9, 2022
Thomas Rabeyron
15 citations
Psychoanalytic therapies require a specific setting, psychic state, and processes such as transference, free association, dreaming, play, reflexivity, and narrativity to induce psychic transformations. These transformations involve non-linear processes that take time and involve high entropy states, characterized by an interplay between extension and reduction of free energy. This interplay allows new orders of subjective experience to emerge after states of disorder, following an energetic threshold that modifies mental functioning. High entropy states also foster random functioning and psychic malleability, enabling exploration of subjective experience. The model supports dialogue between psychoanalysis and other fields, including the neurosciences of subjectivity.
Frontiers in Human Neuroscience
February 16, 2023
Michael Koslowski, Max-Pelgrom de Haas, Tamara Fischmann
14 citations
Dreaming arises from the same hierarchical predictive processing that governs waking cognition, but with key modifications: lack of sensory and motor input and a predominance of associative, non-rational primary process thinking. Emotional needs guide behavior via a value system generating pleasure and unpleasure, and the brain constantly updates its predictions to minimize prediction error. Repressed priors—mental events that cannot be reconsolidated despite ongoing error signals—correspond to conflictual complexes and may become accessible in symbolic form during dreams and psychedelic states. Evidence from neuroimaging supports this framework, and an ongoing trial with stroke patients who lost the ability to dream tests whether dreaming is necessary for intact sleep architecture and memory consolidation.
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.
Frontiers in Human Neuroscience
July 17, 2014
Marieke K. van Vugt
10 citations
A neuroscientist who practices both classical ballet and contemplative movement compares the neural and mental causes and consequences of these two movement disciplines. The author argues that ballet, rather than modern dance, provides a good contrast for contemplative practice because modern dance has been influenced by contemplation. The comparison examines four dimensions: cultivation of attention, development of interoception, cultivation of meta-cognition, and emotion regulation. The author notes that limited studies exist due to movement artifacts in neuroimaging and EEG measures, and identifies important gaps in neuroscientific understanding, with implications for future studies of contemplative practitioners and dancers.
Frontiers in Human Neuroscience
July 7, 2023
Giulia Magni, Cosimo Tuena, Giuseppe Riva
9 citations
Psychedelic substances may enhance creativity by inducing cognitive flexibility, allowing a wider range of associations and possibilities to be explored. Virtual Reality can simulate psychedelic perceptual and cognitive effects without associated risks. The Bayesian brain approach, rooted in predictive coding, offers a framework for understanding how psychedelic hallucinations affect cognition. Cognitive flexibility is linked to creative thinking and depends on prefrontal cortex and networks supporting executive functions, memory, attention, and spontaneous thought. Aging and Mild Cognitive Impairment involve declines in creative processing and divergent thinking. The paper suggests that VR-induced psychedelic hallucinations may help optimize the balance between top-down expectations and bottom-up sensory information, potentially maintaining cognitive functions and preventing pathological conditions in aging.
Frontiers in Human Neuroscience
December 19, 2023
Nuno M.p. de Matos, Philipp Staempfli, Erich Seifritz et al.
8 citations
Hypnosis alters functional connectivity in brain networks involving parieto-occipital-temporal areas, cuneal/precuneal and occipital cortices, lingual gyri, and the occipital pole. Comparing two hypnotic states revealed depth-dependent connectivity changes in left superior temporal/supramarginal gyri, cuneus, planum temporale, and lingual gyri. Respiration rate slowed significantly during hypnosis. These findings provide insights into the neurobiology of altered consciousness.