scholarly journals Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness

2019 ◽  
Author(s):  
David J. Schwartzman ◽  
Michael Schartner ◽  
Benjamin B. Ador ◽  
Francesca Simonelli ◽  
Acer Y.-C. Chang ◽  
...  
Keyword(s):  
Subjective Experience ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Eeg Signal ◽  
Visual Hallucinations ◽  
Subjective Experiences ◽  
Eeg Signals ◽  
Neural Signal ◽  
States Of Consciousness ◽  
Signal Diversity

AbstractWhat are the global neuronal signatures of altered states of consciousness (ASC)? Recently, increases in neural signal diversity, compared to those found in wakeful rest, have been reported during psychedelic states. Neural signal diversity has previously been identified as a robust signature of the state of consciousness, showing lower scores during sleep or anaesthesia compared to wakeful rest. The increased neural signal diversity during psychedelic states raises the additional possibility that it may also reflect the increased diversity of subjective experiences associated with these states. However, psychedelic states involve widespread neuropsychopharmacological changes, only some of which may be associated with altered phenomenology. Therefore, we used stroboscopic stimulation to induce non-pharmacological altered states of consciousness while measuring the diversity of EEG signals. Stroboscopic stimulation caused substantial increases in the intensity and range of subjective experiences, with reports of both simple and complex visual hallucinations. These experiences were accompanied by increases in EEG signal diversity scores (measured using Lempel-Ziv complexity) exceeding those associated with wakeful rest, in line with studies of the psychedelic state. Our findings support the proposal that EEG signal diversity reflects the diversity of subjective experience that is associated with different states of consciousness.

scholarly journals Increased signal diversity/complexity of spontaneous EEG, but not evoked EEG responses, in ketamine-induced psychedelic state in humans

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242056
Author(s):  
Nadine Farnes ◽  
Bjørn E. Juel ◽  
André S. Nilsen ◽  
Luis G. Romundstad ◽  
Johan F. Storm
Keyword(s):  
Subjective Experience ◽  
Brain Activity ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Eeg Signal ◽  
Eyes Closed ◽  
States Of Consciousness ◽  
Significant Difference ◽  
Eyes Open ◽  
Signal Diversity

How and to what extent electrical brain activity reflects pharmacologically altered states and contents of consciousness, is not well understood. Therefore, we investigated whether measures of evoked and spontaneous electroencephalographic (EEG) signal diversity are altered by sub-anaesthetic levels of ketamine compared to normal wakefulness, and how these measures relate to subjective experience. High-density 62-channel EEG was used to record spontaneous brain activity and responses evoked by transcranial magnetic stimulation (TMS) in 10 healthy volunteers before and during administration of sub-anaesthetic doses of ketamine in an open-label within-subject design. Evoked signal diversity was assessed using the perturbational complexity index (PCI), calculated from EEG responses to TMS perturbations. Signal diversity of spontaneous EEG, with eyes open and eyes closed, was assessed by Lempel Ziv complexity (LZc), amplitude coalition entropy (ACE), and synchrony coalition entropy (SCE). Although no significant difference was found in TMS-evoked complexity (PCI) between the sub-anaesthetic ketamine condition and normal wakefulness, all measures of spontaneous EEG signal diversity (LZc, ACE, SCE) showed significantly increased values in the sub-anaesthetic ketamine condition. This increase in signal diversity correlated with subjective assessment of altered states of consciousness. Moreover, spontaneous signal diversity was significantly higher when participants had eyes open compared to eyes closed, both during normal wakefulness and during influence of sub-anaesthetic ketamine. The results suggest that PCI and spontaneous signal diversity may reflect distinct, complementary aspects of changes in brain properties related to altered states of consciousness: the brain’s capacity for information integration, assessed by PCI, might be indicative of the brain’s ability to sustain consciousness, while spontaneous complexity, as measured by EEG signal diversity, may be indicative of the complexity of conscious content. Thus, sub-anaesthetic ketamine may increase the complexity of the conscious content and the brain activity underlying it, while the level or general capacity for consciousness remains largely unaffected.

scholarly journals Increased signal diversity/complexity of spontaneous EEG, but not evoked EEG responses, in ketamine-induced psychedelic state in humans

2019 ◽  
Author(s):  
Nadine Farnes ◽  
Bjørn E. Juel ◽  
André S. Nilsen ◽  
Luis G. Romundstad ◽  
Johan F. Storm
Keyword(s):  
Brain Activity ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Eeg Signal ◽  
Eyes Closed ◽  
Electrical Brain Activity ◽  
States Of Consciousness ◽  
Significant Difference ◽  
Eyes Open ◽  
Signal Diversity

AbstractObjectiveHow and to what extent electrical brain activity is affected in pharmacologically altered states of consciousness, where it is mainly the phenomenological content rather than the level of consciousness that is altered, is not well understood. An example is the moderately psychedelic state caused by low doses of ketamine. Therefore, we investigated whether and how measures of evoked and spontaneous electroencephalographic (EEG) signal diversity are altered by sub-anaesthetic levels of ketamine compared to normal wakefulness, and how these measures relate to subjective assessments of consciousness.MethodsHigh-density electroencephalography (EEG, 62 channels) was used to record spontaneous brain activity and responses evoked by transcranial magnetic stimulation (TMS) in 10 healthy volunteers before and after administration of sub-anaesthetic doses of ketamine in an open-label within-subject design. Evoked signal diversity was assessed using the perturbational complexity index (PCI), calculated from the global EEG responses to local TMS perturbations. Signal diversity of spontaneous EEG, with eyes open and eyes closed, was assessed by Lempel Ziv complexity (LZc), amplitude coalition entropy (ACE), and synchrony coalition entropy (SCE).ResultsAlthough no significant difference was found in the index of TMS-evoked complexity (PCI) between the sub-anaesthetic ketamine condition and normal wakefulness, all the three measures of spontaneous EEG signal diversity showed significantly increased values in the sub-anaesthetic ketamine condition. This increase in signal diversity also correlated with subjective assessment of altered states of consciousness. Moreover, spontaneous signal diversity was significantly higher when participants had eyes open compared to eyes closed, both during normal wakefulness and during influence of sub-anaesthetic ketamine doses.ConclusionThe results suggest that PCI and spontaneous signal diversity may be complementary and potentially measure different aspects of consciousness. Thus, our results seem compatible with PCI being indicative of the brain’s ability to sustain consciousness, as indicated by previous research, while it is possible that spontaneous EEG signal diversity may be indicative of the complexity of conscious content. The observed sensitivity of the latter measures to visual input seems to support such an interpretation. Thus, sub-anaesthetic ketamine may increase the complexity of both the conscious content (experience) and the brain activity underlying it, while the level, degree, or general capacity of consciousness remains largely unaffected.

Synaesthetic Overdrive

2018 ◽  
Author(s):  
Jonathan Weinel
Keyword(s):  
Subjective Experience ◽  
Visual Media ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Visual Music ◽  
Background Theory ◽  
States Of Consciousness ◽  
Feature Films ◽  
Expanded Cinema ◽  
Improved Accuracy

This chapter discusses altered states of consciousness in audio-visual media, such as films, psychedelic light shows, and VJ performances. First, some background theory is introduced, explaining the main categories of film sound, and what research tells us regarding the way in which sound influences the perception of visual images and vice versa. Following this background section, a tour is provided through various films that represent altered states of consciousness, including surrealist movies, ‘trance films’, and Hollywood feature films. These demonstrate a progression, where more recent movies are able to make use of digital audio and visual effects to represent the subjective experience of altered states with improved accuracy. Meanwhile, beyond the traditional confines of the cinema, ‘expanded cinema’ works such as visual music, psychedelic light shows, and VJ performances have provided increasingly sophisticated synaesthetic experiences, which are designed to transform the consciousness of their audience.

scholarly journals Neural correlates of the shamanic state of consciousness

2020 ◽  
Author(s):  
Emma R Huels ◽  
Hyoungkyu Kim ◽  
UnCheol Lee ◽  
Tarik Bel-Bahar ◽  
Angelo Colmenero ◽  
...  
Keyword(s):  
Classical Music ◽  
Empirical Studies ◽  
Neural Correlates ◽  
Altered States Of Consciousness ◽  
Music Listening ◽  
Altered States ◽  
Beta Band ◽  
Drug Induced ◽  
States Of Consciousness ◽  
Signal Diversity

Despite the use of shamanism as a healing practice for several millennia, few empirical studies of the shamanic state of consciousness exist. We investigated the neural correlates of shamanic trance using high-density electroencephalography (EEG) in 24 shamanic practitioners and 24 healthy controls during rest, shamanic drumming, and classical music listening, followed by a validated assessment of altered states of consciousness. EEG data were used to assess changes in absolute power, connectivity, signal diversity, and criticality, which were correlated with assessment measures. We also compared assessment scores to those of individuals in a previous study under the influence of psychedelics. Shamanic practitioners were significantly different from controls in several domains of altered states of consciousness, with scores comparable to or exceeding that of healthy volunteers under the influence of psychedelics. Practitioners also displayed increased gamma power during drumming that positively correlated with elementary visual alterations. Furthermore, shamanic practitioners had decreased low alpha and increased low beta connectivity during drumming and classical music, and decreased neural signal diversity in the gamma band during drumming that inversely correlated with insightfulness. Finally, criticality in practitioners was increased during drumming in the low and high beta and gamma bands, with increases in the low beta band correlating with complex imagery and elementary visual alterations. These findings suggest that psychedelic drug-induced and non-pharmacologic alterations in consciousness have overlapping phenomenal traits but are distinct states of consciousness, as reflected by the unique brain-related changes during shamanic trance compared to previous literature investigating the psychedelic state.

scholarly journals Experiências Anômalas e Dissociativas em Contexto Religioso: Uma Abordagem Autoetnográfica

2020 ◽  
Vol 26 (2) ◽  
pp. 147-161
Author(s):  
Everton de Oliveira MARALDI
Keyword(s):  
Scientific Literature ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Subjective Experiences ◽  
Significant Similarity ◽  
Subjective Data ◽  
States Of Consciousness ◽  
Ethnographic Approach ◽  
Different Levels ◽  
Do So

The present study explored the phenomenological characteristics of anomalous experiences (AEs) reported during Umbanda rituals, a mediumistic Brazilian religion, with the aim of comparing AEs reported during rituals involving the use of Ayahuasca (an entheogen frequently used in some Umbanda contexts) and rituals without the use of this substance. In order to do so, we compared individuals with different levels of involvement with the mediumistic practices. The study was based on an auto-ethnographic approach. This methodological perspective allowed us to confront subjective data with the available knowledge in the scientific literature about AEs, dissociative phenomena and altered states of consciousness and was of fundamental importance for a more sensitive understanding of the nuances and characteristics of these experiences. The results attest to a significant similarity between the experiences reported with and without the use of Ayahuasca in mediumistic contexts. In both groups, the experiencers were able to identify certain similarities in their experiences regarding a reduction of voluntary motor control, changes in memory and perception, communicability and accessibility of experiences, anomalous information reception and increases in interpersonal sensitivity. The results support the methodological feasibility of autoethnography as a research tool and point to its relevance to a deeper understanding of AEs and other subjective experiences usually of difficult investigation by other research methods.

scholarly journals Neural Correlates of the Shamanic State of Consciousness

2021 ◽  
Vol 15 ◽  
Author(s):  
Emma R. Huels ◽  
Hyoungkyu Kim ◽  
UnCheol Lee ◽  
Tarik Bel-Bahar ◽  
Angelo V. Colmenero ◽  
...  
Keyword(s):  
Classical Music ◽  
Empirical Studies ◽  
Neural Correlates ◽  
Altered States Of Consciousness ◽  
Music Listening ◽  
Altered States ◽  
Beta Band ◽  
Drug Induced ◽  
States Of Consciousness ◽  
Signal Diversity

Psychedelics have been recognized as model interventions for studying altered states of consciousness. However, few empirical studies of the shamanic state of consciousness, which is anecdotally similar to the psychedelic state, exist. We investigated the neural correlates of shamanic trance using high-density electroencephalography (EEG) in 24 shamanic practitioners and 24 healthy controls during rest, shamanic drumming, and classical music listening, followed by an assessment of altered states of consciousness. EEG data were used to assess changes in absolute power, connectivity, signal diversity, and criticality, which were correlated with assessment measures. We also compared assessment scores to those of individuals in a previous study under the influence of psychedelics. Shamanic practitioners were significantly different from controls in several domains of altered states of consciousness, with scores comparable to or exceeding that of healthy volunteers under the influence of psychedelics. Practitioners also displayed increased gamma power during drumming that positively correlated with elementary visual alterations. Furthermore, shamanic practitioners had decreased low alpha and increased low beta connectivity during drumming and classical music and decreased neural signal diversity in the gamma band during drumming that inversely correlated with insightfulness. Finally, criticality in practitioners was increased during drumming in the low and high beta and gamma bands, with increases in the low beta band correlating with complex imagery and elementary visual alterations. These findings suggest that psychedelic drug-induced and non-pharmacologic alterations in consciousness have overlapping phenomenal traits but are distinct states of consciousness, as reflected by the unique brain-related changes during shamanic trance compared to previous literature investigating the psychedelic state.

Inner Worlds

2018 ◽  
Author(s):  
Jonathan Weinel
Keyword(s):  
Sensory Deprivation ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Subjective Experiences ◽  
States Of Consciousness ◽  
Discrete States ◽  
Dimensional Models ◽  
Hypnagogic Hallucinations

This chapter provides an introduction to consciousness, and explores how our subjective experiences change during a variety of altered states of consciousness. An overview of cognition is given, outlining the processes involved in the construction of our experiences within the ‘stream’ or ‘theatre of consciousness’. Next, the main varieties of altered states of consciousness are discussed: psychosis, psychedelic experience, dreaming, hypnagogic hallucinations, sensory deprivation, meditation, trance, and hypnosis. Using existing dimensional models, these can be understood not as discrete states, but as points on a continuum, which significantly diverge from ‘normal waking consciousness’. For the purposes of Inner Sound, these altered states of consciousness can be represented or induced with the aid of sound and music; here an initial outline of how this may occur is given.

scholarly journals How does it feel to be on psilocybin? Dose-response relationships of subjective experiences in humans

2020 ◽  
Author(s):  
Tim Hirschfeld ◽  
Timo Torsten Schmidt
Keyword(s):  
Dose Response ◽  
Variance Estimation ◽  
Rating Scale ◽  
Mystical Experience ◽  
Meta Analysis ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Subjective Experiences ◽  
States Of Consciousness ◽  
Study Participants

AbstractPsilocybin is the active component of magic mushrooms and is well known for its psychoactive properties. Different questionnaires have been developed to systematically quantify altered states of consciousness induced by psychoactive drugs. The aim of this study was to obtain the dose-response relationships of the subjective experiences induced by psilocybin in healthy study participants. For this purpose, we applied a linear meta-regression approach on questionnaire ratings after oral administration of psilocybin in a controlled setting. Data was obtained from The Altered States Database, which contains psychometric data extracted from peer-reviewed articles published in MEDLINE-listed journals that used standardized and validated questionnaires. Our meta-analysis included data of the Altered States of Consciousness Rating Scale, the Mystical Experience Questionnaire (MEQ30), and the Hallucinogen Rating Scale (HRS). We used the Robust Variance Estimation Framework to obtain linear dose-response relationship estimates for each dimension of the given questionnaires. Ratings on most dimensions and subscales of the included questionnaires correlated positively with dose. Since subjective experiences are not only determined by dose, but also by individual differences and environmental factors, our results do not necessarily generalize to recreational use, as our analyses are based on data from controlled laboratory experiments. The paper at hand could serve as a general literature citation for the use of psilocybin in experimental and clinical research, especially for the comparison of expected and observed subjective drug experiences.

scholarly journals Dose–response relationships of psilocybin-induced subjective experiences in humans

2021 ◽  
pp. 026988112199267
Author(s):  
Tim Hirschfeld ◽  
Timo T Schmidt
Keyword(s):  
Dose Response ◽  
Variance Estimation ◽  
Rating Scale ◽  
Mystical Experience ◽  
Meta Analysis ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Subjective Experiences ◽  
States Of Consciousness ◽  
Almost All

Background: Psilocybin is the psychoactive component in Psilocybe mushrooms (‘magic mushrooms’). Whether and how the quality of the psilocybin-induced experience might mediate beneficial health outcomes is currently under investigation, for example, in therapeutic applications. However, to date, no meta-analysis has investigated the dose-dependency of subjective experiences across available studies. Aim: Establishing dose–response relationships of the subjective experiences induced by psilocybin in healthy study participants and a comparison of patient groups. Method: We applied a linear meta-regression approach, based on the robust variance estimation framework, to obtain linear dose–response relationship estimates on questionnaire ratings after oral psilocybin administration. Data were obtained from the Altered States Database, which contains data extracted from MEDLINE-listed journal articles that used standardized and validated questionnaires: the Altered States of Consciousness Rating Scale, the Mystical Experience Questionnaire and the Hallucinogen Rating Scale. Results: Psilocybin dose positively correlated with ratings on most factors and scales, mainly those referring to perceptual alterations and positively experienced ego dissolution. Measures referring to challenging experiences exhibited small effects and were barely modulated by dose. Conclusion: Psilocybin intensified almost all characteristics of altered states of consciousness assessed with the given questionnaires. Because subjective experiences are not only determined by dose, but also by individual and environmental factors, the results may only apply to controlled laboratory experiments and not to recreational use. This paper may serve as a general literature citation for the use of psilocybin in experimental and clinical research, to compare expected and observed subjective experiences.

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