Unifying Theories of Psychedelic Drug Effects

Swanson, Link R.

doi:10.3389/fphar.2018.00172

Cited by 142 publications

(151 citation statements)

References 228 publications

(427 reference statements)

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“…Therefore, building a richer statistical description of the brain’s dynamics using recent information-theoretic tools (such as multivariate extensions of mutual information 28 or Integrated Information Theory, IIT 46 ) remains an exciting open problem. In fact, recent attempts of unifying IIT and the EBH in a single framework to understand the effects of psychedelic drugs 47 are helping to bridge the gap between the univariate EBH and the multivariate IIT.…”

Section: Discussionmentioning

confidence: 99%

RETRACTED ARTICLE: A mechanistic model of the neural entropy increase elicited by psychedelic drugs

Herzog

Mediano

Rosas

et al. 2020

Sci Rep

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Psychedelic drugs, including lysergic acid diethylamide and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain’s anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.

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Section: Discussionmentioning

confidence: 99%

RETRACTED ARTICLE: A mechanistic model of the neural entropy increase elicited by psychedelic drugs

Herzog

Mediano

Rosas

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…In addition, a recent study showed that LSD attenuates top-down suppression of prediction error in response to surprising auditory stimuli, as measured by mismatch negativity in the auditory oddball paradigm (Timmermann et al, in press ). It is possible that a similar disruption of top-down processing of somatosensory stimuli plays a role in the modulation of body ownership by psychedelics (see also Swanson, 2018 for a discussion of the effects of psychedelics on top-down processing).…”

Section: Alterations Of Self-consciousness Induced By Meditation and mentioning

confidence: 99%

Psychedelics, Meditation, and Self-Consciousness

et al. 2018

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In recent years, the scientific study of meditation and psychedelic drugs has seen remarkable developments. The increased focus on meditation in cognitive neuroscience has led to a cross-cultural classification of standard meditation styles validated by functional and structural neuroanatomical data. Meanwhile, the renaissance of psychedelic research has shed light on the neurophysiology of altered states of consciousness induced by classical psychedelics, such as psilocybin and LSD, whose effects are mainly mediated by agonism of serotonin receptors. Few attempts have been made at bridging these two domains of inquiry, despite intriguing evidence of overlap between the phenomenology and neurophysiology of meditation practice and psychedelic states. In particular, many contemplative traditions explicitly aim at dissolving the sense of self by eliciting altered states of consciousness through meditation, while classical psychedelics are known to produce significant disruptions of self-consciousness, a phenomenon known as drug-induced ego dissolution. In this article, we discuss available evidence regarding convergences and differences between phenomenological and neurophysiological data on meditation practice and psychedelic drug-induced states, with a particular emphasis on alterations of self-experience. While both meditation and psychedelics may disrupt self-consciousness and underlying neural processes, we emphasize that neither meditation nor psychedelic states can be conceived as simple, uniform categories. Moreover, we suggest that there are important phenomenological differences even between conscious states described as experiences of self-loss. As a result, we propose that self-consciousness may be best construed as a multidimensional construct, and that “self-loss,” far from being an unequivocal phenomenon, can take several forms. Indeed, various aspects of self-consciousness, including narrative aspects linked to autobiographical memory, self-related thoughts and mental time travel, and embodied aspects rooted in multisensory processes, may be differently affected by psychedelics and meditation practices. Finally, we consider long-term outcomes of experiences of self-loss induced by meditation and psychedelics on individual traits and prosocial behavior. We call for caution regarding the problematic conflation of temporary states of self-loss with “selflessness” as a behavioral or social trait, although there is preliminary evidence that correlations between short-term experiences of self-loss and long-term trait alterations may exist.

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“…During dosing sessions, which are embedded in a brief intervention model with preparatory and integrative counseling sessions, therapists usually take a non-directive approach. The patient, who is encouraged to turn attention inward, is mostly lying down, wearing eyeshades, and listening to a carefully selected playlist of music over headphones as the acute psychedelic experience unfolds [for concise summaries of the phenomenology of psychedelic states see (42,43)].…”

Section: Avoidance and Acceptance In Psychedelic Therapymentioning

confidence: 99%

Learning to Let Go: A Cognitive-Behavioral Model of How Psychedelic Therapy Promotes Acceptance

et al. 2020

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The efficacy of psychedelic-assisted therapies for mental disorders has been attributed to the lasting change from experiential avoidance to acceptance that these treatments appear to facilitate. This article presents a conceptual model that specifies potential psychological mechanisms underlying such change, and that shows substantial parallels between psychedelic therapy and cognitive behavioral therapy: We propose that in the carefully controlled context of psychedelic therapy as applied in contemporary clinical research, psychedelic-induced belief relaxation can increase motivation for acceptance via operant conditioning, thus engendering episodes of relatively avoidance-free exposure to greatly intensified private events. Under these unique learning conditions, relaxed avoidance-related beliefs can be exposed to corrective information and become revised accordingly, which may explain long-term increases in acceptance and corresponding reductions in psychopathology. Open research questions and implications for clinical practice are discussed.

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Unifying Theories of Psychedelic Drug Effects

Cited by 142 publications

References 228 publications

RETRACTED ARTICLE: A mechanistic model of the neural entropy increase elicited by psychedelic drugs

RETRACTED ARTICLE: A mechanistic model of the neural entropy increase elicited by psychedelic drugs

Psychedelics, Meditation, and Self-Consciousness

Learning to Let Go: A Cognitive-Behavioral Model of How Psychedelic Therapy Promotes Acceptance

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