A scoping review for building a criticality-based conceptual framework of altered states of consciousness
Charles Gervais, Louis-Philippe Boucher, Guillermo Martinez Villar, UnCheol Lee, Catherine Duclos
Frontiers in Systems Neuroscience May 25, 2023 DOI: 10.3389/fnsys.2023.1085902 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Scoping review Peer reviewed |
|---|---|
| Sample size | 49 |
| Population | Studies on altered states of consciousness |
| Topics | Altered states of consciousness |
| Keywords | Criticality Consciousness Delirium Cognitive psychology Wakefulness Cognitive science |
| Citations | 25 |
| Key findings | Altered states of consciousness are characterized by a deviation from the critical state, though the direction of deviation is not clearly reported in most studies. |
Abstract
The healthy conscious brain is thought to operate near a critical state, reflecting optimal information processing and high susceptibility to external stimuli. Conversely, deviations from the critical state are hypothesized to give rise to altered states of consciousness (ASC). Measures of criticality could therefore be an effective way of establishing the conscious state of an individual. Furthermore, characterizing the direction of a deviation from criticality may enable the development of treatment strategies for pathological ASC. The aim of this scoping review is to assess the current evidence supporting the criticality hypothesis, and the use of criticality as a conceptual framework for ASC. Using the PRISMA guidelines, Web of Science and PubMed were searched from inception to February 7th 2022 to find articles relating to measures of criticality across ASC. N = 427 independent papers were initially found on the subject. N = 378 were excluded because they were either: not related to criticality; not related to consciousness; not presenting results from a primary study; presenting model data. N = 49 independent papers were included in the present research, separated in 7 sub-categories of ASC: disorders of consciousness (DOC) ( n = 5); sleep ( n = 13); anesthesia ( n = 18); epilepsy ( n = 12); psychedelics and shamanic state of consciousness ( n = 4); delirium ( n = 1); meditative state ( n = 2). Each category included articles suggesting a deviation of the critical state. While most studies were only able to identify a deviation from criticality without being certain of its direction, the preliminary consensus arising from the literature is that non-rapid eye movement (NREM) sleep reflects a subcritical state, epileptic seizures reflect a supercritical state, and psychedelics are closer to the critical state than normal consciousness. This scoping review suggests that, though the literature is limited and methodologically inhomogeneous, ASC are characterized by a deviation from criticality, though its direction is not clearly reported in a majority of studies. Criticality could become, with more extensive research, an effective and objective way to characterize ASC, and help identify therapeutic avenues to improve criticality in pathological brain states. Furthermore, we suggest how anesthesia and psychedelics could potentially be used as neuromodulation techniques to restore criticality in DOC.
Comparable studies
Other narrative reviews on altered states of consciousness, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| The Subjective Effects of Psychedelics Are Necessary for Their Enduring Therapeutic Effects. | 2020 | Review | |
| Psychobiology of Altered States of Consciousness. | 2005 | Review | |
| Intrinsic Brain Activity in Altered States of Consciousness | 2008 | Review | |
| Dynamic functional connectivity and brain metastability during altered states of consciousness | 2017 | Review | |
| A default mode of brain function in altered states of consciousness. | 2013 | Review |
Citations in the library
Cited by 14
- Critical dynamics in spontaneous EEG predict anesthetic-induced loss of consciousness and perturbational complexity. Communications Biology August 5, 2024
- Psychedelics and disorders of consciousness: the current landscape and the path forward. Neuroscience of Consciousness June 15, 2024
- A pilot human study using ketamine to treat disorders of consciousness. iScience January 17, 2025
- Pharmacological therapies for early and long-term recovery in disorders of consciousness: current knowledge and promising avenues. Expert Review of Neurotherapeutics June 1, 2025
- Criticality of resting-state EEG predicts perturbational complexity and level of consciousness during anesthesia. bioRxiv : the preprint server for biology October 31, 2023
and 9 more in the library
Cites 38
- Detecting Awareness in the Vegetative State Science September 7, 2006
- An information integration theory of consciousness BMC Neuroscience November 2, 2004
- A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior Science Translational Medicine August 14, 2013
- Unresponsiveness ≠ Unconsciousness Anesthesiology February 7, 2012
- Meditation leads to reduced default mode network activity beyond an active task Cognitive, Affective, & Behavioral Neuroscience April 22, 2015
and 33 more in the library