Neuroscience of Consciousness
January 1, 2017
Chris Letheby, Philip Gerrans
280 citations
Psychedelic-induced ego dissolution—where the sense of being a distinct self disappears—is best explained by predictive processing models of self-awareness. Self-awareness arises from hierarchical predictive models that posit a stable, enduring entity to which representations are bound. The self-model functions as a useful Cartesian fiction: a false representation of a simple substance that integrates cognitive processing across levels and domains. Unlike narrative accounts, this self-model has a robust cognitive function, but it does not qualify as a real self. Ego dissolution reveals the self-model's binding role in cognition, yet the self itself does not exist.
Neuroscience of Consciousness
January 1, 2021
Simone Sarasso, Adenauer G. Casali, Silvia Casarotto et al.
183 citations
A growing body of empirical studies has identified complexity-related measures as reliable markers of consciousness across conditions including sleep, anesthesia, hallucinatory states, coma, and related disorders. These measures were proposed independently by researchers working within different frameworks and using diverse methods. This paper systematically reviews that literature, identifies a common denominator among the measures, and traces it to theoretical principles and predictions made over 20 years ago. The authors highlight a consistent trajectory across two decades of consciousness research and offer a provisional taxonomy of the existing work. They argue that this convergence provides a solid foundation for designing future experiments and advancing the field.
Neuroscience of Consciousness
January 1, 2018
Tim Bayne, Olivia Carter
153 citations
The popular and academic claim that the psychedelic state is a 'higher' state of consciousness is critically examined. The article distinguishes between conscious contents and global states, reviewing lab-based findings on psilocybin and LSD. While some aspects of consciousness are enhanced, many functional capacities are seriously compromised. The authors argue that because psychedelics affect different dimensions of consciousness in opposing ways, the unidimensional 'level-based' view of consciousness is unsupported; instead, a multidimensional conception is strongly supported. The analysis also considers implications for Global Workspace Theory and Integrated Information Theory.
Neuroscience of Consciousness
January 1, 2022
Jolien C. Francken, L. Beerendonk, D. Molenaar et al.
96 citations
A survey of 166 consciousness researchers reveals ongoing debate about the definition and study of consciousness. Most respondents believe machines could have consciousness, that consciousness is gradual across the animal kingdom, and that unconscious processing is extensive, covering both low-level and high-level cognitive functions. The survey identifies which theories of consciousness are considered most promising and how different theories cluster, which dependent measures best index consciousness, and which neural measures are thought to be its most likely signatures. These findings offer a snapshot of current views to help prioritize research and theoretical approaches.
Neuroscience of Consciousness
January 1, 2017
Giulio Ruffini
75 citations
Conscious experience can be understood as a mental construct arising from information compression. Using algorithmic information theory, specifically Kolmogorov complexity, provides a natural framework to quantify consciousness from brain data, assuming the brain's primary role is information processing. The theory hypothesizes that compressive models in cognitive systems, such as biological recurrent neural networks, enable structured phenomenal experience, with self-awareness emerging naturally as part of a better model in systems interacting bidirectionally with the world. This approach, called KT theory, is compared to other information-centric theories, and methods are described for studying brain complexity as a correlate of conscious state through input probing, spontaneous activity analysis, perturbation, and behavioral quantification.
Neuroscience of Consciousness
January 1, 2019
Gregory Scott, Robin Carhart‐Harris
72 citations
The classic psychedelic psilocybin may increase conscious awareness in patients with disorders of consciousness, based on its ability to increase brain complexity—a reliable index of conscious level. The authors propose testing this hypothesis but also confront the considerable ethical and practical challenges that must be addressed for direct assessment.
Neuroscience of Consciousness
January 1, 2023
Inês Hipólito, Jonas Mago, Fernando E. Rosas et al.
60 citations
Psychedelic therapy shows promise for mental health, but the psychological mechanisms behind its benefits are unclear. This paper proposes that psychedelics act as destabilizers, both psychologically and neurophysiologically, drawing on the 'entropic brain' hypothesis and the 'RElaxed Beliefs Under pSychedelics' model. Using complex systems theory, it suggests that psychedelics disrupt fixed points or attractors, breaking reinforced patterns of thinking and behavior. The approach explains how increased brain entropy destabilizes neurophysiological set points, leading to new understandings of psychedelic psychotherapy. These insights have implications for reducing risks and optimizing treatment during both the peak experience and the subacute recovery period.
Neuroscience of Consciousness
January 1, 2022
Austin Clinton Cooper, Bianca Ventura, Georg Northoff
54 citations
Advanced meditators often report experiences of nondual awareness—a state without boundaries between self and environment. This review of functional magnetic resonance imaging studies across meditation types and experience levels finds that meditation reorganizes the brain's spatial topography. Key neural changes include decreased activity in the posterior default mode network (DMN), increased activity in the central executive network (CEN), reduced connectivity within the posterior DMN and between posterior and anterior DMN, increased connectivity within the anterior DMN and CEN, and significantly altered connectivity between DMN and CEN, likely nonlinear. These changes suggest a shift from mental-self-processing toward interoceptive and exteroceptive self-processing, enabling explicit nondual awareness. The authors propose a topographic reorganization model of meditation (TRoM) linking neural and experiential effects.
Neuroscience of Consciousness
January 1, 2017
53 citations
Dreaming occurs during both rapid eye movement (REM) and non-REM sleep, but the phenomenological characteristics differ between these stages. Lucid dreaming, where the dreamer is aware they are dreaming, offers a unique window into consciousness during sleep. The review synthesizes previous literature on brain activity across the sleep cycle, showing how neurofunctional changes relate to variations in dream content and the level of consciousness experienced. The authors aim to clarify how these neural shifts may underlie the subjective qualities of dreams.
Neuroscience of Consciousness
November 1, 2021
Andrea I. Luppi, Pedro A. M. Mediano, Fernando E. Rosas et al.
42 citations
Consciousness can be better understood by decomposing it into distinct information-theoretic elements rather than measuring it as a single quantity of integrated information. The authors propose Integrated Information Decomposition (ΦID), which provides a formal argument that whether consciousness is an emergent phenomenon depends on its information-theoretic composition. Two organisms may have the same amount of integrated information yet differ in composition. A new measure, ΦR, and the ΦR-ing ratio quantify how efficiently information is used for conscious processing. This approach enables identification of qualitatively different 'modes of consciousness' and mapping them to phenomenology, starting with selfhood. ΦID offers new ways to explore the relationship between information, consciousness, and neural dynamics.
Neuroscience of Consciousness
January 1, 2021
Vaibhav Tripathi, P. Bharadwaj
28 citations
Yoga, a practice and philosophy with roots over 4500 years old, has gained renewed scientific interest. This review outlines the dualistic Sankhya philosophy of yoga as summarized by Patanjali, describing the five vrittis (modulations of mind), practices like pratyahara and dhyana, and states of samadhi. The authors propose a yogic theory of consciousness (YTC) that models both external modulations and internal mental states, suggesting attention, sleep, and mind wandering are unique modulatory states. YTC can model external states, meditation, samadhi, and disorders of consciousness. The article lists testable neuroscientific hypotheses and discusses benefits and limitations of this framework.
Neuroscience of Consciousness
January 1, 2019
25 citations
An ethical analysis of proposed psychedelic research with patients who have disorders of consciousness, using the Value-Validity Framework and Component Analysis, finds that the approach by Scott and Carhart-Harris is ethically permissible under certain conditions. The frameworks applied are also relevant for evaluating other novel consciousness research protocols.
Neuroscience of Consciousness
January 1, 2024
Niccolò Negro
19 citations
The neuroscience of consciousness is accelerating empirically through adversarial collaborations that test rival theories. This paper argues that consciousness science should be paired with confirmation theory, the philosophical study of evidence and hypotheses, to understand how experiments challenge or validate theories. Using Lakatos's philosophy of science, the author proposes a model of theory-appraisal built on three criteria: the distinction between prediction and accommodation, the structural relevance of predictions, and the boldness of predictions. This Lakatosian model offers both normative and descriptive advantages, advancing the debate by considering theories' diachronic development, logical structure, and relationship with background knowledge.
Neuroscience of Consciousness
January 1, 2020
Michael Schartner, Christopher Timmermann
17 citations
The serotonergic system regulates the balance between prior expectations and sensory information in shaping conscious visual perception. Psychedelic drugs like N,N-Dimethyltryptamine can perturb this system, altering how the brain gates internal and external inputs. Two generative deep neural networks are discussed as tools to both illustrate the visual effects of psychedelics and to model the biological mechanisms of sensory gating. This approach offers a new medium, alongside paintings and verbal reports, for understanding how the brain constructs conscious experience.
Neuroscience of Consciousness
January 1, 2024
Charlotte Martial, Robin Carhart-Harris, Christopher Timmermann
9 citations
People who have had both a near-death experience (NDE) and a psychedelic experience (PE) report overlapping mystical-like effects, such as feelings of unity and transcendence, and similar attributions of reality, psychological insights, and lasting changes. However, low-level sensory phenomena differ: NDEs involve stronger disembodiment, while psychedelics produce more visual imagery. The study used an online survey of 31 adults who had experienced both an NDE (scoring ≥27 on the NDE-C scale) and a PE with classic psychedelics. Bayesian and frequentist analyses confirmed these overlaps and differences, suggesting psychedelics can model the mystical aspects of NDEs but not their sensory features.
Neuroscience of Consciousness
January 1, 2024
Arthur Juliani, Adam Safron, Ryota Kanai
8 citations
Psychedelic therapy shows promise for treating mental disorders, and the "RElaxed Beliefs Under pSychedelics" (REBUS) model explains this by suggesting psychedelics loosen maladaptive high-level beliefs. The newer "CANAL" model proposes that overly rigid belief landscapes (canalization) contribute to psychopathology. This work uses deep neural network learning theory to refine the CANAL model, distinguishing two separate optimization landscapes for belief representation in the brain. Each can develop unique pathologies from either too much or too little canalization, indicating that canalization's link to psychopathology is not simply linear. The refined model makes novel predictions about which aspects of psychopathology psychedelic therapy may treat and which therapy forms might benefit a given individual.
Neuroscience of Consciousness
August 29, 2022
Camilo Miguel Signorelli, Ignacio Cea, Robert Prentner
8 citations
Integrated information theory (IIT) aims to explain consciousness by linking its subjective structure to physical systems without reducing it to neural activity alone. This article identifies ambiguities in IIT, particularly tensions between its claim that experience is ontologically and epistemologically primary and its goal of explaining consciousness in physical, operational terms. The authors propose ways to resolve these issues and suggest alternative explanatory approaches—mathematical, processual, and autonomy-based—that may better guide future models of consciousness. The goal is to clarify points of contention for both supporters and critics of IIT.
Neuroscience of Consciousness
January 1, 2025
Stephanie Muller, Federico Cavanna, Laura Alethia de la Fuente et al.
1 citation
Psilocybin alters how people process visual salience during natural scene perception, leading to more focused and exploratory gaze patterns. In a self-blinded study, 23 participants viewed natural scenes under low and high doses of psilocybin while their eye movements were tracked. Under the high dose, fixations concentrated more on salient image regions, inter-fixation distance decreased, and the Shannon entropy of fixations on high-saliency areas indicated more exploratory and less predictable scanning. Resting-state electroencephalography showed broadband spectral power reductions and increased Lempel-Ziv complexity, with delta power negatively correlating with salience metrics. These findings suggest psilocybin shifts attentional dynamics, heightening sensitivity to visual salience and altering gaze behavior.