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 27, 2017
Michael Schartner, Andrea Pigorini, Steve A. Gibbs et al.
158 citations
During non-rapid eye movement (NREM) sleep, neural dynamical complexity—measured by Lempel-Ziv complexity, amplitude coalition entropy, and synchrony coalition entropy—decreased substantially across broadly distributed brain regions in ten epilepsy patients. This decrease partially reversed during late-night NREM sleep and returned to wakeful rest levels during rapid eye movement (REM) sleep. Local brain regions mirrored this global pattern. The frontal lobe showed elevated signal complexity. These changes were not solely due to spectral power differences. The findings suggest that level of consciousness correlates with neural dynamical complexity.
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, 2016
Erik Hoel, Larissa Albantakis, William Marshall et al.
153 citations
Causal interactions in complex systems like the brain can be examined at different spatiotemporal levels. While it is often assumed that the micro level is causally complete, this work shows that causal power can be stronger at macro levels. Using a measure called ΦMax, developed within integrated information theory, the authors systematically evaluated causal power at micro and macro levels in simplified neuronal-like systems. For systems with indeterminism or degeneracy, ΦMax peaked at a macro level when coarse-graining micro elements produced macro mechanisms with high irreducible causal selectivity.
Neuroscience of Consciousness
January 1, 2020
Johnjoe Mcfadden
152 citations
Consciousness represents bound or integrated information, but nearly all examples of so-called 'integrated information'—including neuronal processing and conventional computing—are only temporally integrated, meaning outputs correlate with multiple inputs over time rather than being physically integrated in space. Only energy fields can integrate information spatially. The conscious electromagnetic information (cemi) field theory proposes that consciousness is physically integrated, causally active information encoded in the brain's global electromagnetic field, implementing algorithms in space rather than time. The theory accounts for most observed features of consciousness, has recent experimental support, makes untested predictions, and implies a scientific dualism rooted in the difference between matter and energy.
Neuroscience of Consciousness
January 1, 2021
Lars Sandved-Smith, Casper Hesp, Jérémie Mattout et al.
116 citations
Meta-awareness, the ability to notice the current content of consciousness, is crucial for controlling cognitive states like directing attention. This paper models meta-awareness and attentional control using hierarchical active inference, treating mental actions as policy choices over higher-level cognitive states. A further hierarchical level represents meta-awareness states that modulate the expected confidence in the mapping between observations and hidden cognitive states. Simulations of mind-wandering during a sustained selective attention task illustrate how this inferential architecture enables accessing and controlling cognitive states, offering a computational foundation for a phenomenology of mental action and self-monitoring.
Neuroscience of Consciousness
January 1, 2016
Yair Dor-Ziderman, Yochai Ataria, Stephen Fulder et al.
100 citations
The sense of being a self separate from the world can vary in intensity, is linked to specific brain activity, and can be altered through meditation. A long-term meditation practitioner deliberately produced three mental states with different degrees of self-boundary experience while undergoing magnetoencephalography. The results were partly confirmed in ten other experienced meditators. Right-lateralized beta oscillations in the temporo-parietal junction, which supports the unity of self and body, and in the medial parietal cortex, a key self-representation area, were implicated. The graded, flexible nature of self-specific processes may have clinical relevance for people with disturbed self-boundaries.
Neuroscience of Consciousness
January 1, 2022
Axel Cleeremans, Catherine Tallon-Baudry
97 citations
Consciousness is not a mere byproduct of brain activity but has a function: subjective experience carries intrinsic value that motivates action. The authors propose the 'phenomenal worthiness' hypothesis, arguing that agents act because they experience and care about those experiences. This value-laden quality allows comparison of different experiences in a unified, subject-centered space, explaining why consciousness feels unified. If phenomenal experience has intrinsic value, then consciousness must have a function, making the hard problem of consciousness more tractable by reframing it as a problem about function.
Neuroscience of Consciousness
January 1, 2017
Andrew M. Haun, Giulio Tononi, Christof Koch et al.
97 citations
Some researchers claim that perceptual experience is impoverished—that people perceive and remember very little visual information. However, the evidence indicates that this view is mistaken and that visual phenomenology is actually immensely rich. To accurately assess perceptual content, experiments should go beyond simple binary forced-choice tasks and instead analyze broader reports of experience. Adopting such methods will reveal the genuine richness of experience and its underlying neural basis.
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, 2024
Clara Colombatto, Stephen M Fleming
71 citations
A majority of a sample of 300 US residents were willing to attribute some possibility of phenomenal consciousness—subjective experiences like feelings and sensations—to large language models. These attributions were robust, predicting attributions of mental states typically linked to phenomenality, but also flexible, as they varied with individual differences such as how often participants used the technology. The findings suggest that folk intuitions about AI consciousness can diverge from expert views, with potential implications for the legal and ethical treatment of AI.
Neuroscience of Consciousness
January 1, 2021
Francesco Ellia, Jeremiah Hendren, Matteo Grasso et al.
61 citations
Subjective experience can be objectively explained in physical terms by moving beyond cognitive functions and understanding how experience is structured. Integrated information theory provides a framework to account for both the essential properties of every experience and the specific properties that make particular experiences feel the way they do, avoiding the fallacy that only objective properties should be explained by science.
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
Joachim Bellet, Marion Gay, Abhilash Dwarakanath et al.
57 citations
Neuronal populations in the macaque prefrontal cortex (PFC) reliably encode visual stimuli even under conditions that challenge conscious perception and reduce post-perceptual processing. Recordings from the ventrolateral PFC during isolated trials and rapid serial visual presentation (RSVP) showed that stimulus identity could be decoded from population activity, with first signals at 60 ms and peak information at 150 ms. In RSVP, decoding accuracy dropped to chance by 200 ms as the next stimulus became decodable. Decoding in ventrolateral PFC was stronger than in posterior parietal cortex. The findings indicate PFC encodes visual information under conditions that limit conscious access and post-perceptual elaboration, raising questions about whether this reflects conscious access, phenomenal consciousness, or preconscious bottom-up processing.
Neuroscience of Consciousness
January 1, 2017
Tore Nielsen
57 citations
Sleep onset normally happens quickly and without notice, but in the lab it reveals how waking, perceptually grounded consciousness shifts into the hallucinatory simulations of dreaming. This review focuses on imagery during the sleep-onset transition—especially "microdreams"—as an alternative to studying dreaming in the traditional sleep lab. Preliminary work on microdream phenomenology has helped classify dreaming's core features (the "oneiragogic spectrum"), assess multiple memory inputs ("multi-temporal memory sources"), identify two new imagery types ("autosensory imagery" and "exosensory imagery"), and embed microdreaming in a "multisensory integration approach." These efforts may clarify dream neurophysiology and dreaming's role in memory consolidation, and advance the neuroscience of consciousness.
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
Julian Mutz, Amir-Homayoun Javadi
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
January 1, 2023
Oryan Zacks, Eva Jablonka
45 citations
The Global Neuronal Workspace theory, which links consciousness to cognitive functions like perception and memory, aligns with the Unlimited Associative Learning theory that describes minimal consciousness. However, applying these models to basal vertebrates requires significant adjustments based on brain evolution. Comparative evidence indicates that in these vertebrates, the workspace is implemented by the event memory system in the hippocampal homolog. This offers testable predictions about hippocampal and cortical roles, the evolutionary link between memory and consciousness, and the development of unified perception.
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
George Deane
38 citations
A predictive processing account of consciousness is proposed, grounded in active inference, which holds that phenomenal consciousness arises from 'subjective valuation'—a deep inference about the precision of self-evidencing outcomes of action. The account aims to inform the attribution of consciousness to non-human systems via their deep self-models and sensory attenuation mechanisms. An objection from psychedelic-induced ego-dissolution states is considered; such states do not undermine the theory but instead corroborate subjective valuation as constitutive of experience, highlighting psychedelic research's potential for consciousness science and computational psychiatry.
Neuroscience of Consciousness
January 1, 2020
William Wong, Valdas Noreika, Levente Móró et al.
35 citations
In a test of whether brain activity alone can reveal when someone is dreaming, researchers used an unsupervised machine learning classifier to distinguish dreamful from dreamless sleep based on EEG spectral power and electrode location. Nine participants contributed 54 one-minute polysomnograms from non-rapid eye movement sleep—27 with dreams and 27 without. A blinded Analysis Team attempted to classify each recording over five iterations with gradually reduced blindness. At no stage did the classifier perform significantly better than chance, indicating that EEG spectral power features could not reliably detect signatures of phenomenal consciousness in this dataset.
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.