Science Advances
February 1, 2019
Athena Demertzi, Enzo Tagliazucchi, Stanislas Dehaene et al.
545 citations
Consciousness depends on the brain's ability to sustain rich, dynamic patterns of signal coordination. Using functional magnetic resonance imaging, a complex pattern of coordinated and anticoordinated signals characterized healthy individuals and minimally conscious patients. Unresponsive patients showed low interareal phase coherence mainly mediated by structural connectivity, with fewer transitions between patterns. This complex pattern was also seen in patients with covert cognition who could perform mental imagery tasks, validating its link to consciousness. Anesthesia increased the probability of the less complex pattern to levels seen in unresponsive patients, confirming its role in unconsciousness. These results establish generalizable fingerprints of conscious and unconscious states after brain damage.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
September 19, 2018
Lionel Naccache
138 citations
A popular philosophical distinction holds that conscious experience is far richer than what we can report, calling the reportable part 'access consciousness' and the remainder 'phenomenal consciousness'. This article reviews five major problems with that view and argues that a strict access-consciousness theory, framed within the global workspace model, can account for all conscious experience. Subjective reports are not passive broadcasts but result from dynamic internal processes including interpretation and belief attribution. The article offers testable predictions and counterintuitive hypotheses, suggesting that phenomenal consciousness beyond access may be unnecessary.
Communications Biology
June 29, 2022
Anira Escrichs, Yonatan Sanz Perl, Carme Uribe et al.
67 citations
Different brain states—resting, meditating, deep sleep, and disorders of consciousness after coma—are underpinned by distinct spatiotemporal dynamics that can be characterized using turbulence theory. Non-conscious states tend to be more synchronous, while conscious states are more asynchronous, but the work goes beyond this simple dichotomy. A model-free analysis of human neuroimaging data applied Kuramoto's turbulence framework with coupled oscillators and measured information cascades across spatial scales. A complementary model-based approach used exhaustive computer simulations of whole-brain models fitted to those measures to study information encoding. The framework shows that turbulence theory provides excellent tools for describing and differentiating between brain states.
Progress in brain research
January 1, 2005
Lionel Naccache
13 citations
Recent advances in understanding the brain's role in consciousness come from studying both brain-damaged patients and healthy people. Certain neuropsychological syndromes, like blindsight, visual form agnosia, and neglect, reveal dissociations that point to principles of how consciousness works in the brain. These principles are tested in healthy subjects using experimental psychology and brain imaging. This chapter reviews findings on visual phenomenal consciousness, highlighting four general principles demonstrated through conditions like visual illusions and subliminal perception. It also outlines a scientific model of consciousness based on a 'global workspace' that integrates the reviewed data.
PNAS nexus
December 1, 2024
Emilia Fló, Laouen Belloli, Álvaro Cabana et al.
10 citations
Directing attention toward the body's internal signals (interoception) versus external sounds (exteroception) produces distinct brain activity patterns. Exteroceptive attention flattened overall brain wave power, while interoceptive attention reduced brain signal complexity, increased frontal connectivity and theta oscillations, and modulated the heartbeat-evoked potential (HEP). Classifiers using HEP features correctly identified the attentional state in 17 of 20 healthy participants; power spectral density features classified all 20. In five brain-injured patients, one with unresponsive wakefulness syndrome and one with locked-in syndrome showed willful modulation of the HEP, suggesting they could follow commands. These findings highlight how attention shapes sensory processing and may aid diagnosis in disorders of consciousness.
Proceedings of the National Academy of Sciences of the United States of America
December 30, 2025
Esteban Munoz-Musat, Arthur Le Coz, Andrew W Corcoran et al.
5 citations
Mind blanking—a state of apparent mental emptiness—produces distinct brain signatures that separate it from mind wandering and focused attention. In 62 participants performing a sustained attention task, mind blanking was associated with behavioral lapses, reduced fast brain oscillations and complexity over posterior electrodes, and decreased long-range connectivity compared to both mind wandering and on-task states. Event-related potentials showed disrupted visual processing beginning 200 milliseconds after a stimulus, suggesting a breakdown in conscious access to sensory information. Brain activity patterns predicted mental states on individual trials, revealing dynamics that subjective reports alone miss. These findings indicate that being awake does not guarantee consciousness of something; mind blanking reflects genuine gaps in the stream of thought, arising from disruptions in generating or accessing thought content.
Scientific reports
July 9, 2025
Aude Sangare, Cécile Eymond, Lise Jodaitis et al.
1 citation
Pupil size is influenced not only by light but also by mental factors like perceived brightness. In healthy people, seeing images that semantically imply brightness (e.g., the sun) causes greater pupil constriction than looking at control images of similar luminance. This study tested whether this effect could detect residual cognition in non-communicating patients with disorders of consciousness. In ten healthy participants and seventeen patients (ten minimally conscious, six in vegetative state/unresponsive wakefulness syndrome, one emerging from minimally conscious state), pupillary responses were measured while viewing photographs of the sun versus matched-luminance controls (moon photos, scrambled sun images, gray squares).
PNAS nexus
March 1, 2026
Lina Jeantin, Pierre Bourdillon, Marc Guenot et al.
Signal complexity in intracranial electroencephalography (iEEG) recordings from healthy brain tissue decreases with reduced consciousness, being highest during wakefulness and REM sleep and lowest under propofol anesthesia. Complexity is more variable during N2 and N3 sleep stages, and frontoparietal regions show the highest complexity during conscious states. Epileptic cortex exhibits lower complexity than healthy cortex during wake and REM sleep. A random forest classifier reliably classified sleep stages using complexity markers. These normative data support using iEEG signal complexity as a marker of physiological consciousness, cortical integrity, and sleep-stage detection.
PloS one
January 1, 2026
Matilda Gibbons, Ethan G McBride, Raghuram Holenarasipura Venkatasubbaiah et al.
An adversarial collaboration will test competing predictions from Global Neuronal Workspace Theory and Integrated Information Theory about the neural correlates of consciousness. Non-human primates and mice will perform a go-nogo task with supra-threshold visual and auditory stimuli while neural activity is recorded from multiple cortical areas using Neuropixels electrodes. To causally test timing and location predictions, prefrontal cortex activity will be manipulated via electrical stimulation in primates or optogenetic silencing in mice. The protocol details experimental design, analyses, divergent predictions, and anticipated outcomes.
Journal of Consciousness Studies
November 20, 2021
Lionel Naccache
The author agrees with Solms that consciousness is rooted in the brainstem's affective systems, but diverges from Solms' view that the cortex is merely a cognitive elaboration of these affects. The author proposes integrating Solms' key concepts—such as the role of the brainstem's ascending reticular activating system and the distinction between affective and cognitive consciousness—into the global neuronal workspace theory (GNWT). This integration would allow GNWT to account for both the felt, affective dimension of consciousness and the informational, cognitive processes that GNWT traditionally emphasizes.
Scientific reports
October 4, 2018
Marion Quirins, Clémence Marois, Melanie Valente et al.
Pupil dilation is a reliable marker of conscious mental effort. In healthy volunteers, consciously detected violations of global auditory patterns triggered pupil dilation, whether participants actively counted or passively listened. This effect appeared at both group and individual levels. Unreported violations of global patterns, and local violations that do not require conscious awareness, produced no pupil dilation. The results were replicated with phonemes. Pupil dilation appears to be a somatic marker of conscious access in the auditory modality, offering a way to probe conscious processing without interrupting a person's stream of thought.