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.
Proceedings of the National Academy of Sciences of the United States of America
March 18, 2025
Yusuke Moriguchi, Ryoichi Watanabe, Chifumi Sakata et al.
13 citations
Color qualia—the subjective experience of color, such as the quality of redness—are similar across age and culture. Using a task that obtained pairwise similarity judgments via intuitive visual interfaces, researchers tested children aged 3 to 12 in Japan and 6 to 8 in China, comparing them with Japanese adults. About half of 3-year-olds completed the touch-panel task reliably. Despite developmental and cultural differences in color-term usage, color qualia structures were quite similar across all groups. This suggests that these structures emerge early in life. Subtle age-related differences in evaluations of some color pairs imply minor changes in color experience with development.
Advances in Consciousness Research
June 17, 2015
Jeroen J.a. Van Boxtel, Naotsugu Tsuchiya
11 citations
A chapter examines confounds that must be controlled when studying the neural basis of phenomenal conscious perception. It reviews psychological and neural studies that dissociate attention, report, and memory from phenomenal consciousness, discussing phenomena such as aftereffects, change blindness, inattentional blindness, and brain-imaging results whose implications for consciousness theory may be contaminated by these factors. The chapter also considers whether report and memory are necessary or sufficient for phenomenal consciousness.
Nature communications
August 13, 2025
William Wong, Rubén Herzog, Kátia Cristine Andrade et al.
10 citations
A new open database, the DREAM database, combines standardized sleep magneto/electroencephalography (M/EEG) recordings with dream reports from 505 participants across 20 datasets, totaling 2,643 awakenings. Each awakening includes at least 20 seconds of high-resolution sleep EEG (≥100 Hz, ≥2 electrodes) and a classification of the sleeper's reported experience. Analyses showed that reports of conscious experiences during sleep can be predicted from objective EEG features in both REM and NREM sleep. The database aims to overcome limitations of small sample sizes and methodological variability in dream research, enabling larger-scale investigations of the neurocognitive basis of dreaming.
Frontiers in psychology
January 1, 2024
Naotsugu Tsuchiya, Peter Bruza, Makiko Yamada et al.
8 citations
A new hypothesis called Quantum-like Qualia (QQ) proposes that qualia—the qualities of conscious experience—are best described by the mathematical structure of quantum theory, rather than as points in a dimensional space. The standard view assumes qualia can be measured without changing them, but empirical findings show that internal attention can alter qualia during measurement. QQ treats qualia as observables, sensory inputs and internal attention as states, and measurement outcomes as probabilistic. This structure predicts that qualia can be indeterminate, which can be tested through order effects or violations of Bell inequalities. Confirmation would suggest that quantum mathematics offers novel insights into consciousness.
Frontiers in psychology
January 1, 2023
Marius Usher, Niccolò Negro, Hilla Jacobson et al.
7 citations
The Unfolding Argument (UA) against causal structure theories of consciousness relies on unwarranted assumptions that express a behaviorist methodology, despite its proponents' claims. The same reasoning can be applied to functionalist approaches, proving too much and deeming a wide range of non-causal structure theories unscientific. The authors argue that the UA's philosophical assumptions are overly restrictive and fit poorly with common practice in cognitive neuroscience. They propose a more inclusive methodology for consciousness science that incorporates neural, behavioral, and phenomenological evidence from the first-person perspective. Theories of consciousness should be tested and evaluated on humans, not on systems considerably different from us, thus restricting the range of systems rather than the methodology.
Entropy (Basel, Switzerland)
May 29, 2026
Zoe Lee-Youngzie, Naotsugu Tsuchiya, Michael Robinson et al.
4 citations
A structural approach to consciousness models qualia—the qualities of experience—by examining either the internal organization of parts within an experience or the external relations between experiences. Integrating these two perspectives is a key step toward understanding phenomenally unified global experience. This paper describes both types of structural models and their category-theoretic formalizations, then proposes a sheaf-theoretic framework that maps mereological parts of experience to empirical measures of their qualia. Applying the framework to visual space demonstrates a formal description of experience's structure and conditions for phenomenal unity. The approach supports an empirical research program linking local and global phenomenal qualities.
PLoS biology
July 1, 2025
Angus Leung, Ahmed Mahmoud, Travis Jeans et al.
3 citations
Only 47 out of over 7,700 time-series features reliably distinguished wakefulness from anesthesia or sleep across all evaluation groups of flies. Most of these features were related to autocorrelation, indicating that signals during wakefulness remained correlated to their past for longer than during anesthesia or sleep. Features related to complexity or spectral power, often proposed as consciousness markers, failed to generalize across all datasets, though many showed consistent direction of effect. These results caution that many newly discovered potential consciousness markers may not generalize across datasets, and point to autocorrelation as a class of dynamical properties that does.
Neuroscience of consciousness
January 1, 2025
Francesco Ellia, Naotsugu Tsuchiya
2 citations
A commentary argues that recent computational functionalist theories of consciousness, while making a welcome structural turn, largely echo predictions already made by Integrated Information Theory. The authors question whether key claims—about subjective experience, local lateral connectivity in sensory areas, and the role of silent units—are coherent within the functionalist paradigm. They emphasize the need to distinguish genuine predictions from post-hoc accommodations in consciousness science.
bioRxiv Preprint Server
October 1, 2025
Kallum Robinson, Ariel Zeleznikow-Johnston, Jiahao Wu et al.
1 citation
preprint
The qualitative aspects of consciousness (qualia) are difficult to study because they are subjective. This work takes a first step toward linking the structure of qualia to brain activity by comparing human dissimilarity ratings of visual motion experiences with neural population responses in mouse primary visual cortex. Human participants (N=171) rated dissimilarity of 48 visual motion stimuli. Mouse neural activity (n=751 neurons) was recorded from nine mice using optical imaging. Both human and mouse data showed structural commonalities: a categorical organization of stimulus direction best explained both structures. These commonalities were similar in awake and anaesthetized mice, suggesting coarse V1 geometry is relatively insensitive to this anesthesia. The authors note that future work combining behavior with causal intervention is needed to relate such neural structures to conscious experience.
November 6, 2024
Zoe Lee-Youngzie, Naotsugu Tsuchiya, Martin M. Monti et al.
preprint
Qualia—the subjective qualities of experience—can be modeled either by analyzing the internal organization of parts within a single experience or by examining relations between different experiences. A key challenge is combining these two perspectives into a unified account of global conscious experience. This paper describes both types of structural models and their category-theoretic formalizations, then proposes a sheaf-theoretic framework that links mereological parts of experience to empirical measures of their qualia. An application to visual space demonstrates how this framework formally describes the structure of experience and conditions for phenomenal unity. The approach supports empirical research on the relationship between local and global phenomenal qualities and outlines future work toward a structural characterization of global phenomenal consciousness.
arXiv Preprint Archive
December 13, 2024
Steven Phillips, Naotsugu Tsuchiya
Conscious experience has five essential properties—intrinsicality, information, integration, exclusion, and composition—as proposed by Integrated Information Theory (IIT), but the necessity of these axioms is unclear due to their informal presentation and dependence on a specific mathematical model. A category-theoretic approach, a meta-mathematical framework for making relations between formal structures precise, organizes these five properties around a smaller number of meta-mathematical principles. Category theory characterizes structures by universal mapping properties, a unique-existence condition for all instances. This suggests that the axioms for consciousness correspond to universal mapping properties, leading to the idea that consciousness is a universal property.
bioRxiv Preprint Server
August 7, 2019
Matthew J Davidson, Irene Graafsma, Naotsugu Tsuchiya et al.
preprint
Perceptual filling-in (PFI) makes a visible target disappear from awareness while the background fills its location. In this experiment, participants viewed four peripheral targets on a background updating at 20 Hz. Brain activity tracked via steady-state visually evoked potentials (SSVEPs) showed that background signals closely matched participants' reports of target disappearances. More filled-in targets led to longer disappearances, suggesting interactions between targets in different visual quadrants. Distinct neural responses appeared at different harmonics: the second harmonic (40 Hz) increased before the first (20 Hz) prior to genuine PFI, possibly reflecting attention. No such difference occurred for physically removed stimuli. The results demonstrate PFI as a tool for studying multi-object perceptual suppression and the neural correlates of consciousness.
bioRxiv Preprint Server
May 27, 2019
William Wong, Valdas Noreika, Levente Móró et al.
preprint
A test called the Dream Catcher test was conducted for the first time in a simplified form to see if brain activity alone can reveal whether someone is dreaming. Data Team collected brain measurements (polysomnograms) during NREM sleep from 9 participants, producing 54 one-minute recordings—27 from dreamful sleep and 27 from dreamless sleep. A blinded Analysis Team tried to classify each recording as dreamful or dreamless using an unsupervised machine learning classifier based on EEG spectral power and electrode location. Over five iterations with gradually reduced blindness, the team never performed significantly better than chance. The results suggest that EEG spectral power does not carry signatures of phenomenal consciousness, and the study also failed to replicate key findings from earlier reports on dreaming consciousness.