PLoS ONE
May 13, 2015
Melanie Boly, Shuntaro Sasai, Olivia Gosseries et al.
69 citations
A meaningful sequence of stimuli, like movie frames, triggers varied experiences, while meaningless stimuli, like TV noise, produce a uniform experience despite physical differences. The differentiation of cortical responses, measured by Lempel-Ziv complexity of functional MRI images, reflects the overall meaningfulness of a stimulus set rather than differences among stimuli. Brain activity patterns showed highest differentiation during a movie, intermediate for a temporally scrambled movie, and minimal for spatially scrambled TV noise, even though overall cortical activation was strong and widespread in all conditions. Meaningfulness also correlated with higher information integration among cortical regions. This approach can assess stimulus meaningfulness without identifying relevant features or neural locations.
Philosophy and the Mind Sciences
December 23, 2025
Tadahiro Taniguchi, Masafumi Oizumi, Noburo Saji et al.
1 citation
Language emergence and the relational structure of subjective experiences, termed qualia structure, may influence each other bidirectionally. The emergence of languages with distributional semantics, such as syntactic-semantic structures, is hypothesized to link to the coordination of internal representations shaped by experience, potentially facilitating more structured language through reciprocal influence. This mutual dependency is explored through theoretical frameworks like collective predictive coding. Computational studies show that neural network-based language models form systematically structured internal representations, and multimodal language models can share representations between language and perceptual information. Language emergence may serve not only as a communication tool but also as a mechanism for shared understanding of qualitative experiences. The paper outlines future constructive research directions in consciousness studies, linguistics, and cognitive science.
Neuroscience of consciousness
January 1, 2025
Elise G Rowe, Ken Takeda, Masafumi Oizumi et al.
Top-down attention affects not just whether we see something, but how we see it—the quality of conscious experience, or qualia. Using a dual-task paradigm, participants rated similarity of stimulus pairs in the periphery for rotated letters, bisected disks, and greyscale faces. Similarity ratings served as a proxy for qualia structures, analyzed with dimension reduction and optimal transport alignment. Attention withdrawal collapsed qualia structures for letters and disks, but alignment accuracy remained high for face qualia structures under both full and poor attention. This relational judgment approach extends previous binary categorization methods and offers a novel way to study qualia structures.
bioRxiv Preprint Server
July 12, 2021
Jun Kitazono, Yuma Aoki, Masafumi Oizumi
preprint
A method for hierarchically decomposing a brain network into cores based on the strength of bidirectional connections helps identify regions likely essential for consciousness. Applied to a whole-brain mouse connectome, cores with strong bidirectional connections included the isocortex, thalamus, and claustrum—areas thought to support consciousness—and excluded the cerebellum, which is not considered relevant. Simpler methods that ignore bidirectionality failed to show this correspondence. The findings suggest that analyzing bidirectional connectivity offers a novel way to relate brain network structure to consciousness.
PLoS Comput. Biol.
May 1, 2014
Masafumi Oizumi, L. Albantakis, G. Tononi
Integrated Information Theory (IIT) 3.0 proposes that consciousness is identical to a maximally irreducible conceptual structure (MICS) generated by a physical system. Starting from phenomenological axioms—information (each experience is specific), integration (each experience is unified), and exclusion (each experience has unique borders and grain)—IIT formalizes postulates for how mechanisms like neurons must be configured to produce experience. The theory defines intrinsic information as differences that make a difference within a system and integrated information as information of a whole irreducible to its parts. A MICS specifies the quality of an experience, and integrated information (ΦMax) its quantity. The theory entails that consciousness is always about the system itself, that inactive elements can generate experience, and that feed-forward systems can be unconscious zombies functionally equivalent to conscious complexes.
Naotsugu Tsuchiya, Masafumi Oizumi, Makiko Yamada et al.
preprint
The mystery of consciousness—how subjective experience arises from physical and chemical brain processes—is one of modern science's greatest challenges. Approaches that define humans and animals solely by observable behavior cannot scientifically address the conscious experiences of patients with hallucinations or delusions, nor those of non-verbal patients, infants, or animals. Recently, researchers confronting consciousness directly have advanced empirical studies of the brain-consciousness relationship. This article reviews several promising frameworks for consciousness research and introduces the authors' own strategy: clarifying the structure of conscious experience, the structure of information generated by the brain, and the relationships between these structures. The mathematical tool of category theory is briefly introduced as a means to achieve this, along with future prospects.