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Christof Koch

34 papers in the library · 4,042 citations · publishing 1990-2026

Papers

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Psilocybin collapses visual change detection and drives cortical dynamics toward a state of surprise

bioRxiv (Cold Spring Harbor Laboratory) August 25, 2026 Roberto de Filippo, Ryan Gillis, David G Wyrick et al. preprint

Abstract Psilocybin profoundly alters visual perception, yet the neuronal mechanisms underlying these effects remain unclear. Here we combined large-scale Neuropixels recordings with cell-type-specific optogenetics in head-fixed mice performing a visual change-detection task. Psilocybin severely impaired task performance without overt motor deficits. In cortex, the drug modestly suppressed...

Brain-wide reconfiguration of burst firing by psilocybin reveals 5-HT2A-dependent circuit dynamics

bioRxiv August 19, 2026 D. Momi, Y. Nahas, D. Wyrick et al. preprint

Psilocybin produces rapid and lasting therapeutic effects, yet how 5-HT2A receptor activation reshapes brain-wide circuit dynamics during acute drug administration remains poorly understood. Using simultaneous multi-region Neuropixels recordings of 46,360 single units from 35 mice, together with scalp electroencephalography (EEG), pupillometry, and locomotion monitoring, we provide a...

Pupil-DLC: An open-source deep learning pipeline for scalable, marker-less tracking of pupil dynamics across conscious and unconscious states.

Journal of neuroscience methods July 4, 2026 Parsa Seyfourian, Lydia C. Marks, Leslie D. Claar et al.

Pupil diameter is a non-invasive biomarker of brain state, correlating with arousal, attention, cognitive processing, and consciousness. However, existing pupillometry software often lacks scalability and robustness across diverse experimental conditions and species. We introduce Pupil-DLC, an open-source, offline, DeepLabCut-based pipeline for scalable, marker-less pupil tracking, primarily...

Protocol for testing global neuronal workspace and integrated information theories of consciousness in non-human primates and mice.

PLoS One 2026 Matilda Gibbons, Ethan G McBride, Raghuram Holenarasipura Venkatasubbaiah et al.

Identifying the neural correlates of consciousness (NCC) is widely regarded as imperative to our understanding of consciousness. Although several scientific theories of consciousness make predictions about the NCC, they often differ in their level of detail, making direct comparison through experimental findings difficult. Here, we report an adversarial collaboration protocol in which unbiased...

The void and the brain.

Cell Reports July 22, 2025 Christof Koch 1 citation

Blackburne et al. track the electroencephalogram activity of volunteers inhaling a high dose of the powerful psychedelic 5-methoxy-N,N-dimethyltryptamine, revealing profoundly slowed-down brain activity but no significant reduction of alpha band power that is typical of other psychedelics.1.

Adversarial testing of global neuronal workspace and integrated information theories of consciousness.

Nature June 1, 2025 Oscar Ferrante, Urszula Gorska-Klimowska, Simon Henin et al. 94 citations

Different theories explain how subjective experience arises from brain activity1,2. These theories have independently accrued evidence, but have not been directly compared3. Here we present an open science adversarial collaboration directly juxtaposing integrated information theory (IIT)4,5 and global neuronal workspace theory (GNWT)6-10 via a theory-neutral consortium11-13. The theory...

Dissociating Artificial Intelligence from Artificial Consciousness

arXiv Preprint Archive December 5, 2024 Graham Findlay, William Marshall, Larissa Albantakis et al.

Developments in machine learning and computing power suggest that artificial general intelligence is within reach. This raises the question of artificial consciousness: if a computer were to be functionally equivalent to a human, being able to do all we do, would it experience sights, sounds, and thoughts, as we do when we are conscious? Answering this question in a principled manner can only...

Testing the Conjecture That Quantum Processes Create Conscious Experience.

Entropy (Basel, Switzerland) May 28, 2024 Hartmut Neven, Adam Zalcman, Peter Read et al.

The question of what generates conscious experience has mesmerized thinkers since the dawn of humanity, yet its origins remain a mystery. The topic of consciousness has gained traction in recent years, thanks to the development of large language models that now arguably pass the Turing test, an operational test for intelligence. However, intelligence and consciousness are not related in obvious...

Transition to chaos separates learning regimes and relates to measure of consciousness in recurrent neural networks

bioRxiv Preprint Server May 15, 2024 Dana Mastrovito, Yuhan Helena Liu, Lukasz Kusmierz et al. preprint

Recurrent neural networks exhibit chaotic dynamics when the variance in their connection strengths exceed a critical value. Recent work indicates connection variance also modulates learning strategies; networks learn ”rich” representations when initialized with low coupling and ”lazier”solutions with larger variance. Using Watts-Strogatz networks of varying sparsity, structure, and hidden...

An adversarial collaboration to critically evaluate theories of consciousness

bioRxiv Preprint Server June 23, 2023 Oscar Ferrante, Urszula Gorska-Klimowska, Simon Henin et al. preprint

Different theories explain how subjective experience arises from brain activity1,2. These theories have independently accrued evidence, yet, confirmation bias and dependence on design choices hamper progress in the field3. Here, we present an open science adversarial collaboration which directly juxtaposes Integrated Information Theory (IIT)4,5 and Global Neuronal Workspace Theory (GNWT)6–10,...

Cortico-thalamo-cortical interactions modulate electrically evoked EEG responses in mice

bioRxiv March 28, 2023 Leslie D. Claar, Irene Rembado, Jacqulyn R. Kuyat et al.

Perturbational complexity analysis predicts the presence of consciousness in volunteers and patients by stimulating the brain with brief pulses, recording electroencephalographic (EEG) responses, and computing their spatiotemporal complexity. We examined the underlying neural circuits in mice by directly stimulating cortex while recording with EEG and Neuropixels probes during wakefulness and...

An adversarial collaboration protocol for testing contrasting predictions of global neuronal workspace and integrated information theory

PLoS One February 10, 2023 Lucia Melloni, Liad Mudrik, Michael Pitts et al. 106 citations

The relationship between conscious experience and brain activity has intrigued scientists and philosophers for centuries. In the last decades, several theories have suggested different accounts for these relationships. These theories have developed in parallel, with little to no cross-talk among them. To advance research on consciousness, we established an adversarial collaboration between...

Only what exists can cause: An intrinsic powers view of free will

arXiv Preprint Archive June 4, 2022 Giulio Tononi, Larissa Albantakis, Melanie Boly et al. preprint

This essay addresses the implications of integrated information theory (IIT) for free will. IIT is a theory of what consciousness is and of how its presence and quality can be accounted for in physical terms. According to IIT, the presence of consciousness is accounted for by a maximum of cause-effect power in the brain. Moreover, the way an experience feels is accounted for by how that...

Only what exists can cause: An intrinsic view of free will

arXiv Preprint Archive June 4, 2022 Giulio Tononi, Larissa Albantakis, Melanie Boly et al.

This essay addresses the implications of integrated information theory (IIT) for free will. IIT is a theory of what consciousness is and what it takes to have it. According to IIT, the presence of consciousness is accounted for by a maximum of cause-effect power in the brain. Moreover, the way specific experiences feel is accounted for by how that cause-effect power is structured. If IIT is...

IIT, half masked and half disfigured.

The Behavioral and brain sciences March 23, 2022 Giulio Tononi, Melanie Boly, Matteo Grasso et al.

The target article misrepresents the foundations of integrated information theory (IIT) and ignores many essential publications. It, thus, falls to this lead commentary to outline the axioms and postulates of IIT and correct major misconceptions. The commentary also explains why IIT starts from phenomenology and why it predicts that only select physical substrates can support consciousness....

Perceptual awareness negativity: a physiological correlate of sensory consciousness.

Trends in Cognitive Sciences June 22, 2021 Cole Dembski, Christof Koch, Michael Pitts

Much research on the neural correlates of consciousness (NCC) has focused on two evoked potentials, the P3b and the visual or auditory awareness negativity (VAN, AAN). Surveying a broad range of recent experimental evidence, we find that repeated failures to observe the P3b during conscious perception eliminate it as a putative NCC. Neither the VAN nor the AAN have been dissociated from...

Making the hard problem of consciousness easier

Science May 28, 2021 Lucia Melloni, Liad Mudrik, Michael Pitts et al.

Championing open science, an adversarial collaboration aims to unravel the footprints of consciousness The history of science includes numerous challenging problems, including the “hard problem” (1) of consciousness: Why does an assembly of neurons—no matter how complex, such as the human brain—give rise to perceptions and feelings that are consciously experienced, such as the sweetness of...

Physiological Correlates of Sensory Consciousness: Evidence for a Perceptual Awareness Negativity

March 10, 2021 Cole Dembski, Christof Koch, Michael Pitts preprint

We critically review the recent literature on six EEG and MEG markers of the neural correlates of consciousness (NCC) for visual, auditory and tactile stimuli in neurotypical volunteers and neurological patients. After ruling out four of these as candidate NCC, we focus on two prominent evoked signals – an early, modality-specific negativity, termed the visual or auditory awareness negativity...

Reflections of a Natural Scientist on Panpsychism

Journal of Consciousness Studies 2021 Christof Koch

Panpsychism shares many intuitions with integrated information theory (IIT), in particular that consciousness is an intrinsic fundamental property of reality, is graded, and can be found in small amounts in simple physical systems. Unlike panpsychism, however, IIT clearly articulates which systems are conscious and which ones are not (resolving panpsychism's combination problem) and why...

Conscious machines: Defining questions

Science January 25, 2018 Olivia Carter, Jakob Hohwy, Jeroen J A Van Boxtel et al. 86 citations

In their Review “What is consciousness, and could machines have it?” (27 October 2017, p. [486][1]), S. Dehaene et al. argue that the science of consciousness indicates that we are not on the verge of creating conscious machines. However, Dehaene et al. ask and answer the wrong questions. To

Are the Neural Correlates of Consciousness in the Front or in the Back of the Cerebral Cortex? Clinical and Neuroimaging Evidence

Journal of Neuroscience October 4, 2017 Melanie Boly, Marcello Massimini, Naotsugu Tsuchiya et al. 591 citations

The role of the frontal cortex in consciousness remains a matter of debate. In this Perspective, we will critically review the clinical and neuroimaging evidence for the involvement of the front versus the back of the cortex in specifying conscious contents and discuss promising research avenues. Dual Perspectives Companion Paper: Should a Few Null Findings Falsify Prefrontal Theories of...

Are we underestimating the richness of visual experience?

Neuroscience of Consciousness 2017 Andrew M. Haun, Giulio Tononi, Christof Koch et al. 97 citations

It has been argued that the bandwidth of perceptual experience is low-that the richness of experience is illusory and that the amount of visual information observers can perceive and remember is extremely limited. However, the evidence suggests that this postulated poverty of experiential content is illusory and that visual phenomenology is immensely rich. To properly estimate perceptual...

Neural correlates of consciousness: progress and problems

Nature reviews. Neuroscience April 20, 2016 Christof Koch, Marcello Massimini, Melanie Boly et al. 1,654 citations

There have been a number of advances in the search for the neural correlates of consciousness--the minimum neural mechanisms sufficient for any one specific conscious percept. In this Review, we describe recent findings showing that the anatomical neural correlates of consciousness are primarily localized to a posterior cortical hot zone that includes sensory areas, rather than to a...

Consciousness: here, there and everywhere?

Philosophical Transactions of the Royal Society B: Biological Sciences May 19, 2015 Giulio Tononi, Christof Koch

The science of consciousness has made great strides by focusing on the behavioural and neuronal correlates of experience. However, while such correlates are important for progress to occur, they are not enough if we are to understand even basic facts, for example, why the cerebral cortex gives rise to consciousness but the cerebellum does not, though it has even more neurons and appears to be...