Brain
March 6, 2021
Joel Frohlich, Daniel Toker, Martin M. Monti
204 citations
High amplitude delta waves (1–4 Hz) in EEG have long been considered a marker of unconsciousness, observed during deep sleep, anesthesia, seizures, and disorders of consciousness. However, recent studies report prominent delta activity during conscious states, including Angelman syndrome, epilepsy, propofol anesthesia with behavioral responsiveness, postoperative delirium, dreaming, and psychedelic states. Older clinical reports also describe awake, conscious patients with high amplitude delta in Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and non-convulsive status epilepticus.
Proc Natl Acad Sci U S A
February 1, 2022
Daniel Toker, Ioannis Pappas, Janna D. Lendner et al.
148 citations
During conscious states, the cortex operates near a mathematically specific critical point called the edge-of-chaos, the boundary between stability and chaos. Applying a modified 0-1 chaos test to ECoG and MEG recordings from humans and macaques, evidence suggests that unconscious states—such as generalized seizure and anesthesia—involve a shift of low-frequency cortical oscillations away from this critical point, disrupting information processing. Psychedelic states tune these oscillations closer to the critical point, potentially increasing information richness. Analysis of clinical EEG from patients with disorders of consciousness indicates that measuring proximity to this critical point may serve as a clinical index of consciousness.
bioRxiv Preprint Server
February 22, 2023
Daniel Toker, Eli Müller, Hiroyuki Miyamoto et al.
3 citations
preprint
Consciousness depends on bidirectional communication between the cortex and thalamus. A specific pattern of cross-frequency communication—low-frequency waves (1.5–13 Hz) from one region encoded as high gamma waves (50–100 Hz) in the other—is present during conscious states in humans, mice, and rats. This communication diminishes during propofol-induced anesthesia and generalized spike-and-wave seizures, but is enhanced by the psychedelic 5-MeO-DMT. Numerical simulations and neural recordings show that these changes are mediated by shifts in thalamocortical dynamics toward or away from edge-of-chaos criticality, the phase transition between stability and chaos. The findings offer a mathematically defined framework linking thalamic-cortical communication to consciousness.
bioRxiv
June 11, 2021
Daniel Toker, Ioannis Pappas, Janna D. Lendner et al.
3 citations
preprint
During conscious states, the cortex's electrical activity operates near the edge-of-chaos critical point—the boundary between stability and chaos. Applying a new chaos test to ECoG and MEG recordings from humans and macaques across waking, seizure, anesthesia, and psychedelic states shows that unconsciousness shifts cortical dynamics away from this critical point, disrupting information processing. Psychedelics may enhance information-richness by tuning activity closer to this point. Analysis of EEG from patients with disorders of consciousness suggests that measuring proximity to the edge-of-chaos critical point could serve as a clinical biomarker of consciousness.
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.
bioRxiv Preprint Server
July 10, 2019
Joel Frohlich, Lynne M. Bird, John Dell’italia et al.
preprint
Children with Angelman syndrome, who are fully conscious, have brainwave patterns that look like those seen during unconsciousness, challenging theories that link consciousness to complex neural activity. However, when comparing wakefulness to sleep, the brainwaves of 35 children with Angelman syndrome show greater complexity during wakefulness, even when accounting for slow-wave activity. This supports the idea that consciousness is tied to neural complexity and warns against assuming a lack of consciousness based solely on EEG readings.