Consciousness is supported by near-critical slow cortical electrodynamics.
Daniel Toker, Ioannis Pappas, Janna D. Lendner, Joel Frohlich, Diego M. Mateos, Suresh Muthukumaraswamy, Robin Carhart-Harris, Michelle Paff, Paul M. Vespa, Martin M. Monti, Friedrich T. Sommer, Robert T. Knight, Mark D’Esposito
Proc Natl Acad Sci U S A February 1, 2022 DOI: 10.1073/pnas.2024455119 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Population | Humans and macaques |
| Keywords | Consciousness Awareness Sentience Perception Cognition Neural activity Brain rhythms Electrical brain activity Cortical activity Brain dynamics Neural oscillations Neural criticality Brain criticality Near-criticality Critical brain states |
| Citations | 148 |
| Key findings | Conscious states are characterized by low-frequency cortical oscillations operating near the edge-of-chaos critical point, while unconscious states involve a shift away from this point. |
Abstract
Mounting evidence suggests that during conscious states, the electrodynamics of the cortex are poised near a critical point or phase transition and that this near-critical behavior supports the vast flow of information through cortical networks during conscious states. Here, we empirically identify a mathematically specific critical point near which waking cortical oscillatory dynamics operate, which is known as the edge-of-chaos critical point, or the boundary between stability and chaos. We do so by applying the recently developed modified 0-1 chaos test to electrocorticography (ECoG) and magnetoencephalography (MEG) recordings from the cortices of humans and macaques across normal waking, generalized seizure, anesthesia, and psychedelic states. Our evidence suggests that cortical information processing is disrupted during unconscious states because of a transition of low-frequency cortical electric oscillations away from this critical point; conversely, we show that psychedelics may increase the information richness of cortical activity by tuning low-frequency cortical oscillations closer to this critical point. Finally, we analyze clinical electroencephalography (EEG) recordings from patients with disorders of consciousness (DOC) and show that assessing the proximity of slow cortical oscillatory electrodynamics to the edge-of-chaos critical point may be useful as an index of consciousness in the clinical setting.