Criticality of resting-state EEG predicts perturbational complexity and level of consciousness during anesthesia.
Charlotte Maschke, Jordan O'Byrne, Michele Angelo Colombo, Melanie Boly, Olivia Gosseries, Steven Laureys, Mario Rosanova, Karim Jerbi, Stefanie Blain-Moraes
bioRxiv : the preprint server for biology October 31, 2023 preprint DOI: 10.1101/2023.10.26.564247 via PubMed
Summary
AI-generated from the abstractConsciousness may depend on brain activity poised at criticality, a state with optimal computational properties. Electroencephalograms were recorded from healthy, unresponsive volunteers under propofol, xenon, or ketamine anesthesia. Ketamine spared consciousness (vivid dreams), allowing separation of unresponsiveness from unconsciousness. Unconscious states showed a departure from both the edge of activity propagation and the edge of chaos. The perturbational complexity index (PCI), a sensitive consciousness measure, was predicted from these dynamical properties with a mean absolute error below 7%. Results link PCI to criticality and support criticality's role in consciousness.
Study at a glance
| Characteristics | Observational cohort |
|---|---|
| Population | Healthy subjects undergoing general anesthesia |
| Interventions | Propofol Xenon Ketamine |
| Citations | 7 |
| Key finding | Unconsciousness under anesthesia is characterized by a distancing from both the edge of activity propagation and the edge of chaos, and individual PCI values can be predicted from these dynamical properties with a mean absolute error below 7%. |
Abstract
Consciousness has been proposed to be supported by electrophysiological patterns poised at criticality, a dynamical regime which exhibits adaptive computational properties, maximally complex patterns and divergent sensitivity to perturbation. Here, we investigated dynamical properties of the resting-state electroencephalogram of healthy subjects undergoing general anesthesia with propofol, xenon or ketamine. We then studied the relation of these dynamic properties with the perturbational complexity index (PCI), which has shown remarkably high sensitivity in detecting consciousness independent of behavior. All participants were unresponsive under anesthesia, while consciousness was retained only during ketamine anesthesia (in the form of vivid dreams)., enabling an experimental dissociation between unresponsiveness and unconsciousness. We estimated (i) avalanche criticality, (ii) chaoticity, and (iii) criticality-related measures, and found that states of unconsciousness were characterized by a distancing from both the edge of activity propagation and the edge of chaos. We were then able to predict individual subjects' PCI (i.e., PCImax) with a mean absolute error below 7%. Our results establish a firm link between the PCI and criticality and provide further evidence for the role of criticality in the emergence of consciousness.