Non-equilibrium brain dynamics as a signature of consciousness
Yonatan Sanz Perl, Hernan Bocaccio, Ignacio Perez-Ipina, Steven Laureys, Helmut Laufs, Morten Kringelbach, Gustavo Deco, Enzo Tagliazucchi
arXiv Preprint Archive December 19, 2020 via arXiv
Summary
AI-generated from the abstractConsciousness depends on brain activity that is far from thermodynamic equilibrium. Analyzing electrocorticography data from non-human primates during sleep and various anesthetics, and fMRI data from humans during deep sleep and propofol anesthesia, all states of reduced consciousness showed dynamics closer to equilibrium than conscious wakefulness. This was measured by entropy production and the curl of probability flux in phase space. Non-equilibrium macroscopic brain dynamics therefore serve as a robust signature of consciousness, offering a statistical mechanics approach to studying cognition and awareness.
Study at a glance
| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Non-human primates and humans |
| Interventions | propofol ketamine ketamine plus medetomidine |
| Keywords | Q-bio.nc Consciousness Neuroscience Brain-states Sleep-research |
| Key finding | All states of reduced consciousness (sleep and anesthesia) unfold at higher proximity to equilibrium dynamics than conscious wakefulness, establishing non-equilibrium brain dynamics as a signature of consciousness. |
Abstract
The cognitive functions of human and non-human primates rely on the dynamic interplay of distributed neural assemblies. As such, it seems unlikely that cognition can be supported by macroscopic brain dynamics at the proximity of thermodynamic equilibrium. We confirmed this hypothesis by investigating electrocorticography data from non human primates undergoing different states of unconsciousness (sleep, and anesthesia with propofol, ketamine, and ketamine plus medetomidine), and funcional magnetic resonance imaging data from humans, both during deep sleep and under propofol anesthesia. Systematically, all states of reduced consciousness unfolded at higher proximity to equilibrium dynamics than conscious wakefulness, as demonstrated by entropy production and the curl of probability flux in phase space. Our results establish non-equilibrium macroscopic brain dynamics as a robust signature of consciousness, opening the way for the characterization of cognition and awareness using tools from statistical mechanics.