Nonequilibrium brain dynamics as a signature of consciousness
Yonatan Sanz Perl, Hernan Bocaccio, Carla Pallavicini, Ignacio Perez-Ipina, Steven Laureys, Helmut Laufs, Morten L. Kringelbach, Gustavo Deco, Enzo Tagliazucchi
Physical review. E July 28, 2021 DOI: 10.1103/physreve.104.014411 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Nonhuman primates and humans |
| Topics | Ketamine |
| Keywords | Unconsciousness Wakefulness Electrocorticography Cognition Electroencephalography Statistical physics Quantum mechanics |
| Citations | 82 |
| Key findings | All states of reduced consciousness unfolded at higher proximity to equilibrium compared to conscious wakefulness, as demonstrated by entropy production and the curl of probability flux. |
Abstract
The cognitive functions of human and nonhuman 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 equilibrium. We confirmed this hypothesis by investigating electrocorticography data from nonhuman primates undergoing different states of unconsciousness (sleep, and anesthesia with propofol, ketamine, and ketamine plus medetomidine), and functional 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 compared to conscious wakefulness, as demonstrated by the computation of entropy production and the curl of probability flux in phase space. Our results establish nonequilibrium macroscopic brain dynamics as a robust signature of consciousness, opening the way for the characterization of cognition and awareness using tools from statistical mechanics.
Comparable studies
Other preclinical and animal studies on ketamine, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| mTOR-Dependent Synapse Formation Underlies the Rapid Antidepressant Effects of NMDA Antagonists Rats | 2010 | Observational study | |
| Activation of Glutamatergic Neurotransmission by Ketamine: A Novel Step in the Pathway from NMDA Receptor Blockade to Dopaminergic and Cognitive Disruptions Associated with the Prefrontal Cortex Conscious rats | 1997 | Dose-response study with microdialysis and behavioral testing | |
| NMDAR inhibition-independent antidepressant actions of ketamine metabolites Mice | 2016 | Preclinical study | |
| The dissociative anaesthetics, ketamine and phencyclidine, selectively reduce excitation of central mammalian neurones by N‐methyl‐aspartate Spinal neurons in decerebrate or pentobarbitone-anaesthetized cats and rats | 1983 | Experimental study | |
| R-ketamine: a rapid-onset and sustained antidepressant without psychotomimetic side effects Mice | 2015 | Experimental study |
Citations in the library
Cited by 21
- Understanding brain states across spacetime informed by whole-brain modelling Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences May 23, 2022
- The arrow of time of brain signals in cognition: Potential intriguing role of parts of the default mode network Network Neuroscience December 23, 2022
- Different hierarchical reconfigurations in the brain by psilocybin and escitalopram for depression Nature Mental Health August 5, 2024
- The lack of temporal brain dynamics asymmetry as a signature of impaired consciousness states Interface Focus April 14, 2023
- Deep learning the arrow of time in brain activity: characterising brain-environment behavioural interactions in health and disease bioRxiv (Cold Spring Harbor Laboratory) July 4, 2021
and 16 more in the library
Cites 11
- Neural correlates of consciousness: progress and problems Nature Reviews Neuroscience April 20, 2016
- A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior Science Translational Medicine August 14, 2013
- Are There Levels of Consciousness? Trends in Cognitive Sciences April 22, 2016
- Large-scale signatures of unconsciousness are consistent with a departure from critical dynamics Journal of the Royal Society, Interface 2016
- Measures of entropy and complexity in altered states of consciousness Cognitive Neurodynamics October 20, 2017
and 6 more in the library