State-Dependent and Bandwidth-Specific Effects of Ketamine and Propofol on Electroencephalographic Complexity in Rats
Michael A. Brito, Duan Li, George A. Mashour, Dinesh Pal
Frontiers in Systems Neuroscience August 11, 2020 DOI: 10.3389/fnsys.2020.00050 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Rat |
| Interventions | Ketamine Propofol |
| Topics | Ketamine Esketamine |
| Keywords | Propofol Anesthesia Electroencephalography |
| Citations | 15 |
| Key findings | Ketamine anesthesia is characterized by reduced cortical complexity in the high gamma frequency range (65–175 Hz), while propofol anesthesia reduces complexity in lower frequencies (0.5–55 Hz). |
Abstract
There is an ongoing debate as to whether ketamine anesthesia suppresses neurophysiologic complexity at doses sufficient for surgical anesthesia, with previous human studies reporting surrogates of both suppressed and preserved levels of cortical complexity. However, these studies have not assessed cortical dynamics in higher gamma frequencies, which have previously been demonstrated to correlate with the level of consciousness during anesthesia. In this study, we used Lempel-Ziv complexity (LZc) to characterize frontal and parietal electroencephalographic complexity (0.5-175 Hz, 0.5-55 Hz, 65-175 Hz) before, during, and after ketamine or propofol anesthesia in the rat. To control for the potential influence of spectral changes in complexity estimation, LZc was normalized with phase-shuffled surrogate data. We demonstrate that ketamine and propofol anesthesia were characterized by a significant reduction in broadband (0.5-175 Hz) LZc. Further analysis showed that while the reduction of LZc during ketamine anesthesia was significant in 65-175 Hz range, during propofol anesthesia, a significant decrease was observed in 0.5-55 Hz bandwidth. LZc in broadband and 0.5-55 Hz range showed a significant increase during emergence from ketamine anesthesia. Phase-shuffled normalized LZc revealed that (1) decrease in complexity during ketamine and propofol anesthesia-not increase in complexity during emergence-were dissociable from the influence of spectral changes, and (2) reduced LZc during ketamine anesthesia was present across all three bandwidths. Ketamine anesthesia was characterized by reduced complexity in high gamma bandwidth, as reflected in both raw and phase-shuffled normalized LZc, which suggests that reduced high gamma complexity is a neurophysiological feature of ketamine anesthesia.
Comparable studies
Other experimental studies on ketamine, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Ketamine activates psychosis and alters limbic blood flow in schizophrenia Schizophrenic individuals | 1995 | Experimental study | |
| The spectral exponent of the resting EEG indexes the presence of consciousness during unresponsiveness induced by propofol, xenon, and ketamine Healthy participants | 2019 | Controlled experimental study | n = 15 |
| Ketamine Increases Human Motor Cortex Excitability to Transcranial Magnetic Stimulation Normal human subjects | 2003 | Experimental study | n = 7 |
| Evidence that Subanesthetic Doses of Ketamine Cause Sustained Disruptions of NMDA and AMPA-Mediated Frontoparietal Connectivity in Humans Human participants | 2015 | Experimental study | |
| Simultaneous population pharmacokinetic modelling of ketamine and three major metabolites in patients with treatment‐resistant bipolar depression Patients with treatment-resistant bipolar depression | 2012 | Population pharmacokinetic analysis | n = 9 |
Citations in the library
Cited by 7
- Consciousness is supported by near-critical slow cortical electrodynamics. Proceedings of the National Academy of Sciences February 1, 2022
- Dynamic reconfiguration of frequency-specific cortical coactivation patterns during psychedelic and anesthetized states induced by ketamine Neuroimage January 7, 2022
- Consciousness is supported by near-critical cortical electrodynamics bioRxiv June 11, 2021
- Differential Effects of Propofol and Ketamine on Critical Brain Dynamics bioRxiv Preprint Server March 27, 2020
- High-frequency oscillations in the mammalian brain after ketamine and other NMDA receptor antagonists. Journal of Psychopharmacology July 24, 2025
and 2 more in the library
Cites 17
- An information integration theory of consciousness BMC Neuroscience November 2, 2004
- A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior Science Translational Medicine August 14, 2013
- Are the Neural Correlates of Consciousness in the Front or in the Back of the Cerebral Cortex? Clinical and Neuroimaging Evidence Journal of Neuroscience October 4, 2017
- Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin Scientific Reports April 19, 2017
- Enhanced repertoire of brain dynamical states during the psychedelic experience Human Brain Mapping July 3, 2014
and 12 more in the library