EEG 40 Hz Coherence Decreases in REM Sleep and Ketamine Model of Psychosis
Santiago Castro-Zaballa, Matías Cavelli, Joaquín González, A. Nardi, Sérgio Machado, Cecilia Scorza, Pablo Torterolo
Frontiers in Psychiatry January 17, 2019 DOI: 10.3389/fpsyt.2018.00766 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental animal study Peer reviewed |
|---|---|
| Sample size | 5 |
| Population | Cats chronically prepared for polysomnographic recordings |
| Intervention | Ketamine |
| Dose | 5, 10, and 15 mg/kg, i.m. |
| Measures | EEG low gamma (30–45 Hz) band power and coherence |
| Topics | Esketamine Ketamine |
| Key findings | Ketamine at sub-anesthetic doses and REM sleep both reduced gamma-band coherence among cortical regions relative to wakefulness and NREM sleep, while gamma power remained relatively high under ketamine, similar to quiet wakefulness and REM sleep. The authors conclude that gamma-frequency functional coupling between cortical areas decreases in both experimental models of psychosis and suggest this uncoupling may contribute to cognitive features shared by dreaming and psychosis. |
Abstract
Cognitive processes are carried out during wakefulness by means of extensive interactions between cortical and subcortical areas. In psychiatric conditions, such as psychosis, these processes are altered. Interestingly, REM sleep where most dreams occurs, shares electrophysiological, pharmacological, and neurochemical features with psychosis. Because of this fact, REM sleep is considered a natural model of psychosis. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that at sub-anesthetic dose induces psychotomimetic-like effects in humans and animals, and is employed as a pharmacological model of psychosis. Oscillations in the gamma frequency band of the electroencephalogram (EEG), mainly at about 40 Hz, have been involved in cognitive functions. Hence, the present study was conducted to analyze the EEG low gamma (30–45 Hz) band power and coherence of the cat, in natural (REM sleep) and pharmacological (sub-anesthetic doses of ketamine) models of psychosis. These results were compared with the gamma activity during alert (AW) and quiet wakefulness (QW), as well as during non-REM (NREM) sleep. Five cats were chronically prepared for polysomnographic recordings, with electrodes in different cortical areas. Basal recordings were obtained and ketamine (5, 10, and 15 mg/kg, i.m.) was administrated. Gamma activity (power and coherence) was analyzed in the abovementioned conditions. Compared to wakefulness and NREM sleep, following ketamine administration gamma coherence decreased among all cortical regions studied; the same coherence profile was observed during REM sleep. On the contrary, gamma power was relatively high under ketamine, and similar to QW and REM sleep. We conclude that functional interactions between cortical areas in the gamma frequency band decrease in both experimental models of psychosis. This uncoupling of gamma frequency activity may be involved in the cognitive features shared by dreaming and psychosis.
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 6
- A hidden Markov model reliably characterizes ketamine-induced spectral dynamics in macaque local field potentials and human electroencephalograms PLoS Computational Biology August 18, 2021
- EEG Gamma Band Alterations and REM-like Traits Underpin the Acute Effect of the Atypical Psychedelic Ibogaine in the Rat. ACS Pharmacology & Translational Science April 9, 2021
- Ketamine and sleep modulate neural complexity dynamics in cats. European Journal of Neuroscience March 1, 2022
- Gamma band alterations and REM-like traits underpin the acute effect of the atypical psychedelic ibogaine bioRxiv (Cold Spring Harbor Laboratory) June 29, 2020
- Cortical high-frequency oscillations (≈ 110 Hz) in cats are state-dependent and enhanced by a subanesthetic dose of ketamine. Behavioural Brain Research January 5, 2025
and 1 more in the library
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and 12 more in the library