Cortical dynamics during psychedelic and anesthetized states induced by ketamine
Neuroimage April 5, 2019 DOI: 10.1016/j.neuroimage.2019.03.076 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Healthy volunteers |
| Intervention | Ketamine |
| Dose | subanesthetic and anesthetic doses |
| Topics | Ketamine Esketamine |
| Keywords | Anesthetic Electroencephalography Consciousness Anesthesia |
| Citations | 103 |
| Key findings | Subanesthetic ketamine elevates spatiotemporal complexity relative to baseline, while anesthetic ketamine produces alternating low and high complexity levels that eventually stabilize at baseline-like high complexity. |
Abstract
Ketamine is a unique drug that has psychedelic and anesthetic properties in a dose-dependent manner. Recent studies have shown that ketamine anesthesia appears to maintain the spatiotemporal complexity of cortical activation evoked by transcranial magnetic stimulation, while a psychedelic dose of ketamine is associated with increased spontaneous magnetoencephalographic signal diversity. However, a systematic investigation of the dose-dependent effects of ketamine on cortical complexity using the same modality is required. Furthermore, it is unknown whether the complexity level stabilizes or fluctuates over time for the duration of ketamine exposure. Here we investigated the spatiotemporal complexity of spontaneous high-density scalp electroencephalography (EEG) signals in healthy volunteers during alterations of consciousness induced by both subanesthetic and anesthetic doses of ketamine. Given the fast transient spectral dynamics, especially during the gamma-burst pattern after loss of consciousness, we employed a method based on Hidden Markov modeling to classify the EEG signals into a discrete set of brain states that correlated with different behavioral states. We characterized the spatiotemporal complexity specific for each brain state as measured through the Lempel-Ziv complexity algorithm. After controlling for signal diversity due to spectral changes, we found that the subanesthetic dose of ketamine is associated with an elevated complexity level relative to baseline, while the brain activity following an anesthetic dose of ketamine is characterized by alternating low and high complexity levels until stabilizing at a high level comparable to that during baseline. Thus, spatiotemporal complexity associated with ketamine-induced state transitions has features of general anesthesia, normal consciousness, and altered states of consciousness. These results improve our understanding of the complex pharmacological, neurophysiological, and phenomenological properties of ketamine.
Comparable studies
Other observational and cohort studies on ketamine, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Taming the Ketamine Tiger Volunteers from a prison population | 2010 | Observational study | n = 20 |
| Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin Humans | 2017 | Observational study | |
| Disruption of Frontal–Parietal Communication by Ketamine, Propofol, and Sevoflurane Surgical patients undergoing induction of anesthesia with intravenous ketamine | 2013 | Observational cohort | n = 30 |
| Do the dissociative side effects of ketamine mediate its antidepressant effects? Treatment-resistant inpatients with major depressive disorder or bipolar disorder | 2014 | Observational cohort | n = 108 |
| Concomitant BDNF and sleep slow wave changes indicate ketamine-induced plasticity in major depressive disorder Patients with treatment-resistant major depressive disorder | 2012 | Observational cohort | n = 30 |
Citations in the library
Cited by 57
- Consciousness among delta waves: a paradox? Brain March 6, 2021
- Consciousness and complexity: a consilience of evidence Neuroscience of Consciousness 2021
- Are There Islands of Awareness? Trends in Neurosciences December 10, 2019
- Distributed harmonic patterns of structure-function dependence orchestrate human consciousness. Communications Biology January 28, 2023
- Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants The International Journal of Neuropsychopharmacology November 16, 2020
and 52 more in the library
Cites 12
- Subanesthetic Effects of the Noncompetitive NMDA Antagonist, Ketamine, in Humans Archives of General Psychiatry March 1, 1994
- A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior Science Translational Medicine August 14, 2013
- Psychometric Evaluation of the Altered States of Consciousness Rating Scale (OAV) PLoS One August 31, 2010
- Taming the Ketamine Tiger Anesthesiology August 6, 2010
- Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin Scientific Reports April 19, 2017
and 7 more in the library