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Cortical dynamics during psychedelic and anesthetized states induced by ketamine
1Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, United States; Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, United States.
Neuroimage
|April 9, 2019
Summary
Ketamine
Area of Science:
- Neuroscience
- Pharmacology
- Computational Biology
Background:
- Ketamine exhibits dose-dependent psychedelic and anesthetic properties.
- Previous research suggests ketamine anesthesia preserves cortical complexity, while psychedelic doses increase signal diversity.
- A systematic investigation of ketamine's dose-dependent effects on cortical complexity is needed.
Purpose of the Study:
- To investigate the dose-dependent effects of ketamine on the spatiotemporal complexity of spontaneous electroencephalography (EEG) signals.
- To determine if ketamine-induced complexity levels fluctuate or stabilize over time.
- To correlate brain states with behavioral states during ketamine administration.
Main Methods:
- Utilized high-density scalp electroencephalography (EEG) in healthy volunteers.
- Employed Hidden Markov modeling to classify EEG signals into distinct brain states.
- Applied the Lempel-Ziv complexity algorithm to quantify spatiotemporal complexity within each brain state.
Main Results:
- Subanesthetic ketamine doses elevated EEG complexity compared to baseline.
- Anesthetic ketamine doses initially showed fluctuating complexity, then stabilized at a high level.
- Complexity levels were analyzed after controlling for spectral changes.
Conclusions:
- Ketamine's effects on spatiotemporal complexity vary with dosage, influencing brain states.
- Ketamine-induced state transitions exhibit characteristics of general anesthesia, normal consciousness, and altered states.
- Findings enhance understanding of ketamine's neurophysiological and phenomenological properties.
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