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Updated: Jul 11, 2026

Recording Brain Electromagnetic Activity During the Administration of the Gaseous Anesthetic Agents Xenon and Nitrous Oxide in Healthy Volunteers
Published on: January 13, 2018
Hypersensitivity of the anesthesia-induced comatose brain
Daniel Kroeger1, Florin Amzica
1Laboratoire de Neurophysiologie, Centre de Recherche Université Laval Robert-Giffard, Quebec, Quebec, Canada G1J 2G3.
Anesthesia-induced coma can feature a surprising window of heightened brain excitability, where stimuli trigger whole-brain activity bursts. This discovery challenges current understanding of brain states during anesthesia and coma.
Area of Science:
- Neuroscience
- Anesthesiology
- Computational Biology
Background:
- Anesthesia typically causes progressive loss of brain responsiveness.
- The burst suppression pattern on EEG is usually linked to reduced brain activity.
Purpose of the Study:
- To report the novel finding of a state window with increased brain excitability during anesthesia-induced coma.
- To investigate the mechanisms underlying this phenomenon and its relation to burst suppression.
Main Methods:
- In vivo intracellular recordings of neurons and glia.
- Extracellular calcium and electroencephalography (EEG) recordings.
- Mechanical, auditory, and visual microstimulations.
Main Results:
- A state window with dramatically increased brain excitability was identified during anesthesia-induced coma.
- Stimuli elicited bursts of whole-brain activity, dependent on NMDA receptor modulation, gap junction transmission, and extracellular calcium.
- Bursting events were followed by a refractory period, contributing to the burst suppression pattern.
Conclusions:
- Anesthesia-induced coma can involve paradoxical periods of heightened brain excitability.
- These findings necessitate a re-evaluation of burst spontaneity during coma.
- Opens new avenues for managing comatose patients.
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