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Modulatory dynamics mark the transition between anesthetic states of unconsciousness

Unconsciousness maintained by GABAergic anesthetics, such as propofol and sevoflurane, is characterized by slow-delta oscillations (0.3 to 4 Hz) and alpha oscillations (8 to 14 Hz) that are readily visible in the electroencephalogram. At higher doses, these slow-delta–alpha (SDA) oscillations transi...

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Autores principales: Adam, Elie, Kwon, Ohyoon, Montejo, Karla A., Brown, Emery N.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10372635/
https://www.ncbi.nlm.nih.gov/pubmed/37467269
http://dx.doi.org/10.1073/pnas.2300058120
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author Adam, Elie
Kwon, Ohyoon
Montejo, Karla A.
Brown, Emery N.
author_facet Adam, Elie
Kwon, Ohyoon
Montejo, Karla A.
Brown, Emery N.
author_sort Adam, Elie
collection PubMed
description Unconsciousness maintained by GABAergic anesthetics, such as propofol and sevoflurane, is characterized by slow-delta oscillations (0.3 to 4 Hz) and alpha oscillations (8 to 14 Hz) that are readily visible in the electroencephalogram. At higher doses, these slow-delta–alpha (SDA) oscillations transition into burst suppression. This is a marker of a state of profound brain inactivation during which isoelectric (flatline) periods alternate with periods of the SDA patterns present at lower doses. While the SDA and burst suppression patterns have been analyzed separately, the transition from one to the other has not. Using state–space methods, we characterize the dynamic evolution of brain activity from SDA to burst suppression and back during unconsciousness maintained with propofol or sevoflurane in volunteer subjects and surgical patients. We uncover two dynamical processes that continuously modulate the SDA oscillations: alpha-wave amplitude and slow-wave frequency modulation. We present an alpha modulation index and a slow modulation index which characterize how these processes track the transition from SDA oscillations to burst suppression and back to SDA oscillations as a function of increasing and decreasing anesthetic doses, respectively. Our biophysical model reveals that these dynamics track the combined evolution of the neurophysiological and metabolic effects of a GABAergic anesthetic on brain circuits. Our characterization of the modulatory dynamics mediated by GABAergic anesthetics offers insights into the mechanisms of these agents and strategies for monitoring and precisely controlling the level of unconsciousness in patients under general anesthesia.
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spelling pubmed-103726352023-07-28 Modulatory dynamics mark the transition between anesthetic states of unconsciousness Adam, Elie Kwon, Ohyoon Montejo, Karla A. Brown, Emery N. Proc Natl Acad Sci U S A Biological Sciences Unconsciousness maintained by GABAergic anesthetics, such as propofol and sevoflurane, is characterized by slow-delta oscillations (0.3 to 4 Hz) and alpha oscillations (8 to 14 Hz) that are readily visible in the electroencephalogram. At higher doses, these slow-delta–alpha (SDA) oscillations transition into burst suppression. This is a marker of a state of profound brain inactivation during which isoelectric (flatline) periods alternate with periods of the SDA patterns present at lower doses. While the SDA and burst suppression patterns have been analyzed separately, the transition from one to the other has not. Using state–space methods, we characterize the dynamic evolution of brain activity from SDA to burst suppression and back during unconsciousness maintained with propofol or sevoflurane in volunteer subjects and surgical patients. We uncover two dynamical processes that continuously modulate the SDA oscillations: alpha-wave amplitude and slow-wave frequency modulation. We present an alpha modulation index and a slow modulation index which characterize how these processes track the transition from SDA oscillations to burst suppression and back to SDA oscillations as a function of increasing and decreasing anesthetic doses, respectively. Our biophysical model reveals that these dynamics track the combined evolution of the neurophysiological and metabolic effects of a GABAergic anesthetic on brain circuits. Our characterization of the modulatory dynamics mediated by GABAergic anesthetics offers insights into the mechanisms of these agents and strategies for monitoring and precisely controlling the level of unconsciousness in patients under general anesthesia. National Academy of Sciences 2023-07-19 2023-07-25 /pmc/articles/PMC10372635/ /pubmed/37467269 http://dx.doi.org/10.1073/pnas.2300058120 Text en Copyright © 2023 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Biological Sciences
Adam, Elie
Kwon, Ohyoon
Montejo, Karla A.
Brown, Emery N.
Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title_full Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title_fullStr Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title_full_unstemmed Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title_short Modulatory dynamics mark the transition between anesthetic states of unconsciousness
title_sort modulatory dynamics mark the transition between anesthetic states of unconsciousness
topic Biological Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10372635/
https://www.ncbi.nlm.nih.gov/pubmed/37467269
http://dx.doi.org/10.1073/pnas.2300058120
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