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Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin

What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for s...

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Autores principales: Schartner, Michael M., Carhart-Harris, Robin L., Barrett, Adam B., Seth, Anil K., Muthukumaraswamy, Suresh D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396066/
https://www.ncbi.nlm.nih.gov/pubmed/28422113
http://dx.doi.org/10.1038/srep46421
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author Schartner, Michael M.
Carhart-Harris, Robin L.
Barrett, Adam B.
Seth, Anil K.
Muthukumaraswamy, Suresh D.
author_facet Schartner, Michael M.
Carhart-Harris, Robin L.
Barrett, Adam B.
Seth, Anil K.
Muthukumaraswamy, Suresh D.
author_sort Schartner, Michael M.
collection PubMed
description What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for spontaneous magnetoencephalographic (MEG) signals from humans during altered states of consciousness induced by three psychedelic substances: psilocybin, ketamine and LSD. For all three, we find reliably higher spontaneous signal diversity, even when controlling for spectral changes. This increase is most pronounced for the single-channel LZ complexity measure, and hence for temporal, as opposed to spatial, signal diversity. We also uncover selective correlations between changes in signal diversity and phenomenological reports of the intensity of psychedelic experience. This is the first time that these measures have been applied to the psychedelic state and, crucially, that they have yielded values exceeding those of normal waking consciousness. These findings suggest that the sustained occurrence of psychedelic phenomenology constitutes an elevated level of consciousness - as measured by neural signal diversity.
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spelling pubmed-53960662017-04-21 Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin Schartner, Michael M. Carhart-Harris, Robin L. Barrett, Adam B. Seth, Anil K. Muthukumaraswamy, Suresh D. Sci Rep Article What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for spontaneous magnetoencephalographic (MEG) signals from humans during altered states of consciousness induced by three psychedelic substances: psilocybin, ketamine and LSD. For all three, we find reliably higher spontaneous signal diversity, even when controlling for spectral changes. This increase is most pronounced for the single-channel LZ complexity measure, and hence for temporal, as opposed to spatial, signal diversity. We also uncover selective correlations between changes in signal diversity and phenomenological reports of the intensity of psychedelic experience. This is the first time that these measures have been applied to the psychedelic state and, crucially, that they have yielded values exceeding those of normal waking consciousness. These findings suggest that the sustained occurrence of psychedelic phenomenology constitutes an elevated level of consciousness - as measured by neural signal diversity. Nature Publishing Group 2017-04-19 /pmc/articles/PMC5396066/ /pubmed/28422113 http://dx.doi.org/10.1038/srep46421 Text en Copyright © 2017, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Schartner, Michael M.
Carhart-Harris, Robin L.
Barrett, Adam B.
Seth, Anil K.
Muthukumaraswamy, Suresh D.
Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title_full Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title_fullStr Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title_full_unstemmed Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title_short Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin
title_sort increased spontaneous meg signal diversity for psychoactive doses of ketamine, lsd and psilocybin
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396066/
https://www.ncbi.nlm.nih.gov/pubmed/28422113
http://dx.doi.org/10.1038/srep46421
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