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Loss of consciousness is related to hyper-1 correlated gamma-band activity in anesthetized macaques and sleeping humans

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posted on 2023-06-09, 08:56 authored by Michal Bola, Adam BarrettAdam Barrett, Andrea Pigorini, Lino Nobili, Anil SethAnil Seth, Artur Marchewka
Loss of consciousness can result from a wide range of causes, including natural sleep and pharmacologically induced anesthesia. Important insights might thus come from identifying neuronal mechanisms of loss and re-emergence of consciousness independent of a specific manipulation. Therefore, to seek neuronal signatures of loss of consciousness common to sleep and anesthesia we analyzed spontaneous electrophysiological activity recorded in two experiments. First, electrocorticography (ECoG) acquired from 4 macaque monkeys anesthetized with different anesthetic agents (ketamine, medetomidine, propofol) and, second, stereo-electroencephalography (sEEG) from 10 epilepsy patients in different wake-sleep stages (wakefulness, NREM, REM). Specifically, we investigated co-activation patterns among brain areas, defined as correlations between local amplitudes of gamma-band activity. We found that resting wakefulness was associated with intermediate levels of gamma-band coupling, indicating neither complete dependence, nor full independence among brain regions. In contrast, loss of consciousness during NREM sleep and propofol anesthesia was associated with excessively correlated brain activity, as indicated by a robust increase of number and strength of positive correlations. However, such excessively correlated brain signals were not observed during REM sleep, and were present only to a limited extent during ketamine anesthesia. This might be related to the fact that, despite suppression of behavioral responsiveness, REM sleep and ketamine anesthesia often involve presence of dream-like conscious experiences. We conclude that hyper-correlated gamma-band activity might be a signature of loss of consciousness common across various manipulations and independent of behavioral responsiveness.

History

Publication status

  • Published

File Version

  • Accepted version

Journal

NeuroImage

ISSN

1053-8119

Publisher

Elsevier

Volume

167

Page range

130-142

Department affiliated with

  • Informatics Publications

Research groups affiliated with

  • Sackler Centre for Consciousness Science Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2017-11-21

First Open Access (FOA) Date

2018-11-21

First Compliant Deposit (FCD) Date

2017-11-21

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