Abstract

Key to understanding the neuronal basis of consciousness is the characterization of the neural signatures of changes in level of consciousness during sleep. Here we analysed three measures of dynamical complexity on spontaneous depth electrode recordings from 10 epilepsy patients during wakeful rest (WR) and different stages of sleep: (i) Lempel–Ziv complexity, which is derived from how compressible the data are; (ii) amplitude coalition entropy, which measures the variability over time of the set of channels active above a threshold; (iii) synchrony coalition entropy, which measures the variability over time of the set of synchronous channels. When computed across sets of channels that are broadly distributed across multiple brain regions, all three measures decreased substantially in all participants during early-night non-rapid eye movement (NREM) sleep. This decrease was partially reversed during late-night NREM sleep, while the measures scored similar to WR during rapid eye movement (REM) sleep. This global pattern was in almost all cases mirrored at the local level by groups of channels located in a single region. In testing for differences between regions, we found elevated signal complexity in the frontal lobe. These differences could not be attributed solely to changes in spectral power between conditions. Our results provide further evidence that the level of consciousness correlates with neural dynamical complexity.

Details

Title
Global and local complexity of intracranial EEG decreases during NREM sleep
Author
Schartner, Michael M 1 ; Pigorini, Andrea 2 ; Gibbs, Steve A 3 ; Arnulfo, Gabriele 4 ; Sarasso, Simone 2 ; Barnett, Lionel 1 ; Nobili, Lino 3 ; Massimini, Marcello 5 ; Seth, Anil K 1 ; Barrett, Adam B 6 

 Sackler Centre for Consciousness Science and School of Engineering and Informatics, University of Sussex, Brighton, UK; 
 Dipartimento di Scienze Biomediche e Cliniche ‘L. Sacco’, Universitá degli Studi di Milano, Milan, Italy; 
 Niguarda Hospital, C. Munari Center of Epilepsy Surgery, Milan, Italy; 
 Deparment of Informatics and Engineering (DIBRIS), University of Genoa, Italy 
 Dipartimento di Scienze Biomediche e Cliniche ‘L. Sacco’, Universitá degli Studi di Milano, Milan, Italy;; Istituto di Ricovero e Cura a Carattere Scientifico, Fondazione Don Gnocchi Onlus, Milan, Italy 
 Sackler Centre for Consciousness Science and School of Engineering and Informatics, University of Sussex, Brighton, UK;; Dipartimento di Scienze Biomediche e Cliniche ‘L. Sacco’, Universitá degli Studi di Milano, Milan, Italy; 
Publication year
2017
Publication date
2017
Publisher
Oxford University Press
e-ISSN
20572107
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3170928531
Copyright
© The Author 2017. Published by Oxford University Press. This work is published under http://creativecommons.org/licenses/by-nc/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.