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Brain network integration dynamics are associated with loss and recovery of consciousness induced by sevoflurane.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Ranft, Andreas 
Ilg, Rüdiger 
Jordan, Denis 

Abstract

The dynamic interplay of integration and segregation in the brain is at the core of leading theoretical accounts of consciousness. The human brain dynamically alternates between a sub-state where integration predominates, and a predominantly segregated sub-state, with different roles in supporting cognition and behaviour. Here, we combine graph theory and dynamic functional connectivity to compare resting-state functional MRI data from healthy volunteers before, during, and after loss of responsiveness induced with different concentrations of the inhalational anaesthetic, sevoflurane. We show that dynamic states characterised by high brain integration are especially vulnerable to general anaesthesia, exhibiting attenuated complexity and diminished small-world character. Crucially, these effects are reversed upon recovery, demonstrating their association with consciousness. Higher doses of sevoflurane (3% vol and burst-suppression) also compromise the temporal balance of integration and segregation in the human brain. Additionally, we demonstrate that reduced anticorrelations between the brain's default mode and executive control networks dynamically reconfigure depending on the brain's state of integration or segregation. Taken together, our results demonstrate that the integrated sub-state of brain connectivity is especially vulnerable to anaesthesia, in terms of both its complexity and information capacity, whose breakdown represents a generalisable biomarker of loss of consciousness and its recovery.

Description

Keywords

anaesthesia, complexity, consciousness, dynamic functional connectivity, integration-segregation, sevoflurane, small-world network, Adult, Anesthesia, Anesthetics, Inhalation, Brain, Connectome, Consciousness, Default Mode Network, Humans, Magnetic Resonance Imaging, Male, Nerve Net, Sevoflurane, Young Adult

Journal Title

Hum Brain Mapp

Conference Name

Journal ISSN

1065-9471
1097-0193

Volume Title

42

Publisher

Wiley
Sponsorship
Medical Research Council (MR/M009041/1)
Cambridge University Hospitals NHS Foundation Trust (CUH) (146281)
Royal College of Anaesthetists (RCoA) (unknown)