Perioperative Medicine  |   June 2019
Changes in Whole Brain Dynamics and Connectivity Patterns during Sevoflurane- and Propofol-induced Unconsciousness Identified by Functional Magnetic Resonance Imaging
Author Notes
  • From the Department of Neurology (D.G., R.I.), and Department of Anesthesiology (A.R., G.S., D.J.), Klinikum rechts der Isar, Technical University Munich, München, Germany; GIGA-Consciousness, Coma Science Group (S.K.L., C.D.P., S.L.), and GIGA-Consciousness, Sensation and Perception Research Group (A.V., V.B.), GIGA Research, University, and Department of Algology and Palliative Care, Department of Neurology (S.L.), and Department of Anesthesia and Intensive Care Medicine (V.B.), CHU University Hospital of Liège (C.D.P.), Liège, Belgium; GIGA-Cyclotron Research Center: In Vivo Imaging, University of Liège, Liège, Belgium (A.P.); University Department of Anesthesia and Intensive Care Medicine, CHR Citadelle, Liège, Belgium (V.B.); Department of Neurology, University of Wisconsin, Madison, Wisconsin (M.B.); and Asklepios Clinic, Department of Neurology, Bad Tölz, Germany (R.I.).
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Submitted for publication June 11, 2018. Accepted for publication February 22, 2019.
    Submitted for publication June 11, 2018. Accepted for publication February 22, 2019.×
  • Address correspondence to Dr. Golkowski: Department of Neurology, Klinikum rechts der Isar, Technical University Munich, Ismaninger Straße 22, 81675 München, Germany. daniel.golkowski@tum.de. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Clinical Science / Central and Peripheral Nervous Systems / Pharmacology / Radiological and Other Imaging
Perioperative Medicine   |   June 2019
Changes in Whole Brain Dynamics and Connectivity Patterns during Sevoflurane- and Propofol-induced Unconsciousness Identified by Functional Magnetic Resonance Imaging
Anesthesiology 6 2019, Vol.130, 898-911. doi:10.1097/ALN.0000000000002704
Anesthesiology 6 2019, Vol.130, 898-911. doi:10.1097/ALN.0000000000002704
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • The extent to which alterations within specific brain networks impairs communication among networks remains unknown

What This Article Tells Us That Is New:

  • In a volunteer functional magnetic resonance study, general anesthesia reduced activity within and among networks

  • Specific between-network connectivity is necessary for consciousness

Background: A key feature of the human brain is its capability to adapt flexibly to changing external stimuli. This capability can be eliminated by general anesthesia, a state characterized by unresponsiveness, amnesia, and (most likely) unconsciousness. Previous studies demonstrated decreased connectivity within the thalamus, frontoparietal, and default mode networks during general anesthesia. We hypothesized that these alterations within specific brain networks lead to a change of communication between networks and their temporal dynamics.

Methods: We conducted a pooled spatial independent component analysis of resting-state functional magnetic resonance imaging data obtained from 16 volunteers during propofol and 14 volunteers during sevoflurane general anesthesia that have been previously published. Similar to previous studies, mean z-scores of the resulting spatial maps served as a measure of the activity within a network. Additionally, correlations of associated time courses served as a measure of the connectivity between networks. To analyze the temporal dynamics of between-network connectivity, we computed the correlation matrices during sliding windows of 1 min and applied k-means clustering to the matrices during both general anesthesia and wakefulness.

Results: Within-network activity was decreased in the default mode, attentional, and salience networks during general anesthesia (P < 0.001, range of median changes: –0.34, –0.13). Average between-network connectivity was reduced during general anesthesia (P < 0.001, median change: –0.031). Distinct between-network connectivity patterns for both wakefulness and general anesthesia were observed irrespective of the anesthetic agent (P < 0.001), and there were fewer transitions in between-network connectivity patterns during general anesthesia (P < 0.001, median number of transitions during wakefulness: 4 and during general anesthesia: 0).

Conclusions: These results suggest that (1) higher-order brain regions play a crucial role in the generation of specific between-network connectivity patterns and their dynamics, and (2) the capability to interact with external stimuli is represented by complex between-network connectivity patterns.