Editorial Views  |   June 2019
Syncopated Tempi of the Anesthetized Brain
Author Notes
  • From the Department of Anaesthesia and Pain Medicine, Waikato Clinical School, University of Auckland, Hamilton, New Zealand.
  • This editorial accompanies the articles on p. 870 and p. 885.
    This editorial accompanies the articles on p. 870 and p. 885.×
  • Accepted for publication February 6, 2019.
    Accepted for publication February 6, 2019.×
  • Address correspondence to Dr. Sleigh: Jamie.sleigh@waikatodhb.health.nz
Article Information
Editorial Views / Central and Peripheral Nervous Systems
Editorial Views   |   June 2019
Syncopated Tempi of the Anesthetized Brain
Anesthesiology 6 2019, Vol.130, 861-863. doi:10.1097/ALN.0000000000002695
Anesthesiology 6 2019, Vol.130, 861-863. doi:10.1097/ALN.0000000000002695
In this issue of Anesthesiology, there are two articles looking at changes in patterns of connectivity between different brain regions during general anesthesia.1,2  These articles are full of the technical language of dynamics that might be somewhat daunting for clinicians. Can we make terms like “metastability,” “spatiotemporal invariance,” and even “connectivity” less abstract and more relevant to our day-to-day work? A common metaphor is to compare the function of the conscious brain to that of an orchestra making music. A symphony is made up of an evolving balance of synchrony and syncopation, harmony and dissonance, regularity and surprise. As the orchestra moves between fast and slow and loud and soft sections of music, so too does the brain move between fast waves and slow waves, high amplitude waves and low amplitude waves. There is no single fixed steady state, but conversely the brain activity is not completely unconstrained—therefore the brain is described as being “metastable.” Similarly, the music sometimes requires that the flutes play synchronously with the violas, and sometimes half a step behind the trumpets. These papers use the weighted phase lag index as a measure of frontoparietal brain “connectivity.” This index is simply quantifying whether the parietal lobe consistently activated after the frontal lobe. If it were to be applied to the symphony metaphor, it would give an estimate of whether the flutes tended to play after the trumpets on average.