Distinct and Dissociable EEG Networks Are Associated With Recovery of Cognitive Function Following Anesthesia-Induced Unconsciousness

Alexander Rokos; Bratislav Mišić; Kathleen Berkun; Catherine Duclos; Vijay Tarnal; Ellen Janke; Paul Picton; Goodarz Golmirzaie; Mathias Basner; Michael S Avidan; Max B Kelz; George A Mashour; Stefanie Blain-Moraes

doi:10.3389/fnhum.2021.706693

Distinct and Dissociable EEG Networks Are Associated With Recovery of Cognitive Function Following Anesthesia-Induced Unconsciousness

Front Hum Neurosci. 2021 Sep 14:15:706693. doi: 10.3389/fnhum.2021.706693. eCollection 2021.

Authors

Affiliations

¹ Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
² Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.
³ Cognitive Science, McGill University, Montreal, QC, Canada.
⁴ School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.
⁵ Department of Anesthesiology, Center of Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States.
⁶ Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
⁷ Department of Anesthesiology, Washington University School of Medicine, St. Louis, WA, United States.
⁸ Deparment of Anesthesiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.

Abstract

The temporal trajectories and neural mechanisms of recovery of cognitive function after a major perturbation of consciousness is of both clinical and neuroscientific interest. The purpose of the present study was to investigate network-level changes in functional brain connectivity associated with the recovery and return of six cognitive functions after general anesthesia. High-density electroencephalograms (EEG) were recorded from healthy volunteers undergoing a clinically relevant anesthesia protocol (propofol induction and isoflurane maintenance), and age-matched healthy controls. A battery of cognitive tests (motor praxis, visual object learning test, fractal-2-back, abstract matching, psychomotor vigilance test, digital symbol substitution test) was administered at baseline, upon recovery of consciousness (ROC), and at half-hour intervals up to 3 h following ROC. EEG networks were derived using the strength of functional connectivity measured through the weighted phase lag index (wPLI). A partial least squares (PLS) analysis was conducted to assess changes in these networks: (1) between anesthesia and control groups; (2) during the 3-h recovery from anesthesia; and (3) for each cognitive test during recovery from anesthesia. Networks were maximally perturbed upon ROC but returned to baseline 30-60 min following ROC, despite deficits in cognitive performance that persisted up to 3 h following ROC. Additionally, during recovery from anesthesia, cognitive tests conducted at the same time-point activated distinct and dissociable functional connectivity networks across all frequency bands. The results highlight that the return of cognitive function after anesthetic-induced unconsciousness is task-specific, with unique behavioral and brain network trajectories of recovery.

Keywords: anesthesia; brain networks; cognitive function; electroencephalography; functional connectivity; partial least squares.