Resting-state Dynamics as a Cortical Signature of Anesthesia in Monkeys

• Published in: Anesthesiology (Philadelphia) 2018-11, Vol.129 (5), p.942-958
• Main Authors: Uhrig, Lynn, Sitt, Jacobo D, Jacob, Amaury, Tasserie, Jordy, Barttfeld, Pablo, Dupont, Morgan, Dehaene, Stanislas, Jarraya, Bechir
• Format: Article
• Language: English
• Subjects: Anesthetics - pharmacology; Animals; Brain - diagnostic imaging; Brain - drug effects; Brain - metabolism; Brain Mapping - methods; Electroencephalography - methods; Female; Haplorhini; Magnetic Resonance Imaging - methods; Male; Rest
• ISSN: 0003-3022; 1528-1175
• DOI: 10.1097/ALN.0000000000002336

WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW BACKGROUND:The mechanism by which anesthetics induce a loss of consciousness remains a puzzling problem. We hypothesized that a cortical signature of anesthesia could be found in an increase in similarity between the matrix of resting-state functional correlations and the anatomical connectivity matrix of the brain, resulting in an increased function-structure similarity. METHODS:We acquired resting-state functional magnetic resonance images in macaque monkeys during wakefulness (n = 3) or anesthesia with propofol (n = 3), ketamine (n = 3), or sevoflurane (n = 3). We used the k-means algorithm to cluster dynamic resting-state data into independent functional brain states. For each condition, we performed a regression analysis to quantify function-structure similarity and the repertoire of functional brain states. RESULTS:Seven functional brain states were clustered and ranked according to their similarity to structural connectivity, with higher ranks corresponding to higher function-structure similarity and lower ranks corresponding to lower correlation between brain function and brain anatomy. Anesthesia shifted the brain state composition from a low rank (rounded rank [mean ± SD]) in the awake condition (awake rank = 4 [3.58 ± 1.03]) to high ranks in the different anesthetic conditions (ketamine rank = 6 [6.10 ± 0.32]; moderate propofol rank = 6 [6.15 ± 0.76]; deep propofol rank = 6 [6.16 ± 0.46]; moderate sevoflurane rank = 5 [5.10 ± 0.81]; deep sevoflurane rank = 6 [5.81 ± 1.11]; P < 0.0001). CONCLUSIONS:Whatever the molecular mechanism, anesthesia led to a massive reconfiguration of the repertoire of functional brain states that became predominantly shaped by brain anatomy (high function-structure similarity), giving rise to a well-defined cortical signature of anesthesia-induced loss of consciousness.