Regional entropy of functional imaging signals varies differently in sensory and cognitive systems during propofol-modulated loss and return of behavioral responsiveness. Brain Imaging Behav 2019 Apr;13(2):514-525
Date
05/09/2018Pubmed ID
29737490Pubmed Central ID
PMC6239968DOI
10.1007/s11682-018-9886-0Scopus ID
2-s2.0-85046653018 (requires institutional sign-in at Scopus site) 8 CitationsAbstract
The level and richness of consciousness depend on information integration in the brain. Altered interregional functional interactions may indicate disrupted information integration during anesthetic-induced unconsciousness. How anesthetics modulate the amount of information in various brain regions has received less attention. Here, we propose a novel approach to quantify regional information content in the brain by the entropy of the principal components of regional blood oxygen-dependent imaging signals during graded propofol sedation. Fifteen healthy individuals underwent resting-state scans in wakeful baseline, light sedation (conscious), deep sedation (unconscious), and recovery (conscious). Light sedation characterized by lethargic behavioral responses was associated with global reduction of entropy in the brain. Deep sedation with completely suppressed overt responsiveness was associated with further reductions of entropy in sensory (primary and higher sensory plus orbital prefrontal cortices) but not high-order cognitive (dorsal and medial prefrontal, cingulate, parietotemporal cortices and hippocampal areas) systems. Upon recovery of responsiveness, entropy was restored in the sensory but not in high-order cognitive systems. These findings provide novel evidence for a reduction of information content of the brain as a potential systems-level mechanism of reduced consciousness during propofol anesthesia. The differential changes of entropy in the sensory and high-order cognitive systems associated with losing and regaining overt responsiveness are consistent with the notion of "disconnected consciousness", in which a complete sensory-motor disconnection from the environment occurs with preserved internal mentation.
Author List
Liu X, Lauer KK, Ward BD, Roberts CJ, Liu S, Gollapudy S, Rohloff R, Gross W, Xu Z, Chen S, Wang L, Yang Z, Li SJ, Binder JR, Hudetz AGAuthors
Jeffrey R. Binder MD Professor in the Neurology department at Medical College of WisconsinSuneeta Gollapudy MD Associate Professor in the Anesthesiology department at Medical College of Wisconsin
William Gross MD, PhD Assistant Professor in the Anesthesiology department at Medical College of Wisconsin
Kathryn K. Lauer MD Vice Chair, Professor in the Anesthesiology department at Medical College of Wisconsin
Christopher J. Roberts MD, PhD Assistant Professor in the Anesthesiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AdultBrain
Consciousness
Deep Sedation
Entropy
Female
Humans
Hypnotics and Sedatives
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Male
Neural Pathways
Propofol
Unconsciousness
Wakefulness
