Background: Significant advances have been made in our understanding of subcortical processes related to anesthetic- and sleep-induced unconsciousness, but the associated changes in cortical connectivity and cortical neurochemistry have yet to be fully clarified.
Methods: Male Sprague–Dawley rats were instrumented for simultaneous measurement of cortical acetylcholine and electroencephalographic indices of corticocortical connectivity—coherence and symbolic transfer entropy—before, during, and after general anesthesia (propofol, n = 11; sevoflurane, n = 13). In another group of rats (n = 7), these electroencephalographic indices were analyzed during wakefulness, slow wave sleep (SWS), and rapid eye movement (REM) sleep.
Results: Compared to wakefulness, anesthetic-induced unconsciousness was characterized by a significant decrease in cortical acetylcholine that recovered to preanesthesia levels during recovery wakefulness. Corticocortical coherence and frontal–parietal symbolic transfer entropy in high γ band (85 to 155 Hz) were decreased during anesthetic-induced unconsciousness and returned to preanesthesia levels during recovery wakefulness. Sleep-wake states showed a state-dependent change in coherence and transfer entropy in high γ bandwidth, which correlated with behavioral arousal: high during wakefulness, low during SWS, and lowest during REM sleep. By contrast, frontal–parietal θ connectivity during sleep-wake states was not correlated with behavioral arousal but showed an association with well-established changes in cortical acetylcholine: high during wakefulness and REM sleep and low during SWS.
Conclusions: Corticocortical coherence and frontal–parietal connectivity in high γ bandwidth correlates with behavioral arousal and is not mediated by cholinergic mechanisms, while θ connectivity correlates with cortical acetylcholine levels.
Accumulating evidence suggests that fragmentation of cortical networks occurs during physiologic, pharmacologic, and pathologic states of unconsciousness
Cortical connectivity and acetylcholine levels were examined in relation to changes in behavioral arousal due to propofol or sevoflurane anesthesia and normal sleep in rat
Disruption of cortical connectivity in high γ band correlated with anesthetic- and sleep-induced unconsciousness, while θ connectivity correlated with cholinergic tone and cortical activation
Functional fragmentation of high-frequency activity in the cortex may be a common network-level mechanism of unconsciousness during general anesthesia and sleep
Dinesh Pal, Brian H. Silverstein, Heonsoo Lee, George A. Mashour; Neural Correlates of Wakefulness, Sleep, and General Anesthesia: An Experimental Study in Rat. Anesthesiology 2016;125(5):929-942. doi: https://doi.org/10.1097/ALN.0000000000001342.
Download citation file:
© 2019 American Society of Anesthesiologists
Welcome!
We have emailed you at with instructions on how to set up a new password. If you do not receive an email in the next 24 hours, or if you misplace your new password, please contact:
ASA members: Contact WK Member Services Memberservice@lww.com US and Canada: 866-489-0443 Worldwide: 301-223-2300
or
Non-member individual subscribers: Contact WK Customer Service Customerservice@lww.com US and Canada: 1-800-638-3030 Worldwide: 301-223-2300
...but there is no email account associated with it. To get started with Anesthesiology, we'll need to send you an email. To add an email address to your ASA account please contact us:
Forgot your password? Enter your username and email address. We'll send you a link to reset your password.
Forgot your username? Enter your email address. We'll send you your username identified by your email account.