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Ming Q, Liou JY, Yang F, Li J, Chu C, Zhou Q, Wu D, Xu S, Luo P, Liang J, Li D, Pryor KO, Lin W, Schwartz TH, Ma H. Isoflurane-Induced Burst Suppression Is a Thalamus-Modulated, Focal-Onset Rhythm With Persistent Local Asynchrony and Variable Propagation Patterns in Rats. Front Syst Neurosci 2021; 14:599781. [PMID: 33510621 PMCID: PMC7835516 DOI: 10.3389/fnsys.2020.599781] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/14/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Inhalational anesthetic-induced burst suppression (BS) is classically considered a bilaterally synchronous rhythm. However, local asynchrony has been predicted in theoretical studies and reported in patients with pre-existing focal pathology. Method: We used high-speed widefield calcium imaging to study the spatiotemporal dynamics of isoflurane-induced BS in rats. Results: We found that isoflurane-induced BS is not a globally synchronous rhythm. In the neocortex, neural activity first emerged in a spatially shifting, variably localized focus. Subsequent propagation across the whole cortex was rapid, typically within <100 milliseconds, giving the superficial resemblance to global synchrony. Neural activity remained locally asynchronous during the bursts, forming complex recurrent propagating waves. Despite propagation variability, spatial sequences of burst propagation were largely preserved between the hemispheres, and neural activity was highly correlated between the homotopic areas. The critical role of the thalamus in cortical burst initiation was demonstrated by using unilateral thalamic tetrodotoxin injection. Conclusion: The classical impression that anesthetics-induced BS is a state of global brain synchrony is inaccurate. Bursts are a series of shifting local cortical events facilitated by thalamic projection that unfold as rapid, bilaterally asynchronous propagating waves.
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Affiliation(s)
- Qianwen Ming
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jyun-You Liou
- Department of Anesthesiology, New York-Presbyterian Hospital/Weill Cornell Medicine, New York, NY, United States
| | - Fan Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jing Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Chaojia Chu
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Qingchen Zhou
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Dan Wu
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Shujia Xu
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Peijuan Luo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jianmin Liang
- Department of Pediatrics, The First Hospital of Jilin University, Changchun, China
| | - Dan Li
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Kane O Pryor
- Department of Anesthesiology, New York-Presbyterian Hospital/Weill Cornell Medicine, New York, NY, United States
| | - Weihong Lin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Theodore H Schwartz
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, NewYork-Presbyterian Hospital, New York, NY, United States
| | - Hongtao Ma
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, NewYork-Presbyterian Hospital, New York, NY, United States
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Bojak I, Stoyanov ZV, Liley DTJ. Emergence of spatially heterogeneous burst suppression in a neural field model of electrocortical activity. Front Syst Neurosci 2015; 9:18. [PMID: 25767438 PMCID: PMC4341547 DOI: 10.3389/fnsys.2015.00018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/02/2015] [Indexed: 11/17/2022] Open
Abstract
Burst suppression in the electroencephalogram (EEG) is a well-described phenomenon that occurs during deep anesthesia, as well as in a variety of congenital and acquired brain insults. Classically it is thought of as spatially synchronous, quasi-periodic bursts of high amplitude EEG separated by low amplitude activity. However, its characterization as a “global brain state” has been challenged by recent results obtained with intracranial electrocortigraphy. Not only does it appear that burst suppression activity is highly asynchronous across cortex, but also that it may occur in isolated regions of circumscribed spatial extent. Here we outline a realistic neural field model for burst suppression by adding a slow process of synaptic resource depletion and recovery, which is able to reproduce qualitatively the empirically observed features during general anesthesia at the whole cortex level. Simulations reveal heterogeneous bursting over the model cortex and complex spatiotemporal dynamics during simulated anesthetic action, and provide forward predictions of neuroimaging signals for subsequent empirical comparisons and more detailed characterization. Because burst suppression corresponds to a dynamical end-point of brain activity, theoretically accounting for its spatiotemporal emergence will vitally contribute to efforts aimed at clarifying whether a common physiological trajectory is induced by the actions of general anesthetic agents. We have taken a first step in this direction by showing that a neural field model can qualitatively match recent experimental data that indicate spatial differentiation of burst suppression activity across cortex.
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Affiliation(s)
- Ingo Bojak
- Systems Neuroscience Research Group, School of Systems Engineering, University of Reading Reading, UK
| | - Zhivko V Stoyanov
- Systems Neuroscience Research Group, School of Systems Engineering, University of Reading Reading, UK
| | - David T J Liley
- Brain and Psychological Sciences Research Centre, School of Health Sciences, Swinburne University of Technology Hawthorn, VIC, Australia
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Liley DTJ, Walsh M. The Mesoscopic Modeling of Burst Suppression during Anesthesia. Front Comput Neurosci 2013; 7:46. [PMID: 23641211 PMCID: PMC3639728 DOI: 10.3389/fncom.2013.00046] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 04/05/2013] [Indexed: 11/13/2022] Open
Abstract
The burst-suppression pattern is well recognized as a distinct feature of the mammalian electroencephalogram (EEG) waveform. Consisting of alternating periods of high amplitude oscillatory and isoelectric activity, it can be induced in health by deep anesthesia as well as being evoked by a range of pathophysiological processes that include coma and anoxia. While the electroencephalographic phenomenon and clinical implications of burst suppression have been studied extensively, the physiological mechanisms underlying its emergence remain unresolved and obscure. Because electroencephalographic bursting phenomenologically resembles the bursting observed in single neurons, it would be reasonable to assume that the theoretical insights developed to understand bursting at the cellular ("microscopic") level would enable insights into the dynamical genesis of bursting at the level of the whole brain ("macroscopic"). In general action potential bursting is the result of the interplay of two time scales: a fast time scale responsible for spiking, and a slow time scale that modulates such activity. We therefore hypothesize that such fast-slow systems dynamically underpin electroencephalographic bursting. Here we show that a well-known mean field dynamical model of the electroencephalogram, the Liley model, while unable to produce burst suppression unmodified, is able to give rise to a wide variety of burst-like activity by the addition of one or more slow systems modulating model parameters speculated to be major "targets" for anesthetic action. The development of a physiologically plausible theoretical framework to account for burst suppression will lead to a more complete physiological understanding of the EEG and the mechanisms that serve to modify ongoing brain activity necessary for purposeful behavior and consciousness.
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Affiliation(s)
- David T J Liley
- Brain and Psychological Sciences Research Centre, Faculty of Life and Social Sciences, Swinburne University of Technology Hawthorn, VIC, Australia
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