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Zhang D, Wei Y. Distinct Neural Mechanisms Between Anesthesia Induction and Emergence: A Narrative Review. Anesth Analg 2024:00000539-990000000-00840. [PMID: 38861419 DOI: 10.1213/ane.0000000000007114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Anesthesia induction and emergence are critical periods for perioperative safety in the clinic. Traditionally, the emergence from general anesthesia has been recognized as a simple inverse process of induction resulting from the elimination of general anesthetics from the central nervous system. However, accumulated evidence has indicated that anesthesia induction and emergence are not mirror-image processes because of the occurrence of hysteresis/neural inertia in both animals and humans. An increasing number of studies have highlighted the critical role of orexinergic neurons and their involved circuits in the selective regulation of emergence but not the induction of general anesthesia. Moreover, additional brain regions have also been implicated in distinct neural mechanisms for anesthesia induction and emergence, which extends the concept that anesthetic induction and emergence are not antiparallel processes. Here, we reviewed the current literature and summarized the evidence regarding the differential mechanism of neural modulation in anesthesia induction and emergence, which will facilitate the understanding of the underlying neural mechanism for emergence from general anesthesia.
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Affiliation(s)
- Donghang Zhang
- From the Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- Department of Anesthesiology, Weill Cornell Medicine, New York, New York
| | - Yiyong Wei
- Department of Anesthesiology, Longgang District Maternity & Child Healthcare Hospital of Shenzhen City (Longgang Maternity and Child Institute of Shantou University Medical College), Shenzhen, China
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2
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Mashour GA. Anesthesia and the neurobiology of consciousness. Neuron 2024; 112:1553-1567. [PMID: 38579714 PMCID: PMC11098701 DOI: 10.1016/j.neuron.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/07/2024]
Abstract
In the 19th century, the discovery of general anesthesia revolutionized medical care. In the 21st century, anesthetics have become indispensable tools to study consciousness. Here, I review key aspects of the relationship between anesthesia and the neurobiology of consciousness, including interfaces of sleep and anesthetic mechanisms, anesthesia and primary sensory processing, the effects of anesthetics on large-scale functional brain networks, and mechanisms of arousal from anesthesia. I discuss the implications of the data derived from the anesthetized state for the science of consciousness and then conclude with outstanding questions, reflections, and future directions.
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Affiliation(s)
- George A Mashour
- Center for Consciousness Science, Department of Anesthesiology, Department of Pharmacology, Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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3
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Jang H, Mashour GA, Hudetz AG, Huang Z. Measuring the dynamic balance of integration and segregation underlying consciousness, anesthesia, and sleep. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589265. [PMID: 38659759 PMCID: PMC11042232 DOI: 10.1101/2024.04.12.589265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Consciousness requires a dynamic balance of integration and segregation in functional brain networks. An optimal integration-segregation balance depends on two key aspects of functional connectivity: global efficiency (i.e., integration) and clustering (i.e., segregation). We developed a new fMRI-based measure, termed the integration-segregation difference (ISD), which captures both aspects. We used this metric to quantify changes in brain state from conscious wakefulness to loss of responsiveness induced by the anesthetic propofol. The observed changes in ISD suggest a profound shift to segregation in both whole brain and all brain subnetworks during anesthesia. Moreover, brain networks displayed similar sequences of disintegration and subsequent reintegration during, respectively, loss and return of responsiveness. Random forest machine learning models, trained with the integration and segregation of brain networks, identified the awake vs. unresponsive states and their transitions with accuracy up to 93%. We found that metastability (i.e., the dynamic recurrence of non-equilibrium transient states) is more effectively explained by integration, while complexity (i.e., diversity and intricacy of neural activity) is more closely linked with segregation. The analysis of a sleep dataset revealed similar findings. Our results demonstrate that the integration-segregation balance is a useful index that can differentiate among various conscious and unconscious states.
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Affiliation(s)
- Hyunwoo Jang
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - George A. Mashour
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Anthony G. Hudetz
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Zirui Huang
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
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4
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Monteil A, Guérineau NC, Gil-Nagel A, Parra-Diaz P, Lory P, Senatore A. New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN. Physiol Rev 2024; 104:399-472. [PMID: 37615954 DOI: 10.1152/physrev.00014.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.
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Affiliation(s)
- Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Antonio Gil-Nagel
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Paloma Parra-Diaz
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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5
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De J, Wu M, Lambatan V, Hua Y, Joiner WJ. Re-examining the role of the dorsal fan-shaped body in promoting sleep in Drosophila. Curr Biol 2023; 33:3660-3668.e4. [PMID: 37552985 PMCID: PMC10573663 DOI: 10.1016/j.cub.2023.07.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/10/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023]
Abstract
The needs fulfilled by sleep are unknown, though the effects of insufficient sleep are manifold. To better understand how the need to sleep is sensed and discharged, much effort has gone into identifying the neural circuits involved in regulating arousal, especially those that promote sleep. In prevailing models, the dorsal fan-shaped body (dFB) plays a central role in this process in the fly brain. In the present study we manipulated various properties of the dFB including its electrical activity, synaptic output, and endogenous gene expression. In each of these experimental contexts we were unable to identify any effect on sleep that could be unambiguously mapped to the dFB. Furthermore, we found evidence that sleep phenotypes previously attributed to the dFB were caused by genetic manipulations that inadvertently targeted the ventral nerve cord. We also examined expression of two genes whose purported effects have been attributed to functions within a specific subpopulation of dFB neurons. In both cases we found little to no expression in the expected cells. Collectively, our results cast doubt on the prevailing hypothesis that the dFB plays a central role in promoting sleep.
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Affiliation(s)
- Joydeep De
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Meilin Wu
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Vanessa Lambatan
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yue Hua
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - William J Joiner
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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6
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Duhart JM, Buchler JR, Inami S, Kennedy KJ, Jenny BP, Afonso DJS, Koh K. Modulation and neural correlates of postmating sleep plasticity in Drosophila females. Curr Biol 2023; 33:2702-2716.e3. [PMID: 37352854 PMCID: PMC10527417 DOI: 10.1016/j.cub.2023.05.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/09/2023] [Accepted: 05/24/2023] [Indexed: 06/25/2023]
Abstract
Sleep is essential, but animals may forgo sleep to engage in other critical behaviors, such as feeding and reproduction. Previous studies have shown that female flies exhibit decreased sleep after mating, but our understanding of the process is limited. Here, we report that postmating nighttime sleep loss is modulated by diet and sleep deprivation, demonstrating a complex interaction among sleep, reproduction, and diet. We also find that female-specific pC1 neurons and sleep-promoting dorsal fan-shaped body (dFB) neurons are required for postmating sleep plasticity. Activating pC1 neurons leads to sleep suppression on standard fly culture media but has little sleep effect on sucrose-only food. Published connectome data suggest indirect, inhibitory connections among pC1 subtypes. Using calcium imaging, we show that activating the pC1e subtype inhibits dFB neurons. We propose that pC1 and dFB neurons integrate the mating status, food context, and sleep drive to modulate postmating sleep plasticity.
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Affiliation(s)
- José M Duhart
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir-IIBBA-CONICET, Buenos Aires C1405BWE, Argentina; Universidad Nacional de Quilmes, Quilmes B1876BXD, Argentina.
| | - Joseph R Buchler
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Sho Inami
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Kyle J Kennedy
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - B Peter Jenny
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Dinis J S Afonso
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Kyunghee Koh
- Department of Neuroscience, the Farber Institute for Neurosciences, and Synaptic Biology Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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7
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Miranda M, Frasca M, Estrada E. Topologically induced suppression of explosive synchronization. CHAOS (WOODBURY, N.Y.) 2023; 33:2887742. [PMID: 37125934 DOI: 10.1063/5.0142418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/06/2023] [Indexed: 05/03/2023]
Abstract
Nowadays, explosive synchronization is a well-documented phenomenon consisting in a first-order transition that may coexist with classical synchronization. Typically, explosive synchronization occurs when the network structure is represented by the classical graph Laplacian, and the node frequency and its degree are correlated. Here, we answer the question on whether this phenomenon can be observed in networks when the oscillators are coupled via degree-biased Laplacian operators. We not only observe that this is the case but also that this new representation naturally controls the transition from explosive to standard synchronization in a network. We prove analytically that explosive synchronization emerges when using this theoretical setting in star-like networks. As soon as this star-like network is topologically converted into a network containing cycles, the explosive synchronization gives rise to classical synchronization. Finally, we hypothesize that this mechanism may play a role in switching from normal to explosive states in the brain, where explosive synchronization has been proposed to be related to some pathologies like epilepsy and fibromyalgia.
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Affiliation(s)
- Manuel Miranda
- Institute of Cross-Disciplinary Physics and Complex Systems, IFISC (UIB-CSIC), 07122 Palma de Mallorca, Spain
| | - Mattia Frasca
- Department of Electrical, Electronics and Computer Science Engineering, University of Catania, I-95125 Catania, Italy
- Istituto di Analisi dei Sistemi ed Informatica "A. Ruberti", Consiglio Nazionale delle Ricerche (IASI-CNR), 00185 Roma, Italy
| | - Ernesto Estrada
- Institute of Cross-Disciplinary Physics and Complex Systems, IFISC (UIB-CSIC), 07122 Palma de Mallorca, Spain
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8
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Kim M, Harris RE, DaSilva AF, Lee U. Explosive Synchronization-Based Brain Modulation Reduces Hypersensitivity in the Brain Network: A Computational Model Study. Front Comput Neurosci 2022; 16:815099. [PMID: 35311218 PMCID: PMC8927545 DOI: 10.3389/fncom.2022.815099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/18/2022] [Indexed: 11/29/2022] Open
Abstract
Fibromyalgia (FM) is a chronic pain condition that is characterized by hypersensitivity to multimodal sensory stimuli, widespread pain, and fatigue. We have previously proposed explosive synchronization (ES), a phenomenon wherein a small perturbation to a network can lead to an abrupt state transition, as a potential mechanism of the hypersensitive FM brain. Therefore, we hypothesized that converting a brain network from ES to general synchronization (GS) may reduce the hypersensitivity of FM brain. To find an effective brain network modulation to convert ES into GS, we constructed a large-scale brain network model near criticality (i.e., an optimally balanced state between order and disorders), which reflects brain dynamics in conscious wakefulness, and adjusted two parameters: local structural connectivity and signal randomness of target brain regions. The network sensitivity to global stimuli was compared between the brain networks before and after the modulation. We found that only increasing the local connectivity of hubs (nodes with intense connections) changes ES to GS, reducing the sensitivity, whereas other types of modulation such as decreasing local connectivity, increasing and decreasing signal randomness are not effective. This study would help to develop a network mechanism-based brain modulation method to reduce the hypersensitivity in FM.
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Affiliation(s)
- MinKyung Kim
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Richard E. Harris
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Alexandre F. DaSilva
- Headache & Orofacial Pain Effort Laboratory, Biologic & Materials Sciences Department, University of Michigan School of Dentistry, Ann Arbor, MI, United States
| | - UnCheol Lee
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States
- *Correspondence: UnCheol Lee,
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9
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Wasilczuk AZ, Meng QC, McKinstry-Wu AR. Electroencephalographic Evidence for Individual Neural Inertia in Mice That Decreases With Time. Front Syst Neurosci 2022; 15:787612. [PMID: 35095434 PMCID: PMC8794956 DOI: 10.3389/fnsys.2021.787612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/14/2021] [Indexed: 12/02/2022] Open
Abstract
Previous studies have demonstrated that the brain has an intrinsic resistance to changes in arousal state. This resistance is most easily measured at the population level in the setting of general anesthesia and has been termed neural inertia. To date, no study has attempted to determine neural inertia in individuals. We hypothesize that individuals with markedly increased or decreased neural inertia might be at increased risk for complications related to state transitions, from awareness under anesthesia, to delayed emergence or confusion/impairment after emergence. Hence, an improved theoretical and practical understanding of neural inertia may have the potential to identify individuals at increased risk for these complications. This study was designed to explicitly measure neural inertia in individuals and empirically test the stochastic model of neural inertia using spectral analysis of the murine EEG. EEG was measured after induction of and emergence from isoflurane administered near the EC50 dose for loss of righting in genetically inbred mice on a timescale that minimizes pharmacokinetic confounds. Neural inertia was assessed by employing classifiers constructed using linear discriminant or supervised machine learning methods to determine if features of EEG spectra reliably demonstrate path dependence at steady-state anesthesia. We also report the existence of neural inertia at the individual level, as well as the population level, and that neural inertia decreases over time, providing direct empirical evidence supporting the predictions of the stochastic model of neural inertia.
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Affiliation(s)
- Andrzej Z. Wasilczuk
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Qing Cheng Meng
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States
| | - Andrew R. McKinstry-Wu
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States
- *Correspondence: Andrew Rich McKinstry-Wu
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10
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Murakami K, Palermo J, Stanhope BA, Gibbs AG, Keene AC. A screen for sleep and starvation resistance identifies a wake-promoting role for the auxiliary channel unc79. G3 (BETHESDA, MD.) 2021; 11:6300522. [PMID: 34849820 PMCID: PMC8496288 DOI: 10.1093/g3journal/jkab199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/25/2021] [Indexed: 11/22/2022]
Abstract
The regulation of sleep and metabolism are highly interconnected, and dysregulation of sleep is linked to metabolic diseases that include obesity, diabetes, and heart disease. Furthermore, both acute and long-term changes in diet potently impact sleep duration and quality. To identify novel factors that modulate interactions between sleep and metabolic state, we performed a genetic screen for their roles in regulating sleep duration, starvation resistance, and starvation-dependent modulation of sleep. This screen identified a number of genes with potential roles in regulating sleep, metabolism, or both processes. One such gene encodes the auxiliary ion channel UNC79, which was implicated in both the regulation of sleep and starvation resistance. Genetic knockdown or mutation of unc79 results in flies with increased sleep duration, as well as increased starvation resistance. Previous findings have shown that unc79 is required in pacemaker for 24-hours circadian rhythms. Here, we find that unc79 functions in the mushroom body, but not pacemaker neurons, to regulate sleep duration and starvation resistance. Together, these findings reveal spatially localized separable functions of unc79 in the regulation of circadian behavior, sleep, and metabolic function.
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Affiliation(s)
- Kazuma Murakami
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Justin Palermo
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Bethany A Stanhope
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Allen G Gibbs
- Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
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11
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Huang Z, Tarnal V, Vlisides PE, Janke EL, McKinney AM, Picton P, Mashour GA, Hudetz AG. Asymmetric neural dynamics characterize loss and recovery of consciousness. Neuroimage 2021; 236:118042. [PMID: 33848623 PMCID: PMC8310457 DOI: 10.1016/j.neuroimage.2021.118042] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/01/2021] [Accepted: 04/04/2021] [Indexed: 02/07/2023] Open
Abstract
Anesthetics are known to disrupt neural interactions in cortical and subcortical brain circuits. While the effect of anesthetic drugs on consciousness is reversible, the neural mechanism mediating induction and recovery may be different. Insight into these distinct mechanisms can be gained from a systematic comparison of neural dynamics during slow induction of and emergence from anesthesia. To this end, we used functional magnetic resonance imaging (fMRI) data obtained in healthy volunteers before, during, and after the administration of propofol at incrementally adjusted target concentrations. We analyzed functional connectivity of corticocortical and subcorticocortical networks and the temporal autocorrelation of fMRI signal as an index of neural processing timescales. We found that en route to unconsciousness, temporal autocorrelation across the entire brain gradually increased, whereas functional connectivity gradually decreased. In contrast, regaining consciousness was associated with an abrupt restoration of cortical but not subcortical temporal autocorrelation and an abrupt boost of subcorticocortical functional connectivity. Pharmacokinetic effects could not account for the difference in neural dynamics between induction and emergence. We conclude that the induction and recovery phases of anesthesia follow asymmetric neural dynamics. A rapid increase in the speed of cortical neural processing and subcorticocortical neural interactions may be a mechanism that reboots consciousness.
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Affiliation(s)
- Zirui Huang
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Vijay Tarnal
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Phillip E Vlisides
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ellen L Janke
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Amy M McKinney
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Paul Picton
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anthony G Hudetz
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
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12
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13
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Coetzee J, Links A, Levin A. Assessment of the clinical validity of an adjusted Marsh pharmacokinetic model using an effect-site rate constant (ke0) of 1.21 min-1. SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2021. [DOI: 10.36303/sajaa.2021.27.2.2583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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14
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Luppi AI, Spindler LRB, Menon DK, Stamatakis EA. The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia. Front Neurosci 2021; 15:643871. [PMID: 33737863 PMCID: PMC7960927 DOI: 10.3389/fnins.2021.643871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/05/2021] [Indexed: 12/13/2022] Open
Abstract
"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.
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Affiliation(s)
- Andrea I. Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Lennart R. B. Spindler
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - David K. Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Emmanuel A. Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Sehgal A. The 2020 Pittendrigh/Aschoff Lecture: My Circadian Journey. J Biol Rhythms 2021; 36:84-96. [PMID: 33428509 PMCID: PMC8815313 DOI: 10.1177/0748730420982398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The circadian field has come a long way since I started as a postdoctoral fellow ~30 years ago. At the time, the only known animal clock gene was period, so I had the privilege of witnessing, and participating in, the molecular revolution that took us from the discovery of the circadian clock mechanism to the identification of pathways that link clocks to behavior and physiology. This lecture highlights my role and perspective in these developments, and also demonstrates how the successful use of Drosophila for studies of circadian rhythms inspired us to develop a fly model for sleep. I also touch upon my experiences as a non-white immigrant woman navigating my way through the US science and education system, and hope my story will be of interest to some.
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Affiliation(s)
- Amita Sehgal
- Howard Hughes Medical Institute, Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Luppi AI, Spindler LRB, Menon DK, Stamatakis EA. The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia. Front Neurosci 2021; 15:643871. [PMID: 33737863 DOI: 10.3389/fnins.2021.64387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/05/2021] [Indexed: 05/20/2023] Open
Abstract
"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.
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Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Lennart R B Spindler
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Proekt A, Kelz MB. Explaining anaesthetic hysteresis with effect-site equilibration. Br J Anaesth 2020; 126:265-278. [PMID: 33081972 DOI: 10.1016/j.bja.2020.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/16/2020] [Accepted: 09/07/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Anaesthetic induction occurs at higher plasma drug concentrations than emergence in animal studies. Some studies find evidence for such anaesthetic hysteresis in humans, whereas others do not. Traditional thinking attributes hysteresis to drug equilibration between plasma and the effect site. Indeed, a key difference between human studies showing anaesthetic hysteresis and those that do not is in how effect-site equilibration was modelled. However, the effect-site is a theoretical compartment in which drug concentration cannot be measured experimentally. Thus, it is not clear whether drug equilibration models with experimentally intractable compartments are sufficiently constrained to unequivocally establish evidence for the presence or absence of anaesthetic hysteresis. METHODS We constructed several models. One lacked hysteresis beyond effect-site equilibration. In another, neuronal dynamics contributed to hysteresis. We attempted to distinguish between these two systems using drug equilibration models. RESULTS Our modelling studies showed that one can always construct an effect-site equilibration model such that hysteresis collapses. So long as the concentration in the effect-site cannot be measured directly, the correct effect-site equilibration model and the one that erroneously collapses hysteresis are experimentally indistinguishable. We also found that hysteresis can naturally arise even in a simple network of neurones independently of drug equilibration. CONCLUSIONS Effect-site equilibration models can readily collapse hysteresis. However, this does not imply that hysteresis is solely attributable to the kinetics of drug equilibration.
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Affiliation(s)
- Alex Proekt
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Max B Kelz
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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18
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Abstract
General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.
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Affiliation(s)
- Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, 3620 Hamilton Walk, 334 John Morgan Building, Philadelphia, PA 19104, USA; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Translational Research Laboratories, 125 S. 31st St., Philadelphia, PA 19104-3403, USA; Mahoney Institute for Neuroscience, University of Pennsylvania, Clinical Research Building, 415 Curie Blvd, Philadelphia, PA 19104, USA.
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Patterns of Hysteresis Between Induction and Emergence of Neuroanesthesia Are Present in Spinal and Intracranial Surgeries. J Neurosurg Anesthesiol 2020; 32:82-89. [PMID: 30371631 DOI: 10.1097/ana.0000000000000559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Recovery of consciousness is usually seen as a passive process, with emergence from anesthesia depicted as the inverse process of induction resulting from the elimination of anesthetic drugs from their central nervous system sites of action. However, that need not be the case. Recently it has been argued that we might encounter hysteresis to changes in the state of consciousness, known as neural inertia. This phenomenon has been debated in neuroanesthesia, as manipulation of the brain might further influence recovery of consciousness. The present study is aimed at assessing hysteresis between induction and emergence under propofol-opioid neuroanesthesia in humans using estimated propofol concentrations in both spinal and intracranial surgeries. METHODS We identified the moments of loss (LOR) and recovery of responsiveness (ROR) in 21 craniotomies and 25 spinal surgeries. Propofol was given slowly until loss of responsiveness and stopped at the end of surgery. An opioid was present at induction and recovery. Propofol infused was recorded and plasma and effect-site concentrations were estimated using 2 pharmacokinetic models. Dose-response curves were generated. Estimated propofol plasma and effect-site concentrations were compared to assess hysteresis. RESULTS Estimated propofol concentrations at LOR and ROR showed hysteresis. Whether for spinal or intracranial surgeries, the EC50 of propofol at which half of the patients entered and exited the state of responsiveness was significantly different. CONCLUSIONS Hysteresis was observed between propofol concentrations at LOR and ROR, in both patients presenting for spinal and intracranial surgeries. Manipulation of the brain does not appear to change patterns of hysteresis, suggesting that neural inertia may occur in humans, in a way similar to that found in animal species. These findings justify performing a clinical study in patients using measured propofol concentrations to assess neural inertia.
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Resistance to state transitions in responsiveness is differentially modulated by different volatile anaesthetics in male mice. Br J Anaesth 2020; 125:308-320. [PMID: 32660718 DOI: 10.1016/j.bja.2020.05.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/07/2020] [Accepted: 05/03/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Recent studies point to a fundamental distinction between population-based and individual-based anaesthetic pharmacology. At the population level, anaesthetic potency is defined as the relationship between drug concentration and the likelihood of response to a stimulus. At the individual level, even when the anaesthetic concentration is held constant, fluctuations between the responsive and unresponsive states are observed. Notably, these spontaneous fluctuations exhibit resistance to state transitions Rst. Therefore, the response probability in each individual depends not just upon the drug concentration, but also upon responses to previous stimuli. Here, we hypothesise that Rst is distinct from drug potency and is differentially modulated by different anaesthetics. METHODS Adult (14-24 weeks old) C57BL/6J male mice (n=60) were subjected to repeated righting reflex (RR) assays at equipotent steady-state concentrations of isoflurane (0.6 vol%), sevoflurane (1.0 vol%), and halothane (0.4 vol%). RESULTS Fluctuations in RR were observed for all tested anaesthetics. Analysis of these fluctuations revealed that Rst was differentially modulated by different anaesthetics (F[2, 56.01]=49.59; P<0.0001). Fluctuations in RR were modelled using a stochastic dynamical system. This analysis confirmed that the amount of noise that drives behavioural state transitions depends on the anaesthetic agent (F[2, 42.86]=16.72; P<0.0001). CONCLUSIONS Whilst equipotent doses of distinct anaesthetics produce comparable population response probabilities, they engage dramatically different dynamics in each individual animal. This manifests as a differential aggregate propensity to exhibit state transitions. Thus, resistance to state transitions is a fundamentally distinct, novel measure of individualised anaesthetic pharmacology.
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21
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Eckenhoff RG, Maze M, Xie Z, Culley DJ, Goodlin SJ, Zuo Z, Wei H, Whittington RA, Terrando N, Orser BA, Eckenhoff MF. Perioperative Neurocognitive Disorder: State of the Preclinical Science. Anesthesiology 2020; 132:55-68. [PMID: 31834869 PMCID: PMC6913778 DOI: 10.1097/aln.0000000000002956] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The purpose of this article is to provide a succinct summary of the different experimental approaches that have been used in preclinical postoperative cognitive dysfunction research, and an overview of the knowledge that has accrued. This is not intended to be a comprehensive review, but rather is intended to highlight how the many different approaches have contributed to our understanding of postoperative cognitive dysfunction, and to identify knowledge gaps to be filled by further research. The authors have organized this report by the level of experimental and systems complexity, starting with molecular and cellular approaches, then moving to intact invertebrates and vertebrate animal models. In addition, the authors' goal is to improve the quality and consistency of postoperative cognitive dysfunction and perioperative neurocognitive disorder research by promoting optimal study design, enhanced transparency, and "best practices" in experimental design and reporting to increase the likelihood of corroborating results. Thus, the authors conclude with general guidelines for designing, conducting and reporting perioperative neurocognitive disorder rodent research.
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Affiliation(s)
- Roderic G Eckenhoff
- From Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (R.G.E., H.W., M.F.E.) Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California (M.M.) Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (Z.X.) Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts (D.J.C.) Harvard Medical School, Boston, Massachusetts (Z.X., D.J.C.) Department of Medicine, Oregon Health and Science University and Veterans Administration Portland Health Care System, Portland, Oregon (S.J.G.) Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, Virginia (Z.Z.) Department of Anesthesiology, Columbia University Irving Medical Center, New York, New York (R.A.W.) Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (N.T.) Department of Anesthesia, University of Toronto, Toronto, Canada (B.A.O.)
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22
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Escape From Oblivion: Neural Mechanisms of Emergence From General Anesthesia. Anesth Analg 2019; 128:726-736. [PMID: 30883418 DOI: 10.1213/ane.0000000000004006] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. Emergence is driven by mechanisms that can be distinct from entry to the anesthetized state. In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.
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McKinstry-Wu AR, Wasilczuk AZ, Harrison BA, Bedell VM, Sridharan MJ, Breig JJ, Pack M, Kelz MB, Proekt A. Analysis of stochastic fluctuations in responsiveness is a critical step toward personalized anesthesia. eLife 2019; 8:50143. [PMID: 31793434 PMCID: PMC6890463 DOI: 10.7554/elife.50143] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/29/2019] [Indexed: 12/24/2022] Open
Abstract
Traditionally, drug dosing is based on a concentration-response relationship estimated in a population. Yet, in specific individuals, decisions based on the population-level effects frequently result in over or under-dosing. Here, we interrogate the relationship between population-based and individual-based responses to anesthetics in mice and zebrafish. The anesthetic state was assessed by quantifying responses to simple stimuli. Individual responses dynamically fluctuated at a fixed drug concentration. These fluctuations exhibited resistance to state transitions. Drug sensitivity varied dramatically across individuals in both species. The amount of noise driving transitions between states, in contrast, was highly conserved in vertebrates separated by 400 million years of evolution. Individual differences in anesthetic sensitivity and stochastic fluctuations in responsiveness complicate the ability to appropriately dose anesthetics to each individual. Identifying the biological substrate of noise, however, may spur novel therapies, assure consistent drug responses, and encourage the shift from population-based to personalized medicine. Every year, millions of patients undergo general anesthesia for complex or life-saving surgeries. In the vast majority of cases, the drugs work as intended. But a minority of patients take longer than expected to regain consciousness after anesthetic, and a few wake up during the surgery itself. It is unclear what causes these unintended events. When choosing an anesthetic dose for each patient, physicians rely on data from large clinical studies. These studies expose many patients to different doses of an anesthetic drug. At higher doses, fewer and fewer patients remain conscious. This enables physicians to identify the dose at which an average person will lose consciousness. But this approach ignores the difference between the response of an individual and that of the population as a whole. At the population level, the likelihood of a patient being awake decreases smoothly as the concentration of anesthetic increases. But within that population, each individual patient can only ever show a binary response: awake or not awake. To compare anesthetic effects on individuals versus populations, McKinstry-Wu, Wasilczuk et al. exposed mice to a commonly used anesthetic called isoflurane. During prolonged exposure to a constant dose of the drug, each mouse was sometimes unconscious and sometimes awake. These fluctuations in responsiveness seemed to occur at random. Exposing zebrafish to propofol, an anesthetic that works via a different mechanism, had a similar effect. Notably, the responses of both species to anesthesia showed a phenomenon known as inertia. If an individual was unresponsive at one point in time, they were likely to still be unresponsive when assessed again after three minutes. The amount of inertia was similar in mice and zebrafish. This suggests that the mechanism responsible for inertia has remained unchanged over more than 400 million years of evolution. The results reveal similarities between how individuals respond to anesthetics and how individual anesthetic molecules act on cells. When a molecule binds to its receptor protein on a cell, the receptor fluctuates spontaneously between active and inactive states. Studying how individuals respond to drugs could thus provide clues to how the drugs themselves work. Future studies should explore the biological basis of fluctuations in anesthetic responses. Understanding how these arise will help us tailor anesthetics to individual patients.
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Affiliation(s)
- Andrew R McKinstry-Wu
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Andrzej Z Wasilczuk
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States.,Department of Bioengineering, University of Pennsylvania, Philadelphia, United States
| | - Benjamin A Harrison
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Victoria M Bedell
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | | | - Jayce J Breig
- Department of Medicine, Drexel University College of Medicine, Philadelphia, United States
| | - Michael Pack
- Department of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States.,Department of Bioengineering, University of Pennsylvania, Philadelphia, United States
| | - Alexander Proekt
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
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Sepúlveda PO, Tapia LF, Monsalves S. Neural inertia and differences between loss of and recovery from consciousness during total intravenous anaesthesia: a narrative review. Anaesthesia 2019; 74:801-809. [DOI: 10.1111/anae.14609] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2019] [Indexed: 12/31/2022]
Affiliation(s)
- P. O. Sepúlveda
- Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
- Department of Anaesthesia , Universidad del Desarrollo Santiago de Chile Chile
| | - L. F. Tapia
- Consultant, Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
| | - S. Monsalves
- Consultant, Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
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O'Donnell JC, Browne KD, Kilbaugh TJ, Chen HI, Whyte J, Cullen DK. Challenges and demand for modeling disorders of consciousness following traumatic brain injury. Neurosci Biobehav Rev 2019; 98:336-346. [PMID: 30550859 PMCID: PMC7847278 DOI: 10.1016/j.neubiorev.2018.12.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/02/2018] [Accepted: 12/11/2018] [Indexed: 12/29/2022]
Abstract
Following severe traumatic brain injury (TBI), many patients experience coma - an unresponsive state lacking wakefulness or awareness. Coma rarely lasts more than two weeks, and emergence involves passing through a state of wakefulness without awareness of self or environment. Patients that linger in these Disorders of Consciousness (DoC) undergo clinical assessments of awareness for diagnosis into Unresponsive Wakefulness Syndrome (no awareness, also called vegetative state) or Minimally Conscious State (periodic increases in awareness). These diagnoses are notoriously inaccurate, offering little prognostic value. Recovery of awareness is unpredictable, returning within weeks, years, or never. This leaves patients' families with difficult decisions and little information on which to base them. Clinical studies have made significant advancements, but remain encumbered by high variability, limited data output, and a lack of necessary controls. Herein we discuss the clear and present need to establish a preclinical model of TBI-induced DoC, the significant challenges involved, and how such a model can be applied to support DoC research.
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Affiliation(s)
- John C O'Donnell
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Kevin D Browne
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Todd J Kilbaugh
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - H Isaac Chen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - John Whyte
- Moss Rehabilitation Research Institute, Elkins Park, PA, United States
| | - D Kacy Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States.
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26
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Ramadasan-Nair R, Hui J, Itsara LS, Morgan PG, Sedensky MM. Mitochondrial Function in Astrocytes Is Essential for Normal Emergence from Anesthesia in Mice. Anesthesiology 2019; 130:423-434. [PMID: 30707122 PMCID: PMC6375739 DOI: 10.1097/aln.0000000000002528] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC In mice, restriction of loss of the mitochondrial complex I gene Ndufs4 to glutamatergic neurons confers a profound hypersensitivity to volatile anesthetics.Astrocytes are crucial to glutamatergic synapse functioning during excitatory transmission. WHAT THIS ARTICLE TELLS US THAT IS NEW In a tamoxifen-activated astrocyte-specific Ndufs4(KO) mouse, the induction EC50s for tail clamp in both isoflurane and halothane were similar between the control and astrocyte-specific Ndufs4(KO) mice at 3 weeks after 4-hydroxy tamoxifen injection. However, the emergent concentrations in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were half that of the controls.Similarly, the induction EC50s for loss of righting reflex were similar between the control and astrocyte-specific Ndufs4(KO) mice; concentrations for regain of righting reflex in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were much less than the control.Thus, mitochondrial complex I function within astrocytes is essential for normal emergence from anesthesia. BACKGROUND In mice, restriction of loss of the mitochondrial complex I gene Ndufs4 to glutamatergic neurons confers a profound hypersensitivity to volatile anesthetics similar to that seen with global genetic knockout of Ndufs4. Astrocytes are crucial to glutamatergic synapse functioning during excitatory transmission. Therefore, the authors examined the role of astrocytes in the anesthetic hypersensitivity of Ndufs4(KO). METHODS A tamoxifen-activated astrocyte-specific Ndufs4(KO) mouse was constructed. The specificity of the astrocyte-specific inducible model was confirmed by using the green fluorescent protein reporter line Ai6. Approximately 120 astrocyte-specific knockout and control mice were used for the experiments. Mice were anesthetized with varying concentrations of isoflurane or halothane; loss of righting reflex and response to a tail clamp were determined and quantified as the induction and emergence EC50s. Because norepinephrine has been implicated in emergence from anesthesia and astrocytes respond to norepinephrine to release gliotransmitters, the authors measured norepinephrine levels in the brains of control and knockout Ndufs4 animals. RESULTS The induction EC50s for tail clamp in both isoflurane and halothane were similar between the control and astrocyte-specific Ndufs4(KO) mice at 3 weeks after 4-hydroxy tamoxifen injection (induction concentration, EC50(ind)-isoflurane: control = 1.27 ± 0.12, astrocyte-specific knockout = 1.21 ± 0.18, P = 0.495; halothane: control = 1.28 ± 0.05, astrocyte-specific knockout = 1.20 ± 0.05, P = 0.017). However, the emergent concentrations in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were less than the controls for tail clamp; (emergence concentration, EC50(em)-isoflurane: control = 1.18 ± 0.10, astrocyte-specific knockout = 0.67 ± 0.11, P < 0.0001; halothane: control = 1.08 ± 0.09, astrocyte-specific knockout = 0.59 ± 0.12, P < 0.0001). The induction EC50s for loss of righting reflex were also similar between the control and astrocyte-specific Ndufs4(KO) mice (EC50(ind)-isoflurane: control = 1.02 ± 0.10, astrocyte-specific knockout = 0.97 ± 0.06, P = 0.264; halothane: control = 1.03 ± 0.05, astrocyte-specific knockout = 0.99 ± 0.08, P = 0.207). The emergent concentrations for loss of righting reflex in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were less than the control (EC50(em)-isoflurane: control = 1.0 ± 0.07, astrocyte-specific knockout = 0.62 ± 0.12, P < 0.0001; halothane: control = 1.0 ± 0.04, astrocyte-specific KO = 0.64 ± 0.09, P < 0.0001); N ≥ 6 for control and astrocyte-specific Ndufs4(KO) mice. For all tests, similar results were seen at 7 weeks after 4-hydroxy tamoxifen injection. The total norepinephrine content of the brain in global or astrocyte-specific Ndufs4(KO) mice was unchanged compared to control mice. CONCLUSIONS The only phenotype of the astrocyte-specific Ndufs4(KO) mouse was a specific impairment in emergence from volatile anesthetic-induced general anesthesia. The authors conclude that normal mitochondrial function within astrocytes is essential for emergence from anesthesia.
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Affiliation(s)
- Renjini Ramadasan-Nair
- From the Center for Integrative Brain Research, Seattle Children's Research Institute, Washington (R.R.-N., J.H., L.S.I., P.G.M., M.M.S.) the Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington (P.G.M., M.M.S.)
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Abstract
The functions of sleep remain a mystery. Yet they must be important since sleep is highly conserved, and its chronic disruption is associated with various metabolic, psychiatric, and neurodegenerative disorders. This review will cover our evolving understanding of the mechanisms by which sleep is controlled and the complex relationship between sleep and disease states.
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Affiliation(s)
- William J Joiner
- Department of Pharmacology, Biomedical Sciences Graduate Program, Neurosciences Graduate Program, and Center for Circadian Biology, University of California San Diego , La Jolla, California
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Ni JD, Gurav AS, Liu W, Ogunmowo TH, Hackbart H, Elsheikh A, Verdegaal AA, Montell C. Differential regulation of the Drosophila sleep homeostat by circadian and arousal inputs. eLife 2019; 8:40487. [PMID: 30719975 PMCID: PMC6363385 DOI: 10.7554/elife.40487] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/15/2019] [Indexed: 11/25/2022] Open
Abstract
One output arm of the sleep homeostat in Drosophila appears to be a group of neurons with projections to the dorsal fan-shaped body (dFB neurons) of the central complex in the brain. However, neurons that regulate the sleep homeostat remain poorly understood. Using neurogenetic approaches combined with Ca2+ imaging, we characterized synaptic connections between dFB neurons and distinct sets of upstream sleep-regulatory neurons. One group of the sleep-promoting upstream neurons is a set of circadian pacemaker neurons that activates dFB neurons via direct glutaminergic excitatory synaptic connections. Opposing this population, a group of arousal-promoting neurons downregulates dFB axonal output with dopamine. Co-activating these two inputs leads to frequent shifts between sleep and wake states. We also show that dFB neurons release the neurotransmitter GABA and inhibit octopaminergic arousal neurons. We propose that dFB neurons integrate synaptic inputs from distinct sets of upstream sleep-promoting circadian clock neurons, and arousal neurons.
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Affiliation(s)
- Jinfei D Ni
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Adishthi S Gurav
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Weiwei Liu
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Tyler H Ogunmowo
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Hannah Hackbart
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Ahmed Elsheikh
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Andrew A Verdegaal
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Craig Montell
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
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Investigation of hysteresis during anesthetic-induced unconsciousness by using brain functional networks. Biomed Signal Process Control 2018. [DOI: 10.1016/j.bspc.2018.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kim H, Moon JY, Mashour GA, Lee U. Mechanisms of hysteresis in human brain networks during transitions of consciousness and unconsciousness: Theoretical principles and empirical evidence. PLoS Comput Biol 2018; 14:e1006424. [PMID: 30161118 PMCID: PMC6135517 DOI: 10.1371/journal.pcbi.1006424] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 09/12/2018] [Accepted: 08/08/2018] [Indexed: 11/18/2022] Open
Abstract
Hysteresis, the discrepancy in forward and reverse pathways of state transitions, is observed during changing levels of consciousness. Identifying the underlying mechanism of hysteresis phenomena in the brain will enhance the ability to understand, monitor, and control state transitions related to consciousness. We hypothesized that hysteresis in brain networks shares the same underlying mechanism of hysteresis as other biological and non-biological networks. In particular, we hypothesized that the principle of explosive synchronization, which can mediate abrupt state transitions, would be critical to explaining hysteresis in the brain during conscious state transitions. We analyzed high-density electroencephalogram (EEG) that was acquired in healthy human volunteers during conscious state transitions induced by the general anesthetics sevoflurane or ketamine. We developed a novel method to monitor the temporal evolution of EEG networks in a parameter space, which consists of the strength and topography of EEG-based networks. Furthermore, we studied conditions of explosive synchronization in anatomically informed human brain network models. We identified hysteresis in the trajectory of functional brain networks during state transitions. The model study and empirical data analysis explained various hysteresis phenomena during the loss and recovery of consciousness in a principled way: (1) more potent anesthetics induce a larger hysteresis; (2) a larger range of EEG frequencies facilitates transitions into unconsciousness and impedes the return of consciousness; (3) hysteresis of connectivity is larger than that of EEG power; and (4) the structure and strength of functional brain networks reconfigure differently during the loss vs. recovery of consciousness. We conclude that the hysteresis phenomena observed during the loss and recovery of consciousness are generic network features. Furthermore, the state transitions are grounded in the same principle as state transitions in complex non-biological networks, especially during perturbation. These findings suggest the possibility of predicting and modulating hysteresis of conscious state transitions in large-scale brain networks. Hysteresis, characterized by distinct forward and reverse phase transitions, is ubiquitous in nature. For example, there are distinct temperatures for water freezing and ice melting. Similarly, it has been found that state transitions related to consciousness exhibit hysteresis. In particular, the concentration of general anesthetics required to achieve loss of consciousness is significantly higher than the concentration at which consciousness is regained. However, it is unknown whether this is trivially reducible to the pharmacology of these drugs or if it is something related to brain function itself. In this study, we took a novel, network-based approach and hypothesized that the hysteresis observed during anesthetic state transitions shares the same underlying mechanism as that observed in non-biological networks. Our computational modeling, analytic study, and high-density human EEG analysis suggest that various hysteresis phenomena during loss and recovery of consciousness can be explained in principled ways by generic network features. Identifying these network mechanisms of hysteresis in the brain also provides a unified framework for understanding the radically different conscious state transitions associated with sleep, anesthesia, and disorders of consciousness.
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Affiliation(s)
- Hyoungkyu Kim
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Joon-Young Moon
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - George A. Mashour
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - UnCheol Lee
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States of America
- * E-mail:
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31
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Lee U, Mashour GA. Stochastic nature of neural inertia. Br J Anaesth 2018; 121:7-8. [PMID: 29935597 DOI: 10.1016/j.bja.2018.04.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 04/17/2018] [Indexed: 11/18/2022] Open
Affiliation(s)
- U Lee
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - G A Mashour
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
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Development and validation of brain target controlled infusion of propofol in mice. PLoS One 2018; 13:e0194949. [PMID: 29684039 PMCID: PMC5912730 DOI: 10.1371/journal.pone.0194949] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 03/13/2018] [Indexed: 12/25/2022] Open
Abstract
Mechanisms through which anesthetics disrupt neuronal activity are incompletely understood. In order to study anesthetic mechanisms in the intact brain, tight control over anesthetic pharmacology in a genetically and neurophysiologically accessible animal model is essential. Here, we developed a pharmacokinetic model that quantitatively describes propofol distribution into and elimination out of the brain. To develop the model, we used jugular venous catheters to infuse propofol in mice and measured propofol concentration in serial timed brain and blood samples using high performance liquid chromatography (HPLC). We then used adaptive fitting procedures to find parameters of a three compartment pharmacokinetic model such that all measurements collected in the blood and in the brain across different infusion schemes are fit by a single model. The purpose of the model was to develop target controlled infusion (TCI) capable of maintaining constant brain propofol concentration at the desired level. We validated the model for two different targeted concentrations in independent cohorts of experiments not used for model fitting. The predictions made by the model were unbiased, and the measured brain concentration was indistinguishable from the targeted concentration. We also verified that at the targeted concentration, state of anesthesia evidenced by slowing of the electroencephalogram and behavioral unresponsiveness was attained. Thus, we developed a useful tool for performing experiments necessitating use of anesthetics and for the investigation of mechanisms of action of propofol in mice.
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33
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Proekt A, Hudson AE. A stochastic basis for neural inertia in emergence from general anaesthesia. Br J Anaesth 2018; 121:86-94. [PMID: 29935600 DOI: 10.1016/j.bja.2018.02.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 02/23/2018] [Accepted: 03/05/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Transitions into and out of the anaesthetised state exhibit resistance to state transitions known as neural inertia. As a consequence, emergence from anaesthesia occurs at a consistently lower anaesthetic concentration than induction. Motivated by stochastic switching between discrete activity patterns observed at constant anaesthetic concentration, we investigated the consequences of such switching for neural inertia. METHODS We simulated stochastic switching in MATLAB as Brownian motion on an energy landscape or equivalently as a discrete Markov process. Effects of anaesthetics were modelled as changing stability of the awake and the anaesthetised states. Simulation results were compared with re-analysed neural inertia data from mice and Drosophila. RESULTS Diffusion on a two-well energy landscape gives rise to hysteresis. With additive noise, hysteresis collapses. This collapse occurs over a mixing time that is independent from pharmacokinetics. The two-well potential gives rise to the leftward shift for the emergence dose-response curve. Yet, from in vivo data, ΔEC50 and Δ Hill slope are strongly negatively correlated (R2=0.45, P<1.7×10-15). This correlation is not explained by a two-well potential. The extension of the diffusion model to a Markov process with 10 states (three awake, seven unconscious) reproduces both the left shift and the shallower Hill slope for emergence. CONCLUSIONS Stochastic state switching accounts for all known features of neural inertia. More than two states are required to explain the consistent increase observed in variability of recovery from general anaesthesia. This model predicts that hysteresis should collapse with a time scale independent of anaesthetic drug pharmacokinetics.
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Affiliation(s)
- A Proekt
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA.
| | - A E Hudson
- Department of Anesthesiology and Perioperative Medicine, UCLA, Los Angeles, CA, USA
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Karunanithi S, Troup M, van Swinderen B. Using Drosophila to Understand General Anesthesia: From Synapses to Behavior. Methods Enzymol 2018; 602:153-176. [PMID: 29588027 DOI: 10.1016/bs.mie.2018.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Investigating mechanisms of general anesthesia requires access to multiple levels of neuronal function, from effects at individual synapses to responses in behaving animals. Drosophila melanogaster provides an excellent model to test different theories for general anesthesia because it offers robust methods for testing local as well as global target processes, in an animal that is similarly impacted by these diverse drugs as humans. Here, we outline methods to quantify two such endpoints, neurotransmission and behavioral responsiveness, focusing on the intravenous drug propofol.
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Affiliation(s)
- Shanker Karunanithi
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia; School of Medical Science and Menzies Health Institute Queensland, Griffith University Gold Coast Campus, Gold Coast, QLD, Australia
| | - Michael Troup
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
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35
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Schrödinger's cat: anaesthetised and not! Br J Anaesth 2018; 120:424-428. [DOI: 10.1016/j.bja.2017.11.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/10/2017] [Accepted: 11/14/2017] [Indexed: 01/17/2023] Open
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36
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McKinstry-Wu A, Carspecken CW, Proekt A, Kelz MB. Xenon Anesthesia and CT: Noninvasive Measures of Brain Anesthetic Concentration. Methods Enzymol 2018; 602:289-298. [PMID: 29588035 PMCID: PMC6241249 DOI: 10.1016/bs.mie.2018.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The existence of a barrier between anesthetic behavioral state transitions has been observed across phyla, but demonstrating that such a barrier exists and is not a pharmacokinetic artifact has not yet been possible in humans. Such an investigation requires temporally precise information regarding the brain concentration of anesthetic in order to demonstrate the specific pharmacokinetic-pharmacodynamic mismatch that is hysteresis. We propose a method to noninvasively determine brain tissue anesthetic concentration using computerized tomography and the radiopaque gaseous anesthetic xenon. Such a technique can be used to investigate pharmacokinetic-pharmacodynamic mismatches in humans.
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Abstract
Despite decades of intense study, the functions of sleep are still shrouded in mystery. The difficulty in understanding these functions can be at least partly attributed to the varied manifestations of sleep in different animals. Daily sleep duration can range from 4-20 hrs among mammals, and sleep can manifest throughout the brain, or it can alternate over time between cerebral hemispheres, depending on the species. Ecological factors are likely to have shaped these and other sleep behaviors during evolution by altering the properties of conserved arousal circuits in the brain. Nonetheless, core functions of sleep are likely to have arisen early and to have persisted to the present day in diverse organisms. This review will discuss the evolutionary forces that may be responsible for phylogenetic differences in sleep and the potential core functions that sleep fulfills.
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Affiliation(s)
- William J Joiner
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093-0636, USA; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093-0636, USA; Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093-0636, USA; Center for Circadian Biology, University of California San Diego, La Jolla, CA 92093-0636, USA.
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38
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Abstract
Achieving a smooth and rapid emergence from general anesthesia is of particular importance for neurosurgical patients and is a clinical goal for neuroanesthesiologists. Recent data suggest that the process of emergence is not simply the mirror image of induction, but rather controlled by distinct neural circuits. In this narrative review, we discuss (1) hysteresis, (2) the concept of neural inertia, (3) the asymmetry between the neurobiology of induction and emergence, and (4) recent attempts at actively inducing emergence.
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39
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Sepúlveda PO, Carrasco E, Tapia LF, Ramos M, Cruz F, Conget P, Olivares QFB, Cortínez I. Evidence of hysteresis in propofol pharmacodynamics. Anaesthesia 2017; 73:40-48. [DOI: 10.1111/anae.14009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2017] [Indexed: 12/22/2022]
Affiliation(s)
- P. O. Sepúlveda
- Servicio de Anestesia; Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - E. Carrasco
- Servicio de Anestesia; Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - L. F. Tapia
- Servicio de Anestesia; Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - M. Ramos
- Servicio de Anestesia; Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - F. Cruz
- Servicio de Anestesia; Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - P. Conget
- Centro de Química Médica; Facultad de Medicina, Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - Q. F. B. Olivares
- Centro de Medicina Regenerativa; Facultad de Medicina Clínica Alemana Universidad del Desarrollo; Santiago de Chile Chile
| | - I. Cortínez
- División de Anestesiología; Pontificia Universidad Católica de Chile; Santiago de Chile Chile
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40
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Guidera JA, Taylor NE, Lee JT, Vlasov KY, Pei J, Stephen EP, Mayo JP, Brown EN, Solt K. Sevoflurane Induces Coherent Slow-Delta Oscillations in Rats. Front Neural Circuits 2017; 11:36. [PMID: 28725184 PMCID: PMC5495862 DOI: 10.3389/fncir.2017.00036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/16/2017] [Indexed: 12/04/2022] Open
Abstract
Although general anesthetics are routinely administered to surgical patients to induce loss of consciousness, the mechanisms underlying anesthetic-induced unconsciousness are not fully understood. In rats, we characterized changes in the extradural EEG and intracranial local field potentials (LFPs) within the prefrontal cortex (PFC), parietal cortex (PC), and central thalamus (CT) in response to progressively higher doses of the inhaled anesthetic sevoflurane. During induction with a low dose of sevoflurane, beta/low gamma (12–40 Hz) power increased in the frontal EEG and PFC, PC and CT LFPs, and PFC–CT and PFC–PFC LFP beta/low gamma coherence increased. Loss of movement (LOM) coincided with an abrupt decrease in beta/low gamma PFC–CT LFP coherence. Following LOM, cortically coherent slow-delta (0.1–4 Hz) oscillations were observed in the frontal EEG and PFC, PC and CT LFPs. At higher doses of sevoflurane sufficient to induce loss of the righting reflex, coherent slow-delta oscillations were dominant in the frontal EEG and PFC, PC and CT LFPs. Dynamics similar to those observed during induction were observed as animals emerged from sevoflurane anesthesia. We conclude that the rat is a useful animal model for sevoflurane-induced EEG oscillations in humans, and that coherent slow-delta oscillations are a correlate of sevoflurane-induced behavioral arrest and loss of righting in rats.
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Affiliation(s)
- Jennifer A Guidera
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States
| | - Norman E Taylor
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States.,Department of Anaesthesia, Harvard Medical School, BostonMA, United States
| | - Justin T Lee
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States
| | - Ksenia Y Vlasov
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States
| | - JunZhu Pei
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States
| | - Emily P Stephen
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, CambridgeMA, United States
| | - J Patrick Mayo
- Department of Neurobiology, Duke University, DurhamNC, United States
| | - Emery N Brown
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States.,Department of Anaesthesia, Harvard Medical School, BostonMA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, CambridgeMA, United States.,The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, CambridgeMA, United States
| | - Ken Solt
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, BostonMA, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, CambridgeMA, United States.,Department of Anaesthesia, Harvard Medical School, BostonMA, United States
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Hashemi M, Hutt A, Hight D, Sleigh J. Anesthetic action on the transmission delay between cortex and thalamus explains the beta-buzz observed under propofol anesthesia. PLoS One 2017; 12:e0179286. [PMID: 28622355 PMCID: PMC5473556 DOI: 10.1371/journal.pone.0179286] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 05/26/2017] [Indexed: 11/18/2022] Open
Abstract
In recent years, more and more surgeries under general anesthesia have been performed with the assistance of electroencephalogram (EEG) monitors. An increase in anesthetic concentration leads to characteristic changes in the power spectra of the EEG. Although tracking the anesthetic-induced changes in EEG rhythms can be employed to estimate the depth of anesthesia, their precise underlying mechanisms are still unknown. A prominent feature in the EEG of some patients is the emergence of a strong power peak in the β-frequency band, which moves to the α-frequency band while increasing the anesthetic concentration. This feature is called the beta-buzz. In the present study, we use a thalamo-cortical neural population feedback model to reproduce observed characteristic features in frontal EEG power obtained experimentally during propofol general anesthesia, such as this beta-buzz. First, we find that the spectral power peak in the α- and δ-frequency ranges depend on the decay rate constant of excitatory and inhibitory synapses, but the anesthetic action on synapses does not explain the beta-buzz. Moreover, considering the action of propofol on the transmission delay between cortex and thalamus, the model reveals that the beta-buzz may result from a prolongation of the transmission delay by increasing propofol concentration. A corresponding relationship between transmission delay and anesthetic blood concentration is derived. Finally, an analytical stability study demonstrates that increasing propofol concentration moves the systems resting state towards its stability threshold.
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Affiliation(s)
- Meysam Hashemi
- INRIA Grand Est - Nancy, Team NEUROSYS, Villers-lès-Nancy, France
- CNRS, Loria, UMR nō 7503, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Loria, UMR nō 7503, Vandoeuvre-lès-Nancy, France
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Axel Hutt
- German Meteorology Service, Offenbach am Main, Germany
- Department of Mathematics and Statistics, University of Reading, Reading, United Kingdom
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Maier KL, McKinstry-Wu AR, Palanca BJA, Tarnal V, Blain-Moraes S, Basner M, Avidan MS, Mashour GA, Kelz MB. Protocol for the Reconstructing Consciousness and Cognition (ReCCognition) Study. Front Hum Neurosci 2017; 11:284. [PMID: 28638328 PMCID: PMC5461274 DOI: 10.3389/fnhum.2017.00284] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/15/2017] [Indexed: 01/07/2023] Open
Abstract
Important scientific and clinical questions persist about general anesthesia despite the ubiquitous clinical use of anesthetic drugs in humans since their discovery. For example, it is not known how the brain reconstitutes consciousness and cognition after the profound functional perturbation of the anesthetized state, nor has a specific pattern of functional recovery been characterized. To date, there has been a lack of detailed investigation into rates of recovery and the potential orderly return of attention, sensorimotor function, memory, reasoning and logic, abstract thinking, and processing speed. Moreover, whether such neurobehavioral functions display an invariant sequence of return across individuals is similarly unknown. To address these questions, we designed a study of healthy volunteers undergoing general anesthesia with electroencephalography and serial testing of cognitive functions (NCT01911195). The aims of this study are to characterize the temporal patterns of neurobehavioral recovery over the first several hours following termination of a deep inhaled isoflurane general anesthetic and to identify common patterns of cognitive function recovery. Additionally, we will conduct spectral analysis and reconstruct functional networks from electroencephalographic data to identify any neural correlates (e.g., connectivity patterns, graph-theoretical variables) of cognitive recovery after the perturbation of general anesthesia. To accomplish these objectives, we will enroll a total of 60 consenting adults aged 20-40 across the three participating sites. Half of the study subjects will receive general anesthesia slowly titrated to loss of consciousness (LOC) with an intravenous infusion of propofol and thereafter be maintained for 3 h with 1.3 age adjusted minimum alveolar concentration of isoflurane, while the other half of subjects serves as awake controls to gauge effects of repeated neurobehavioral testing, spontaneous fatigue and endogenous rest-activity patterns.
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Affiliation(s)
- Kaitlyn L. Maier
- Department of Pharmacology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Andrew R. McKinstry-Wu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Ben Julian A. Palanca
- Department of Anesthesiology, Washington University School of Medicine, Washington University in St. LouisSt. Louis, MO, United States
| | - Vijay Tarnal
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States
| | | | - Mathias Basner
- Department of Psychiatry, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Michael S. Avidan
- Department of Anesthesiology, Washington University School of Medicine, Washington University in St. LouisSt. Louis, MO, United States
| | - George A. Mashour
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States
| | - Max B. Kelz
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,*Correspondence: Max B. Kelz
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43
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Forward-genetics analysis of sleep in randomly mutagenized mice. Nature 2016; 539:378-383. [PMID: 27806374 PMCID: PMC6076225 DOI: 10.1038/nature20142] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/06/2016] [Indexed: 12/22/2022]
Abstract
Sleep is conserved from invertebrates to vertebrates, and is tightly regulated in a homeostatic manner. The molecular and cellular mechanisms that determine the amount of rapid eye movement sleep (REMS) and non-REMS (NREMS) remain unknown. Here we identify two dominant mutations that affect sleep and wakefulness by using an electroencephalogram/electromyogram-based screen of randomly mutagenized mice. A splicing mutation in the Sik3 protein kinase gene causes a profound decrease in total wake time, owing to an increase in inherent sleep need. Sleep deprivation affects phosphorylation of regulatory sites on the kinase, suggesting a role for SIK3 in the homeostatic regulation of sleep amount. Sik3 orthologues also regulate sleep in fruitflies and roundworms. A missense, gain-of-function mutation in the sodium leak channel NALCN reduces the total amount and episode duration of REMS, apparently by increasing the excitability of REMS-inhibiting neurons. Our results substantiate the use of a forward-genetics approach for studying sleep behaviours in mice, and demonstrate the role of SIK3 and NALCN in regulating the amount of NREMS and REMS, respectively.
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44
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Liu S, Ching S. Homeostatic dynamics, hysteresis and synchronization in a low-dimensional model of burst suppression. J Math Biol 2016; 74:1011-1035. [PMID: 27549764 DOI: 10.1007/s00285-016-1048-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 05/03/2016] [Indexed: 01/24/2023]
Abstract
Burst suppression, a pattern of the electroencephalogram characterized by quasi-periodic alternation of high-voltage activity (burst) and isoelectric silence (suppression), is typically associated with states of unconsciousness, such as in deep general anesthesia and certain etiologies of coma. Recent computational models for burst suppression have attributed the slow (up to tens of seconds) time-scale of burst termination and re-initiation to cycling in supportive physiological process, such as cerebral metabolism. That is, activity-dependent substrate ('energy') depletion during bursts, followed by substrate recovery during suppression. Such a model falls into the category of a fast-slow dynamical system, commonly used to describe neuronal bursting more generally. Here, following this basic paradigm, we develop a low dimensional mean field model for burst suppression that adds several new features and capabilities to previous models. Most notably, this new model includes explicit homeostatic interactions wherein the rates of substrate recovery are tied to neuronal activity in a supply demand loop, creating a physiologically consistent, reciprocal interaction between the neural and substrate processes. We develop formal analysis of the model dynamics, showing, in particular, the capability of the model to produce burst-like activity as a consequence of neuronal downregulation only, without any direct perturbation to the substrate dynamics. Further, we use a synchronization analysis to contrast different mechanisms for spatially local versus global bursting. The analysis performed generates characterizations that are consistent with experimental observations of spatiotemporal features such as burst onset, duration, and spatial organization and, moreover, generates predictions regarding the presence of bistability and hysteresis in the underlying system. Thus, the model provides new dynamical insight into the mechanisms of burst suppression and, moreover, a tractable platform for more detailed future characterizations.
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Affiliation(s)
- Sensen Liu
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - ShiNung Ching
- Department of Electrical and Systems Engineering, Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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45
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Barekat A, Gonzalez A, Mauntz RE, Kotzebue RW, Molina B, El-Mecharrafie N, Conner CJ, Garza S, Melkani GC, Joiner WJ, Lipinski MM, Finley KD, Ratliff EP. Using Drosophila as an integrated model to study mild repetitive traumatic brain injury. Sci Rep 2016; 6:25252. [PMID: 27143646 PMCID: PMC4855207 DOI: 10.1038/srep25252] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/13/2016] [Indexed: 12/19/2022] Open
Abstract
Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. In addition, there has been a growing appreciation that even repetitive, milder forms of TBI (mTBI) can have long-term deleterious consequences to neural tissues. Hampering our understanding of genetic and environmental factors that influence the cellular and molecular responses to injury has been the limited availability of effective genetic model systems that could be used to identify the key genes and pathways that modulate both the acute and long-term responses to TBI. Here we report the development of a severe and mild-repetitive TBI model using Drosophila. Using this system, key features that are typically found in mammalian TBI models were also identified in flies, including the activation of inflammatory and autophagy responses, increased Tau phosphorylation and neuronal defects that impair sleep-related behaviors. This novel injury paradigm demonstrates the utility of Drosophila as an effective tool to validate genetic and environmental factors that influence the whole animal response to trauma and to identify prospective therapies needed for the treatment of TBI.
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Affiliation(s)
- Ayeh Barekat
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA
| | - Arysa Gonzalez
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA
| | - Ruth E Mauntz
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA
| | - Roxanne W Kotzebue
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA
| | - Brandon Molina
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA
| | - Nadja El-Mecharrafie
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA
| | | | - Shannon Garza
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Girish C Melkani
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - William J Joiner
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA
| | - Marta M Lipinski
- Shock, Trauma, and Anesthesiology Research (STAR) Center; Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kim D Finley
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Chemistry, San Diego State University, San Diego, CA, USA
| | - Eric P Ratliff
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA, USA.,Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Chemistry, San Diego State University, San Diego, CA, USA
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46
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Flourakis M, Kula-Eversole E, Hutchison AL, Han TH, Aranda K, Moose DL, White KP, Dinner AR, Lear BC, Ren D, Diekman CO, Raman IM, Allada R. A Conserved Bicycle Model for Circadian Clock Control of Membrane Excitability. Cell 2016; 162:836-48. [PMID: 26276633 DOI: 10.1016/j.cell.2015.07.036] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 05/17/2015] [Accepted: 07/06/2015] [Indexed: 01/04/2023]
Abstract
Circadian clocks regulate membrane excitability in master pacemaker neurons to control daily rhythms of sleep and wake. Here, we find that two distinctly timed electrical drives collaborate to impose rhythmicity on Drosophila clock neurons. In the morning, a voltage-independent sodium conductance via the NA/NALCN ion channel depolarizes these neurons. This current is driven by the rhythmic expression of NCA localization factor-1, linking the molecular clock to ion channel function. In the evening, basal potassium currents peak to silence clock neurons. Remarkably, daily antiphase cycles of sodium and potassium currents also drive mouse clock neuron rhythms. Thus, we reveal an evolutionarily ancient strategy for the neural mechanisms that govern daily sleep and wake.
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Affiliation(s)
- Matthieu Flourakis
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | | | - Alan L Hutchison
- Medical Scientist Training Program, James Franck Institute, Department of Chemistry, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Tae Hee Han
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Kimberly Aranda
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Devon L Moose
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Kevin P White
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL 60637, USA
| | - Aaron R Dinner
- Medical Scientist Training Program, James Franck Institute, Department of Chemistry, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Bridget C Lear
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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47
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Kim M, Mashour GA, Moraes SB, Vanini G, Tarnal V, Janke E, Hudetz AG, Lee U. Functional and Topological Conditions for Explosive Synchronization Develop in Human Brain Networks with the Onset of Anesthetic-Induced Unconsciousness. Front Comput Neurosci 2016; 10:1. [PMID: 26834616 PMCID: PMC4720783 DOI: 10.3389/fncom.2016.00001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/04/2016] [Indexed: 11/18/2022] Open
Abstract
Sleep, anesthesia, and coma share a number of neural features but the recovery profiles are radically different. To understand the mechanisms of reversibility of unconsciousness at the network level, we studied the conditions for gradual and abrupt transitions in conscious and anesthetized states. We hypothesized that the conditions for explosive synchronization (ES) in human brain networks would be present in the anesthetized brain just over the threshold of unconsciousness. To test this hypothesis, functional brain networks were constructed from multi-channel electroencephalogram (EEG) recordings in seven healthy subjects across conscious, unconscious, and recovery states. We analyzed four variables that are involved in facilitating ES in generic, non-biological networks: (1) correlation between node degree and frequency, (2) disassortativity (i.e., the tendency of highly-connected nodes to link with less-connected nodes, or vice versa), (3) frequency difference of coupled nodes, and (4) an inequality relationship between local and global network properties, which is referred to as the suppressive rule. We observed that the four network conditions for ES were satisfied in the unconscious state. Conditions for ES in the human brain suggest a potential mechanism for rapid recovery from the lightly-anesthetized state. This study demonstrates for the first time that the network conditions for ES, formerly shown in generic networks only, are present in empirically-derived functional brain networks. Further investigations with deep anesthesia, sleep, and coma could provide insight into the underlying causes of variability in recovery profiles of these unconscious states.
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Affiliation(s)
- Minkyung Kim
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Department of Physics, Pohang University of Science and TechnologyPohang, South Korea
| | - George A Mashour
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Stefanie-Blain Moraes
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Vijay Tarnal
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Ellen Janke
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Anthony G Hudetz
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Uncheol Lee
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA
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48
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Minert A, Devor M. Brainstem node for loss of consciousness due to GABA(A) receptor-active anesthetics. Exp Neurol 2015; 275 Pt 1:38-45. [PMID: 26436687 DOI: 10.1016/j.expneurol.2015.10.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/31/2015] [Accepted: 10/01/2015] [Indexed: 12/01/2022]
Abstract
The molecular agents that induce loss of consciousness during anesthesia are classically believed to act by binding to cognate transmembrane receptors widely distributed in the CNS and critically suppressing local processing and network connectivity. However, previous work has shown that microinjection of anesthetics into a localized region of the brainstem mesopontine tegmentum (MPTA) rapidly and reversibly induces anesthesia in the absence of global spread. This implies that functional extinction is determined by neural pathways rather than vascular distribution of the anesthetic agent. But does clinical (systemic-induced) anesthesia employ MPTA-linked circuitry? Here we show that cell-selective lesioning of the MPTA in rats does not, in itself, induce anesthesia or coma. However, it increases the systemic dose of pentobarbital required to induce anesthesia, in a manner proportional to the extent of the lesion. Such lesions also affect emergence, extending the duration of anesthesia. Off-target and sham lesions were ineffective. Combined with the prior microinjection data, we conclude that drug delivery to the MPTA is sufficient to induce loss-of-consciousness and that neurons in this locus are necessary for anesthetic induction at clinically relevant doses. Together, the results support an architecture for anesthesia with the MPTA serving as a key node in an endogenous network of dedicated pathways that switch between wake and unconsciousness. As such, the MPTA might also play a role in syncope, concussion and sleep.
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Affiliation(s)
- Anne Minert
- Department of Cell and Developmental Biology, Institute of Life Sciences and the Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Marshall Devor
- Department of Cell and Developmental Biology, Institute of Life Sciences and the Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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49
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Pal D, Jones JM, Wisidagamage S, Meisler MH, Mashour GA. Reduced Nav1.6 Sodium Channel Activity in Mice Increases In Vivo Sensitivity to Volatile Anesthetics. PLoS One 2015; 10:e0134960. [PMID: 26252017 PMCID: PMC4529172 DOI: 10.1371/journal.pone.0134960] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/16/2015] [Indexed: 11/22/2022] Open
Abstract
Nav1.6 is a major voltage-gated sodium channel in the central and peripheral nervous systems. Within neurons, the channel protein is concentrated at the axon initial segment and nodes of Ranvier, where it functions in initiation and propagation of action potentials. We examined the role of Nav1.6 in general anesthesia using two mouse mutants with reduced activity of Nav1.6, Scn8amedJ/medJ and Scn8a9J/9J. The mice were exposed to the general anesthetics isoflurane and sevoflurane in step-wise increments; the concentration required to produce loss of righting reflex, a surrogate for anesthetic-induced unconsciousness in rodents, was determined. Mice homozygous for these mutations exhibited increased sensitivity to both isoflurane and sevoflurane. The increased sensitivity was observed during induction of unconsciousness but not during the recovery phase, suggesting that the effect is not attributable to compromised systemic physiology. Electroencephalographic theta power during baseline waking was lower in mutants, suggesting decreased arousal and reduced neuronal excitability. This is the first report linking reduced activity of a specific voltage-gated sodium channel to increased sensitivity to general anesthetics in vivo.
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Affiliation(s)
- Dinesh Pal
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150, West Medical Center Drive, Ann Arbor, Michigan, United States of America
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Julie M. Jones
- Department of Human Genetics, University of Michigan, 4808 Medical Science Building 2, 1241 East Catherine Street, Ann Arbor, Michigan, United States of America
| | - Stella Wisidagamage
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150, West Medical Center Drive, Ann Arbor, Michigan, United States of America
| | - Miriam H. Meisler
- Department of Human Genetics, University of Michigan, 4808 Medical Science Building 2, 1241 East Catherine Street, Ann Arbor, Michigan, United States of America
| | - George A. Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150, West Medical Center Drive, Ann Arbor, Michigan, United States of America
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, United States of America
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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50
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Ratliff EP, Mauntz RE, Kotzebue RW, Gonzalez A, Achal M, Barekat A, Finley KA, Sparhawk JM, Robinson JE, Herr DR, Harris GL, Joiner WJ, Finley KD. Aging and Autophagic Function Influences the Progressive Decline of Adult Drosophila Behaviors. PLoS One 2015; 10:e0132768. [PMID: 26182057 PMCID: PMC4504520 DOI: 10.1371/journal.pone.0132768] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/19/2015] [Indexed: 12/11/2022] Open
Abstract
Multiple neurological disorders are characterized by the abnormal accumulation of protein aggregates and the progressive impairment of complex behaviors. Our Drosophila studies demonstrate that middle-aged wild-type flies (WT, ~4-weeks) exhibit a marked accumulation of neural aggregates that is commensurate with the decline of the autophagy pathway. However, enhancing autophagy via neuronal over-expression of Atg8a (Atg8a-OE) reduces the age-dependent accumulation of aggregates. Here we assess basal locomotor activity profiles for single- and group-housed male and female WT flies and observed that only modest behavioral changes occurred by 4-weeks of age, with the noted exception of group-housed male flies. Male flies in same-sex social groups exhibit a progressive increase in nighttime activity. Infrared videos show aged group-housed males (4-weeks) are engaged in extensive bouts of courtship during periods of darkness, which is partly repressed during lighted conditions. Together, these nighttime courtship behaviors were nearly absent in young WT flies and aged Atg8a-OE flies. Previous studies have indicated a regulatory role for olfaction in male courtship partner choice. Coincidently, the mRNA expression profiles of several olfactory genes decline with age in WT flies; however, they are maintained in age-matched Atg8a-OE flies. Together, these results suggest that middle-aged male flies develop impairments in olfaction, which could contribute to the dysregulation of courtship behaviors during dark time periods. Combined, our results demonstrate that as Drosophila age, they develop early behavior defects that are coordinate with protein aggregate accumulation in the nervous system. In addition, the nighttime activity behavior is preserved when neuronal autophagy is maintained (Atg8a-OE flies). Thus, environmental or genetic factors that modify autophagic capacity could have a positive impact on neuronal aging and complex behaviors.
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Affiliation(s)
- Eric P. Ratliff
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Ruth E. Mauntz
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
| | - Roxanne W. Kotzebue
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Arysa Gonzalez
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Madhulika Achal
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Ayeh Barekat
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Kaelyn A. Finley
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
| | - Jonathan M. Sparhawk
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - James E. Robinson
- Departments of Neurosciences and Pharmacology, University of California San Diego, La Jolla, California, United States of America
| | - Deron R. Herr
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
| | - Greg L. Harris
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - William J. Joiner
- Departments of Neurosciences and Pharmacology, University of California San Diego, La Jolla, California, United States of America
| | - Kim D. Finley
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California, United States of America
- Expression Drug Designs, LLC, San Diego, California, United States of America
- Department of Biology, San Diego State University, San Diego, California, United States of America
- * E-mail:
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