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Dieudonné Rahm N, Morawska G, Pautex S, Elia N. Monitoring nociception and awareness during palliative sedation: A systematic review. Palliat Med 2021; 35:1407-1420. [PMID: 34109873 DOI: 10.1177/02692163211022943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Providing unawareness and pain relief are core elements of palliative sedation. In addition to clinical scales, nociception and electroencephalogram-based depth of sedation monitoring are used to assess the level of consciousness and analgesia during sedation in intensive care units and during procedures. AIM To determine whether reported devices impact the outcomes of palliative sedation. DESIGN Systematic review and narrative synthesis of research published between January 2000 and December 2020. DATA SOURCES Embase, Google Scholar, PubMed, CENTRAL, and the Cochrane Library. All reports describing the use of any monitoring device to assess the level of consciousness or analgesia during palliative sedation were screened for inclusion. Data concerning safety and efficacy were extracted. Patient comfort was the primary outcome of interest. Articles reporting sedation but that did not meet guidelines of the European Association for Palliative Care were excluded. RESULTS Six reports of five studies were identified. Four of these were case series and two were case reports. Together, these six reports involved a total of 67 sedated adults. Methodological quality was assessed fair to good. Medication regimens were adjusted to bispectral index monitoring values in two studies, which found poor correlation between monitoring values and observational scores. In another study, high nociception index values, representing absence of pain, were used to detect opioid overdosing. Relatives and caregivers found the procedures feasible and acceptable.
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Affiliation(s)
- Nathalie Dieudonné Rahm
- Division of Palliative Medicine, Department of Geriatrics and Rehabilitation, Geneva University Hospitals, Hôpital de Bellerive, Collonge-Bellerive, Geneva, Switzerland
| | - Ghizlaine Morawska
- Division of Palliative Medicine, Department of Geriatrics and Rehabilitation, Geneva University Hospitals, Hôpital de Bellerive, Collonge-Bellerive, Geneva, Switzerland
| | - Sophie Pautex
- Division of Palliative Medicine, Department of Geriatrics and Rehabilitation, Geneva University Hospitals, Hôpital de Bellerive, Collonge-Bellerive, Geneva, Switzerland
| | - Nadia Elia
- Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, Geneva University Hospitals, Geneva, Switzerland
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102
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Ciria LF, Suárez-Pinilla M, Williams AG, Jagannathan SR, Sanabria D, Bekinschtein TA. Different underlying mechanisms for high and low arousal in probabilistic learning in humans. Cortex 2021; 143:180-194. [PMID: 34450566 DOI: 10.1016/j.cortex.2021.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
Humans are uniquely capable of adapting to highly changing environments by updating relevant information and adjusting ongoing behaviour accordingly. Here we show how this ability -termed cognitive flexibility- is differentially modulated by high and low arousal fluctuations. We implemented a probabilistic reversal learning paradigm in healthy participants as they transitioned towards sleep or physical extenuation. The results revealed, in line with our pre-registered hypotheses, that low arousal leads to diminished behavioural performance through increased decision volatility, while performance decline under high arousal was attributed to increased perseverative behaviour. These findings provide evidence for distinct patterns of maladaptive decision-making on each side of the arousal inverted u-shaped curve, differentially affecting participants' ability to generate stable evidence-based strategies, and introduces wake-sleep and physical exercise transitions as complementary experimental models for investigating neural and cognitive dynamics.
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Affiliation(s)
- Luis F Ciria
- Mind, Brain & Behavior Research Center and Department of Experimental Psychology, University of Granada, Spain; Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK.
| | - Marta Suárez-Pinilla
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK; Office of the National Director for Dementia Research, Department of Neurodegenerative Disease, Institute of Neurology, University College of London, London, UK
| | - Alex G Williams
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK
| | - Sridhar R Jagannathan
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK
| | - Daniel Sanabria
- Mind, Brain & Behavior Research Center and Department of Experimental Psychology, University of Granada, Spain
| | - Tristán A Bekinschtein
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK.
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103
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Wang J, Xu Y, Deshpande G, Li K, Sun P, Liang P. The Effect of Light Sedation with Midazolam on Functional Connectivity of the Dorsal Attention Network. Brain Sci 2021; 11:brainsci11081107. [PMID: 34439725 PMCID: PMC8392174 DOI: 10.3390/brainsci11081107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 11/19/2022] Open
Abstract
Altered connectivity within and between the resting-state networks (RSNs) brought about by anesthetics that induce altered consciousness remains incompletely understood. It is known that the dorsal attention network (DAN) and its anticorrelations with other RSNs have been implicated in consciousness. However, the role of DAN-related functional patterns in drug-induced sedative effects is less clear. In the current study, we investigated altered functional connectivity of the DAN during midazolam-induced light sedation. In a placebo-controlled and within-subjects experimental study, fourteen healthy volunteers received midazolam or saline with a 1-week interval. Resting-state fMRI data were acquired before and after intravenous drug administration. A multiple region of interest-driven analysis was employed to investigate connectivity within and between RSNs. It was found that functional connectivity was significantly decreased by midazolam injection in two regions located in the left inferior parietal lobule and the left middle temporal area within the DAN as compared with the saline condition. We also identified three clusters in anticorrelation between the DAN and other RSNs for the interaction effect, which included the left medial prefrontal cortex, the right superior temporal gyrus, and the right superior frontal gyrus. Connectivity between all regions and DAN was significantly decreased by midazolam injection. The sensorimotor network was minimally affected. Midazolam decreased functional connectivity of the dorsal attention network. These findings advance the understanding of the neural mechanism of sedation, and such functional patterns might have clinical implications in other medical conditions related to patients with cognitive impairment.
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Affiliation(s)
- Junkai Wang
- Department of Psychology, Tsinghua University, Haidian District, Beijing 100084, China;
| | - Yachao Xu
- Department of Anesthesiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China;
| | - Gopikrishna Deshpande
- School of Psychology, Capital Normal University, Haidian District, Beijing 100048, China;
- Beijing Key Laboratory of Learning and Cognition, Capital Normal University, Beijing 100048, China
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36849, USA
- Department of Psychological Sciences, Auburn University, Auburn, AL 36849, USA
- Alabama Advanced Imaging Consortium, Birmingham, AL 35233, USA
- Center for Neuroscience, Auburn University, Auburn, AL 36849, USA
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore 560030, India
- Center for Brain Research, Indian Institute of Science, Bangalore 560012, India
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China;
- Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Capital Medical University, Beijing 100053, China
| | - Pei Sun
- Department of Psychology, Tsinghua University, Haidian District, Beijing 100084, China;
- Correspondence: (P.S.); (P.L.)
| | - Peipeng Liang
- School of Psychology, Capital Normal University, Haidian District, Beijing 100048, China;
- Beijing Key Laboratory of Learning and Cognition, Capital Normal University, Beijing 100048, China
- Correspondence: (P.S.); (P.L.)
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104
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Linassi F, Obert DP, Maran E, Tellaroli P, Kreuzer M, Sanders RD, Carron M. Implicit Memory and Anesthesia: A Systematic Review and Meta-Analysis. Life (Basel) 2021; 11:850. [PMID: 34440594 PMCID: PMC8400596 DOI: 10.3390/life11080850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 12/01/2022] Open
Abstract
General anesthesia should induce unconsciousness and provide amnesia. Amnesia refers to the absence of explicit and implicit memories. Unlike explicit memory, implicit memory is not consciously recalled, and it can affect behavior/performance at a later time. The impact of general anesthesia in preventing implicit memory formation is not well-established. We performed a systematic review with meta-analysis of studies reporting implicit memory occurrence in adult patients after deep sedation (Observer's Assessment of Alertness/Sedation of 0-1 with spontaneous breathing) or general anesthesia. We also evaluated the impact of different anesthetic/analgesic regimens and the time point of auditory task delivery on implicit memory formation. The meta-analysis included the estimation of odds ratios (ORs) and 95% confidence intervals (CIs). We included a total of 61 studies with 3906 patients and 119 different cohorts. For 43 cohorts (36.1%), implicit memory events were reported. The American Society of Anesthesiologists (ASA) physical status III-IV was associated with a higher likelihood of implicit memory formation (OR:3.48; 95%CI:1.18-10.25, p < 0.05) than ASA physical status I-II. Further, there was a lower likelihood of implicit memory formation for deep sedation cases, compared to general anesthesia (OR:0.10; 95%CI:0.01-0.76, p < 0.05) and for patients receiving premedication with benzodiazepines compared to not premedicated patients before general anesthesia (OR:0.35; 95%CI:0.13-0.93, p = 0.05).
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Affiliation(s)
- Federico Linassi
- Department of Anaesthesia and Intensive Care, Ca’ Foncello Treviso Regional Hospital, Piazzale Ospedale 1, 31100 Treviso, Italy;
| | - David Peter Obert
- Department of Anaesthesiology and Intensive Care, School of Medicine, Technical University of Munich, Ismaninger Str. 22, 81675 Muenchen, Germany; (D.P.O.); (M.K.)
| | - Eleonora Maran
- Department of Anaesthesia and Intensive Care, Ca’ Foncello Treviso Regional Hospital, Piazzale Ospedale 1, 31100 Treviso, Italy;
| | - Paola Tellaroli
- Department of Developmental Psychology and Socialisation, University of Padova, Via Venezia 8, 35121 Padova, Italy;
| | - Matthias Kreuzer
- Department of Anaesthesiology and Intensive Care, School of Medicine, Technical University of Munich, Ismaninger Str. 22, 81675 Muenchen, Germany; (D.P.O.); (M.K.)
| | - Robert David Sanders
- Department of Anaesthetics, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia;
| | - Michele Carron
- Department of Medicine, Anaesthesiology and Intensive Care, University of Padova, Via C. Battisti 267, 35121 Padova, Italy;
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105
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Sabetian G, Zand F, Mirhadi F, Hadavi MR, Asadpour E, Dehghanpisheh L, Fattahi Saravi Z, Razavi SM. Adequacy of maternal anesthesia depth with two sodium thiopental doses in elective caesarean section: a randomized clinical trial. BMC Anesthesiol 2021; 21:201. [PMID: 34376153 PMCID: PMC8353765 DOI: 10.1186/s12871-021-01421-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 07/28/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Administration of an optimal dose of anesthetic agent to ensure adequate depth of hypnosis with the lowest risk of adverse effects to the fetus is highly important in cesarean section. Sodium thiopental (STP) is still the first choice for induction of anesthesia in some countries for this obstetric surgery. We aimed to compare two doses of STP with regarding the depth of anesthesia and the condition of newborn infants. METHODS In this clinical trial, parturient undergoing elective Caesarian section were randomized into two groups receiving either low-dose (5 mg/kg) or high-dose (7 mg/kg) STP. Muscle relaxation was provided with succinylcholine 2 mg/kg and anesthesia was maintained with O2/N2O and sevoflurane. The depth of anesthesia was evaluated using isolated forearm technique (IFT) and bispectral index (BIS) in various phases. Additionally, infants were assessed using Apgar score and neurobehavioral test. RESULTS Forty parturient were evaluated in each group. BIS was significantly lower in high-dose group at skin incision to delivery and subcutaneous and skin closure. Also, significant differences were noticed in IFT over induction to incision and incision to delivery. Apgar score was significantly lower in high-dose group at 1 min after delivery. Newborn infants in low-dose group had significantly better outcomes in all three domains of the neurobehavioral test. CONCLUSION 7 mg/kg STP is superior to 5 mg/kg in creating deeper hypnosis for mothers. However, it negatively impacts Apgar score and neurobehavioral test of neonates. STP seems to has dropped behind as an acceptable anesthetic in Cesarean section. TRIAL REGISTRATION IRCT No: 2016082819470 N45 , 13/03/2019.
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Affiliation(s)
- Golnar Sabetian
- Trauma Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Farid Zand
- Anesthesiology and Critical Care Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Fatemeh Mirhadi
- Trauma Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Reza Hadavi
- Anesthesiology and Critical Care Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Elham Asadpour
- Anesthesiology and Critical Care Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Laleh Dehghanpisheh
- Anesthesiology and Critical Care Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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106
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Salemi-Mokri-Boukani P, Karimian-Sani-Varjovi H, Safari MS. The promoting effect of vagus nerve stimulation on Lempel-Ziv complexity index of consciousness. Physiol Behav 2021; 240:113553. [PMID: 34375622 DOI: 10.1016/j.physbeh.2021.113553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/27/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Recent studies suggest that vagus nerve stimulation (VNS) promotes cognitive and behavioral restoration after traumatic brain injuries. As vagus nerve has wide effects over the brain and visceral organs, stimulation of the sensory/visceral afferents might have a therapeutic potential to modulate the level of consciousness. One of the most important challenges in studying consciousness is objective evaluation of the consciousness level. Brain complexity that can be measured through Lempel-Ziv complexity (LZC) index was used as a novel mathematical approach for objective measurement of consciousness. The main goal of our study was to examine the effects of VNS on LZC index of consciousness. In this study, we did VNS on the anesthetized rats, and simultaneously LFPs recording was performed in two different cortical areas of primary somatosensory (S1) or visual (V1) cortex. LZC and the amplitude of slow waves were computed during different periods of VNS. We found that the LZC index during VNS period was significantly higher in both of the cortical areas of S1 and V1. Slow-wave activity decreased during VNS in S1, while there was no significant change in V1. Our findings showed that VNS can augment the consciousness level, and LZC index is a more sensitive parameter for detecting the level of consciousness.
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Affiliation(s)
- Paria Salemi-Mokri-Boukani
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Habib Karimian-Sani-Varjovi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Brain Future Institute, Tehran, Iran
| | - Mir-Shahram Safari
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Brain Future Institute, Tehran, Iran.
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107
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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: 26] [Impact Index Per Article: 6.5] [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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108
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Abstract
The electroencephalogram (EEG) can be analyzed in its raw form for characteristic drug-induced patterns of change or summarized using mathematical parameters as a processed electroencephalogram (pEEG). In this article we aim to summarize the contemporary literature pertaining to the commonly available pEEG monitors including the effects of commonly used anesthetic drugs on the EEG and pEEG parameters, pEEG monitor pitfalls, and the clinical implications of pEEG monitoring for anesthesia, pediatrics, and intensive care.
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Affiliation(s)
- David Roche
- Department of Anaesthesiology and Critical Care, Cork University Hospital, Wilton Road, Wilton, Cork T12 DC4A, Ireland.
| | - Padraig Mahon
- Department of Anaesthesiology and Critical Care, Cork University Hospital, Wilton Road, Wilton, Cork T12 DC4A, Ireland
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109
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Luppi AI, Cain J, Spindler LRB, Górska UJ, Toker D, Hudson AE, Brown EN, Diringer MN, Stevens RD, Massimini M, Monti MM, Stamatakis EA, Boly M. Mechanisms Underlying Disorders of Consciousness: Bridging Gaps to Move Toward an Integrated Translational Science. Neurocrit Care 2021; 35:37-54. [PMID: 34236622 PMCID: PMC8266690 DOI: 10.1007/s12028-021-01281-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/17/2021] [Indexed: 01/08/2023]
Abstract
AIM In order to successfully detect, classify, prognosticate, and develop targeted therapies for patients with disorders of consciousness (DOC), it is crucial to improve our mechanistic understanding of how severe brain injuries result in these disorders. METHODS To address this need, the Curing Coma Campaign convened a Mechanisms Sub-Group of the Coma Science Work Group (CSWG), aiming to identify the most pressing knowledge gaps and the most promising approaches to bridge them. RESULTS We identified a key conceptual gap in the need to differentiate the neural mechanisms of consciousness per se, from those underpinning connectedness to the environment and behavioral responsiveness. Further, we characterised three fundamental gaps in DOC research: (1) a lack of mechanistic integration between structural brain damage and abnormal brain function in DOC; (2) a lack of translational bridges between micro- and macro-scale neural phenomena; and (3) an incomplete exploration of possible synergies between data-driven and theory-driven approaches. CONCLUSION In this white paper, we discuss research priorities that would enable us to begin to close these knowledge gaps. We propose that a fundamental step towards this goal will be to combine translational, multi-scale, and multimodal data, with new biomarkers, theory-driven approaches, and computational models, to produce an integrated account of neural mechanisms in DOC. Importantly, we envision that reciprocal interaction between domains will establish a "virtuous cycle," leading towards a critical vantage point of integrated knowledge that will enable the advancement of the scientific understanding of DOC and consequently, an improvement of clinical practice.
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Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK.
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
| | - Joshua Cain
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Lennart R B Spindler
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK.
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
| | - Urszula J Górska
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Daniel Toker
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Andrew E Hudson
- Department of Anesthesia and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Emery N Brown
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Harvard University, Boston, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michael N Diringer
- Department of Neurology and Neurosurgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Robert D Stevens
- Departments of Anesthesiology and Critical Care Medicine, Neurology and Neurosurgery, and Radiology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Marcello Massimini
- Dipartimento di Scienze Biomediche e Cliniche "L. Sacco", Università Degli Studi Di Milano, Milan, Italy
- Istituto Di Ricovero e Cura a Carattere Scientifico, Fondazione Don Carlo Gnocchi, Milan, Italy
| | - Martin M Monti
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA
- Brain Injury Research Center, Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Melanie Boly
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
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110
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Oknina LB, Zaitsev OS, Masherov EL, Pogosbekyan EL, Zigmantovich AS, Kopachka MM, Alexandrova EV. A Stable Reduction of the Number of Brain Functional Connectivity Patterns Determines Prolonged Disorders of Consciousness in Patients with Traumatic Brain Injuries. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921040199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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111
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Pal N, Butterworth J. Comment on: Variation in propofol induction doses administered to surgical patients over age 65. J Am Geriatr Soc 2021; 69:2678-2679. [PMID: 34185880 DOI: 10.1111/jgs.17328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Nirvik Pal
- Department of Anesthesiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - John Butterworth
- Department of Anesthesiology, Virginia Commonwealth University, Richmond, Virginia, USA
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112
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Nourski KV, Steinschneider M, Rhone AE, Krause BM, Mueller RN, Kawasaki H, Banks MI. Cortical Responses to Vowel Sequences in Awake and Anesthetized States: A Human Intracranial Electrophysiology Study. Cereb Cortex 2021; 31:5435-5448. [PMID: 34117741 PMCID: PMC8568007 DOI: 10.1093/cercor/bhab168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/22/2021] [Accepted: 05/22/2021] [Indexed: 02/07/2023] Open
Abstract
Elucidating neural signatures of sensory processing across consciousness states is a major focus in neuroscience. Noninvasive human studies using the general anesthetic propofol reveal differential effects on auditory cortical activity, with a greater impact on nonprimary and auditory-related areas than primary auditory cortex. This study used intracranial electroencephalography to examine cortical responses to vowel sequences during induction of general anesthesia with propofol. Subjects were adult neurosurgical patients with intracranial electrodes placed to identify epileptic foci. Data were collected before electrode removal surgery. Stimuli were vowel sequences presented in a target detection task during awake, sedated, and unresponsive states. Averaged evoked potentials (AEPs) and high gamma (70-150 Hz) power were measured in auditory, auditory-related, and prefrontal cortex. In the awake state, AEPs were found throughout studied brain areas; high gamma activity was limited to canonical auditory cortex. Sedation led to a decrease in AEP magnitude. Upon LOC, there was a decrease in the superior temporal gyrus and adjacent auditory-related cortex and a further decrease in AEP magnitude in core auditory cortex, changes in the temporal structure and increased trial-to-trial variability of responses. The findings identify putative biomarkers of LOC and serve as a foundation for future investigations of altered sensory processing.
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Affiliation(s)
- Kirill V Nourski
- Address correspondence to Kirill V. Nourski, MD, PhD, Department of Neurosurgery, The University of Iowa, 200 Hawkins Dr. 1815 JCP, Iowa City, IA 52242, USA.
| | - Mitchell Steinschneider
- Department of Neurology and Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ariane E Rhone
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA
| | - Bryan M Krause
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Rashmi N Mueller
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA,Department of Anesthesia, The University of Iowa, Iowa City, IA 52242, USA
| | - Hiroto Kawasaki
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA
| | - Matthew I Banks
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA,Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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Differential classification of states of consciousness using envelope- and phase-based functional connectivity. Neuroimage 2021; 237:118171. [PMID: 34000405 DOI: 10.1016/j.neuroimage.2021.118171] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/06/2021] [Accepted: 05/09/2021] [Indexed: 12/14/2022] Open
Abstract
The development of sophisticated computational tools to quantify changes in the brain's oscillatory dynamics across states of consciousness have included both envelope- and phase-based measures of functional connectivity (FC), but there are very few direct comparisons of these techniques using the same dataset. The goal of this study was to compare an envelope-based (i.e. Amplitude Envelope Correlation, AEC) and a phase-based (i.e. weighted Phase Lag Index, wPLI) measure of FC in their classification of states of consciousness. Nine healthy participants underwent a three-hour experimental anesthetic protocol with propofol induction and isoflurane maintenance, in which five minutes of 128-channel electroencephalography were recorded before, during, and after anesthetic-induced unconsciousness, at the following time points: Baseline; light sedation with propofol (Light Sedation); deep unconsciousness following three hours of surgical levels of anesthesia with isoflurane (Unconscious); five minutes prior to the recovery of consciousness (Pre-ROC); and three hours following the recovery of consciousness (Recovery). Support vector machine classification was applied to the source-localized EEG in the alpha (8-13 Hz) frequency band in order to investigate the ability of AEC and wPLI (separately and together) to discriminate i) the four states from Baseline; ii) Unconscious ("deep" unconsciousness) vs. Pre-ROC ("light" unconsciousness); and iii) responsiveness (Baseline, Light Sedation, Recovery) vs. unresponsiveness (Unconscious, Pre-ROC). AEC and wPLI yielded different patterns of global connectivity across states of consciousness, with AEC showing the strongest network connectivity during the Unconscious epoch, and wPLI showing the strongest connectivity during full consciousness (i.e., Baseline and Recovery). Both measures also demonstrated differential predictive contributions across participants and used different brain regions for classification. AEC showed higher classification accuracy overall, particularly for distinguishing anesthetic-induced unconsciousness from Baseline (83.7 ± 0.8%). AEC also showed stronger classification accuracy than wPLI when distinguishing Unconscious from Pre-ROC (i.e., "deep" from "light" unconsciousness) (AEC: 66.3 ± 1.2%; wPLI: 56.2 ± 1.3%), and when distinguishing between responsiveness and unresponsiveness (AEC: 76.0 ± 1.3%; wPLI: 63.6 ± 1.8%). Classification accuracy was not improved compared to AEC when both AEC and wPLI were combined. This analysis of source-localized EEG data demonstrates that envelope- and phase-based FC provide different information about states of consciousness but that, on a group level, AEC is better able to detect relative alterations in brain FC across levels of anesthetic-induced unconsciousness compared to wPLI.
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114
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Wang Y, Wan C, Zhang Y, Zhou Y, Wang H, Yan F, Song D, Du R, Wang Q, Huang L. Detecting Connected Consciousness During Propofol-Induced Anesthesia Using EEG Based Brain Decoding. Int J Neural Syst 2021; 31:2150021. [PMID: 33970056 DOI: 10.1142/s0129065721500210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Connected consciousness refers to the state when external stimuli can enter into the stream of our consciousness experience. Emerging evidence suggests that although patients may not respond behaviorally to external stimuli during anesthesia, they may be aware of their surroundings. In this work, we investigated whether EEG based brain decoding could be used for detecting connected consciousness in the absence of behavioral responses during propofol infusion. A total of 14 subjects participated in our experiment. Subjects were asked to discriminate two types of auditory stimuli with a finger press during an ultraslow propofol infusion. We trained an EEG based brain decoding model using data collected in the awakened state using the same auditory stimuli and tested the model on data collected during the propofol infusion. The model provided a correct classification rate (CCR) of [Formula: see text]% when subjects were able to respond to the stimuli during the propofol infusion. The CCR dropped to [Formula: see text]% when subjects ceased responding and further decreased to [Formula: see text]% when we increased the propofol concentration by another 0.2 [Formula: see text]g/ml. After terminating the propofol infusion, we observed that the CCR rebounded to [Formula: see text]% before the subjects regained consciousness. With the classification results, we provided evidence that loss of consciousness is a gradual process and may progress from full consciousness to connected consciousness and then to disconnected consciousness.
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Affiliation(s)
- Yubo Wang
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
| | - Chenghao Wan
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
| | - Yun Zhang
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
| | - Yu Zhou
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
| | - Haidong Wang
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
| | - Fei Yan
- Department of Anesthesiology and Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, P. R. China
| | - Dawei Song
- Department of Anesthesiology and Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, P. R. China
| | - Ruini Du
- Department of Anesthesiology and Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, P. R. China
| | - Qiang Wang
- Department of Anesthesiology and Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, P. R. China
| | - Liyu Huang
- School of Life Science and Technology, Xidian University, Xi'an, P. R. China
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115
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Pujol J, Blanco-Hinojo L, Gallart L, Moltó L, Martínez-Vilavella G, Vilà E, Pacreu S, Adalid I, Deus J, Pérez-Sola V, Fernández-Candil J. Largest scale dissociation of brain activity at propofol-induced loss of consciousness. Sleep 2021; 44:5894260. [PMID: 32813022 DOI: 10.1093/sleep/zsaa152] [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: 05/15/2020] [Revised: 08/06/2020] [Indexed: 11/14/2022] Open
Abstract
The brain is a functional unit made up of multilevel connected elements showing a pattern of synchronized activity that varies in different states. The wake-sleep cycle is a major variation of brain functional condition that is ultimately regulated by subcortical arousal- and sleep-promoting cell groups. We analyzed the evolution of functional MRI (fMRI) signal in the whole cortex and in a deep region including most sleep- and wake-regulating subcortical nuclei at loss of consciousness induced by the hypnotic agent propofol. Optimal data were obtained in 21 of the 30 healthy participants examined. A dynamic analysis of fMRI time courses on a time-scale of seconds was conducted to characterize consciousness transition, and functional connectivity maps were generated to detail the anatomy of structures showing different dynamics. Inside the magnet, loss of consciousness was marked by the participants ceasing to move their hands. We observed activity synchronization after loss of consciousness within both the cerebral cortex and subcortical structures. However, the evolution of fMRI signal was dissociated, showing a transient reduction of global cortico-subcortical coupling that was restored during the unconscious state. An exception to cortico-subcortical decoupling was a brain network related to self-awareness (i.e. the default mode network) that remained connected to subcortical brain structures. Propofol-induced unconsciousness is thus characterized by an initial, transitory dissociated synchronization at the largest scale of brain activity. Such cortico-subcortical decoupling and subsequent recoupling may allow the brain to detach from waking activity and reorganize into a functionally distinct state.
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Affiliation(s)
- Jesus Pujol
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain
| | - Laura Blanco-Hinojo
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain
| | - Lluís Gallart
- Department of Anesthesiology, Hospital del Mar-IMIM, Barcelona, Spain.,Department of Surgery, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Luís Moltó
- Department of Anesthesiology, Hospital del Mar-IMIM, Barcelona, Spain
| | | | - Esther Vilà
- Department of Anesthesiology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Susana Pacreu
- Department of Anesthesiology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Irina Adalid
- Department of Anesthesiology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Joan Deus
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Department of Psychobiology and Methodology in Health Sciences, Autonomous University of Barcelona, Barcelona, Spain
| | - Víctor Pérez-Sola
- Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain.,Institute of Neuropsychiatry and Addictions, Hospital del Mar-IMIM and Department of Psychiatry, Autonomous University of Barcelona, Barcelona, Spain
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Sattin D, Duran D, Visintini S, Schiaffi E, Panzica F, Carozzi C, Rossi Sebastiano D, Visani E, Tobaldini E, Carandina A, Citterio V, Magnani FG, Cacciatore M, Orena E, Montano N, Caldiroli D, Franceschetti S, Picozzi M, Matilde L. Analyzing the Loss and the Recovery of Consciousness: Functional Connectivity Patterns and Changes in Heart Rate Variability During Propofol-Induced Anesthesia. Front Syst Neurosci 2021; 15:652080. [PMID: 33889078 PMCID: PMC8055941 DOI: 10.3389/fnsys.2021.652080] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/15/2021] [Indexed: 11/13/2022] Open
Abstract
The analysis of the central and the autonomic nervous systems (CNS, ANS) activities during general anesthesia (GA) provides fundamental information for the study of neural processes that support alterations of the consciousness level. In the present pilot study, we analyzed EEG signals and the heart rate (HR) variability (HRV) in a sample of 11 patients undergoing spinal surgery to investigate their CNS and ANS activities during GA obtained with propofol administration. Data were analyzed during different stages of GA: baseline, the first period of anesthetic induction, the period before the loss of consciousness, the first period after propofol discontinuation, and the period before the recovery of consciousness (ROC). In EEG spectral analysis, we found a decrease in posterior alpha and beta power in all cortical areas observed, except the occipital ones, and an increase in delta power, mainly during the induction phase. In EEG connectivity analysis, we found a significant increase of local efficiency index in alpha and delta bands between baseline and loss of consciousness as well as between baseline and ROC in delta band only and a significant reduction of the characteristic path length in alpha band between the baseline and ROC. Moreover, connectivity results showed that in the alpha band there was mainly a progressive increase in the number and in the strength of incoming connections in the frontal region, while in the beta band the parietal region showed mainly a significant increase in the number and in the strength of outcoming connections values. The HRV analysis showed that the induction of anesthesia with propofol was associated with a progressive decrease in complexity and a consequent increase in the regularity indexes and that the anesthetic procedure determined bradycardia which was accompanied by an increase in cardiac sympathetic modulation and a decrease in cardiac parasympathetic modulation during the induction. Overall, the results of this pilot study showed as propofol-induced anesthesia caused modifications on EEG signal, leading to a "rebalance" between long and short-range cortical connections, and had a direct effect on the cardiac system. Our data suggest interesting perspectives for the interactions between the central and autonomic nervous systems for the modulation of the consciousness level.
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Affiliation(s)
- Davide Sattin
- Neurology, Public Health, Disability Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Clinical and Experimental Medicine and Medical Humanities-PhD Program, Insubria University, Varese, Italy
| | - Dunja Duran
- Clinical and Experimental Epileptology Division, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Sergio Visintini
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elena Schiaffi
- Neurophysiology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ferruccio Panzica
- Clinical Engineering Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Carla Carozzi
- Department of Anaesthesia, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | - Elisa Visani
- Clinical and Experimental Epileptology Division, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleonora Tobaldini
- Department of Internal Medicine, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Angelica Carandina
- Department of Internal Medicine, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Valeria Citterio
- Department of Internal Medicine, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Francesca Giulia Magnani
- Neurology, Public Health, Disability Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Martina Cacciatore
- Neurology, Public Health, Disability Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleonora Orena
- Department of Anaesthesia, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Nicola Montano
- Department of Internal Medicine, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Dario Caldiroli
- Department of Anaesthesia, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silvana Franceschetti
- Neurophysiology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Mario Picozzi
- Center for Clinical Ethics, Biotechnology and Life Sciences Department, Insubria University, Varese, Italy
| | - Leonardi Matilde
- Neurology, Public Health, Disability Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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117
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Yang W, Chini M, Pöpplau JA, Formozov A, Dieter A, Piechocinski P, Rais C, Morellini F, Sporns O, Hanganu-Opatz IL, Wiegert JS. Anesthetics fragment hippocampal network activity, alter spine dynamics, and affect memory consolidation. PLoS Biol 2021; 19:e3001146. [PMID: 33793545 PMCID: PMC8016109 DOI: 10.1371/journal.pbio.3001146] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/15/2021] [Indexed: 02/07/2023] Open
Abstract
General anesthesia is characterized by reversible loss of consciousness accompanied by transient amnesia. Yet, long-term memory impairment is an undesirable side effect. How different types of general anesthetics (GAs) affect the hippocampus, a brain region central to memory formation and consolidation, is poorly understood. Using extracellular recordings, chronic 2-photon imaging, and behavioral analysis, we monitor the effects of isoflurane (Iso), medetomidine/midazolam/fentanyl (MMF), and ketamine/xylazine (Keta/Xyl) on network activity and structural spine dynamics in the hippocampal CA1 area of adult mice. GAs robustly reduced spiking activity, decorrelated cellular ensembles, albeit with distinct activity signatures, and altered spine dynamics. CA1 network activity under all 3 anesthetics was different to natural sleep. Iso anesthesia most closely resembled unperturbed activity during wakefulness and sleep, and network alterations recovered more readily than with Keta/Xyl and MMF. Correspondingly, memory consolidation was impaired after exposure to Keta/Xyl and MMF, but not Iso. Thus, different anesthetics distinctly alter hippocampal network dynamics, synaptic connectivity, and memory consolidation, with implications for GA strategy appraisal in animal research and clinical settings.
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Affiliation(s)
- Wei Yang
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mattia Chini
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jastyn A. Pöpplau
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrey Formozov
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Dieter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Patrick Piechocinski
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cynthia Rais
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabio Morellini
- Research Group Behavioral Biology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Olaf Sporns
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
- Indiana University Network Science Institute, Indiana University, Bloomington, Indiana, United States of America
| | - Ileana L. Hanganu-Opatz
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - J. Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
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118
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Frohlich J, Toker D, Monti MM. Consciousness among delta waves: a paradox? Brain 2021; 144:2257-2277. [PMID: 33693596 DOI: 10.1093/brain/awab095] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/12/2021] [Accepted: 02/25/2021] [Indexed: 01/29/2023] Open
Abstract
A common observation in EEG research is that consciousness vanishes with the appearance of delta (1 - 4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are very frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalised epileptic seizures, and disorders of consciousness such as coma and vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the "down states" or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and nonconvulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalogram or MEG signals strongly relates to an individual's level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.
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Affiliation(s)
- Joel Frohlich
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Daniel Toker
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Martin M Monti
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA.,Department of Neurosurgery, UCLA Brain Injury Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
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119
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Orena EF, Landucci F, Ayadi R, Caldiroli D, Papagno C. Propofol and sevoflurane affect intra-operative memory formation of words differently: A prospective cohort study. Eur J Anaesthesiol 2021; 38:S50-S57. [PMID: 33399379 DOI: 10.1097/eja.0000000000001417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Memory priming seems possible even during apparently adequate anaesthesia. However, the effects of different anaesthetics and type of stimuli, by virtue of their specific neural underpinnings, have not been considered. OBJECTIVE To determine if intra-operative implicit memory is affected by the type of anaesthesia (propofol or sevoflurane) or by the type of stimuli (abstract or concrete words). DESIGN Two consecutive, randomised controlled experiments. SETTING Neurological institute in Milan, Italy. PATIENTS Forty-three patients undergoing anaesthesia with propofol (experiment 1) and 32 patients undergoing anaesthesia with sevoflurane (experiment 2). Patients were ASA I or II, age 18 to 65 years, native Italian speakers, right-handed and without any condition affecting memory or hearing. INTERVENTION During anaesthesia, the patients heard a list of either concrete or abstract words or no words at all (controls). Explicit memory was tested with an explicit recall task and the Brice Interview; implicit memory was assessed through a word stem completion test. OUTCOME MEASURES The number of explicitly recalled words, positivity to the Brice Interview, the proportion of target and nontarget hits, and a derived implicit memory score. RESULTS With propofol, the proportion of target hits was significantly greater than the proportion of nontarget hits for the concrete word experimental group (P = 0.018). The implicit memory score of the concrete word experimental group was significantly higher than the score of both the abstract word experimental group (P = 0.000) and the concrete word control group (P = 0.023). With sevoflurane, the proportion of target hits was significantly higher than the proportion of nontarget hits for the abstract word experimental group only (P = 0.027). No patients had a BIS above 60 and no one could recall intra-operative events or words. CONCLUSION Intra-operative memory for words can form during apparently adequate BIS-guided anaesthesia but is modified by propofol or sevoflurane acting on different brain targets. Further studies on larger samples and using neuroimaging techniques are needed. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT03727464.
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Affiliation(s)
- Eleonora F Orena
- From the Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico Carlo Besta (EFO, RA, DC), Department of Psychology, Università degli Studi di Milano-Bicocca, Milan (EFO, CP), Department of Anaesthesia and Intensive Care, San Giovanni di Dio Hospital, Florence (FL) and CeRiN and CIMeC, University of Trento, Rovereto, Italy (CP)
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120
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Brain network motifs are markers of loss and recovery of consciousness. Sci Rep 2021; 11:3892. [PMID: 33594110 PMCID: PMC7887248 DOI: 10.1038/s41598-021-83482-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 02/03/2021] [Indexed: 01/12/2023] Open
Abstract
Motifs are patterns of inter-connections between nodes of a network, and have been investigated as building blocks of directed networks. This study explored the re-organization of 3-node motifs during loss and recovery of consciousness. Nine healthy subjects underwent a 3-h anesthetic protocol while 128-channel electroencephalography (EEG) was recorded. In the alpha (8-13 Hz) band, 5-min epochs of EEG were extracted for: Baseline; Induction; Unconscious; 30-, 10- and 5-min pre-recovery of responsiveness; 30- and 180-min post-recovery of responsiveness. We constructed a functional brain network using the weighted and directed phase lag index, on which we calculated the frequency and topology of 3-node motifs. Three motifs (motifs 1, 2 and 5) were significantly present across participants and epochs, when compared to random networks (p < 0.05). The topology of motifs 1 and 5 changed significantly between responsive and unresponsive epochs (p-values < 0.01; Kendall's W = 0.664 (motif 1) and 0.529 (motif 5)). Motif 1 was constituted of long-range chain-like connections, while motif 5 was constituted of short-range, loop-like connections. Our results suggest that anesthetic-induced unconsciousness is associated with a topological re-organization of network motifs. As motif topological re-organization may precede (motif 5) or accompany (motif 1) the return of responsiveness, motifs could contribute to the understanding of the neural correlates of consciousness.
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121
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Foundations of Human Consciousness: Imaging the Twilight Zone. J Neurosci 2020; 41:1769-1778. [PMID: 33372062 PMCID: PMC8115882 DOI: 10.1523/jneurosci.0775-20.2020] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/07/2020] [Accepted: 11/03/2020] [Indexed: 11/30/2022] Open
Abstract
What happens in the brain when conscious awareness of the surrounding world fades? We manipulated consciousness in two experiments in a group of healthy males and measured brain activity with positron emission tomography. Measurements were made during wakefulness, escalating and constant levels of two anesthetic agents (experiment 1, n = 39), and during sleep-deprived wakefulness and non-rapid eye movement sleep (experiment 2, n = 37). In experiment 1, the subjects were randomized to receive either propofol or dexmedetomidine until unresponsiveness. In both experiments, forced awakenings were applied to achieve rapid recovery from an unresponsive to a responsive state, followed by immediate and detailed interviews of subjective experiences during the preceding unresponsive condition. Unresponsiveness rarely denoted unconsciousness, as the majority of the subjects had internally generated experiences. Unresponsive anesthetic states and verified sleep stages, where a subsequent report of mental content included no signs of awareness of the surrounding world, indicated a disconnected state. Functional brain imaging comparing responsive and connected versus unresponsive and disconnected states of consciousness during constant anesthetic exposure revealed that activity of the thalamus, cingulate cortices, and angular gyri are fundamental for human consciousness. These brain structures were affected independent from the pharmacologic agent, drug concentration, and direction of change in the state of consciousness. Analogous findings were obtained when consciousness was regulated by physiological sleep. State-specific findings were distinct and separable from the overall effects of the interventions, which included widespread depression of brain activity across cortical areas. These findings identify a central core brain network critical for human consciousness. SIGNIFICANCE STATEMENT Trying to understand the biological basis of human consciousness is currently one of the greatest challenges of neuroscience. While the loss and return of consciousness regulated by anesthetic drugs and physiological sleep are used as model systems in experimental studies on consciousness, previous research results have been confounded by drug effects, by confusing behavioral “unresponsiveness” and internally generated consciousness, and by comparing brain activity levels across states that differ in several other respects than only consciousness. Here, we present carefully designed studies that overcome many previous confounders and for the first time reveal the neural mechanisms underlying human consciousness and its disconnection from behavioral responsiveness, both during anesthesia and during normal sleep, and in the same study subjects.
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122
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Linassi F, Kreuzer M, Maran E, Farnia A, Zanatta P, Navalesi P, Carron M. Age influences on Propofol estimated brain concentration and entropy during maintenance and at return of consciousness during total intravenous anesthesia with target-controlled infusion in unparalyzed patients: An observational prospective trial. PLoS One 2020; 15:e0244145. [PMID: 33351856 PMCID: PMC7755218 DOI: 10.1371/journal.pone.0244145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 12/03/2020] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Aging affects pharmacodynamics/pharmacokinetics of anesthetics, but age effects on Entropy-guided total intravenous anesthesia with target-controlled infusions (TIVA-TCI) are not fully characterized. We compared aging effects on effective estimated brain concentration of Propofol (CeP) during TIVA-TCI Entropy-guided anesthesia, without neuromuscular blockade (NMB). METHODS We performed an observational, prospective, single-center study enrolling 75 adult women undergoing Entropy-guided Propofol-Remifentanil TIVA-TCI for breast surgery. Primary endpoint was the relationship between age and CeP at maintenance of anesthesia (MA) during Entropy-guided anesthesia. Secondary endpoints were relationships between age and CeP at arousal reaction (AR), return of consciousness (ROC) and explicit recall evenience. We calculated a linear model to evaluate the age's impact on observational variable and performed pairwise tests to compare old (≥65 years, n = 50) and young (<65 years, n = 25) patients or patients with and without an AR. RESULTS We did not observe age-related differences in CeP during MA, but CeP significantly (p = 0,01) decreased with age at ROC. Entropy values during MA increased with age and were significantly higher in the elderly (RE: median 56[IQR49.3-61] vs 47.5[42-52.5],p = 0.001; SE: 51.6[45-55.5] vs 44[IQR40-50],p = 0.005). 18 patients had an AR, having higher maximum RE (92.5[78-96.3] vs 65[56.5-80.5],p<0.001), SE (79[64.8-84] vs 61[52.5-69],p = 0.03, RE-SE (12.5[9.5-16.5] vs 6 [3-9],p<0.001. CONCLUSION Older age was associated with lower CeP at ROC, but not during MA in unparalysed patients undergoing breast surgery. Although RE and SE during MA, at comparable CeP, were higher in the elderly, Entropy, and in particular an increasing RE-SE, is a reliable index to detect an AR.
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Affiliation(s)
- Federico Linassi
- Department of Medicine—DIMED, Section of Anesthesiology and Intensive Care, University of Padova, Padova, Italy
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Matthias Kreuzer
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Eleonora Maran
- Department of Medicine—DIMED, Section of Anesthesiology and Intensive Care, University of Padova, Padova, Italy
| | - Antonio Farnia
- Department of Anesthesia and Intensive Care, Treviso Regional Hospital, Piazzale Ospedale, Treviso, Italy
| | - Paolo Zanatta
- Department of Anesthesia and Intensive Care, Integrated University Hospital of Verona, Piazzale Aristide Stefani, Verona, Italy
| | - Paolo Navalesi
- Department of Medicine—DIMED, Section of Anesthesiology and Intensive Care, University of Padova, Padova, Italy
| | - Michele Carron
- Department of Medicine—DIMED, Section of Anesthesiology and Intensive Care, University of Padova, Padova, Italy
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123
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McIsaac DI, Boet S. Can we sooth the subconscious during general anaesthesia? BMJ 2020; 371:m4547. [PMID: 33599624 DOI: 10.1136/bmj.m4547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Daniel I McIsaac
- Departments of Anesthesiology & Pain Medicine, University of Ottawa and The Ottawa Hospital, Ottawa, ON, Canada
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- School of Epidemiology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Sylvain Boet
- Departments of Anesthesiology & Pain Medicine, University of Ottawa and The Ottawa Hospital, Ottawa, ON, Canada
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Francophone Affairs, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Innovation in Medical Education, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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124
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Halder S, Juel BE, Nilsen AS, Raghavan LV, Storm JF. Changes in measures of consciousness during anaesthesia of one hemisphere (Wada test). Neuroimage 2020; 226:117566. [PMID: 33221442 DOI: 10.1016/j.neuroimage.2020.117566] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/25/2020] [Accepted: 11/16/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND In the Wada test, one hemisphere is selectively anaesthetised by unilateral intracarotid injection of a fast-acting anaesthetic agent. This gives a unique opportunity to observe the functions and physiological activity of one hemisphere while anaesthetising the other, allowing direct comparisons between brain states and hemispheres that are not possible in any other setting. AIM To test whether potential measures of consciousness would be affected by selective anaesthesia of one hemisphere, and reliably distinguish the states of the anesthetised and non-anesthetised hemispheres. METHODS We analysed EEG data from 7 patients undergoing Wada-tests in preparation for neurosurgery and computed several measures reported to correlate with the state of consciousness: power spectral density, functional connectivity, and measures of signal diversity. These measures were compared between conditions (normal rest vs. unilateral anaesthesia) and hemispheres (injected vs. non-injected), and used with a support vector machine to classify the state and site of injection objectively from individual patient's recordings. RESULTS Although brain function, assessed behaviourally, appeared to be substantially altered only on the injected side, we found large bilateral changes in power spectral density for all frequency bands tested, and functional connectivity changed significantly both between and within both hemispheres. Surprisingly, we found no statistically significant differences in the measures of signal diversity between hemispheres or states, for the group of 7 patients, although 4 of the individual patients showed a significant decrease in signal diversity on the injected side. Nevertheless, including signal diversity measures improved the classification results, indicating that these measures carry at least some non-redundant information about the condition and injection site. We propose that several of these results may be explained by conduction of activity, via the corpus callosum, from the injected to the contralateral hemisphere and vice versa, without substantially affecting the function of the receiving hemisphere, thus reflecting what we call "cross-state unreceptiveness".
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Affiliation(s)
- Sebastian Halder
- Brain Signalling Group, Section for Physiology, Department of Molecular Medicine, IMB, University of Oslo, 0317 Oslo, Norway; School of Computer Science and Electronic Engineering, University of Essex, CO4 3SQ Colchester, United Kingdom.
| | - Bjørn E Juel
- Brain Signalling Group, Section for Physiology, Department of Molecular Medicine, IMB, University of Oslo, 0317 Oslo, Norway; Department of Psychiatry, Center for Sleep and Consciousness, University of Wisconsin, Madison, WI, USA
| | - André S Nilsen
- Brain Signalling Group, Section for Physiology, Department of Molecular Medicine, IMB, University of Oslo, 0317 Oslo, Norway
| | - Lashmi Venkat Raghavan
- Department of Anesthesia and Pain Medicine, Toronto Western Hospital, University of Toronto, Canada
| | - Johan F Storm
- Brain Signalling Group, Section for Physiology, Department of Molecular Medicine, IMB, University of Oslo, 0317 Oslo, Norway.
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125
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Pullon RM, Yan L, Sleigh JW, Warnaby CE. Granger Causality of the Electroencephalogram Reveals Abrupt Global Loss of Cortical Information Flow during Propofol-induced Loss of Responsiveness. Anesthesiology 2020; 133:774-786. [PMID: 32930729 PMCID: PMC7495984 DOI: 10.1097/aln.0000000000003398] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is a commonly held view that information flow between widely separated regions of the cerebral cortex is a necessary component in the generation of wakefulness (also termed “connected” consciousness). This study therefore hypothesized that loss of wakefulness caused by propofol anesthesia should be associated with loss of information flow, as estimated by the effective connectivity in the scalp electroencephalogram (EEG) signal. In healthy adult volunteers, propofol anesthesia–induced loss of consciousness was associated with an abrupt, substantial, and global decrease in connectivity. These changes are comparably reversed at regain of consciousness. These observations suggest that information flow is an important indicator of wakefulness. Supplemental Digital Content is available in the text.
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126
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Tomczyk M, Schumacher BN. Nurses' experience with palliative sedation procedures in line with the 2005 Swiss guidelines: an exploratory study. Can Oncol Nurs J 2020; 30:261-268. [PMID: 33165398 DOI: 10.5737/23688076304261268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Many international studies have shown that the process of palliative sedation in an end-of-life context can be an adverse, even emotionally distressing experience for nurses. However, to the best of our knowledge, the experience of nurses working in palliative care in Switzerland has never been explored. The purpose of our study was, therefore, to understand and describe nurses' experience with the process of palliative sedation in line with the Swiss guidelines developed in 2005. We opted for an exploratory qualitative monocentric study using comprehensive individual interviews to achieve this objective. A total of 10 nurses were approached, and nine agreed to take part. After the interviews were transcribed, eight were ultimately included in the analysis. This analysis shows that nurses' attitudes toward the process of palliative sedation tended to be hesitant, resistant, or confident and that this was linked to the length of time they had worked in palliative care. These findings suggest that the 2005 Swiss guidelines do not protect nurses against the uncertainty related to process of palliative sedation. A national comprehensive multicentric study therefore needs to be developed to consolidate these results.
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Affiliation(s)
- Martyna Tomczyk
- Medical Ethics Researcher, PhD, Postdoctoral Fellow, Institute of Humanities in Medicine, Lausanne University Hospital (CHUV), Avenue de Provence 82, CH-1007 Lausanne, Switzerland, , +33 (0)6 95 11 86 45
| | - Bernard N Schumacher
- Philosopher, Professor, PhD-HDR, Coordinator, Interdisciplinary Institute of Ethics and Human Rights, University of Fribourg, Switzerland. Avenue de Beauregard 13, CH-1700 Fribourg, Switzerland,
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127
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The influence of induction speed on the frontal (processed) EEG. Sci Rep 2020; 10:19444. [PMID: 33173114 PMCID: PMC7655958 DOI: 10.1038/s41598-020-76323-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
The intravenous injection of the anaesthetic propofol is clinical routine to induce loss of responsiveness (LOR). However, there are only a few studies investigating the influence of the injection rate on the frontal electroencephalogram (EEG) during LOR. Therefore, we focused on changes of the frontal EEG especially during this period. We included 18 patients which were randomly assigned to a slow or fast induction group and recorded the frontal EEG. Based on this data, we calculated the power spectral density, the band powers and band ratios. To analyse the behaviour of processed EEG parameters we calculated the beta ratio, the spectral entropy, and the spectral edge frequency. Due to the prolonged induction period in the slow injection group we were able to distinguish loss of responsiveness to verbal command (LOvR) from loss of responsiveness to painful stimulus (LOpR) whereas in the fast induction group we could not. At LOpR, we observed a higher relative alpha and beta power in the slow induction group while the relative power in the delta range was lower than in the fast induction group. When concentrating on the slow induction group the increase in relative alpha power pre-LOpR and even before LOvR indicated that frontal EEG patterns, which have been suggested as an indicator of unconsciousness, can develop before LOR. Further, LOvR was best reflected by an increase of the alpha to delta ratio, and LOpR was indicated by a decrease of the beta to alpha ratio. These findings highlight the different spectral properties of the EEG at various levels of responsiveness and underline the influence of the propofol injection rate on the frontal EEG during induction of general anesthesia.
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128
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Wang J, Sun P, Liang P. Neuropsychopharmacological effects of midazolam on the human brain. Brain Inform 2020; 7:15. [PMID: 33170396 PMCID: PMC7655878 DOI: 10.1186/s40708-020-00116-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
As a commonly used anesthetic agent, midazolam has the properties of water-soluble, rapid onset, and short duration of action. With the rapid development in the field of neuroimaging, numerous studies have investigated how midazolam acts on the human brain to induce the alteration of consciousness. However, the neural bases of midazolam-induced sedation or anesthesia remain beginning to be understood in detail. In this review, we summarize findings from neuroimaging studies that have used midazolam to study altered consciousness at different levels and content. We also compare the results to those of neuroimaging studies using diverse anesthetic agents and describe the common neural correlates of anesthetic-induced alteration of consciousness.
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Affiliation(s)
- Junkai Wang
- School of Psychology, Capital Normal University, Haidian District, Beijing, 100048, China.,Beijing Key Laboratory of Learning and Cognition, Beijing, China.,Department of Psychology, Tsinghua University, Haidian District, Beijing, 100084, China
| | - Pei Sun
- Department of Psychology, Tsinghua University, Haidian District, Beijing, 100084, China.
| | - Peipeng Liang
- School of Psychology, Capital Normal University, Haidian District, Beijing, 100048, China. .,Beijing Key Laboratory of Learning and Cognition, Beijing, China.
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129
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Six S, Laureys S, Poelaert J, Maîresse O, Theuns P, Bilsen J, Deschepper R. Neurophysiological Assessments During Continuous Sedation Until Death Put Validity of Observational Assessments Into Question: A Prospective Observational Study. Pain Ther 2020; 10:377-390. [PMID: 33151515 PMCID: PMC8119559 DOI: 10.1007/s40122-020-00214-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/19/2020] [Indexed: 11/26/2022] Open
Abstract
Introduction In case of untreatable suffering at the end of life, continuous sedation until death (CSD) may be the only treatment option left. Because these patients cannot communicate anymore, caregivers have to rely on behavioral observation to assess the patient’s comfort. Recently, however, a number of studies from the neurosciences have shown that sometimes consciousness and pain are undetectable with these traditional behavioral methods. The aim of this study was to find out if subjective caregiver assessments of consciousness and pain would be confirmed by objective neurophysiological measures. Methods In this prospective observational study, we observed patients from the start of palliative sedation until death. Subjective caregiver assessments of level of consciousness and pain based on behavioral observations were compared with objective measures from neurophysiological monitoring devices. Results We collected and analyzed 108 subjective caregiver assessments in a sample of 12 patients and 32 assessments by traditionally used observational scales. We compared these with objective neurophysiological measures. Sensitivity and specificity of caregivers’ subjective assessments of consciousness was 23.6 and 91.1% respectively, with an accuracy of 54.0% and interrater reliability (κ) of 0.13. For pain, this was 0 and 94.79%, respectively, an accuracy of 88%, and an inter-rater reliability (κ) of − 0.063. Agreement between caregivers’ subjective assessments and objective neurophysiological measures of consciousness and pain was very poor. Conclusions Caregivers’ subjective assessment of level of consciousness and pain during CSD is unreliable compared with objective neurophysiological monitoring. Our results suggest that assessments of patient comfort during CSD could have been improved substantially by including objective monitoring of level of consciousness and pain. Trial Registration The protocol for this observational study has been registered retrospectively at Clinical-Trials.gov (ID NCT03273244).
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Affiliation(s)
- Stefaan Six
- Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium.
- Coma Science group, Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Avenue de l'hôpital 11, 4000, Liège, Belgium.
| | - Steven Laureys
- Coma Science group, Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Avenue de l'hôpital 11, 4000, Liège, Belgium
| | - Jan Poelaert
- Department of Anesthesiology and Perioperative Medicine, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
| | - Olivier Maîresse
- Department of Experimental and Applied Psychology, Vrije Universiteit Brussel, Pleinlaan 2, 1000, Brussels, Belgium
| | - Peter Theuns
- Department of Experimental and Applied Psychology, Vrije Universiteit Brussel, Pleinlaan 2, 1000, Brussels, Belgium
| | - Johan Bilsen
- Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
| | - Reginald Deschepper
- Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
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130
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Lane TJ. The minimal self hypothesis. Conscious Cogn 2020; 85:103029. [PMID: 33091792 DOI: 10.1016/j.concog.2020.103029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 09/07/2020] [Accepted: 09/26/2020] [Indexed: 12/01/2022]
Abstract
For millennia self has been conjectured to be necessary for consciousness. But scant empirical evidence has been adduced to support this hypothesis. Inconsistent explications of "self" and failure to design apt experiments have impeded progress. Advocates of phenomenological psychiatry, however, have helped explicate "self," and employed it to explain some psychopathological symptoms. In those studies, "self" is understood in a minimalist sense, sheer "for-me-ness." Unfortunately, explication of the "minimal self" (MS) has relied on conceptual analysis, and applications to psychopathology have been hermeneutic, allowing for many degrees of interpretive latitude. The result is that MS's current scientific status is analogous to that of the "atom," at the time when "atom" was just beginning to undergo transformation from a philosophical to a scientific concept. Fortunately, there is now an opportunity to promote a similar transformation for "MS." Discovery of the brain's Default Mode Network (DMN) opened the door to neuroimaging investigations of self. Taking the DMN and other forms of intrinsic activity as a starting point, an empirical foothold can be established, one that spurs experimental research and that enables extension of research into multiple phenomena. New experimental protocols that posit "MS" can help explain phenomena hitherto not thought to be related to self, thereby hastening development of a mature science of self. In particular, targeting phenomena wherein consciousness is lost and recovered, as in some cases of Unresponsive Wakefulness Syndrome (UWS), allow for design of neuroimaging probes that enable detection of MS during non-conscious states. These probes, as well as other experimental protocols applied to NREM Sleep, General Anesthesia (GA), and the waking state, provide some evidence to suggest that not only can self and consciousness dissociate, MS might be a necessary precondition for conscious experience. Finally, these findings have implications for the science of consciousness: it has been suggested that "levels of consciousness" (LoC) is not a legitimate concept for the science of consciousness. But because we have the conceptual and methodological tools with which to refine investigations of MS, we have the means to identify a possible foundation-a bifurcation point-for consciousness, as well as the means by which to measure degrees of distance from that foundation. These neuroimaging investigations of MS position us to better assess whether LoC has a role to play in a mature science of consciousness.
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Affiliation(s)
- Timothy Joseph Lane
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, TMU Shuang-Ho Hospital, New Taipei City, Taiwan; Institute of European and American Studies, Academia Sinica, Taipei, Taiwan.
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Patlatzoglou K, Chennu S, Gosseries O, Bonhomme V, Wolff A, Laureys S. Generalized Prediction of Unconsciousness during Propofol Anesthesia using 3D Convolutional Neural Networks. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:134-137. [PMID: 33017948 DOI: 10.1109/embc44109.2020.9175324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Neuroscience has generated a number of recent advances in the search for the neural correlates of consciousness, but these have yet to find valuable real-world applications. Electroencephalography under anesthesia provides a powerful experimental setup to identify electrophysiological signatures of altered states of consciousness, as well as a testbed for developing systems for automatic diagnosis and prognosis of awareness in clinical settings. In this work, we use deep convolutional neural networks to automatically differentiate sub-anesthetic states and depths of anesthesia, solely from one second of raw EEG signal. Our results with leave-one-participant-out-cross-validation show that behavioral measures, such as the Ramsay score, can be used to learn generalizable neural networks that reliably predict levels of unconsciousness in unseen transitional anesthetic states, as well as in unseen experimental setups and behaviors. Our findings highlight the potential of deep learning to detect progressive changes in anesthetic-induced unconsciousness with higher granularity than behavioral or pharmacological markers. This work has broader significance for identifying generalized patterns of brain activity that index states of consciousness.Clinical Relevance- In the United States alone, over 100,000 people receive general anesthesia every day, from which up to 1% is affected by unintended intraoperative awareness [1]. Despite this, brain-based monitoring of consciousness is not common in the clinic, and has had mixed success [2]. Given this context, our aim is to develop and explore an automated deep learning model that accurately predicts and interprets the depth and quality of anesthesia from the raw EEG signal.
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132
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Montupil J, Defresne A, Bonhomme V. The Raw and Processed Electroencephalogram as a Monitoring and Diagnostic Tool. J Cardiothorac Vasc Anesth 2020; 33 Suppl 1:S3-S10. [PMID: 31279351 DOI: 10.1053/j.jvca.2019.03.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this narrative review, different aspects of electroencephalogram (EEG) monitoring during anesthesia are approached, with a special focus on cardiothoracic and vascular anesthesia, from the basic principles to more sophisticated diagnosis and monitoring utilities. The available processed EEG-derived indexes of the depth of the hypnotic component of anesthesia have well-defined limitations and usefulness. They prevent intraoperative awareness with recall in specific patient populations and under a specific anesthetic regimen. They prevent intraoperative overdose, and they shorten recovery times. They also help to avoid lengthy intraoperative periods of suppression activity, which are known to be deleterious in terms of outcome. Other than those available indexes, the huge amount of information contained in the EEG currently is being used only partially. Several other areas of interest regarding EEG during anesthesia have emerged in terms of anesthesia mechanisms elucidation, nociception monitoring, and diagnosis or prevention of brain insults.
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Affiliation(s)
- Javier Montupil
- University Department of Anesthesia and Intensive Care Medicine, CHR Citadelle, Liège, Belgium
| | - Aline Defresne
- Department of Anesthesia and Intensive Care Medicine, CHU Liege, Liège, Belgium
| | - Vincent Bonhomme
- Anesthesia and Intensive Care Laboratory, GIGA-Consciousness Thematic Unit, GIGA Research, Liege University, Liège, Belgium.
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Robert D. Sanders, B.Sc., M.B.B.S., Ph.D., F.R.C.A., Recipient of the 2020 James E. Cottrell, M.D., Presidential Scholar Award. Anesthesiology 2020; 133:720-723. [DOI: 10.1097/aln.0000000000003512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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134
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Does Delta Connectivity Differentiate Sleep and Anesthesia? Anesthesiology 2020; 133:700-701. [PMID: 32796199 DOI: 10.1097/aln.0000000000003478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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135
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Sanders RD, Casey C, Saalmann YB. Predictive coding as a model of sensory disconnection: relevance to anaesthetic mechanisms. Br J Anaesth 2020; 126:37-40. [PMID: 32912603 DOI: 10.1016/j.bja.2020.08.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 10/23/2022] Open
Affiliation(s)
- Robert D Sanders
- University of Sydney, Sydney, NSW, Australia; Department of Anaesthetics, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
| | - Cameron Casey
- Department of Anesthesiology, University of Wisconsin - Madison, Madison, WI, USA
| | - Yuri B Saalmann
- Department of Psychology, University of Wisconsin - Madison, Madison, WI, USA
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Kaiser HA, Peus M, Luedi MM, Lersch F, Krejci V, Reineke D, Sleigh J, Hight D. Frontal electroencephalogram reveals emergence-like brain activity occurring during transition periods in cardiac surgery. Br J Anaesth 2020; 125:291-297. [DOI: 10.1016/j.bja.2020.05.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/29/2020] [Accepted: 05/16/2020] [Indexed: 12/22/2022] Open
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Six S, Van Overmeire R, Bilsen J, Laureys S, Poelaert J, Theuns P, Deschepper R. Attitudes of Professional Caregivers and Family Members Regarding the Use of Monitoring Devices to Improve Assessments of Pain and Discomfort During Continuous Sedation Until Death. J Pain Symptom Manage 2020; 60:390-399. [PMID: 32105791 DOI: 10.1016/j.jpainsymman.2020.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/14/2020] [Accepted: 02/14/2020] [Indexed: 12/31/2022]
Abstract
CONTEXT Assessing consciousness and pain during continuous sedation until death (CSD) by behavior-based observational scales alone has recently been put into question. Instead, the use of monitoring technology has been suggested to make more objective and reliable assessments. Insights into which factors influence attitudes toward using these monitoring devices in a context of CSD is a first step in formulating recommendations to inform future practice. OBJECTIVES The aim of this study was to find out what influences professional caregivers' and family members' (FMs) attitudes regarding the use of monitors during CSD. METHODS We conducted semistructured face-to-face interviews with 20 professional caregivers and 15 FMs, who cared for a patient or had an FM, respectively, who took part in a study using monitoring devices. Recruitment took place in an academic hospital, a locoregional hospital, and two nursing homes, all located in Belgium. Two researchers independently analyzed the data, using grounded theory to inductively develop a model that represents the emerging attitude toward use of monitors during CSD. RESULTS Our model shows that the emerging attitudes toward using monitors during CSD is determined by view on CSD, desire for peace of mind, emotional valence attached to using monitors, and the realization that the sole use of behavior-based observational measures could be unreliable in a CSD context. We identified several facilitators and barriers to inform future implementation strategies. CONCLUSION Most participants had no objections, and all participants found the use of monitoring devices during CSD feasible and acceptable. We identified a number of facilitators and barriers and suggested that being aware that care can be improved, good communication, shared decision making, and continuing professional education can overcome the identified barriers. We suggest future research would focus on developing implementation strategies and guidelines for introducing objective monitoring devices in diverse palliative care settings.
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Affiliation(s)
- Stefaan Six
- Department of Public Health, Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussel, Belgium; Cyclotron Research Centre and Neurology Department, Coma Science Group, University and University Hospital of Liège, Liège, Belgium.
| | - Roel Van Overmeire
- Department of Public Health, Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Johan Bilsen
- Department of Public Health, Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Steven Laureys
- Cyclotron Research Centre and Neurology Department, Coma Science Group, University and University Hospital of Liège, Liège, Belgium
| | - Jan Poelaert
- Department of Anesthesiology & Perioperative Medicine, Vrije Universiteit Brussel, Brussel, Belgium
| | - Peter Theuns
- Department of Public Health, Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Reginald Deschepper
- Department of Public Health, Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussel, Belgium
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138
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Blundon EG, Gallagher RE, Ward LM. Electrophysiological evidence of preserved hearing at the end of life. Sci Rep 2020; 10:10336. [PMID: 32587364 PMCID: PMC7316981 DOI: 10.1038/s41598-020-67234-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 06/04/2020] [Indexed: 11/17/2022] Open
Abstract
This study attempts to answer the question: “Is hearing the last to go?” We present evidence of hearing among unresponsive actively dying hospice patients. Individual ERP (MMN, P3a, and P3b) responses to deviations in auditory patterns are reported for conscious young, healthy control participants, as well as for hospice patients, both when the latter were conscious, and again when they became unresponsive to their environment. Whereas the MMN (and perhaps too the P3a) is considered an automatic response to auditory irregularities, the P3b is associated with conscious detection of oddball targets. All control participants, and most responsive hospice patients, evidenced a “local” effect (either a MMN, a P3a, or both) and some a “global” effect (P3b) to deviations in tone, or deviations in auditory pattern. Importantly, most unresponsive patients showed evidence of MMN responses to tone changes, and some showed a P3a or P3b response to either tone or pattern changes. Thus, their auditory systems were responding similarly to those of young, healthy controls just hours from end of life. Hearing may indeed be one of the last senses to lose function as humans die.
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Affiliation(s)
| | - Romayne E Gallagher
- Department of Family Medicine, Vancouver, Canada.,Department of Family and Community Medicine, Providence Health Care, Vancouver, Canada
| | - Lawrence M Ward
- Department of Psychology, Vancouver, Canada. .,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.
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139
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Bailey CR. Dexmedetomidine in children - when should we be using it? Anaesthesia 2020; 76:309-311. [PMID: 32578205 DOI: 10.1111/anae.15169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2020] [Indexed: 01/10/2023]
Affiliation(s)
- C R Bailey
- Department of Anaesthesia, Guy's and St, Thomas' NHS Foundation Trust, London, UK
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140
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Benítez-Rosario MA, Ascanio-León B. Palliative sedation: beliefs and decision-making among Spanish palliative care physicians. Support Care Cancer 2020; 28:2651-2658. [PMID: 31637516 DOI: 10.1007/s00520-019-05086-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/16/2019] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe physician attitudes to deep palliative sedation. METHODS A nationwide e-survey of Spanish palliative care specialists was performed using vignettes which described patients close to death with intractable symptoms. Sedation levels were defined according to the Richmond Agitation-Sedation Scale. Multivariate analyses were performed to assess the explanatory factors involved in decision-making. RESULTS Responses of 292 palliative care specialists were analyzed (response rate 40%). Ninety-four percent, 87%, and 81% of the respondents supported the use of palliative sedation in cases of irreversible refractory symptoms as hyperactive delirium and dyspnea at rest secondary to lung cancer and GOLD stage IV COPD; 60% agreed with the use of palliative sedation in cases of existential suffering. Logistic regression analysis found as the explanatory factor in not performing palliative sedation the physicians' belief that sedation therapy constitutes undercover euthanasia (OR = 12, p < 0.01). Around 80% of physicians who decided on palliative sedation chose deep/complete sedation for every vignette; there were no common explanatory factors for decision-making for every vignette. The belief that sedation therapy equates to undercover euthanasia justifies not performing deep sedation in cases of irreversible refractory agitated delirium (OR = 7) and irreversible intractable dyspnea (OR = 6). Physician background in palliative care and sedation were associated with the selection of deep/complete sedation in cases of refractory delirium and cancer-associated dyspnea. CONCLUSIONS Spanish palliative physicians generally agree with the use of deep sedation as a proportionate treatment in dying patients with refractory symptoms. Decision-making is associated with physician beliefs regarding euthanasia and with the physician's background in palliative care and sedation.
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Affiliation(s)
- Miguel Angel Benítez-Rosario
- Palliative Care Unit, La Candelaria Hospital, Canary Health Service, Facultad de Medicina, Universidad de La Laguna, Crtra del Rosario 145, 38010, Santa Cruz de Tenerife, Spain.
| | - Belén Ascanio-León
- Palliative Care Unit, La Candelaria Hospital, Canary Health Service, Facultad de Medicina, Universidad de La Laguna, Crtra del Rosario 145, 38010, Santa Cruz de Tenerife, Spain
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141
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Andrillon T, Kouider S. The vigilant sleeper: neural mechanisms of sensory (de)coupling during sleep. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2019.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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142
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Reimann HM, Niendorf T. The (Un)Conscious Mouse as a Model for Human Brain Functions: Key Principles of Anesthesia and Their Impact on Translational Neuroimaging. Front Syst Neurosci 2020; 14:8. [PMID: 32508601 PMCID: PMC7248373 DOI: 10.3389/fnsys.2020.00008] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
In recent years, technical and procedural advances have brought functional magnetic resonance imaging (fMRI) to the field of murine neuroscience. Due to its unique capacity to measure functional activity non-invasively, across the entire brain, fMRI allows for the direct comparison of large-scale murine and human brain functions. This opens an avenue for bidirectional translational strategies to address fundamental questions ranging from neurological disorders to the nature of consciousness. The key challenges of murine fMRI are: (1) to generate and maintain functional brain states that approximate those of calm and relaxed human volunteers, while (2) preserving neurovascular coupling and physiological baseline conditions. Low-dose anesthetic protocols are commonly applied in murine functional brain studies to prevent stress and facilitate a calm and relaxed condition among animals. Yet, current mono-anesthesia has been shown to impair neural transmission and hemodynamic integrity. By linking the current state of murine electrophysiology, Ca2+ imaging and fMRI of anesthetic effects to findings from human studies, this systematic review proposes general principles to design, apply and monitor anesthetic protocols in a more sophisticated way. The further development of balanced multimodal anesthesia, combining two or more drugs with complementary modes of action helps to shape and maintain specific brain states and relevant aspects of murine physiology. Functional connectivity and its dynamic repertoire as assessed by fMRI can be used to make inferences about cortical states and provide additional information about whole-brain functional dynamics. Based on this, a simple and comprehensive functional neurosignature pattern can be determined for use in defining brain states and anesthetic depth in rest and in response to stimuli. Such a signature can be evaluated and shared between labs to indicate the brain state of a mouse during experiments, an important step toward translating findings across species.
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Affiliation(s)
- Henning M. Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
- Experimental and Clinical Research Center, A Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
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143
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Fehnel CR, Armengol de la Hoz M, Celi LA, Campbell ML, Hanafy K, Nozari A, White DB, Mitchell SL. Incidence and Risk Model Development for Severe Tachypnea Following Terminal Extubation. Chest 2020; 158:1456-1463. [PMID: 32360728 DOI: 10.1016/j.chest.2020.04.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 04/03/2020] [Accepted: 04/20/2020] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Palliative ventilator withdrawal (PVW) in the ICU is a common occurrence. RESEARCH QUESTION The goal of this study was to measure the rate of severe tachypnea as a proxy for dyspnea and to identify characteristics associated with episodes of tachypnea. STUDY DESIGN AND METHODS This study assessed a retrospective cohort of ICU patients from 2008 to 2012 mechanically ventilated at a single academic medical center who underwent PVW. The primary outcome of at least one episode of severe tachypnea (respiratory rate > 30 breaths/min) within 6 h after PVW was measured by using detailed physiologic and medical record data. Multivariable logistic regression was used to examine the association between patient and treatment characteristics with the occurrence of a severe episode of tachypnea post extubation. RESULTS Among 822 patients undergoing PVW, 19% and 30% had an episode of severe tachypnea during the 1-h and 6-h postextubation period, respectively. Within 1 h postextubation, patients with the following characteristics were more likely to experience tachypnea: no pre-extubation opiates (adjusted OR [aOR], 2.08; 95% CI, 1.03-4.19), lung injury (aOR, 3.33; 95% CI, 2.19-5.04), Glasgow Coma Scale score > 8 (aOR, 2.21; 95% CI, 1.30-3.77), and no postextubation opiates (aOR, 1.90; 95% CI, 1.19-3.00). INTERPRETATION Up to one-third of ICU patients undergoing PVW experience severe tachypnea. Administration of pre-extubation opiates (anticipatory dosing) represents a key modifiable factor that may reduce poor symptom control.
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Affiliation(s)
- Corey R Fehnel
- Hebrew SeniorLife Hinda and Arthur Marcus Institute for Aging Research, Boston, MA; Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA.
| | - Miguel Armengol de la Hoz
- Division of Clinical Informatics, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA; Laboratory for Computational Physiology, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA; Biomedical Engineering and Telemedicine Group, Biomedical Technology Centre CTB, ETSI Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | - Leo A Celi
- Department of Medicine, Division of Pulmonary and Critical Care, Beth Israel Deaconess Medical Center, Boston, MA; Massachusetts Institute of Technology, Cambridge, MA
| | | | - Khalid Hanafy
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA
| | - Ala Nozari
- Department of Medicine, Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA
| | - Douglas B White
- Department of Critical Care, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Susan L Mitchell
- Hebrew SeniorLife Hinda and Arthur Marcus Institute for Aging Research, Boston, MA; Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA
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144
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Huang Y, Hu K, Green AL, Ma X, Gillies MJ, Wang S, Fitzgerald JJ, Pan Y, Martin S, Huang P, Zhan S, Li D, Tan H, Aziz TZ, Sun B. Dynamic changes in rhythmic and arrhythmic neural signatures in the subthalamic nucleus induced by anaesthesia and tracheal intubation. Br J Anaesth 2020; 125:67-76. [PMID: 32336475 DOI: 10.1016/j.bja.2020.03.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Subcortical structures, including the basal ganglia, have been proposed to be crucial for arousal, consciousness, and behavioural responsiveness. How the basal ganglia contribute to the loss and recovery of consciousness during anaesthesia has, however, not yet been well characterised. METHODS Twelve patients with advanced Parkinson's disease, who were undergoing deep brain stimulation (DBS) electrode implantation in the subthalamic nucleus (STN), were included in this study. Local field potentials (LFPs) were recorded from the DBS electrodes and EEG was recorded from the scalp during induction of general anaesthesia (with propofol and sufentanil) and during tracheal intubation. Neural signatures of loss of consciousness and of the expected arousal during intubation were sought in the STN and EEG recordings. RESULTS Propofol-sufentanil anaesthesia resulted in power increases in delta, theta, and alpha frequencies, and broadband power decreases in higher frequencies in both STN and frontal cortical areas. This was accompanied by increased STN-frontal cortical coherence only in the alpha frequency band (119 [68]%; P=0.0049). We observed temporal activity changes in STN after tracheal intubation, including power increases in high-beta (22-40 Hz) frequency (98 [123]%; P=0.0064) and changes in the power-law exponent in the power spectra at lower frequencies (2-80 Hz), which were not observed in the frontal cortex. During anaesthesia, the dynamic changes in the high-gamma power in STN LFPs correlated with the power-law exponent in the power spectra at lower frequencies (2-80 Hz). CONCLUSIONS Apart from similar activity changes in both STN and cortex associated with anaesthesia-induced unresponsiveness, we observed specific neuronal activity changes in the STN in response to the anaesthesia and tracheal intubation. We also show that the power-law exponent in the power spectra in the STN was modulated by tracheal intubation in anaesthesia. Our results support the hypothesis that subcortical nuclei may play an important role in the loss and return of responsiveness.
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Affiliation(s)
- Yongzhi Huang
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK.
| | - Kejia Hu
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Xin Ma
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Martin J Gillies
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Shouyan Wang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - James J Fitzgerald
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Yixin Pan
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sean Martin
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Peng Huang
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shikun Zhan
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dianyou Li
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiling Tan
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Oxford, UK; Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK.
| | - Tipu Z Aziz
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Bomin Sun
- Center of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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145
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Six S, Bilsen J, Laureys S, Poelaert J, Theuns P, Deschepper R. A Reflection on Using Observational Measures for the Assessment and/or Monitoring of Level of Consciousness in Palliatively Sedated Patients. J Palliat Med 2020; 23:442-443. [DOI: 10.1089/jpm.2019.0574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Stefaan Six
- Mental Health and Wellbeing Research Group, Department of Public Health, Vrije Universiteit Brussel, Brussel, Belgium
| | - Johan Bilsen
- Mental Health and Wellbeing Research Group, Department of Public Health, Vrije Universiteit Brussel, Brussel, Belgium
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Jan Poelaert
- Department of Anesthesiology & Perioperative Medicine, Vrije Universiteit Brussel, Brussel, Belgium
| | - Peter Theuns
- Mental Health and Wellbeing Research Group, Department of Public Health, Vrije Universiteit Brussel, Brussel, Belgium
| | - Reginald Deschepper
- Mental Health and Wellbeing Research Group, Department of Public Health, Vrije Universiteit Brussel, Brussel, Belgium
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146
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Modolo J, Hassan M, Wendling F, Benquet P. Decoding the circuitry of consciousness: From local microcircuits to brain-scale networks. Netw Neurosci 2020; 4:315-337. [PMID: 32537530 PMCID: PMC7286300 DOI: 10.1162/netn_a_00119] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/09/2019] [Indexed: 01/25/2023] Open
Abstract
Identifying the physiological processes underlying the emergence and maintenance of consciousness is one of the most fundamental problems of neuroscience, with implications ranging from fundamental neuroscience to the treatment of patients with disorders of consciousness (DOCs). One major challenge is to understand how cortical circuits at drastically different spatial scales, from local networks to brain-scale networks, operate in concert to enable consciousness, and how those processes are impaired in DOC patients. In this review, we attempt to relate available neurophysiological and clinical data with existing theoretical models of consciousness, while linking the micro- and macrocircuit levels. First, we address the relationships between awareness and wakefulness on the one hand, and cortico-cortical and thalamo-cortical connectivity on the other hand. Second, we discuss the role of three main types of GABAergic interneurons in specific circuits responsible for the dynamical reorganization of functional networks. Third, we explore advances in the functional role of nested oscillations for neural synchronization and communication, emphasizing the importance of the balance between local (high-frequency) and distant (low-frequency) activity for efficient information processing. The clinical implications of these theoretical considerations are presented. We propose that such cellular-scale mechanisms could extend current theories of consciousness.
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Affiliation(s)
- Julien Modolo
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
| | - Mahmoud Hassan
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
| | | | - Pascal Benquet
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
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147
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Mashour GA, Roelfsema P, Changeux JP, Dehaene S. Conscious Processing and the Global Neuronal Workspace Hypothesis. Neuron 2020; 105:776-798. [PMID: 32135090 PMCID: PMC8770991 DOI: 10.1016/j.neuron.2020.01.026] [Citation(s) in RCA: 465] [Impact Index Per Article: 93.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/31/2019] [Accepted: 01/22/2020] [Indexed: 10/24/2022]
Abstract
We review the central tenets and neuroanatomical basis of the global neuronal workspace (GNW) hypothesis, which attempts to account for the main scientific observations regarding the elementary mechanisms of conscious processing in the human brain. The GNW hypothesis proposes that, in the conscious state, a non-linear network ignition associated with recurrent processing amplifies and sustains a neural representation, allowing the corresponding information to be globally accessed by local processors. We examine this hypothesis in light of recent data that contrast brain activity evoked by either conscious or non-conscious contents, as well as during conscious or non-conscious states, particularly general anesthesia. We also discuss the relationship between the intertwined concepts of conscious processing, attention, and working memory.
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Affiliation(s)
- George A Mashour
- Center for Consciousness Science, Neuroscience Graduate Program, and Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Pieter Roelfsema
- Department of Vision & Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands; Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Department of Psychiatry, Academic Medical Center, Amsterdam, the Netherlands
| | - Jean-Pierre Changeux
- CNRS UMR 3571, Institut Pasteur, 75724 Paris, France; Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France; Kavli Institute for Brain & Mind, University of California, San Diego, La Jolla, CA, USA.
| | - Stanislas Dehaene
- Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France; Cognitive Neuroimaging Unit, CEA, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France.
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148
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Suhre W, Van Norman GA. Ethical Issues in Organ Transplantation at End of Life: Defining Death. Anesthesiol Clin 2020; 38:231-246. [PMID: 32008655 DOI: 10.1016/j.anclin.2019.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
End-of-life vital organ transplantation involves singular ethical issues, because survival of the donor is impossible, and organ retrieval is ideally as close to the death of the donor as possible to minimize organ ischemic time. Historical efforts to define death have been met with confusion and discord. Fifty years on, the Harvard criteria for brain death continue to be problematic and now face significant legislative efforts to limit their authority.
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Affiliation(s)
- Wendy Suhre
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Box 356540, 1959 Northeast Pacific Street, Seattle, WA 98195, USA
| | - Gail A Van Norman
- Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; Bioethics, University of Washington, Seattle, WA, USA.
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149
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Winter U, LeVan P, Borghardt TL, Akin B, Wittmann M, Leyens Y, Schmidt S. Content-Free Awareness: EEG-fcMRI Correlates of Consciousness as Such in an Expert Meditator. Front Psychol 2020; 10:3064. [PMID: 32132942 PMCID: PMC7040185 DOI: 10.3389/fpsyg.2019.03064] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/26/2019] [Indexed: 11/21/2022] Open
Abstract
The minimal neural correlate of the conscious state, regardless of the neural activity correlated with the ever-changing contents of experience, has still not been identified. Different attempts have been made, mainly by comparing the normal waking state to seemingly unconscious states, such as deep sleep or general anesthesia. A more direct approach would be the neuroscientific investigation of conscious states that are experienced as free of any specific phenomenal content. Here we present serendipitous data on content-free awareness (CFA) during an EEG-fMRI assessment reported by an extraordinarily qualified meditator with over 50,000 h of practice. We focused on two specific cortical networks related to external and internal awareness, i.e., the dorsal attention network (DAN) and the default mode network (DMN), to explore the neural correlates of this experience. The combination of high-resolution EEG and ultrafast fMRI enabled us to analyze the dynamic aspects of fMRI connectivity informed by EEG power analysis. The neural correlates of CFA were characterized by a sharp decrease in alpha power and an increase in theta power as well as increases in functional connectivity in the DAN and decreases in the posterior DMN. We interpret these findings as correlates of a top-down-initiated attentional state excluding external sensory stimuli and internal mentation from conscious experience. We conclude that the investigation of states of CFA could provide valuable input for new methodological and conceptual approaches in the search for the minimal neural correlate of consciousness.
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Affiliation(s)
- Ulf Winter
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Pierre LeVan
- Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.,Departments of Radiology and Paediatrics, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | | | - Burak Akin
- Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Marc Wittmann
- Institute for Frontier Areas of Psychology and Mental Health, Freiburg im Breisgau, Germany
| | - Yeshe Leyens
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Stefan Schmidt
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
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150
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Abstract
The science of transitional states of consciousness is reviewed. Despite intensive study, determining the subjective experience of animals during transitional states of consciousness remains inherently limited. Until better assessment tools become available, behavior-based observations, such as loss of righting reflex/loss of posture, remain among our most useful guides to the onset of unconsciousness in animals. To minimize potential animal suffering and to ensure a truly unconscious state is unambiguously achieved, a state of general anesthesia relying on gamma amino butyric acid type A agonists or N-methyl-d-aspartate antagonist agents continues to be a necessary component of the companion animal euthanasia process.
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Affiliation(s)
- Robert E Meyer
- Veterinary Anesthesiology, College of Veterinary Medicine, PO Box 6100, Campus Mailstop 9825, 240 Wise Center Drive, Mississippi State, MS 39762-6100, USA.
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