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Dong K, Zhang L, Zhong Y, Xu T, Zhao Y, Chen S, Mahmoud SS, Fang Q. Meso-scale reorganization of local-global brain networks under mild sedation of propofol anesthesia. Neuroimage 2024; 297:120744. [PMID: 39033791 DOI: 10.1016/j.neuroimage.2024.120744] [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] [Received: 05/16/2024] [Revised: 06/30/2024] [Accepted: 07/18/2024] [Indexed: 07/23/2024] Open
Abstract
The fragmentation of the functional brain network has been identified through the functional connectivity (FC) analysis in studies investigating anesthesia-induced loss of consciousness (LOC). However, it remains unclear whether mild sedation of anesthesia can cause similar effects. This paper aims to explore the changes in local-global brain network topology during mild anesthesia, to better understand the macroscopic neural mechanism underlying anesthesia sedation. We analyzed high-density EEG from 20 participants undergoing mild and moderate sedation of propofol anesthesia. By employing a local-global brain parcellation in EEG source analysis, we established binary functional brain networks for each participant. Furthermore, we investigated the global-scale properties of brain networks by estimating global efficiency and modularity, and examined the changes in meso-scale properties of brain networks by quantifying the distribution of high-degree and high-betweenness hubs and their corresponding rich-club coefficients. It is evident from the results that the mild sedation of anesthesia does not cause a significant change in the global-scale properties of brain networks. However, network components centered on SomMot L show a significant decrease, while those centered on Default L, Vis L and Limbic L exhibit a significant increase during the transition from wakefulness to mild sedation (p<0.05). Compared to the baseline state, mild sedation almost doubled the number of high-degree hubs in Vis L, DorsAttn L, Limbic L, Cont L, and reduced by half the number of high-degree hubs in SomMot R, DorsAttn R, SalVentAttn R. Further, mild sedation almost doubled the number of high-betweenness hubs in Vis L, Vis R, Limbic R, Cont R, and reduced by half the number of high-betweenness hubs in SomMot L, SalVentAttn L, Default L, and SomMot R. Our results indicate that mild anesthesia cannot affect the global integration and segregation of brain networks, but influence meso-scale function for integrating different resting-state systems involved in various segregation processes. Our findings suggest that the meso-scale brain network reorganization, situated between global integration and local segregation, could reflect the autonomic compensation of the brain for drug effects. As a direct response and adjustment of the brain network system to drug administration, this spontaneous reorganization of the brain network aims at maintaining consciousness in the case of sedation.
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Affiliation(s)
- Kangli Dong
- Department of Biomedical Engineering, College of Engineering, Shantou University, Shantou 515063, Guangdong, China.
| | - Lu Zhang
- Department of Rehabilitation, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310027, Zhejiang, China.
| | - Yuming Zhong
- Department of Biomedical Engineering, College of Engineering, Shantou University, Shantou 515063, Guangdong, China.
| | - Tao Xu
- Department of Biomedical Engineering, College of Engineering, Shantou University, Shantou 515063, Guangdong, China.
| | - Yue Zhao
- Department of Urology, Xiang'an Hospital of Xiamen University, Xiamen University, Xiamen 361102, Fujian, China.
| | - Siya Chen
- Department of Computer Science, City University of Hong Kong, Hong Kong 999077, Hong Kong, China.
| | - Seedahmed S Mahmoud
- Department of Biomedical Engineering, College of Engineering, Shantou University, Shantou 515063, Guangdong, China.
| | - Qiang Fang
- Department of Biomedical Engineering, College of Engineering, Shantou University, Shantou 515063, Guangdong, China.
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Hansen E. Touching the unconscious in the unconscious - hypnotic communication with unconscious patients. Front Psychol 2024; 15:1389449. [PMID: 38966734 PMCID: PMC11223660 DOI: 10.3389/fpsyg.2024.1389449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/30/2024] [Indexed: 07/06/2024] Open
Abstract
If hypnosis means contact to the unconscious to modulate psychological and physiological functions by means of suggestions, and if this is facilitated by attenuation of the critical mind, then the question arises as to whether suggestions also have an effect when waking consciousness is otherwise eliminated, namely by coma or anesthesia. A prerequisite would be perception, which actually is evidenced by reports of patients after traumatic brain injury, artificial coma, resuscitation or general anesthesia. Moreover, posttraumatic stress disorder (PTSD) frequently observed after these medical situations is hardly explainable without some sort of awareness under such conditions. Even advanced neurophysiological diagnostic cannot yet rule out consciousness or sensory processing. Especially reference to perception during unconsciousness is given by the results of a recent multicenter study on the effects of hypnotic communication with patients under controlled adequate deep general anesthesia. The observed reductions in incidence and severity of postoperative pain, opioid use, nausea and vomiting cannot be explained by the reaction of a few but only by a considerable proportion of patients. This leads to a strong plea for a more careful treatment of unconscious patients in the emergency room, operating theater or intensive care unit, for the abandonment of the restriction of therapeutic communication to awake patients, and for new aspects of communication and hypnosis research. Obviously, loss of consciousness does not protect against psychological injury, and continuation of communication is needed. But how and what to talk to unconscious patients? Generally addressing the unconscious mind with suggestions that generally exert their effects unconsciously, hypnotic communication appears to be the adequate language. Especially addressing meaningful topics, as derived from the basic psychological needs and known stressors, appears essential. With respect to negative effects by negative or missing communication or to the proposed protective and supporting effects of therapeutic communication with patients clinically rated as unconscious, the role of consciousness is secondary. For the effects of perceived signals and suggestions it does not matter whether consciousness is absent, or partial, or unrecognized present.
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Affiliation(s)
- Ernil Hansen
- Department of Anesthesiology, University Hospital Regensburg, Regensburg, Germany
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Mathis M, Steffner KR, Subramanian H, Gill GP, Girardi NI, Bansal S, Bartels K, Khanna AK, Huang J. Overview and Clinical Applications of Artificial Intelligence and Machine Learning in Cardiac Anesthesiology. J Cardiothorac Vasc Anesth 2024; 38:1211-1220. [PMID: 38453558 PMCID: PMC10999327 DOI: 10.1053/j.jvca.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 03/09/2024]
Abstract
Artificial intelligence- (AI) and machine learning (ML)-based applications are becoming increasingly pervasive in the healthcare setting. This has in turn challenged clinicians, hospital administrators, and health policymakers to understand such technologies and develop frameworks for safe and sustained clinical implementation. Within cardiac anesthesiology, challenges and opportunities for AI/ML to support patient care are presented by the vast amounts of electronic health data, which are collected rapidly, interpreted, and acted upon within the periprocedural area. To address such challenges and opportunities, in this article, the authors review 3 recent applications relevant to cardiac anesthesiology, including depth of anesthesia monitoring, operating room resource optimization, and transthoracic/transesophageal echocardiography, as conceptual examples to explore strengths and limitations of AI/ML within healthcare, and characterize this evolving landscape. Through reviewing such applications, the authors introduce basic AI/ML concepts and methodologies, as well as practical considerations and ethical concerns for initiating and maintaining safe clinical implementation of AI/ML-based algorithms for cardiac anesthesia patient care.
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Affiliation(s)
- Michael Mathis
- Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, MI
| | - Kirsten R Steffner
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA
| | - Harikesh Subramanian
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA
| | - George P Gill
- Department of Anesthesiology, Cedars Sinai, Los Angeles, CA
| | | | - Sagar Bansal
- Department of Anesthesiology and Perioperative Medicine, University of Missouri School of Medicine, Columbia, MO
| | - Karsten Bartels
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE
| | - Ashish K Khanna
- Department of Anesthesiology, Section on Critical Care Medicine, School of Medicine, Wake Forest University, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC
| | - Jiapeng Huang
- Department of Anesthesiology and Perioperative Medicine, University of Louisville, Louisville, KY.
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Montupil J, Cardone P, Staquet C, Bonhomme A, Defresne A, Martial C, Alnagger NL, Gosseries O, Bonhomme V. The nature of consciousness in anaesthesia. BJA OPEN 2023; 8:100224. [PMID: 37780201 PMCID: PMC10539891 DOI: 10.1016/j.bjao.2023.100224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 08/28/2023] [Indexed: 10/03/2023]
Abstract
Neuroscientists agree on the value of locating the source of consciousness within the brain. Anaesthesiologists are no exception, and have their own operational definition of consciousness based on phenomenological observations during anaesthesia. The full functional correlates of consciousness are yet to be precisely identified, however rapidly evolving progress in this scientific domain has yielded several theories that attempt to model the generation of consciousness. They have received variable support from experimental observations, including those involving anaesthesia and its ability to reversibly modulate different aspects of consciousness. Aside from the interest in a better understanding of the mechanisms of consciousness, exploring the functional tenets of the phenomenological consciousness states of general anaesthesia has the potential to ultimately improve patient management. It could facilitate the design of specific monitoring devices and approaches, aiming at reliably detecting each of the possible states of consciousness during an anaesthetic procedure, including total absence of mental content (unconsciousness), and internal awareness (sensation of self and internal thoughts) with or without conscious perception of the environment (connected or disconnected consciousness, respectively). Indeed, it must be noted that unresponsiveness is not sufficient to infer absence of connectedness or even absence of consciousness. This narrative review presents the current knowledge in this field from a system-level, underlining the contribution of anaesthesia studies in supporting theories of consciousness, and proposing directions for future research.
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Affiliation(s)
- Javier Montupil
- Anesthesia and Perioperative Neuroscience Laboratory, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege, Belgium
- University Department of Anesthesia and Intensive Care Medicine, Citadelle Regional Hospital, Liege, Belgium
| | - Paolo Cardone
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liege University, Liege, Belgium
- Centre du Cerveau, Liege University Hospital, Liege, Belgium
| | - Cécile Staquet
- Anesthesia and Perioperative Neuroscience Laboratory, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege, Belgium
| | - Arthur Bonhomme
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liege University, Liege, Belgium
| | - Aline Defresne
- Anesthesia and Perioperative Neuroscience Laboratory, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege, Belgium
- University Department of Anesthesia and Intensive Care Medicine, Citadelle Regional Hospital, Liege, Belgium
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liege University, Liege, Belgium
- Centre du Cerveau, Liege University Hospital, Liege, Belgium
| | - Naji L.N. Alnagger
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liege University, Liege, Belgium
- Centre du Cerveau, Liege University Hospital, Liege, Belgium
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liege University, Liege, Belgium
- Centre du Cerveau, Liege University Hospital, Liege, Belgium
| | - Vincent Bonhomme
- Anesthesia and Perioperative Neuroscience Laboratory, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege, Belgium
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Guo F, Li Y, Jian Z, Cui Y, Gong W, Li A, Jing W, Xu P, Chen K, Guo D, Yao D, Xia Y. Dose-related adaptive reconstruction of DMN in isoflurane administration: a study in the rat. BMC Anesthesiol 2023; 23:224. [PMID: 37380958 PMCID: PMC10303294 DOI: 10.1186/s12871-023-02153-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 05/26/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND The anesthetic states are accompanied by functional alterations. However, the dose-related adaptive alterations in the higher-order network under anesthesia, e. g. default mode network (DMN), are poorly revealed. METHODS We implanted electrodes in brain regions of the rat DMN to acquire local field potentials to investigate the perturbations produced by anesthesia. Relative power spectral density, static functional connectivity (FC), fuzzy entropy of dynamic FC, and topological features were computed from the data. RESULTS The results showed that adaptive reconstruction was induced by isoflurane, exhibiting reduced static and stable long-range FC, and altered topological features. These reconstruction patterns were in a dose-related fashion. CONCLUSION These results might impart insights into the neural network mechanisms underlying anesthesia and suggest the potential of monitoring the depth of anesthesia based on the parameters of DMN.
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Affiliation(s)
- Fengru Guo
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Yuqin Li
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Zhaoxin Jian
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Yan Cui
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Wenhui Gong
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Airui Li
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Wei Jing
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 4030030 China
| | - Peng Xu
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Ke Chen
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Daqing Guo
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Dezhong Yao
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
| | - Yang Xia
- Department of Neurosurgery, MOE Key Lab for Neuroinformation, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 611731 China
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Hameroff S. Consciousness, Cognition and the Neuronal Cytoskeleton - A New Paradigm Needed in Neuroscience. Front Mol Neurosci 2022; 15:869935. [PMID: 35782391 PMCID: PMC9245524 DOI: 10.3389/fnmol.2022.869935] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 04/20/2022] [Indexed: 12/03/2022] Open
Abstract
Viewing the brain as a complex computer of simple neurons cannot account for consciousness nor essential features of cognition. Single cell organisms with no synapses perform purposeful intelligent functions using their cytoskeletal microtubules. A new paradigm is needed to view the brain as a scale-invariant hierarchy extending both upward from the level of neurons to larger and larger neuronal networks, but also downward, inward, to deeper, faster quantum and classical processes in cytoskeletal microtubules inside neurons. Evidence shows self-similar patterns of conductive resonances repeating in terahertz, gigahertz, megahertz, kilohertz and hertz frequency ranges in microtubules. These conductive resonances apparently originate in terahertz quantum dipole oscillations and optical interactions among pi electron resonance clouds of aromatic amino acid rings of tryptophan, phenylalanine and tyrosine within each tubulin, the component subunit of microtubules, and the brain's most abundant protein. Evidence from cultured neuronal networks also now shows that gigahertz and megahertz oscillations in dendritic-somatic microtubules regulate specific firings of distal axonal branches, causally modulating membrane and synaptic activities. The brain should be viewed as a scale-invariant hierarchy, with quantum and classical processes critical to consciousness and cognition originating in microtubules inside neurons.
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Affiliation(s)
- Stuart Hameroff
- Department of Anesthesiology, The University of Arizona, Tucson, AZ, United States
- Department of Psychology, The University of Arizona, Tucson, AZ, United States
- Center for Consciousness Studies, The University of Arizona, Tucson, AZ, United States
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7
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Dong K, Zhang D, Wei Q, Wang G, Huang F, Chen X, Muhammad KG, Sun Y, Liu J. Intrinsic phase-amplitude coupling on multiple spatial scales during the loss and recovery of consciousness. Comput Biol Med 2022; 147:105687. [PMID: 35687924 DOI: 10.1016/j.compbiomed.2022.105687] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/13/2022] [Accepted: 05/30/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recent studies have demonstrated that changes in brain information processing during anesthetic-induced loss of consciousness (LOC) might be influenced by phase-amplitude coupling (PAC) in electroencephalogram (EEG). However, most anesthesia research on PAC typically focuses on delta and alpha oscillations. Studies of spatial-frequency characteristics by PAC for EEG may yield additional insights into understanding the impaired information processing under anesthesia unconsciousness and provide potential improvements in anesthesia monitoring. OBJECTIVE Considering different frequency bands of EEG represent neural activities on different spatial scales, we hypothesized that functional coupling simultaneously appears in multiple frequency bands and specific brain regions during anesthesia unconsciousness. In this paper, PAC analysis on whole-brain EEG besides delta and alpha oscillations was investigated to understand the influence of multiple cross-frequency coordination coupling on information processing during the loss and recovery of consciousness. METHOD EEG data from fifteen patients without cognitive diseases (7 males/8 females, aged 43.8 ± 13.4 years, weighing 63.3 ± 14.9 kilograms) undergoing lower limb surgery and sevoflurane anesthesia was recorded. To investigate the spatial-frequency characteristics of EEG source signals during loss and recovery of consciousness, the time-resolved PAC (tPAC) was calculated to reflect cross-frequency coordination in different frequency bands (delta, theta, alpha, beta, gamma) and different functional regions (Visual, Limbic, Dorsal attention, Ventral attention, Default, Somatomotor, Control, Salience networks). Furthermore, different patterns (peak-max and trough-max) of PAC were examined by constructing phase-amplitude histograms using phase bins to investigate the different information processing during LOC. The multivariate analysis of variance (MANOVA) and trend analysis were used for statistical analysis. RESULTS Theta-alpha and alpha-beta PAC were observed during sevoflurane-induced LOC, which significantly changed during loss and recovery of consciousness (F4,70 = 16.553, p < 0.001 for theta-alpha PAC and F4,70 = 12.446, p < 0.001 for alpha-beta PAC, MANOVA test). Simultaneously, PAC was distributed in specific functional regions, i.e., Visual, Limbic, Default, Somatomotor, etc. Furthermore, peak-max patterns of theta-alpha PAC were observed while alpha-beta PAC showed trough-max patterns and vice versa. CONCLUSION Theta-alpha and alpha-beta PAC observed in specific brain regions represent information processing on multiple spatial scales, and the opposite patterns of PAC indicate opposite information processing on multiple spatial scales during LOC. Our study demonstrates the regulation of local-global information processing during sevoflurane-induced LOC. It suggests the utility of evaluating the balance of functional integration and segregation in monitoring anesthetized states.
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Affiliation(s)
- Kangli Dong
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Delin Zhang
- The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310027, China
| | - Qishun Wei
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Guozheng Wang
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Fan Huang
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Xing Chen
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Kanhar G Muhammad
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Yu Sun
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Jun Liu
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China.
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Abstract
Recent years have seen a blossoming of theories about the biological and physical basis of consciousness. Good theories guide empirical research, allowing us to interpret data, develop new experimental techniques and expand our capacity to manipulate the phenomenon of interest. Indeed, it is only when couched in terms of a theory that empirical discoveries can ultimately deliver a satisfying understanding of a phenomenon. However, in the case of consciousness, it is unclear how current theories relate to each other, or whether they can be empirically distinguished. To clarify this complicated landscape, we review four prominent theoretical approaches to consciousness: higher-order theories, global workspace theories, re-entry and predictive processing theories and integrated information theory. We describe the key characteristics of each approach by identifying which aspects of consciousness they propose to explain, what their neurobiological commitments are and what empirical data are adduced in their support. We consider how some prominent empirical debates might distinguish among these theories, and we outline three ways in which theories need to be developed to deliver a mature regimen of theory-testing in the neuroscience of consciousness. There are good reasons to think that the iterative development, testing and comparison of theories of consciousness will lead to a deeper understanding of this most profound of mysteries.
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Saxena N, Muthukumaraswamy SD, Richmond L, Babic A, Singh KD, Hall JE, Wise RG, Shaw AD. A comparison of GABA-ergic (propofol) and non-GABA-ergic (dexmedetomidine) sedation on visual and motor cortical oscillations, using magnetoencephalography. Neuroimage 2021; 245:118659. [PMID: 34767940 PMCID: PMC9227747 DOI: 10.1016/j.neuroimage.2021.118659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/22/2021] [Accepted: 10/14/2021] [Indexed: 11/18/2022] Open
Abstract
Studying changes in cortical oscillations can help elucidate the mechanistic link between receptor physiology and the clinical effects of anaesthetic drugs. Propofol, a GABA-ergic drug produces divergent effects on visual cortical activity: increasing induced gamma-band responses (GBR) while decreasing evoked responses. Dexmedetomidine, an α2- adrenergic agonist, differs from GABA-ergic sedatives both mechanistically and clinically as it allows easy arousability from deep sedation with less cognitive side-effects. Here we use magnetoencephalography (MEG) to characterize and compare the effects of GABA-ergic (propofol) and non-GABA-ergic (dexmedetomidine) sedation, on visual and motor cortical oscillations. Sixteen male participants received target-controlled infusions of propofol and dexmedetomidine, producing mild-sedation, in a placebo-controlled, cross-over study. MEG data was collected during a combined visuomotor task. The key findings were that propofol significantly enhanced visual stimulus induced GBR (44% increase in amplitude) while dexmedetomidine decreased it (40%). Propofol also decreased the amplitudes of the Mv100 (visual M100) (27%) and Mv150 (52%) visual evoked fields (VEF), whilst dexmedetomidine had no effect on these. During the motor task, neither drug had any significant effect on movement related gamma synchrony (MRGS), movement related beta de-synchronisation (MRBD) or Mm100 (movement-related M100) movement-related evoked fields (MEF), although dexmedetomidine slowed the Mm300. Dexmedetomidine increased (92%) post-movement beta synchronisation/rebound (PMBR) power while propofol reduced it (70%, statistically non- significant). Overall, dexmedetomidine and propofol, at equi-sedative doses, produce contrasting effects on visual induced GBR, VEF, PMBR and MEF. These findings provide a mechanistic link between the known receptor physiology of these sedative drugs with their known clinical effects and may be used to explore mechanisms of other anaesthetic drugs on human consciousness.
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Affiliation(s)
- Neeraj Saxena
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff CF24 4HQ, United Kingdom; Department of Anaesthetics, Intensive Care and Pain Medicine, Cwm Taf Morgannwg University Health Board, Llantrisant CF72 8XR, United Kingdom.
| | - Suresh D Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, Auckland University, Auckland 1123, New Zealand; School of Psychology, Faculty of Medical and Health Sciences, Auckland University, Auckland 1123, New Zealand
| | - Lewys Richmond
- Department of Anaesthetics, Morriston Hospital, Swansea, SA6 6NL, United Kingdom
| | - Adele Babic
- Department of Anaesthetics, Royal Gwent Hospital, Newport, NP20 2UB, United Kingdom
| | - Krish D Singh
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff CF24 4HQ, United Kingdom
| | - Judith E Hall
- Department of Anaesthetics, Intensive Care and Pain Medicine, School of Medicine, Cardiff University, Cardiff CF14 4XW, United Kingdom
| | - Richard G Wise
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff CF24 4HQ, United Kingdom; Institute for Advanced Biomedical Technologies, "G. D'Annunzio University" of Chieti-Pescara, 66100, Chieti, Italy; Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio University" of Chieti-Pescara, 66100, Chieti, Italy
| | - Alexander D Shaw
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff CF24 4HQ, United Kingdom; Department of Psychology, University of Exeter, United Kingdom
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George BM, Pandit JJ. General anaesthetics as 'awakening agents'? Re-appraising the evidence for suggested 'pressure reversal' of anaesthesia. Clin Exp Pharmacol Physiol 2021; 48:1454-1468. [PMID: 34309890 DOI: 10.1111/1440-1681.13554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/06/2021] [Accepted: 07/19/2021] [Indexed: 11/30/2022]
Abstract
Increasing ambient pressure has been suggested to reverse general anaesthesia and provides support for the 'lipid theory'. Anaesthetic dissolution into cell membranes is said to cause their expansion to a critical volume. This triggers a sequence of events as basis of a unitary theory of anaesthestic mechanism. Pressure is argued to restore membrane volume to below critical level, reversing this process. We wished to review the original literature to assess internal consistency within and across papers, and to consider if alternative interpretations were possible. A literature search yielded 31 relevant 'pressure reversal' papers for narrative review, and 8 papers that allowed us to re-plot original data more consistently as 'dose-response' curves for the anaesthetics examined. Original studies were heterogenous for end-points, pressure ranges, species, and agents. Pressure effects were inconsistent, with narcosis at certain pressures and excitation at others, influenced by carrier gas (e.g., nitrogen vs helium). Pressure reversal (a right- or downward-shift on the re-plotted dose-response curves) was evident, but only in some species and at certain pressures and anaesthetic concentrations. However, even more striking was a novel 'awakening' effect of anaesthetics: i.e., anaesthetics reversed the narcotic effect of pressure, but this was limited to certain pressures at generally low anaesthetic concentrations. Contrary to the established view, 'pressure reversal' is not a universal phenomenon. The awakening effect of anaesthetics - described here for the first time - has equal evidence to support it, within the same literature, and is something that cannot be fully explained. Pressure cannot meaningfully be used to gain insight into anaesthetic mechanisms because of its heterogenous, non-specific and unpredictable effects on biological systems.
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Affiliation(s)
- Ben M George
- Nuffield Department of Anaesthetics, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Jaideep J Pandit
- Nuffield Department of Anaesthetics, Oxford University Hospitals NHS Trust, Oxford, UK
- University of Oxford, Oxford, UK
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11
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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: 1.7] [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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12
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Abstract
Giulio Tononi's Integrated Information Theory (IIT) proposes explaining consciousness by directly identifying it with integrated information. We examine the construct validity of IIT's measure of consciousness, phi (Φ), by analyzing its formal properties, its relation to key aspects of consciousness, and its co-variation with relevant empirical circumstances. Our analysis shows that IIT's identification of consciousness with the causal efficacy with which differentiated networks accomplish global information transfer (which is what Φ in fact measures) is mistaken. This misidentification has the consequence of requiring the attribution of consciousness to a range of natural systems and artifacts that include, but are not limited to, large-scale electrical power grids, gene-regulation networks, some electronic circuit boards, and social networks. Instead of treating this consequence of the theory as a disconfirmation, IIT embraces it. By regarding these systems as bearers of consciousness ex hypothesi, IIT is led towards the orbit of panpsychist ideation. This departure from science as we know it can be avoided by recognizing the functional misattribution at the heart of IIT's identity claim. We show, for example, what function is actually performed, at least in the human case, by the cortical combination of differentiation with integration that IIT identifies with consciousness. Finally, we examine what lessons may be drawn from IIT's failure to provide a credible account of consciousness for progress in the very active field of research concerned with exploring the phenomenon from formal and neural points of view.
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13
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VanRullen R, Kanai R. Deep learning and the Global Workspace Theory. Trends Neurosci 2021; 44:692-704. [PMID: 34001376 DOI: 10.1016/j.tins.2021.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/19/2021] [Accepted: 04/14/2021] [Indexed: 10/21/2022]
Abstract
Recent advances in deep learning have allowed artificial intelligence (AI) to reach near human-level performance in many sensory, perceptual, linguistic, and cognitive tasks. There is a growing need, however, for novel, brain-inspired cognitive architectures. The Global Workspace Theory (GWT) refers to a large-scale system integrating and distributing information among networks of specialized modules to create higher-level forms of cognition and awareness. We argue that the time is ripe to consider explicit implementations of this theory using deep-learning techniques. We propose a roadmap based on unsupervised neural translation between multiple latent spaces (neural networks trained for distinct tasks, on distinct sensory inputs and/or modalities) to create a unique, amodal Global Latent Workspace (GLW). Potential functional advantages of GLW are reviewed, along with neuroscientific implications.
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Affiliation(s)
- Rufin VanRullen
- The Brain and Cognition Research Center (CerCo), CNRS UMR5549, Toulouse, France; Artificial and Natural Intelligence Toulouse Institute (ANITI), Université de Toulouse, France.
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14
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Areshenkoff CN, Nashed JY, Hutchison RM, Hutchison M, Levy R, Cook DJ, Menon RS, Everling S, Gallivan JP. Muting, not fragmentation, of functional brain networks under general anesthesia. Neuroimage 2021; 231:117830. [PMID: 33549746 DOI: 10.1016/j.neuroimage.2021.117830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/21/2021] [Accepted: 01/30/2021] [Indexed: 12/01/2022] Open
Abstract
Changes in resting-state functional connectivity (rs-FC) under general anesthesia have been widely studied with the goal of identifying neural signatures of consciousness. This work has commonly revealed an apparent fragmentation of whole-brain network structure during unconsciousness, which has been interpreted as reflecting a break-down in connectivity and a disruption of the brain's ability to integrate information. Here we show, by studying rs-FC under varying depths of isoflurane-induced anesthesia in nonhuman primates, that this apparent fragmentation, rather than reflecting an actual change in network structure, can be simply explained as the result of a global reduction in FC. Specifically, by comparing the actual FC data to surrogate data sets that we derived to test competing hypotheses of how FC changes as a function of dose, we found that increases in whole-brain modularity and the number of network communities - considered hallmarks of fragmentation - are artifacts of constructing FC networks by thresholding based on correlation magnitude. Taken together, our findings suggest that deepening levels of unconsciousness are instead associated with the increasingly muted expression of functional networks, an observation that constrains current interpretations as to how anesthesia-induced FC changes map onto existing neurobiological theories of consciousness.
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Affiliation(s)
- Corson N Areshenkoff
- Centre for Neuroscience Studies, Queens University, Kingston, ON, Canada; Department of Psychology, Queens University, Kingston, ON, Canada.
| | - Joseph Y Nashed
- Centre for Neuroscience Studies, Queens University, Kingston, ON, Canada
| | | | | | - Ron Levy
- Centre for Neuroscience Studies, Queens University, Kingston, ON, Canada; Department of Surgery, Queens University, Kingston, ON, Canada
| | - Douglas J Cook
- Centre for Neuroscience Studies, Queens University, Kingston, ON, Canada; Department of Surgery, Queens University, Kingston, ON, Canada
| | - Ravi S Menon
- Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Stefan Everling
- Robarts Research Institute, University of Western Ontario, London, ON, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Jason P Gallivan
- Centre for Neuroscience Studies, Queens University, Kingston, ON, Canada; Department of Psychology, Queens University, Kingston, ON, Canada
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15
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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: 25] [Impact Index Per Article: 6.3] [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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16
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Abstract
General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.
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Affiliation(s)
- Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, 3620 Hamilton Walk, 334 John Morgan Building, Philadelphia, PA 19104, USA; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Translational Research Laboratories, 125 S. 31st St., Philadelphia, PA 19104-3403, USA; Mahoney Institute for Neuroscience, University of Pennsylvania, Clinical Research Building, 415 Curie Blvd, Philadelphia, PA 19104, USA.
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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17
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Aru J, Suzuki M, Larkum ME. Cellular Mechanisms of Conscious Processing. Trends Cogn Sci 2020; 24:814-825. [PMID: 32855048 DOI: 10.1016/j.tics.2020.07.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 01/08/2023]
Abstract
Recent breakthroughs in neurobiology indicate that the time is ripe to understand how cellular-level mechanisms are related to conscious experience. Here, we highlight the biophysical properties of pyramidal cells, which allow them to act as gates that control the evolution of global activation patterns. In conscious states, this cellular mechanism enables complex sustained dynamics within the thalamocortical system, whereas during unconscious states, such signal propagation is prohibited. We suggest that the hallmark of conscious processing is the flexible integration of bottom-up and top-down data streams at the cellular level. This cellular integration mechanism provides the foundation for Dendritic Information Theory, a novel neurobiological theory of consciousness.
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Affiliation(s)
- Jaan Aru
- Institute of Biology, Humboldt University of Berlin, Berlin, Germany; Institute of Computer Science, University of Tartu, Tartu, Estonia.
| | - Mototaka Suzuki
- Institute of Biology, Humboldt University of Berlin, Berlin, Germany
| | - Matthew E Larkum
- Institute of Biology, Humboldt University of Berlin, Berlin, Germany; Neurocure Center for Excellence, Charité Universitätsmedizin, Berlin, Germany.
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18
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Munévar G. A cellular and attentional network explanation of consciousness. Conscious Cogn 2020; 83:102982. [PMID: 32652510 DOI: 10.1016/j.concog.2020.102982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/25/2020] [Accepted: 06/23/2020] [Indexed: 01/02/2023]
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19
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Luo M, Song B, Zhu J. Sleep Disturbances After General Anesthesia: Current Perspectives. Front Neurol 2020; 11:629. [PMID: 32733363 PMCID: PMC7360680 DOI: 10.3389/fneur.2020.00629] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/28/2020] [Indexed: 12/18/2022] Open
Abstract
The purpose of this article is to review (1) sleep mechanism under general anesthesia, harmful effects of postoperative sleep disturbances; (2) risk factors associated with postoperative sleep disturbances; (3) measures to prevent and improve postoperative sleep disturbances. General anesthesia changes the postoperative sleep structure especially in elderly patients after major surgery and results in a high incidence rate of sleep disturbances. Sleep disturbances produce harmful effects on postoperative patients and lead to a higher risk of delirium, more cardiovascular events, and poorer recovery. Some researchers do propose non-pharmacological treatments such as attention to environmental and psychological factors, application of electroacupuncture (EA) technology and pharmacological treatments are helpful, but larger high-quality clinical trials with longer following-up are needed to further investigate the efficacy and safety.
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Affiliation(s)
- Man Luo
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Bijia Song
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China.,Department of Anesthesiology, Friendship Hospital of Capital Medical University, Beijing, China
| | - Junchao Zhu
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
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20
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Krom AJ, Marmelshtein A, Gelbard-Sagiv H, Tankus A, Hayat H, Hayat D, Matot I, Strauss I, Fahoum F, Soehle M, Boström J, Mormann F, Fried I, Nir Y. Anesthesia-induced loss of consciousness disrupts auditory responses beyond primary cortex. Proc Natl Acad Sci U S A 2020; 117:11770-11780. [PMID: 32398367 PMCID: PMC7261054 DOI: 10.1073/pnas.1917251117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Despite its ubiquitous use in medicine, and extensive knowledge of its molecular and cellular effects, how anesthesia induces loss of consciousness (LOC) and affects sensory processing remains poorly understood. Specifically, it is unclear whether anesthesia primarily disrupts thalamocortical relay or intercortical signaling. Here we recorded intracranial electroencephalogram (iEEG), local field potentials (LFPs), and single-unit activity in patients during wakefulness and light anesthesia. Propofol infusion was gradually increased while auditory stimuli were presented and patients responded to a target stimulus until they became unresponsive. We found widespread iEEG responses in association cortices during wakefulness, which were attenuated and restricted to auditory regions upon LOC. Neuronal spiking and LFP responses in primary auditory cortex (PAC) persisted after LOC, while responses in higher-order auditory regions were variable, with neuronal spiking largely attenuated. Gamma power induced by word stimuli increased after LOC while its frequency profile slowed, thus differing from local spiking activity. In summary, anesthesia-induced LOC disrupts auditory processing in association cortices while relatively sparing responses in PAC, opening new avenues for future research into mechanisms of LOC and the design of anesthetic monitoring devices.
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Affiliation(s)
- Aaron J Krom
- Department of Physiology & Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Anesthesiology and Critical Care Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
- Hadassah School of Medicine, Hebrew University, Jerusalem 91120, Israel
| | - Amit Marmelshtein
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Hagar Gelbard-Sagiv
- Department of Physiology & Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ariel Tankus
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
- Functional Neurosurgery Unit, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel
- Department of Neurology & Neurosurgery, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Hanna Hayat
- Department of Physiology & Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Daniel Hayat
- Department of Anesthesia, Intensive Care and Pain, Tel Aviv Medical Center, Sackler Medical School, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Idit Matot
- Department of Anesthesia, Intensive Care and Pain, Tel Aviv Medical Center, Sackler Medical School, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ido Strauss
- Functional Neurosurgery Unit, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel
- Department of Neurology & Neurosurgery, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Firas Fahoum
- Department of Neurology & Neurosurgery, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- EEG and Epilepsy Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel
| | - Martin Soehle
- Department of Anesthesiology and Intensive Care Medicine, University of Bonn Medical Center, 53127 Bonn, Germany
| | - Jan Boström
- Department of Neurosurgery, University of Bonn Medical Center, 53127 Bonn, Germany
| | - Florian Mormann
- Department of Epileptology, University of Bonn Medical Center, 53127 Bonn, Germany
| | - Itzhak Fried
- Functional Neurosurgery Unit, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel;
- Department of Neurology & Neurosurgery, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Neurosurgery, University of California, Los Angeles, CA 90095
| | - Yuval Nir
- Department of Physiology & Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel;
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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21
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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: 382] [Impact Index Per Article: 95.5] [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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22
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Ho SS, Muzik M, Rosenblum KL, Morelen D, Nakamura Y, Swain JE. Potential Neural Mediators of Mom Power Parenting Intervention Effects on Maternal Intersubjectivity and Stress Resilience. Front Psychiatry 2020; 11:568824. [PMID: 33363481 PMCID: PMC7752922 DOI: 10.3389/fpsyt.2020.568824] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/11/2020] [Indexed: 12/11/2022] Open
Abstract
Stress resilience in parenting depends on the parent's capacity to understand subjective experiences in self and child, namely intersubjectivity, which is intimately related to mimicking other's affective expressions (i. e., mirroring). Stress can worsen parenting by potentiating problems that can impair intersubjectivity, e.g., problems of "over-mentalizing" (misattribution of the child's behaviors) and "under-coupling" (inadequate child-oriented mirroring). Previously we have developed Mom Power (MP) parenting intervention to promote maternal intersubjectivity and reduce parenting stress. This study aimed to elucidate neural mechanisms underlying the effects of MP with a novel Child Face Mirroring Task (CFMT) in functional magnetic-resonance-imaging settings. In CFMT, the participants responded to own and other's child's facial pictures in three task conditions: (1) empathic mirroring (Join), (2) non-mirroring observing (Observe), and (3) voluntary responding (React). In each condition, each child's neutral, ambiguous, distressed, and joyful expressions were repeatedly displayed. We examined the CFMT-related neural responses in a sample of healthy mothers (n = 45) in Study 1, and MP effects on CFMT with a pre-intervention (T1) and post-intervention (T2) design in two groups, MP (n = 19) and Control (n = 17), in Study 2. We found that, from T1 to T2, MP (vs. Control) decreased parenting stress, decreased dorsomedial prefrontal cortex (dmPFC) during own-child-specific voluntary responding (React to Own vs. Other's Child), and increased activity in the frontoparietal cortices, midbrain, nucleus accumbens, and amygdala during own-child-specific empathic mirroring (Join vs. Observe of Own vs. Other's Child). We identified that MP effects on parenting stress were potentially mediated by T1-to-T2 changes in: (1) the left superior-temporal-gyrus differential responses in the contrast of Join vs. Observe of own (vs. other's) child, (2) the dmPFC-PAG (periaqueductal gray) differential functional connectivity in the same contrast, and (3) the left amygdala differential responses in the contrast of Join vs. Observe of own (vs. other's) child's joyful vs. distressed expressions. We discussed these results in support of the notion that MP reduces parenting stress via changing neural activities related to the problems of "over-mentalizing" and "under-coupling." Additionally, we discussed theoretical relationships between parenting stress and intersubjectivity in a novel dyadic active inference framework in a two-agent system to guide future research.
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Affiliation(s)
- S Shaun Ho
- Department of Psychiatry and Behavioral Health, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
| | - Maria Muzik
- Departments of Psychiatry, Obstetrics & Gynecology, University of Michigan, Ann Arbor, MI, United States
| | - Katherine L Rosenblum
- Departments of Psychiatry, Obstetrics & Gynecology, University of Michigan, Ann Arbor, MI, United States
| | - Diana Morelen
- Department of Psychology, East Tennessee State University, Johnson City, TN, United States
| | - Yoshio Nakamura
- Department of Anesthesiology, Pain Research Center, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - James E Swain
- Department of Psychiatry and Behavioral Health, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
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23
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Sepúlveda P, Cortinez LI, Irani M, Egaña JI, Contreras V, Sánchez Corzo A, Acosta I, Sitaram R. Differential frontal alpha oscillations and mechanisms underlying loss of consciousness: a comparison between slow and fast propofol infusion rates. Anaesthesia 2019; 75:196-201. [PMID: 31788791 DOI: 10.1111/anae.14885] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2019] [Indexed: 12/19/2022]
Abstract
Mechanisms underlying loss of consciousness following propofol administration remain incompletely understood. The objective of this study was to compare frontal lobe electroencephalography activity and brainstem reflexes during intravenous induction of general anaesthesia, in patients receiving a typical bolus dose (fast infusion) of propofol compared with a slower infusion rate. We sought to determine whether brainstem suppression ('bottom-up') predominates over loss of cortical function ('top-down'). Sixteen ASA physical status-1 patients were randomly assigned to either a fast or slow propofol infusion group. Loss of consciousness and brainstem reflexes were assessed every 30 s by a neurologist blinded to treatment allocation. We performed a multitaper spectral analysis of all electroencephalography data obtained from each participant. Brainstem reflexes were present in all eight patients in the slow infusion group, while being absent in all patients in the fast infusion group, at the moment of loss of consciousness (p = 0.010). An increase in alpha band power was observed before loss of consciousness only in participants allocated to the slow infusion group. Alpha band power emerged several minutes after the loss of consciousness in participants allocated to the fast infusion group. Our results show a predominance of 'bottom-up' mechanisms during fast infusion rates and 'top-down' mechanisms during slow infusion rates. The underlying mechanisms by which propofol induces loss of consciousness are potentially influenced by the speed of infusion.
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Affiliation(s)
- P Sepúlveda
- Department of Anaesthesiology, Clínica Alemana - UDD, Santiago de Chile
| | - L I Cortinez
- Department of Anaesthesia, School of Medicine, Pontificia Universidad Católica Santiago de Chile
| | - M Irani
- Department of Psychiatry and Division of Neuroscience, Pontificia Universidad Católica Santiago de Chile
| | - J I Egaña
- Department of Anaesthesiology and Peri-operative Medicine, Faculty of Medicine, Universidad de Chile
| | - V Contreras
- Department of Adult and Aging Health, School of Nursing, Pontificia Universidad Católica Santiago de Chile
| | - A Sánchez Corzo
- Department of Psychiatry and Division of Neuroscience, Pontificia Universidad Católica Santiago de Chile
| | - I Acosta
- Department of Neurology, Clínica Alemana Santiago de Chile
| | - R Sitaram
- Department of Psychiatry and Division of Neuroscience, Pontificia Universidad Católica Santiago de Chile.,Institute for Biological and Medical Engineering, Pontificia Universidad Católica Santiago de Chile.,Center for Brain-Machine Interfaces and Neuromodulation, Pontificia Universidad Católica Santiago de Chile
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Murphy C, Krause B, Banks M. Selective effects of isoflurane on cortico-cortical feedback afferent responses in murine non-primary neocortex. Br J Anaesth 2019; 123:488-496. [PMID: 31383363 DOI: 10.1016/j.bja.2019.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/28/2019] [Accepted: 06/22/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND General anaesthetics affect loss of consciousness by disrupting information-passing and integration within thalamo-cortical (TC) networks. Feedback cortical connections that carry internally generated signals such as expectation and attention appear more sensitive to anaesthesia than feedforward signals. However, direct evidence for this effect in non-primary cortex is lacking. In addition, direct comparisons between TC core and matrix, and between cortico-cortical (CC) feedforward and feedback responses have not been reported. METHODS We investigated the disruption of synaptic responses by isoflurane of four distinct afferent pathways to non-primary neocortex. We independently activated TC core and matrix and reciprocal CC (feedforward and feedback) pathways using optogenetic techniques, and compared the relative sensitivity of synaptic responses to isoflurane. RESULTS Under control conditions, activation of axon terminals of all pathways evoked postsynaptic currents (recorded extracellularly) and postsynaptic potentials in pyramidal neurones. CC feedback responses were substantially more sensitive to isoflurane (0 to 0.53 mM) compared with TC core, TC matrix, or CC feedforward pathways. CONCLUSION Differential sensitivity of CC feedback synaptic responses to isoflurane in a clinically relevant range suggests a role for disruption of these afferents in the hypnotic effects of anaesthetic agents.
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Affiliation(s)
- Caitlin Murphy
- Physiology Graduate Training Program, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
| | - Bryan Krause
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Matthew Banks
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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Hentschke H, Raz A, Krause BM, Murphy CA, Banks MI. Disruption of cortical network activity by the general anaesthetic isoflurane. Br J Anaesth 2019; 119:685-696. [PMID: 29121295 DOI: 10.1093/bja/aex199] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2017] [Indexed: 02/03/2023] Open
Abstract
Background Actions of general anaesthetics on activity in the cortico-thalamic network likely contribute to loss of consciousness and disconnection from the environment. Previously, we showed that the general anaesthetic isoflurane preferentially suppresses cortically evoked synaptic responses compared with thalamically evoked synaptic responses, but how this differential sensitivity translates into changes in network activity is unclear. Methods We investigated isoflurane disruption of spontaneous and stimulus-induced cortical network activity using multichannel recordings in murine auditory thalamo-cortical brain slices. Results Under control conditions, afferent stimulation elicited short latency, presumably monosynaptically driven, spiking responses, as well as long latency network bursts that propagated horizontally through the cortex. Isoflurane (0.05-0.6 mM) suppressed spiking activity overall, but had a far greater effect on network bursts than on early spiking responses. At isoflurane concentrations >0.3 mM, network bursts were almost entirely blocked, even with increased stimulation intensity and in response to paired (thalamo-cortical + cortical layer 1) stimulation, while early spiking responses were <50% blocked. Isoflurane increased the threshold for eliciting bursts, decreased their propagation speed and prevented layer 1 afferents from facilitating burst induction by thalamo-cortical afferents. Conclusions Disruption of horizontal activity spread and of layer 1 facilitation of thalamo-cortical responses likely contribute to the mechanism by which suppression of cortical feedback connections disrupts sensory awareness under anaesthesia.
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Affiliation(s)
- H Hentschke
- Department of Anesthesiology, Experimental Anesthesiology Section, University Hospital of Tübingen, Tübingen, Germany
| | - A Raz
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA.,Department of Anesthesiology, Rambam Health Care Campus, Haifa, Israel
| | - B M Krause
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - C A Murphy
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA.,Physiology Graduate Training Program, University of Wisconsin, Madison, WI, USA
| | - M I Banks
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
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Abstract
The heterogeneity of molecular mechanisms, target neural circuits, and neurophysiologic effects of general anesthetics makes it difficult to develop a reliable and drug-invariant index of general anesthesia. No single brain region or mechanism has been identified as the neural correlate of consciousness, suggesting that consciousness might emerge through complex interactions of spatially and temporally distributed brain functions. The goal of this review article is to introduce the basic concepts of networks and explain why the application of network science to general anesthesia could be a pathway to discover a fundamental mechanism of anesthetic-induced unconsciousness. This article reviews data suggesting that reduced network efficiency, constrained network repertoires, and changes in cortical dynamics create inhospitable conditions for information processing and transfer, which lead to unconsciousness. This review proposes that network science is not just a useful tool but a necessary theoretical framework and method to uncover common principles of anesthetic-induced unconsciousness.
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Affiliation(s)
- UnCheol Lee
- From the Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, Michigan
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Auditory Predictive Coding across Awareness States under Anesthesia: An Intracranial Electrophysiology Study. J Neurosci 2018; 38:8441-8452. [PMID: 30126970 DOI: 10.1523/jneurosci.0967-18.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 07/03/2018] [Accepted: 08/11/2018] [Indexed: 12/20/2022] Open
Abstract
The systems-level mechanisms underlying loss of consciousness (LOC) under anesthesia remain unclear. General anesthetics suppress sensory responses within higher-order cortex and feedback connections, both critical elements of predictive coding hypotheses of conscious perception. Responses to auditory novelty may offer promise as biomarkers for consciousness. This study examined anesthesia-induced changes in auditory novelty responses over short (local deviant [LD]) and long (global deviant [GD]) time scales, envisioned to engage preattentive and conscious levels of processing, respectively. Electrocorticographic recordings were obtained in human neurosurgical patients (3 male, 3 female) from four hierarchical processing levels: core auditory cortex, non-core auditory cortex, auditory-related, and PFC. Stimuli were vowel patterns incorporating deviants within and across stimuli (LD and GD). Subjects were presented with stimuli while awake, and during sedation (responsive) and following LOC (unresponsive) under propofol anesthesia. LD and GD effects were assayed as the averaged evoked potential and high gamma (70-150 Hz) activity. In the awake state, LD and GD effects were present in all recorded regions, with averaged evoked potential effects more broadly distributed than high gamma activity. Under sedation, LD effects were preserved in all regions, except PFC. LOC was accompanied by loss of LD effects outside of auditory cortex. By contrast, GD effects were markedly suppressed under sedation in all regions and were absent following LOC. Thus, although the presence of GD effects is indicative of being awake, its absence is not indicative of LOC. Loss of LD effects in higher-order cortical areas may constitute an alternative biomarker of LOC.SIGNIFICANCE STATEMENT Development of a biomarker that indexes changes in the brain upon loss of consciousness (LOC) under general anesthesia has broad implications for elucidating the neural basis of awareness and clinical relevance to mechanisms of sleep, coma, and disorders of consciousness. Using intracranial recordings from neurosurgery patients, we investigated changes in the activation of cortical networks involved in auditory novelty detection over short (local deviance) and long (global deviance) time scales associated with sedation and LOC under propofol anesthesia. Our results indicate that, whereas the presence of global deviance effects can index awareness, their loss cannot serve as a biomarker for LOC. The dramatic reduction of local deviance effects in areas beyond auditory cortex may constitute an alternative biomarker of LOC.
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Nourski KV, Steinschneider M, Rhone AE, Kawasaki H, Howard MA, Banks MI. Processing of auditory novelty across the cortical hierarchy: An intracranial electrophysiology study. Neuroimage 2018; 183:412-424. [PMID: 30114466 DOI: 10.1016/j.neuroimage.2018.08.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/02/2018] [Accepted: 08/12/2018] [Indexed: 11/15/2022] Open
Abstract
Under the predictive coding hypothesis, specific spatiotemporal patterns of cortical activation are postulated to occur during sensory processing as expectations generate feedback predictions and prediction errors generate feedforward signals. Establishing experimental evidence for this information flow within cortical hierarchy has been difficult, especially in humans, due to spatial and temporal limitations of non-invasive measures of cortical activity. This study investigated cortical responses to auditory novelty using the local/global deviant paradigm, which engages the hierarchical network underlying auditory predictive coding over short ('local deviance'; LD) and long ('global deviance'; GD) time scales. Electrocorticographic responses to auditory stimuli were obtained in neurosurgical patients from regions of interest (ROIs) including auditory, auditory-related and prefrontal cortex. LD and GD effects were assayed in averaged evoked potential (AEP) and high gamma (70-150 Hz) signals, the former likely dominated by local synaptic currents and the latter largely reflecting local spiking activity. AEP LD effects were distributed across all ROIs, with greatest percentage of significant sites in core and non-core auditory cortex. High gamma LD effects were localized primarily to auditory cortex in the superior temporal plane and on the lateral surface of the superior temporal gyrus (STG). LD effects exhibited progressively longer latencies in core, non-core, auditory-related and prefrontal cortices, consistent with feedforward signaling. The spatial distribution of AEP GD effects overlapped that of LD effects, but high gamma GD effects were more restricted to non-core areas. High gamma GD effects had shortest latencies in STG and preceded AEP GD effects in most ROIs. This latency profile, along with the paucity of high gamma GD effects in the superior temporal plane, suggest that the STG plays a prominent role in initiating novelty detection signals over long time scales. Thus, the data demonstrate distinct patterns of information flow in human cortex associated with auditory novelty detection over multiple time scales.
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Affiliation(s)
- Kirill V Nourski
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242, USA.
| | - Mitchell Steinschneider
- Departments 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
| | - Hiroto Kawasaki
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA
| | - Matthew A Howard
- Department of Neurosurgery, The University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242, USA; Pappajohn Biomedical Institute, The University of Iowa, Iowa City, IA 52242, USA
| | - Matthew I Banks
- Department of Anesthesiology and Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
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Minamoto T, Ikeda T, Kang H, Ito H, Vitayaburananont P, Nakae A, Hagihira S, Fujino Y, Mashimo T, Osaka M. Moderate sedation induced by general anaesthetics disrupts audio-spatial feature binding with sustained P3 components in healthy humans. Neurosci Conscious 2018; 2018:niy002. [PMID: 30042855 PMCID: PMC6007143 DOI: 10.1093/nc/niy002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 11/14/2022] Open
Abstract
Feature binding is considered to be the basis for conscious stimulus perception, while anaesthetics exert a gradient effect on the loss of consciousness (LOC). By integrating these two streams of research, the present study assessed the effect of two anaesthetic agents (i.e. propofol and midazolam) on audio-spatial feature binding. We also recorded the electrophysiological activity of the frontal channels. Using pharmacokinetic simulation, we determined the effect-site concentration (Ce) of the anaesthetics at loss of response to verbal command and eyelash reflex. We subsequently adjusted Ce to 75%, 50% and 25% of Ce-LOC to achieve deep, moderate and light sedation, respectively. Behavioural results showed that moderate sedation selectively disrupted feature binding. The frontal channels showed a P3 component (350-600 ms peristimulus period) following the presentation of audio-spatial stimuli at baseline and under moderate and light sedations. Critically, the late event-related potential component (600-1000 ms) returned to the pre-activated level (0-350 ms) at baseline and under light sedation but was sustained under moderate sedation. We propose that audio-spatial feature binding may require the presence of a P3 component and its subsequent and sufficient decline, as under anaesthetic-induced moderate sedation the P3 component was sustained and featured binding was impaired.
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Affiliation(s)
- Takehiro Minamoto
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan
| | - Takashi Ikeda
- Research Center for Child Mental Development, 13-1 Takaramachi, Kanazawa-shi, Ishikawa, 920-8640, Japan
| | - Hongling Kang
- Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroshi Ito
- Technology Standardization Department, 1-31-4 Nishiochiai, Shinjuku-ku, Tokyo 161-8560, Japan
| | - Piyasak Vitayaburananont
- Faculty of Medicine, Bangkok Metropolitan Administration Medical College and Vajira Hospital, Mahidol University 681 Samsen Rd, Vajiraphayaban, Dusit, Bangkok 10300, Thailand
| | - Aya Nakae
- WPI Immunology Frontier Research Center, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Hagihira
- Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuji Fujino
- Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takashi Mashimo
- Toyonaka Municipal Hospital, 4-14-1 Shibahara, Toyonaka, Osaka 560-8565, Japan
| | - Mariko Osaka
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan
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Safavynia SA, Arora S, Pryor KO, García PS. An update on postoperative delirium: Clinical features, neuropathogenesis, and perioperative management. CURRENT ANESTHESIOLOGY REPORTS 2018; 8:252-262. [PMID: 30555281 PMCID: PMC6290904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
PURPOSE OF REVIEW We present a focused review on postoperative delirium for anesthesiologists, encompassing clinical features, neuropathogenesis, and clinical identification and management strategies based on risk factors and current delirium treatments. RECENT FINDINGS The literature on postoperative delirium is dominated by non-experimental studies. We review delirium phenotypes, diagnostic criteria, and present standard nomenclature based on current literature. Disruption of cortical integration of complex information (CICI) may provide a framework to understand the neuropathogenesis of postoperative delirium, as well as risk factors and clinical modifiers in the perioperative period. We further divide risk factors into patient factors, surgical factors, and medical/pharmacological factors, and present specific considerations for each in the preoperative, intraoperative, and postoperative periods. SUMMARY Postoperative delirium is prevalent, poorly understood, and often missed with current screening techniques. Proper identification of risk factors is useful for perioperative interventions and can help tailor patient-specific management strategies.
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Affiliation(s)
- Seyed A. Safavynia
- Department of Anesthesiology, Weill Cornell Medical
College, New York, NY, USA
| | - Sona Arora
- Department of Anesthesiology, Emory University, Atlanta,
GA, USA
| | - Kane O. Pryor
- Department of Anesthesiology, Weill Cornell Medical
College, New York, NY, USA
| | - Paul S. García
- Department of Anesthesiology, Emory University, Atlanta,
GA, USA
- Neuroanesthesia Laboratory, Atlanta VA Medical Center/Emory
University, Atlanta, GA, USA
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Safavynia SA, Arora S, Pryor KO, García PS. An Update on Postoperative Delirium: Clinical Features,
Neuropathogenesis, and Perioperative Management. CURRENT ANESTHESIOLOGY REPORTS 2018. [DOI: 10.1007/s40140-018-0282-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Banks MI, Moran NS, Krause BM, Grady SM, Uhlrich DJ, Manning KA. Altered stimulus representation in rat auditory cortex is not causal for loss of consciousness under general anaesthesia. Br J Anaesth 2018; 121:605-615. [PMID: 30115259 DOI: 10.1016/j.bja.2018.05.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/13/2018] [Accepted: 05/21/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Current concepts suggest that impaired representation of information in cortical networks contributes to loss of consciousness under anaesthesia. We tested this idea in rat auditory cortex using information theory analysis of multiunit responses recorded under three anaesthetic agents with different molecular targets: isoflurane, propofol, and dexmedetomidine. We reasoned that if changes in the representation of sensory stimuli are causal for loss of consciousness, they should occur regardless of the specific anaesthetic agent. METHODS Spiking responses were recorded with chronically implanted microwire arrays in response to acoustic stimuli incorporating varied temporal and spectral dynamics. Experiments consisted of four drug conditions: awake (pre-drug), sedation (i.e. intact righting reflex), loss of consciousness (a dose just sufficient to cause loss of righting reflex), and recovery. Measures of firing rate, spike timing, and mutual information were analysed as a function of drug condition. RESULTS All three drugs decreased spontaneous and evoked spiking activity and modulated spike timing. However, changes in mutual information were inconsistent with altered stimulus representation being causal for loss of consciousness. First, direction of change in mutual information was agent-specific, increasing under dexmedetomidine and decreasing under isoflurane and propofol. Second, mutual information did not decrease at the transition between sedation and LOC for any agent. Changes in mutual information under anaesthesia correlated strongly with changes in precision and reliability of spike timing, consistent with the importance of temporal stimulus features in driving auditory cortical activity. CONCLUSIONS The primary sensory cortex is not the locus for changes in representation of information causal for loss of consciousness under anaesthesia.
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Affiliation(s)
- M I Banks
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA.
| | - N S Moran
- Neuroscience Training Program, University of Wisconsin, Madison, WI, USA
| | - B M Krause
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - S M Grady
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - D J Uhlrich
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | - K A Manning
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
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Thiery T, Lajnef T, Combrisson E, Dehgan A, Rainville P, Mashour GA, Blain-Moraes S, Jerbi K. Long-range temporal correlations in the brain distinguish conscious wakefulness from induced unconsciousness. Neuroimage 2018; 179:30-39. [PMID: 29885482 DOI: 10.1016/j.neuroimage.2018.05.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/18/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
Rhythmic neuronal synchronization across large-scale networks is thought to play a key role in the regulation of conscious states. Changes in neuronal oscillation amplitude across states of consciousness have been widely reported, but little is known about possible changes in the temporal dynamics of these oscillations. The temporal structure of brain oscillations may provide novel insights into the neural mechanisms underlying consciousness. To address this question, we examined long-range temporal correlations (LRTC) of EEG oscillation amplitudes recorded during both wakefulness and anesthetic-induced unconsciousness. Importantly, the time-varying EEG oscillation envelopes were assessed over the course of a sevoflurane sedation protocol during which the participants alternated between states of consciousness and unconsciousness. Both spectral power and LRTC in oscillation amplitude were computed across multiple frequency bands. State-dependent differences in these features were assessed using non-parametric tests and supervised machine learning. We found that periods of unconsciousness were associated with increases in LRTC in beta (15-30Hz) amplitude over frontocentral channels and with a suppression of alpha (8-13Hz) amplitude over occipitoparietal electrodes. Moreover, classifiers trained to predict states of consciousness on single epochs demonstrated that the combination of beta LRTC with alpha amplitude provided the highest classification accuracy (above 80%). These results suggest that loss of consciousness is accompanied by an augmentation of temporal persistence in neuronal oscillation amplitude, which may reflect an increase in regularity and a decrease in network repertoire compared to the brain's activity during resting-state consciousness.
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Affiliation(s)
- Thomas Thiery
- Psychology Department, University of Montreal, QC, Canada.
| | - Tarek Lajnef
- Psychology Department, University of Montreal, QC, Canada
| | - Etienne Combrisson
- Psychology Department, University of Montreal, QC, Canada; Center of Research and Innovation in Sport, Mental Processes and Motor Performance, University Claude Bernard Lyon I, University of Lyon, Villeurbanne, France; Brain Dynamics and Cognition, Lyon Neuroscience Research Center, INSERM U1028, UMR 5292, University of Lyon, Villeurbanne, France
| | - Arthur Dehgan
- Psychology Department, University of Montreal, QC, Canada
| | | | - George A Mashour
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, USA
| | - Stefanie Blain-Moraes
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
| | - Karim Jerbi
- Psychology Department, University of Montreal, QC, Canada
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Liu X, Lauer KK, Ward BD, Roberts CJ, Liu S, Gollapudy S, Rohloff R, Gross W, Xu Z, Chen G, Binder JR, Li SJ, Hudetz AG. Fine-Grained Parcellation of Brain Connectivity Improves Differentiation of States of Consciousness During Graded Propofol Sedation. Brain Connect 2018; 7:373-381. [PMID: 28540741 DOI: 10.1089/brain.2016.0477] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Conscious perception relies on interactions between spatially and functionally distinct modules of the brain at various spatiotemporal scales. These interactions are altered by anesthesia, an intervention that leads to fading consciousness. Relatively little is known about brain functional connectivity and its anesthetic modulation at a fine spatial scale. Here, we used functional imaging to examine propofol-induced changes in functional connectivity in brain networks defined at a fine-grained parcellation based on a combination of anatomical and functional features. Fifteen healthy volunteers underwent resting-state functional imaging in wakeful baseline, mild sedation, deep sedation, and recovery of consciousness. Compared with wakeful baseline, propofol produced widespread, dose-dependent functional connectivity changes that scaled with the extent to which consciousness was altered. The dominant changes in connectivity were associated with the frontal lobes. By examining node pairs that demonstrated a trend of functional connectivity change between wakefulness and deep sedation, quadratic discriminant analysis differentiated the states of consciousness in individual participants more accurately at a fine-grained parcellation (e.g., 2000 nodes) than at a coarse-grained parcellation (e.g., 116 anatomical nodes). Our study suggests that defining brain networks at a high granularity may provide a superior imaging-based distinction of the graded effect of anesthesia on consciousness.
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Affiliation(s)
- Xiaolin Liu
- 1 Department of Radiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Kathryn K Lauer
- 2 Department of Anesthesiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - B Douglas Ward
- 3 Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | | | - Suyan Liu
- 2 Department of Anesthesiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Suneeta Gollapudy
- 2 Department of Anesthesiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Robert Rohloff
- 4 Department of Neurology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - William Gross
- 2 Department of Anesthesiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Zhan Xu
- 3 Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Guangyu Chen
- 3 Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Jeffrey R Binder
- 4 Department of Neurology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Shi-Jiang Li
- 3 Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Anthony G Hudetz
- 5 Department of Anesthesiology and Center for Consciousness Science, University of Michigan , Ann Arbor, Michigan
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Mashour GA, Hudetz AG. Fading whispers down the lane: signal propagation in anaesthetized cortical networks. Br J Anaesth 2017; 119:568-570. [PMID: 29121276 DOI: 10.1093/bja/aex215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- G A Mashour
- Department of Anesthesiology, Center for Consciousness Science, Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - A G Hudetz
- Department of Anesthesiology, Center for Consciousness Science, Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
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Letheby C, Gerrans P. Self unbound: ego dissolution in psychedelic experience. Neurosci Conscious 2017; 2017:nix016. [PMID: 30042848 PMCID: PMC6007152 DOI: 10.1093/nc/nix016] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/21/2017] [Accepted: 05/15/2017] [Indexed: 11/26/2022] Open
Abstract
Users of psychedelic drugs often report that their sense of being a self or ‘I’ distinct from the rest of the world has diminished or altogether dissolved. Neuroscientific study of such ‘ego dissolution’ experiences offers a window onto the nature of self-awareness. We argue that ego dissolution is best explained by an account that explains self-awareness as resulting from the integrated functioning of hierarchical predictive models which posit the existence of a stable and unchanging entity to which representations are bound. Combining recent work on the ‘integrative self' and the phenomenon of self-binding with predictive processing principles yields an explanation of ego dissolution according to which self-representation is a useful Cartesian fiction: an ultimately false representation of a simple and enduring substance to which attributes are bound which serves to integrate and unify cognitive processing across levels and domains. The self-model is not a mere narrative posit, as some have suggested; it has a more robust and ubiquitous cognitive function than that. But this does not mean, as others have claimed, that the self-model has the right attributes to qualify as a self. It performs some of the right kinds of functions, but it is not the right kind of entity. Ego dissolution experiences reveal that the self-model plays an important binding function in cognitive processing, but the self does not exist.
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Affiliation(s)
- Chris Letheby
- Department of Philosophy, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Philip Gerrans
- Department of Philosophy, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
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Abstract
A quest for a systems-level neuroscientific basis of anesthetic-induced loss and return of consciousness has been in the forefront of research for the past 2 decades. Recent advances toward the discovery of underlying mechanisms have been achieved using experimental electrophysiology, multichannel electroencephalography, magnetoencephalography, and functional magnetic resonance imaging. By the careful dosing of various volatile and IV anesthetic agents to the level of behavioral unresponsiveness, both specific and common changes in functional and effective connectivity across large-scale brain networks have been discovered and interpreted in the context of how the synthesis of neural information might be affected during anesthesia. The results of most investigations to date converge toward the conclusion that a common neural correlate of anesthetic-induced unresponsiveness is a consistent depression or functional disconnection of lateral frontoparietal networks, which are thought to be critical for consciousness of the environment. A reduction in the repertoire of brain states may contribute to the anesthetic disruption of large-scale information integration leading to unconsciousness. In future investigations, a systematic delineation of connectivity changes with multiple anesthetics using the same experimental design, and the same analytical method will be desirable. The critical neural events that account for the transition between responsive and unresponsive states should be assessed at similar anesthetic doses just below and above the loss or return of responsiveness. There will also be a need to identify a robust, sensitive, and reliable measure of information transfer. Ultimately, finding a behavior-independent measure of subjective experience that can track covert cognition in unresponsive subjects and a delineation of causal factors versus correlated events will be essential to understand the neuronal basis of human consciousness and unconsciousness.
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Nowak A, Vallacher RR, Zochowski M, Rychwalska A. Functional Synchronization: The Emergence of Coordinated Activity in Human Systems. Front Psychol 2017; 8:945. [PMID: 28659842 PMCID: PMC5468424 DOI: 10.3389/fpsyg.2017.00945] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 05/22/2017] [Indexed: 12/30/2022] Open
Abstract
The topical landscape of psychology is highly compartmentalized, with distinct phenomena explained and investigated with recourse to theories and methods that have little in common. Our aim in this article is to identify a basic set of principles that underlie otherwise diverse aspects of human experience at all levels of psychological reality, from neural processes to group dynamics. The core idea is that neural, behavioral, mental, and social structures emerge through the synchronization of lower-level elements (e.g., neurons, muscle movements, thoughts and feelings, individuals) into a functional unit—a coherent structure that functions to accomplish tasks. The coherence provided by the formation of functional units may be transient, persisting only as long as necessary to perform the task at hand. This creates the potential for the repeated assembly and disassembly of functional units in accordance with changing task demands. This perspective is rooted in principles of complexity science and non-linear dynamical systems and is supported by recent discoveries in neuroscience and recent models in cognitive and social psychology. We offer guidelines for investigating the emergence of functional units in different domains, thereby honoring the topical differentiation of psychology while providing an integrative foundation for the field.
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Affiliation(s)
- Andrzej Nowak
- Department of Psychology, SWPS University of Social Sciences and HumanitiesWarsaw, Poland.,Department of Psychology, Florida Atlantic University, Boca RatonFL, United States
| | - Robin R Vallacher
- Department of Psychology, Florida Atlantic University, Boca RatonFL, United States
| | - Michal Zochowski
- Department of Physics and Biophysics Program, University of Michigan, Ann ArborMI, United States
| | - Agnieszka Rychwalska
- The Robert Zajonc Institute for Social Studies, University of WarsawWarsaw, Poland
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Li D, Hambrecht-Wiedbusch VS, Mashour GA. Accelerated Recovery of Consciousness after General Anesthesia Is Associated with Increased Functional Brain Connectivity in the High-Gamma Bandwidth. Front Syst Neurosci 2017; 11:16. [PMID: 28392760 PMCID: PMC5364164 DOI: 10.3389/fnsys.2017.00016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/10/2017] [Indexed: 11/13/2022] Open
Abstract
Recent data from our laboratory demonstrate that high-frequency gamma connectivity across the cortex is present during consciousness and depressed during unconsciousness. However, these data were derived from static and well-defined states of arousal rather than during transitions that would suggest functional relevance. We also recently found that subanesthetic ketamine administered during isoflurane anesthesia accelerates recovery upon discontinuation of the primary anesthetic and increases gamma power during emergence. In the current study we re-analyzed electroencephalogram (EEG) data to test the hypothesis that functional cortical connectivity between anterior and posterior cortical regions would be increased during accelerated recovery induced by ketamine when compared to saline-treated controls. Rodents were instrumented with intracranial EEG electrodes and general anesthesia was induced with isoflurane anesthesia. After 37.5 min of continuous isoflurane anesthesia, a subanesthetic dose of ketamine (25 mg/kg intraperitoneal) was administered, with evidence of a 44% reduction in emergence time. In this study, we analyzed gamma and theta coherence (measure of undirected functional connectivity) and normalized symbolic transfer entropy (measure of directed functional connectivity) between frontal and parietal cortices during various levels of consciousness, with a focus on emergence from isoflurane anesthesia. During accelerated emergence in the ketamine-treated group, there was increased frontal-parietal coherence {p = 0.005, 0.05-0.23 [95% confidence interval (CI)]} and normalized symbolic transfer entropy [frontal to parietal: p < 0.001, 0.010-0.026 (95% CI); parietal to frontal: p < 0.001, 0.009-0.025 (95% CI)] in high-frequency gamma bandwidth as compared with the saline-treated group. Surrogates of cortical information exchange in high-frequency gamma are increased in association with accelerated recovery from anesthesia. This finding adds evidence suggesting a functional significance of high-gamma information transfer in consciousness.
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Affiliation(s)
- Duan Li
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, USA; Center for Consciousness Science, University of MichiganAnn Arbor, MI, USA
| | - Viviane S Hambrecht-Wiedbusch
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, USA; Center for Consciousness Science, University of MichiganAnn Arbor, MI, USA
| | - George A Mashour
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, USA; Center for Consciousness Science, University of MichiganAnn Arbor, MI, USA; Neuroscience Graduate Program, University of MichiganAnn Arbor, MI, USA
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42
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Ho SS, Nakamura Y. Healing Dysfunctional Identity: Bridging Mind-Body Intervention to Brain Systems. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/jbbs.2017.73013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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43
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Cascella M, Schiavone V, Muzio MR, Cuomo A. Consciousness fluctuation during general anesthesia: a theoretical approach to anesthesia awareness and memory modulation. Curr Med Res Opin 2016; 32:1351-9. [PMID: 27046232 DOI: 10.1080/03007995.2016.1174679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
With anesthesia awareness as a model of study we debate the both fascinating and dangerous phenomenon called consciousness fluctuation that takes place during surgical anesthesia. In accordance with current scientific knowledge this paradox is the consequence of our limits in both precise knowledge of anesthesia mechanisms and our inability to accurately assess the level of anesthesia with brain monitoring. We also focus on the relationships between memory and anesthesia, as well as the possibility of interfering with memory during general anesthesia.
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Affiliation(s)
- Marco Cascella
- a Division of Anesthesia, Department of Anesthesia, Endoscopy and Cardiology , Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS , Naples , Italy
| | - Vincenzo Schiavone
- b Division of Anesthesia and Intensive Care , Hospital "Pineta Grande" , Castel Volturno , Italy
| | - Maria Rosaria Muzio
- c Division of Infantile Neuropsychiatry , UOMI - Maternal and Infant Health , Torre del Greco , Naples , Italy
| | - Arturo Cuomo
- a Division of Anesthesia, Department of Anesthesia, Endoscopy and Cardiology , Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS , Naples , Italy
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Local Versus Global Effects of Isoflurane Anesthesia on Visual Processing in the Fly Brain. eNeuro 2016; 3:eN-NWR-0116-16. [PMID: 27517084 PMCID: PMC4967815 DOI: 10.1523/eneuro.0116-16.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/27/2016] [Accepted: 07/04/2016] [Indexed: 12/28/2022] Open
Abstract
What characteristics of neural activity distinguish the awake and anesthetized brain? Drugs such as isoflurane abolish behavioral responsiveness in all animals, implying evolutionarily conserved mechanisms. However, it is unclear whether this conservation is reflected at the level of neural activity. Studies in humans have shown that anesthesia is characterized by spatially distinct spectral and coherence signatures that have also been implicated in the global impairment of cortical communication. We questioned whether anesthesia has similar effects on global and local neural processing in one of the smallest brains, that of the fruit fly (Drosophila melanogaster). Using a recently developed multielectrode technique, we recorded local field potentials from different areas of the fly brain simultaneously, while manipulating the concentration of isoflurane. Flickering visual stimuli (‘frequency tags’) allowed us to track evoked responses in the frequency domain and measure the effects of isoflurane throughout the brain. We found that isoflurane reduced power and coherence at the tagging frequency (13 or 17 Hz) in central brain regions. Unexpectedly, isoflurane increased power and coherence at twice the tag frequency (26 or 34 Hz) in the optic lobes of the fly, but only for specific stimulus configurations. By modeling the periodic responses, we show that the increase in power in peripheral areas can be attributed to local neuroanatomy. We further show that the effects on coherence can be explained by impacted signal-to-noise ratios. Together, our results show that general anesthesia has distinct local and global effects on neuronal processing in the fruit fly brain.
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Schroeder KE, Irwin ZT, Gaidica M, Nicole Bentley J, Patil PG, Mashour GA, Chestek CA. Disruption of corticocortical information transfer during ketamine anesthesia in the primate brain. Neuroimage 2016; 134:459-465. [PMID: 27095309 DOI: 10.1016/j.neuroimage.2016.04.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 04/09/2016] [Accepted: 04/15/2016] [Indexed: 11/27/2022] Open
Abstract
The neural mechanisms of anesthetic-induced unconsciousness have yet to be fully elucidated, in part because of the diverse molecular targets of anesthetic agents. We demonstrate, using intracortical recordings in macaque monkeys, that information transfer between structurally connected cortical regions is disrupted during ketamine anesthesia, despite preserved primary sensory representation. Furthermore, transfer entropy, an information-theoretic measure of directed connectivity, decreases significantly between neuronal units in the anesthetized state. This is the first direct demonstration of a general anesthetic disrupting corticocortical information transfer in the primate brain. Given past studies showing that more commonly used GABAergic drugs inhibit surrogate measures of cortical communication, this finding suggests the potential for a common network-level mechanism of anesthetic-induced unconsciousness.
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Affiliation(s)
- Karen E Schroeder
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109
| | - Zachary T Irwin
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109
| | - Matt Gaidica
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, 48109
| | - J Nicole Bentley
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan, 48109
| | - Parag G Patil
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109.,Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan, 48109.,Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, 48109
| | - George A Mashour
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, 48109.,Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan, 48109.,Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, Michigan, 48109
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109.,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, 48109.,Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan, 48109.,Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, 48109.,Department of Robotics, University of Michigan, Ann Arbor, Michigan, 48109
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46
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Ceylan ME, Dönmez A, Ünsalver BÖ, Evrensel A. Neural synchronization as a hypothetical explanation of the psychoanalytic unconscious. Conscious Cogn 2016; 40:34-44. [PMID: 26744848 DOI: 10.1016/j.concog.2015.12.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 11/25/2022]
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47
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Kim M, Mashour GA, Moraes SB, Vanini G, Tarnal V, Janke E, Hudetz AG, Lee U. Functional and Topological Conditions for Explosive Synchronization Develop in Human Brain Networks with the Onset of Anesthetic-Induced Unconsciousness. Front Comput Neurosci 2016; 10:1. [PMID: 26834616 PMCID: PMC4720783 DOI: 10.3389/fncom.2016.00001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/04/2016] [Indexed: 11/18/2022] Open
Abstract
Sleep, anesthesia, and coma share a number of neural features but the recovery profiles are radically different. To understand the mechanisms of reversibility of unconsciousness at the network level, we studied the conditions for gradual and abrupt transitions in conscious and anesthetized states. We hypothesized that the conditions for explosive synchronization (ES) in human brain networks would be present in the anesthetized brain just over the threshold of unconsciousness. To test this hypothesis, functional brain networks were constructed from multi-channel electroencephalogram (EEG) recordings in seven healthy subjects across conscious, unconscious, and recovery states. We analyzed four variables that are involved in facilitating ES in generic, non-biological networks: (1) correlation between node degree and frequency, (2) disassortativity (i.e., the tendency of highly-connected nodes to link with less-connected nodes, or vice versa), (3) frequency difference of coupled nodes, and (4) an inequality relationship between local and global network properties, which is referred to as the suppressive rule. We observed that the four network conditions for ES were satisfied in the unconscious state. Conditions for ES in the human brain suggest a potential mechanism for rapid recovery from the lightly-anesthetized state. This study demonstrates for the first time that the network conditions for ES, formerly shown in generic networks only, are present in empirically-derived functional brain networks. Further investigations with deep anesthesia, sleep, and coma could provide insight into the underlying causes of variability in recovery profiles of these unconscious states.
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Affiliation(s)
- Minkyung Kim
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Department of Physics, Pohang University of Science and TechnologyPohang, South Korea
| | - George A Mashour
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Stefanie-Blain Moraes
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Vijay Tarnal
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Ellen Janke
- Department of Anesthesiology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Anthony G Hudetz
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Uncheol Lee
- Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA
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Mitra A, Snyder AZ, Tagliazucchi E, Laufs H, Raichle ME. Propagated infra-slow intrinsic brain activity reorganizes across wake and slow wave sleep. eLife 2015; 4:e10781. [PMID: 26551562 PMCID: PMC4737658 DOI: 10.7554/elife.10781] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/06/2015] [Indexed: 12/14/2022] Open
Abstract
Propagation of slow intrinsic brain activity has been widely observed in electrophysiogical studies of slow wave sleep (SWS). However, in human resting state fMRI (rs-fMRI), intrinsic activity has been understood predominantly in terms of zero-lag temporal synchrony (functional connectivity) within systems known as resting state networks (RSNs). Prior rs-fMRI studies have found that RSNs are generally preserved across wake and sleep. Here, we use a recently developed analysis technique to study propagation of infra-slow intrinsic blood oxygen level dependent (BOLD) signals in normal adults during wake and SWS. This analysis reveals marked changes in propagation patterns in SWS vs. wake. Broadly, ordered propagation is preserved within traditionally defined RSNs but lost between RSNs. Additionally, propagation between cerebral cortex and subcortical structures reverses directions, and intra-cortical propagation becomes reorganized, especially in visual and sensorimotor cortices. These findings show that propagated rs-fMRI activity informs theoretical accounts of the neural functions of sleep.
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Affiliation(s)
- Anish Mitra
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
| | - Abraham Z Snyder
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
- Department of Neurology, Washington University in St. Louis, St. Louis, United States
| | - Enzo Tagliazucchi
- Institute for Medical Psychology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Department of Neurology, Brain Imaging Center, Goethe-Universität Frankfurt am Main, Frankfurt, Germany
| | - Helmut Laufs
- Department of Neurology, Brain Imaging Center, Goethe-Universität Frankfurt am Main, Frankfurt, Germany
- Department of Neurology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Marcus E Raichle
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
- Department of Neurology, Washington University in St. Louis, St. Louis, United States
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Liang P, Zhang H, Xu Y, Jia W, Zang Y, Li K. Disruption of cortical integration during midazolam-induced light sedation. Hum Brain Mapp 2015; 36:4247-61. [PMID: 26314702 PMCID: PMC5049658 DOI: 10.1002/hbm.22914] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/08/2015] [Accepted: 07/14/2015] [Indexed: 11/05/2022] Open
Abstract
This work examines the effect of midazolam‐induced light sedation on intrinsic functional connectivity of human brain, using a randomized, double‐blind, placebo‐controlled, cross‐over, within‐subject design. Fourteen healthy young subjects were enrolled and midazolam (0.03 mg/kg of the participant's body mass, to a maximum of 2.5 mg) or saline were administrated with an interval of one week. Resting‐state fMRI was conducted before and after administration for each subject. We focus on two types of networks: sensory related lower‐level functional networks and higher‐order functions related ones. Independent component analysis (ICA) was used to identify these resting‐state functional networks. We hypothesize that the sensory (visual, auditory, and sensorimotor) related networks will be intact under midazolam‐induced light sedation while the higher‐order (default mode, executive control, salience networks, etc.) networks will be functionally disconnected. It was found that the functional integrity of the lower‐level networks was maintained, while that of the higher‐level networks was significantly disrupted by light sedation. The within‐network connectivity of the two types of networks was differently affected in terms of direction and extent. These findings provide direct evidence that higher‐order cognitive functions including memory, attention, executive function, and language were impaired prior to lower‐level sensory responses during sedation. Our result also lends support to the information integration model of consciousness. Hum Brain Mapp 36:4247–4261, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Peipeng Liang
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, 100053, China
| | - Han Zhang
- Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, 311121, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, 310015, China.,Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Yachao Xu
- Depart of Anesthesiology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Wenbin Jia
- Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, 311121, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, 310015, China
| | - Yufeng Zang
- Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, 311121, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, 310015, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, 100053, China
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Abstract
BACKGROUND Recent studies of anesthetic-induced unconsciousness in humans have focused predominantly on the intravenous drug propofol and have identified anterior dominance of alpha rhythms and frontal phase-amplitude coupling patterns as neurophysiological markers. However, it is unclear whether the correlates of propofol-induced unconsciousness are generalizable to inhaled anesthetics, which have distinct molecular targets and which are used more commonly in clinical practice. METHODS The authors recorded 64-channel electroencephalograms in healthy human participants during consciousness, sevoflurane-induced unconsciousness, and recovery (n = 10; n = 7 suitable for analysis). Spectrograms and scalp distributions of low-frequency (1 Hz) and alpha (10 Hz) power were analyzed, and phase-amplitude modulation between these two frequencies was calculated in frontal and parietal regions. Phase lag index was used to assess phase relationships across the cortex. RESULTS At concentrations sufficient for unconsciousness, sevoflurane did not result in a consistent anteriorization of alpha power; the relationship between low-frequency phase and alpha amplitude in the frontal cortex did not undergo characteristic transitions. By contrast, there was significant cross-frequency coupling in the parietal region during consciousness that was not observed after loss of consciousness. Furthermore, a reversible disruption of anterior-posterior phase relationships in the alpha bandwidth was identified as a correlate of sevoflurane-induced unconsciousness. CONCLUSION In humans, sevoflurane-induced unconsciousness is not correlated with anteriorization of alpha and related cross-frequency patterns, but rather by a disruption of phase-amplitude coupling in the parietal region and phase-phase relationships across the cortex.
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