1
|
Whyte CJ, Redinbaugh MJ, Shine JM, Saalmann YB. Thalamic contributions to the state and contents of consciousness. Neuron 2024; 112:1611-1625. [PMID: 38754373 DOI: 10.1016/j.neuron.2024.04.019] [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: 02/19/2024] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024]
Abstract
Consciousness can be conceptualized as varying along at least two dimensions: the global state of consciousness and the content of conscious experience. Here, we highlight the cellular and systems-level contributions of the thalamus to conscious state and then argue for thalamic contributions to conscious content, including the integrated, segregated, and continuous nature of our experience. We underscore vital, yet distinct roles for core- and matrix-type thalamic neurons. Through reciprocal interactions with deep-layer cortical neurons, matrix neurons support wakefulness and determine perceptual thresholds, whereas the cortical interactions of core neurons maintain content and enable perceptual constancy. We further propose that conscious integration, segregation, and continuity depend on the convergent nature of corticothalamic projections enabling dimensionality reduction, a thalamic reticular nucleus-mediated divisive normalization-like process, and sustained coherent activity in thalamocortical loops, respectively. Overall, we conclude that the thalamus plays a central topological role in brain structures controlling conscious experience.
Collapse
Affiliation(s)
- Christopher J Whyte
- Centre for Complex Systems, The University of Sydney, Sydney, NSW, Australia; Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
| | | | - James M Shine
- Centre for Complex Systems, The University of Sydney, Sydney, NSW, Australia; Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
| | - Yuri B Saalmann
- Department of Psychology, University of Wisconsin - Madison, Madison, WI, USA; Wisconsin National Primate Research Center, Madison, WI, USA
| |
Collapse
|
2
|
Mckilliam A. A mechanistic alternative to minimal sufficiency as the guiding principle for NCC research. Neurosci Conscious 2024; 2024:niae014. [PMID: 38618486 PMCID: PMC11013376 DOI: 10.1093/nc/niae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/29/2024] [Accepted: 03/05/2024] [Indexed: 04/16/2024] Open
Abstract
A central project for the neuroscience of consciousness is to reveal the neural basis of consciousness. For the past 20-odd years, this project has been conceptualized in terms of minimal sufficiency. Recently, a number of authors have suggested that the project is better conceived in mechanistic terms as the search for difference-makers. In this paper, I (i) motivate this mechanistic alternative to minimal sufficiency, (ii) develop it further by clarifying debates about the prospects of leveraging mutual manipulability to distinguish constitutive difference-makers from those that are merely causal, and (iii) explore the implications this has for recent debates concerning the status of the prefrontal cortex. I argue that adopting a mechanistic approach to the neuroscience of consciousness suggests that the prefrontal cortex is part of the neural mechanisms underlying consciousness even if it is not strictly speaking a necessary part.
Collapse
Affiliation(s)
- Andy Mckilliam
- Cognition and Philosophy Lab, Monash Centre for Consciousness and Contemplative Studies, Department of Philosophy, Monash University, Room 429, 29 Ancora Imparo Way, Melbourne, VIC 3800, Australia
| |
Collapse
|
3
|
Chmiel J, Rybakowski F, Leszek J. EEG in Down Syndrome-A Review and Insights into Potential Neural Mechanisms. Brain Sci 2024; 14:136. [PMID: 38391711 PMCID: PMC10886507 DOI: 10.3390/brainsci14020136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
Introduction: Down syndrome (DS) stands out as one of the most prevalent genetic disorders, imposing a significant burden on both society and the healthcare system. Scientists are making efforts to understand the neural mechanisms behind the pathophysiology of this disorder. Among the valuable methods for studying these mechanisms is electroencephalography (EEG), a non-invasive technique that measures the brain's electrical activity, characterised by its excellent temporal resolution. This review aims to consolidate studies examining EEG usage in individuals with DS. The objective was to identify shared elements of disrupted EEG activity and, crucially, to elucidate the neural mechanisms underpinning these deviations. Searches were conducted on Pubmed/Medline, Research Gate, and Cochrane databases. Results: The literature search yielded 17 relevant articles. Despite the significant time span, small sample size, and overall heterogeneity of the included studies, three common features of aberrant EEG activity in people with DS were found. Potential mechanisms for this altered activity were delineated. Conclusions: The studies included in this review show altered EEG activity in people with DS compared to the control group. To bolster these current findings, future investigations with larger sample sizes are imperative.
Collapse
Affiliation(s)
- James Chmiel
- Institute of Neurofeedback and tDCS Poland, 70-393 Szczecin, Poland
| | - Filip Rybakowski
- Department and Clinic of Psychiatry, Poznan University of Medical Sciences, 61-701 Poznań, Poland
| | - Jerzy Leszek
- Department and Clinic of Psychiatry, Wrocław Medical University, 54-235 Wrocław, Poland
| |
Collapse
|
4
|
Jiang M, Niu Z, Liu G, Huang H, Li X, Su Y. Quantitative EEG and brain network analysis: predicting awakening from early coma after cardiopulmonary resuscitation. Neurol Res 2023; 45:969-978. [PMID: 37643397 DOI: 10.1080/01616412.2023.2252281] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
OBJECTIVE For patients in early coma after cardiopulmonary resuscitation (CPR), quantitative electroencephalogram (EEG) and brain network analysis was performed to identify relevant indicators of awakening. METHODS A prospective cohort study was conducted on comatose patients after CPR in the neuro-critical care unit. The included patients received clinical evaluation. The bedside high-density (64-lead) EEG monitoring was performed for visual grading and calculation of power spectrum and brain network parameters. A 3-month prognostic assessment was performed and the patients were dichotomized into the awakening group and the unawakening group. RESULTS A total of 25 patients were included. The awakening group had higher GCS score, more slow wave pattern and reactive EEG than the unawakening group (P = 0.003, P < 0.001, P < 0.001, respectively). Compared with the unawakening group, (1) the awakening group had significantly higher absolute and relative θ power and slow/fast band ratio of the whole brain (P < 0.05), (2) the awakening group had stronger connection based on coherence, phase synchronization, phase lag index and cross-correlation (P < 0.05), (3) the awakening group had higher small-worldness, clustering coefficient and average path length based on graph theory (P < 0.05). CONCLUSIONS The power spectrum and brain network characteristics in patients in early coma after CPR have predictive value for recovery.
Collapse
Affiliation(s)
- Mengdi Jiang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Currently working at Department of Neurology, Beijing Hospital, National Center of Gerontology, Beijing, China
| | - Zikang Niu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern, Beijing Normal University, Beijing, China
| | - Gang Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Huijin Huang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaoli Li
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern, Beijing Normal University, Beijing, China
| | - Yingying Su
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
5
|
Frohlich J, Crone JS, Mediano PAM, Toker D, Bor D. Editorial: Dissociations between neural activity and conscious state: a key to understanding consciousness. Front Hum Neurosci 2023; 17:1256168. [PMID: 37600551 PMCID: PMC10433896 DOI: 10.3389/fnhum.2023.1256168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Affiliation(s)
- Joel Frohlich
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany
- Institute for Advanced Consciousness Studies, Santa Monica, CA, United States
| | - Julia S. Crone
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria
| | - Pedro A. M. Mediano
- Department of Computing, Imperial College London, London, United Kingdom
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
| | - Daniel Toker
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Daniel Bor
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- Department of Psychology, Queen Mary University of London, London, United Kingdom
| |
Collapse
|
6
|
Paunet T, Mariano-Goulart D, Deverdun J, Le Bars E, Fourcade M, Kucharczak F. Functional PET Neuroimaging in Consciousness Evaluation: Study Protocol. Diagnostics (Basel) 2023; 13:2026. [PMID: 37370921 DOI: 10.3390/diagnostics13122026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Ensuring a robust and reliable evaluation of coma deepness and prognostication of neurological outcome is challenging. We propose to develop PET neuroimaging as a new diagnostic and prognosis tool for comatose patients using a recently published methodology to perform functional PET (fPET). This exam permits the quantification of task-specific changes in neuronal metabolism in a single session. The aim of this protocol is to determine whether task-specific changes in glucose metabolism during the acute phase of coma are able to predict recovery at 18 months. Participation will be proposed for all patients coming for a standard PET-CT in our center in order to evaluate global cerebral metabolism during the comatose state. Legally appointed representative consent will be obtained to slightly modify the exam protocol: (1) 18F-fluorodeoxyglucose (18F-FDG) bolus plus continuous infusion instead of a simple bolus and (2) more time under camera to perform dynamic acquisition. Participants will undergo a 55-min fPET session with a 20% bolus + 80% infusion protocol. Two occurrences of three block (5-min rest, 10-min auditory stimulation and 10-min emotional auditory stimulation) will be performed after reaching equilibrium of FDG arterial concentration. We will compare the regional brain metabolism at rest and during the sessions of auditory and emotional auditory stimulation to search for a determinant of coma recovery (18 months of follow-up after the exam). Emotional auditory stimulation should induce an activation of: the auditory cortex, the consciousness areas and the neural circuitry for emotion (function to coma deepness). An activation analysis will be carried out to highlight regional brain activation using dedicated custom-made software based on Python statistical and image processing toolboxes. The association between activation levels and the Coma Recovery Scale-Revisited (CRS-R) will be assessed using multivariate analysis. If successful, the results from this study will help improve coma prognosis evaluation based on the pattern of neuronal metabolism at the onset of the pathology. The study protocol, rationale and methods are described in this paper.
Collapse
Affiliation(s)
- Tom Paunet
- Department of Nuclear Medicine, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| | - Denis Mariano-Goulart
- Department of Nuclear Medicine, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| | - Jeremy Deverdun
- I2FH, Department of Neuroradiology, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| | - Emmanuelle Le Bars
- I2FH, Department of Neuroradiology, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| | - Marjolaine Fourcade
- Department of Nuclear Medicine, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| | - Florentin Kucharczak
- Department of Nuclear Medicine, Gui de Chauliac Hospital, Montpellier University Hospital Center, University of Montpellier, 34090 Montpellier, France
| |
Collapse
|
7
|
Deng F, Taylor N, Owen AM, Cusack R, Naci L. Responsiveness variability during anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks. Hum Brain Mapp 2023; 44:2142-2157. [PMID: 36617994 PMCID: PMC10028637 DOI: 10.1002/hbm.26199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 10/30/2022] [Accepted: 12/18/2022] [Indexed: 01/10/2023] Open
Abstract
Anaesthesia combined with functional neuroimaging provides a powerful approach for understanding the brain mechanisms of consciousness. Although propofol is used ubiquitously in clinical interventions that reversibly suppress consciousness, it shows large inter-individual variability, and the brain bases of this variability remain poorly understood. We asked whether three networks key to conscious cognition-the dorsal attention (DAN), executive control (ECN), and default mode (DMN)-underlie responsiveness variability under anaesthesia. Healthy participants (N = 17) were moderately anaesthetized during narrative understanding and resting-state conditions inside the Magnetic Resonance Imaging scanner. A target detection task measured behavioural responsiveness. An independent behavioural study (N = 25) qualified the attention demands of narrative understanding. Then, 30% of participants were unaffected in their response times, thus thwarting a key aim of anaesthesia-the suppression of behavioural responsiveness. Individuals with stronger functional connectivity within the DAN and ECN, between them, and to the DMN, and with larger grey matter volume in frontal regions were more resilient to anaesthesia. For the first time, we show that responsiveness variability during propofol anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks, which can be predicted prior to sedation. Results highlight novel markers for improving awareness monitoring during clinical anaesthesia.
Collapse
Affiliation(s)
- Feng Deng
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, Dublin, Ireland
| | - Nicola Taylor
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, Dublin, Ireland
| | - Adrian M Owen
- Brain and Mind Institute, Western University, London, Canada
- Department of Physiology and Pharmacology and Department of Psychology, Western University, London, Canada
| | - Rhodri Cusack
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, Dublin, Ireland
| | - Lorina Naci
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, Dublin, Ireland
- Global Brain Health Institute, Trinity College Dublin, Dublin, Ireland
| |
Collapse
|
8
|
Nourmohammadi A, Swift JR, de Pesters A, Guay CS, Adamo MA, Dalfino JC, Ritaccio AL, Schalk G, Brunner P. Passive functional mapping of receptive language cortex during general anesthesia using electrocorticography. Clin Neurophysiol 2023; 147:31-44. [PMID: 36634533 PMCID: PMC10267852 DOI: 10.1016/j.clinph.2022.11.021] [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: 04/18/2022] [Revised: 09/30/2022] [Accepted: 11/10/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To investigate the feasibility of passive functional mapping in the receptive language cortex during general anesthesia using electrocorticographic (ECoG) signals. METHODS We used subdurally placed ECoG grids to record cortical responses to speech stimuli during awake and anesthesia conditions. We identified the cortical areas with significant responses to the stimuli using the spectro-temporal consistency of the brain signal in the broadband gamma (BBG) frequency band (70-170 Hz). RESULTS We found that ECoG BBG responses during general anesthesia effectively identify cortical regions associated with receptive language function. Our analyses demonstrated that the ability to identify receptive language cortex varies across different states and depths of anesthesia. We confirmed these results by comparing them to receptive language areas identified during the awake condition. Quantification of these results demonstrated an average sensitivity and specificity of passive language mapping during general anesthesia to be 49±7.7% and 100%, respectively. CONCLUSION Our results demonstrate that mapping receptive language cortex in patients during general anesthesia is feasible. SIGNIFICANCE Our proposed protocol could greatly expand the population of patients that can benefit from passive language mapping techniques, and could eliminate the risks associated with electrocortical stimulation during an awake craniotomy.
Collapse
Affiliation(s)
- Amin Nourmohammadi
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - James R Swift
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - Adriana de Pesters
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - Christian S Guay
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.
| | - Matthew A Adamo
- Department of Neurosurgery, Albany Medical College, Albany, NY, USA.
| | - John C Dalfino
- Department of Neurosurgery, Albany Medical College, Albany, NY, USA.
| | - Anthony L Ritaccio
- Department of Neurology, Albany Medical College, Albany, NY, USA; Department of Neurology, Mayo Clinic, Jacksonville, FL, USA.
| | - Gerwin Schalk
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA; Chen Frontier Lab for Applied Neurotechnology, Tianqiao and Chrissy Chen Institute, Shanghai, P.R. China.
| | - Peter Brunner
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA; Department of Neurology, Albany Medical College, Albany, NY, USA.
| |
Collapse
|
9
|
Bieber M, Schwerin S, Kreuzer M, Klug C, Henzler M, Schneider G, Haseneder R, Kratzer S. s-ketamine enhances thalamocortical and corticocortical synaptic transmission in acute murine brain slices via increased AMPA-receptor-mediated pathways. Front Syst Neurosci 2022; 16:1044536. [PMID: 36618009 PMCID: PMC9814968 DOI: 10.3389/fnsys.2022.1044536] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
Despite ongoing research efforts and routine clinical use, the neuronal mechanisms underlying the anesthesia-induced loss of consciousness are still under debate. Unlike most anesthetics, ketamine increases thalamic and cortical activity. Ketamine is considered to act via a NMDA-receptor antagonism-mediated reduction of inhibition, i.e., disinhibition. Intact interactions between the thalamus and cortex constitute a prerequisite for the maintenance of consciousness and are thus a promising target for anesthetics to induce loss of consciousness. In this study, we aim to characterize the influence of s-ketamine on the thalamocortical network using acute brain-slice preparation. We performed whole-cell patch-clamp recordings from pyramidal neurons in cortical lamina IV and thalamocortical relay neurons in acute brain slices from CB57BL/6N mice. Excitatory postsynaptic potentials (EPSPs) were obtained via electrical stimulation of the cortex with a bipolar electrode that was positioned to lamina II/III (electrically induced EPSPs, eEPSPs) or via optogenetic activation of thalamocortical relay neurons (optogenetically induced EPSPs, oEPSPs). Intrinsic neuronal properties (like resting membrane potential, membrane threshold for action potential generation, input resistance, and tonic action potential frequency), as well as NMDA-receptor-dependent and independent spontaneous GABAA-receptor-mediated inhibitory postsynaptic currents (sIPSCs) were evaluated. Wilcoxon signed-rank test (level of significance < 0.05) served as a statistical test and Cohen's U3_1 was used to determine the actual effect size. Within 20 min, s-ketamine (5 μM) significantly increased both intracortical eEPSPs as well as thalamocortical oEPSPs. NMDA-receptor-mediated intracortical eEPSPs were significantly reduced. Intrinsic neuronal properties of cortical pyramidal neurons from lamina IV and thalamocortical relay neurons in the ventrobasal thalamic complex were not substantially affected. Neither a significant effect on NMDA-receptor-dependent GABAA sIPSCs (thought to underly a disinhibitory effect) nor a reduction of NMDA-receptor independent GABAA sIPSCs was observed. Both thalamocortical and intracortical AMPA-receptor-mediated EPSPs were significantly increased.In conclusion, our findings show no evidence for a NMDA-receptor antagonism-based disinhibition, but rather suggest an enhanced thalamocortical and intracortical synaptic transmission, which appears to be driven via increased AMPA-receptor-mediated transmission.
Collapse
|
10
|
Kronemer SI, Aksen M, Ding JZ, Ryu JH, Xin Q, Ding Z, Prince JS, Kwon H, Khalaf A, Forman S, Jin DS, Wang K, Chen K, Hu C, Agarwal A, Saberski E, Wafa SMA, Morgan OP, Wu J, Christison-Lagay KL, Hasulak N, Morrell M, Urban A, Todd Constable R, Pitts M, Mark Richardson R, Crowley MJ, Blumenfeld H. Human visual consciousness involves large scale cortical and subcortical networks independent of task report and eye movement activity. Nat Commun 2022; 13:7342. [PMID: 36446792 PMCID: PMC9707162 DOI: 10.1038/s41467-022-35117-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 11/17/2022] [Indexed: 11/30/2022] Open
Abstract
The full neural circuits of conscious perception remain unknown. Using a visual perception task, we directly recorded a subcortical thalamic awareness potential (TAP). We also developed a unique paradigm to classify perceived versus not perceived stimuli using eye measurements to remove confounding signals related to reporting on conscious experiences. Using fMRI, we discovered three major brain networks driving conscious visual perception independent of report: first, increases in signal detection regions in visual, fusiform cortex, and frontal eye fields; and in arousal/salience networks involving midbrain, thalamus, nucleus accumbens, anterior cingulate, and anterior insula; second, increases in frontoparietal attention and executive control networks and in the cerebellum; finally, decreases in the default mode network. These results were largely maintained after excluding eye movement-based fMRI changes. Our findings provide evidence that the neurophysiology of consciousness is complex even without overt report, involving multiple cortical and subcortical networks overlapping in space and time.
Collapse
Affiliation(s)
- Sharif I Kronemer
- Department of Neurology, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Mark Aksen
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Julia Z Ding
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Jun Hwan Ryu
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Qilong Xin
- Department of Neurology, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Zhaoxiong Ding
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Jacob S Prince
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Hunki Kwon
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Aya Khalaf
- Department of Neurology, Yale University, New Haven, CT, USA
- Biomedical Engineering and Systems, Faculty of Engineering, Cairo University, Giza, Egypt
| | - Sarit Forman
- Department of Neurology, Yale University, New Haven, CT, USA
| | - David S Jin
- Department of Neurology, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Kevin Wang
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Kaylie Chen
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Claire Hu
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Akshar Agarwal
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Erik Saberski
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Syed Mohammad Adil Wafa
- Department of Neurology, Yale University, New Haven, CT, USA
- Child Study Center, Yale University, New Haven, CT, USA
- Division of Psychology and Language Sciences, University College London, London, UK
| | - Owen P Morgan
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Jia Wu
- Child Study Center, Yale University, New Haven, CT, USA
| | | | | | | | | | - R Todd Constable
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
- Department of Neurosurgery, Yale University, New Haven, CT, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | | | - R Mark Richardson
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | | | - Hal Blumenfeld
- Department of Neurology, Yale University, New Haven, CT, USA.
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA.
- Department of Neurosurgery, Yale University, New Haven, CT, USA.
- Department of Neuroscience, Yale University, New Haven, CT, USA.
| |
Collapse
|
11
|
Zheng ZS, Monti MM. Cortical and thalamic connections of the human globus pallidus: Implications for disorders of consciousness. Front Neuroanat 2022; 16:960439. [PMID: 36093291 PMCID: PMC9453545 DOI: 10.3389/fnana.2022.960439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
A dominant framework for understanding loss and recovery of consciousness in the context of severe brain injury, the mesocircuit hypothesis, focuses on the role of cortico-subcortical recurrent interactions, with a strong emphasis on excitatory thalamofugal projections. According to this view, excess inhibition from the internal globus pallidus (GPi) on central thalamic nuclei is key to understanding prolonged disorders of consciousness (DOC) and their characteristic, brain-wide metabolic depression. Recent work in healthy volunteers and patients, however, suggests a previously unappreciated role for the external globus pallidus (GPe) in maintaining a state of consciousness. This view is consistent with empirical findings demonstrating the existence of “direct” (i.e., not mediated by GPi/substantia nigra pars reticulata) GPe connections with cortex and thalamus in animal models, as well as their involvement in modulating arousal and sleep, and with theoretical work underscoring the role of GABA dysfunction in prolonged DOC. Leveraging 50 healthy subjects' high angular resolution diffusion imaging (HARDI) dataset from the Human Connectome Project, which provides a more accurate representation of intravoxel water diffusion than conventional diffusion tensor imaging approaches, we ran probabilistic tractography using extensive a priori exclusion criteria to limit the influence of indirect connections in order to better characterize “direct” pallidal connections. We report the first in vivo evidence of highly probable “direct” GPe connections with prefrontal cortex (PFC) and central thalamic nuclei. Conversely, we find direct connections between the GPi and PFC to be sparse (i.e., less likely indicative of true “direct” connectivity) and restricted to the posterior border of PFC, thus reflecting an extension from the cortical motor zones (i.e., motor association areas). Consistent with GPi's preferential connections with sensorimotor cortices, the GPi appears to predominantly connect with the sensorimotor subregions of the thalamus. These findings are validated against existing animal tracer studies. These findings suggest that contemporary mechanistic models of loss and recovery of consciousness following brain injury must be updated to include the GPe and reflect the actual patterns of GPe and GPi connectivity within large-scale cortico-thalamo-cortical circuits.
Collapse
Affiliation(s)
- Zhong S. Zheng
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
- Research Institute, Casa Colina Hospital and Centers for Healthcare, Pomona, CA, United States
- *Correspondence: Zhong S. Zheng
| | - Martin M. Monti
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
- Brain Injury Research Center (BIRC), Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
12
|
Ward LM, Guevara R. Qualia and Phenomenal Consciousness Arise From the Information Structure of an Electromagnetic Field in the Brain. Front Hum Neurosci 2022; 16:874241. [PMID: 35860400 PMCID: PMC9289677 DOI: 10.3389/fnhum.2022.874241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/17/2022] [Indexed: 11/17/2022] Open
Abstract
In this paper we address the following problems and provide realistic answers to them: (1) What could be the physical substrate for subjective, phenomenal, consciousness (P-consciousness)? Our answer: the electromagnetic (EM) field generated by the movement and changes of electrical charges in the brain. (2) Is this substrate generated in some particular part of the brains of conscious entities or does it comprise the entirety of the brain/body? Our answer: a part of the thalamus in mammals, and homologous parts of other brains generates the critical EM field. (3) From whence arise the qualia experienced in P-consciousness? Our answer, the relevant EM field is “structured” by emulating in the brain the information in EM fields arising from both external (the environment) and internal (the body) sources. (4) What differentiates the P-conscious EM field from other EM fields, e.g., the flux of photons scattered from object surfaces, the EM field of an electro-magnet, or the EM fields generated in the brain that do not enter P-consciousness, such as those generated in the retina or occipital cortex, or those generated in brain areas that guide behavior through visual information in persons exhibiting “blindsight”? Our answer: living systems express a boundary between themselves and the environment, requiring them to model (coarsely emulate) information from their environment in order to control through actions, to the extent possible, the vast sea of variety in which they are immersed. This model, expressed in an EM field, is P-consciousness. The model is the best possible representation of the moment-to-moment niche-relevant (action-relevant: affordance) information an organism can generate (a Gestalt). Information that is at a lower level than niche-relevant, such as the unanalyzed retinal vector-field, is not represented in P-consciousness because it is not niche-relevant. Living organisms have sensory and other systems that have evolved to supply such information, albeit in a coarse form.
Collapse
Affiliation(s)
- Lawrence M. Ward
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Lawrence M. Ward,
| | - Ramón Guevara
- Department of Physics and Astronomy, University of Padua, Padua, Italy
- Department of Developmental Psychology and Socialization, Padova Neuroscience Center, University of Padua, Padua, Italy
| |
Collapse
|
13
|
Presurgical Thalamus Volume in Postoperative Delirium: A Longitudinal Observational Cohort Study in Older Patients. Anesth Analg 2022; 135:136-142. [PMID: 35442218 DOI: 10.1213/ane.0000000000005987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Previous studies suggest a role of the thalamus in cognitive function, while others implicate it as a central effect site of anesthetics. Yet, its role in postoperative neurocognition in the aging brain remains uncertain. We used presurgical thalamic volume as a functional indicator and determined its association with postoperative delirium (POD). METHODS For this study, 301 older adults (aged ≥65) without dementia and scheduled for surgery were enrolled. Before surgery, participants underwent magnetic resonance imaging (MRI). Thalamus volume was segmented using Freesurfer (Version 5.3.). Participants were screened for POD twice a day until discharge or for a maximum of 7 days. POD was defined as a positive screening on ≥1 of 4 validated instruments: Richmond Agitation Sedation Scale (RASS), Nursing Delirium Screening Scale (Nu-DESC), Confusion Assessment Method (CAM), and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) score. A logistic regression associated thalamus volume with POD with adjustment for age, global brain atrophy, and physical status according to the American Society of Anesthesiologists (ASA) classification. RESULTS In this cohort, 44 participants (14.6%) were diagnosed with POD. Independently of age, global brain atrophy, and physical status score, a higher preoperative thalamus volume was associated with a reduced odds of POD (odds ratio per 1-cm3 increment; 0.73 [95% confidence interval (CI), 0.58-0.92]; P = .008). CONCLUSIONS A larger thalamus volume was associated with reduced odds of POD. Thus, the thalamus marks a region of interest in POD in the aging brain. These findings may help to understand the neuronal basis of POD.
Collapse
|
14
|
Eniwaye BP, Booth V, Hudetz AG, Zochowski M. Modeling cortical synaptic effects of anesthesia and their cholinergic reversal. PLoS Comput Biol 2022; 18:e1009743. [PMID: 35737717 PMCID: PMC9258872 DOI: 10.1371/journal.pcbi.1009743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 07/06/2022] [Accepted: 05/31/2022] [Indexed: 01/07/2023] Open
Abstract
General anesthetics work through a variety of molecular mechanisms while resulting in the common end point of sedation and loss of consciousness. Generally, the administration of common anesthetics induces reduction in synaptic excitation while promoting synaptic inhibition. Exogenous modulation of the anesthetics' synaptic effects can help determine the neuronal pathways involved in anesthesia. For example, both animal and human studies have shown that exogenously induced increases in acetylcholine in the brain can elicit wakeful-like behavior despite the continued presence of the anesthetic. However, the underlying mechanisms of anesthesia reversal at the cellular level have not been investigated. Here we apply a computational model of a network of excitatory and inhibitory neurons to simulate the network-wide effects of anesthesia, due to changes in synaptic inhibition and excitation, and their reversal by cholinergic activation through muscarinic receptors. We use a differential evolution algorithm to fit model parameters to match measures of spiking activity, neuronal connectivity, and network dynamics recorded in the visual cortex of rodents during anesthesia with desflurane in vivo. We find that facilitating muscarinic receptor effects of acetylcholine on top of anesthetic-induced synaptic changes predicts the reversal of anesthetic suppression of neurons' spiking activity, functional connectivity, as well as pairwise and population interactions. Thus, our model predicts a specific neuronal mechanism for the cholinergic reversal of anesthesia consistent with experimental behavioral observations.
Collapse
Affiliation(s)
- Bolaji P. Eniwaye
- Department of Applied Physics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Victoria Booth
- Department of Mathematics and Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (VB); (AGH); (MZ)
| | - Anthony G. Hudetz
- Department of Applied Physics, University of Michigan, Ann Arbor, Michigan, United States of America
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (VB); (AGH); (MZ)
| | - Michal Zochowski
- Department of Applied Physics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Physics and Biophysics Program, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (VB); (AGH); (MZ)
| |
Collapse
|
15
|
Leyden C, Brüggemann T, Debinski F, Simacek CA, Dehmelt FA, Arrenberg AB. Efficacy of Tricaine (MS-222) and Hypothermia as Anesthetic Agents for Blocking Sensorimotor Responses in Larval Zebrafish. Front Vet Sci 2022; 9:864573. [PMID: 35419446 PMCID: PMC8996001 DOI: 10.3389/fvets.2022.864573] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/28/2022] [Indexed: 12/12/2022] Open
Abstract
Tricaine, or MS-222, is the most commonly used chemical anesthetic in zebrafish research. It is thought to act via blocking voltage-gated sodium channels, though its mechanism of action, particularly at the neuronal level, is not yet fully understood. Here, we first characterized the effects of tricaine on both body balance and touch responses in freely swimming animals, before determining its effect on the neural activity underlying the optokinetic response at the level of motion perception, sensorimotor signaling and the generation of behavior in immobilized animals. We found that the standard dose for larvae (168 mg/L) induced loss of righting reflex within 30 seconds, which then recovered within 3 minutes. Optokinetic behavior recovered within 15 minutes. Calcium imaging showed that tricaine interferes with optokinetic behavior by interruption of the signals between the pretectum and hindbrain. The motion sensitivity indices of identified sensory neurons were unchanged in larvae exposed to tricaine, though fewer such neurons were detected, leaving a small population of active sensory neurons. We then compared tricaine with gradual cooling, a potential non-chemical alternative method of anesthesia. While neuronal tuning appeared to be affected in a similar manner during gradual cooling, gradual cooling induced a surge in calcium levels in both the pretectum and hindbrain. This calcium surge, alongside a drop in heartrate, is potentially associated with harmful changes in physiology and suggests that tricaine is a better anesthetic agent than gradual cooling for zebrafish laboratory research.
Collapse
Affiliation(s)
- Claire Leyden
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Timo Brüggemann
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Florentyna Debinski
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Clara A Simacek
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Florian A Dehmelt
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Aristides B Arrenberg
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| |
Collapse
|
16
|
Thalamic T-Type Calcium Channels as Targets for Hypnotics and General Anesthetics. Int J Mol Sci 2022; 23:ijms23042349. [PMID: 35216466 PMCID: PMC8876360 DOI: 10.3390/ijms23042349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 12/19/2022] Open
Abstract
General anesthetics mainly act by modulating synaptic inhibition on the one hand (the potentiation of GABA transmission) or synaptic excitation on the other (the inhibition of NMDA receptors), but they can also have effects on numerous other proteins, receptors, and channels. The effects of general anesthetics on ion channels have been the subject of research since the publication of reports of direct actions of these drugs on ion channel proteins. In particular, there is considerable interest in T-type voltage-gated calcium channels that are abundantly expressed in the thalamus, where they control patterns of cellular excitability and thalamocortical oscillations during awake and sleep states. Here, we summarized and discussed our recent studies focused on the CaV3.1 isoform of T-channels in the nonspecific thalamus (intralaminar and midline nuclei), which acts as a key hub through which natural sleep and general anesthesia are initiated. We used mouse genetics and in vivo and ex vivo electrophysiology to study the role of thalamic T-channels in hypnosis induced by a standard general anesthetic, isoflurane, as well as novel neuroactive steroids. From the results of this study, we conclude that CaV3.1 channels contribute to thalamocortical oscillations during anesthetic-induced hypnosis, particularly the slow-frequency range of δ oscillations (0.5–4 Hz), by generating “window current” that contributes to the resting membrane potential. We posit that the role of the thalamic CaV3.1 isoform of T-channels in the effects of various classes of general anesthetics warrants consideration.
Collapse
|
17
|
Tsytsarev V. Methodological aspects of studying the mechanisms of consciousness. Behav Brain Res 2022; 419:113684. [PMID: 34838578 DOI: 10.1016/j.bbr.2021.113684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 11/21/2021] [Accepted: 11/22/2021] [Indexed: 11/24/2022]
Abstract
There are at least two approaches to the definition of consciousness. In the first case, certain aspects of consciousness, called qualia, are considered inaccessible for research from a third person and can only be described through subjective experience. This approach is inextricably linked with the so-called "hard problem of consciousness", that is, the question of why consciousness has qualia or how any physical changes in the environment can generate subjective experience. With this approach, some aspects of consciousness, by definition, cannot be explained on the basis of external observations and, therefore, are outside the scope of scientific research. In the second case, a priori constraints do not constrain the field of scientific investigation, and the best explanation of the experience in the first person is included as a possible subject of empirical research. Historically, in the study of cause-and-effect relationships in biology, it was customary to distinguish between proximate causation and ultimate causation existing in biological systems. Immediate causes are based on the immediate influencing factors [1]. Proximate causation has evolutionary explanations. When studying biological systems themselves, such an approach is undoubtedly justified, but it often seems insufficient when studying the interaction of consciousness and the brain [2,3]. Current scientific communities proceed from the assumption that the physical substrate for the generation of consciousness is a neural network that unites various types of neurons located in various brain structures. Many neuroscientists attach a key role in this process to the cortical and thalamocortical neural networks. This question is directly related to experimental and clinical research in the field of disorder of consciousness. Progress in this area of medicine depends on advances in neuroscience in this area and is also a powerful source of empirical information. In this area of consciousness research, a large amount of experimental data has been accumulated, and in this review an attempt was made to generalize and systematize.
Collapse
|
18
|
Giacometti C, Dureux A, Autran-Clavagnier D, Wilson CRE, Sallet J, Dirheimer M, Procyk E, Hadj-Bouziane F, Amiez C. Frontal Cortical Functional Connectivity Is Impacted by Anaesthesia in Macaques. Cereb Cortex 2021; 32:4050-4067. [PMID: 34974618 DOI: 10.1093/cercor/bhab465] [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: 06/24/2021] [Revised: 10/19/2021] [Accepted: 11/09/2021] [Indexed: 01/02/2023] Open
Abstract
A critical aspect of neuroscience is to establish whether and how brain networks evolved across primates. To date, most comparative studies have used resting-state functional magnetic resonance imaging (rs-fMRI) in anaesthetized nonhuman primates and in awake humans. However, anaesthesia strongly affects rs-fMRI signals. The present study investigated the impact of the awareness state (anaesthesia vs. awake) within the same group of macaque monkeys on the rs-fMRI functional connectivity organization of a well-characterized network in the human brain, the cingulo-frontal lateral network. Results in awake macaques show that rostral seeds in the cingulate sulcus exhibited stronger correlation strength with rostral compared to caudal lateral frontal cortical areas, while more caudal seeds displayed stronger correlation strength with caudal compared to anterior lateral frontal cortical areas. Critically, this inverse rostro-caudal functional gradient was abolished under anaesthesia. This study demonstrated a similar functional connectivity (FC) organization of the cingulo-frontal cortical network in awake macaque to that previously uncovered in the human brain pointing toward a preserved FC organization from macaque to human. However, it can only be observed in awake state suggesting that this network is sensitive to anaesthesia and warranting significant caution when comparing FC patterns across species under different states.
Collapse
Affiliation(s)
- Camille Giacometti
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Audrey Dureux
- Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), Lyon, France, University of Lyon 1, Lyon, France
| | - Delphine Autran-Clavagnier
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France.,Inovarion, 75005 Paris, France
| | - Charles R E Wilson
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Jérôme Sallet
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Manon Dirheimer
- Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), Lyon, France, University of Lyon 1, Lyon, France
| | - Emmanuel Procyk
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Fadila Hadj-Bouziane
- Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), Lyon, France, University of Lyon 1, Lyon, France
| | - Céline Amiez
- Univ Lyon, Université Claude Bernard Lyon 1, Institut National de la Santé Et de la Recherche Médicale, Stem Cell and Brain Research Institute U1208, Bron, France
| |
Collapse
|
19
|
Bachmann T. Representational 'touch' and modulatory 'retouch'-two necessary neurobiological processes in thalamocortical interaction for conscious experience. Neurosci Conscious 2021; 2021:niab045. [PMID: 34925911 PMCID: PMC8672242 DOI: 10.1093/nc/niab045] [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: 01/10/2021] [Revised: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.
Collapse
Affiliation(s)
- Talis Bachmann
- Department of Penal Law, Laboratory of Cognitive Neuroscience, School of Law, University of Tartu (Tallinn Branch), Kaarli puiestee 3, Tallinn 10119, Estonia
| |
Collapse
|
20
|
Pérez-Santos I, Palomero-Gallagher N, Zilles K, Cavada C. Distribution of the Noradrenaline Innervation and Adrenoceptors in the Macaque Monkey Thalamus. Cereb Cortex 2021; 31:4115-4139. [PMID: 34003210 PMCID: PMC8328208 DOI: 10.1093/cercor/bhab073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/18/2021] [Accepted: 03/03/2021] [Indexed: 11/14/2022] Open
Abstract
Noradrenaline (NA) in the thalamus has important roles in physiological, pharmacological, and pathological neuromodulation. In this work, a complete characterization of NA axons and Alpha adrenoceptors distributions is provided. NA axons, revealed by immunohistochemistry against the synthesizing enzyme and the NA transporter, are present in all thalamic nuclei. The most densely innervated ones are the midline nuclei, intralaminar nuclei (paracentral and parafascicular), and the medial sector of the mediodorsal nucleus (MDm). The ventral motor nuclei and most somatosensory relay nuclei receive a moderate NA innervation. The pulvinar complex receives a heterogeneous innervation. The lateral geniculate nucleus (GL) has the lowest NA innervation. Alpha adrenoceptors were analyzed by in vitro quantitative autoradiography. Alpha-1 receptor densities are higher than Alpha-2 densities. Overall, axonal densities and Alpha adrenoceptor densities coincide; although some mismatches were identified. The nuclei with the highest Alpha-1 values are MDm, the parvocellular part of the ventral posterior medial nucleus, medial pulvinar, and midline nuclei. The nucleus with the lowest Alpha-1 receptor density is GL. Alpha-2 receptor densities are highest in the lateral dorsal, centromedian, medial and inferior pulvinar, and midline nuclei. These results suggest a role for NA in modulating thalamic involvement in consciousness, limbic, cognitive, and executive functions.
Collapse
Affiliation(s)
- Isabel Pérez-Santos
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Calle Arzobispo Morcillo 4, 28029 Madrid, Spain
| | - Nicola Palomero-Gallagher
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, 52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.,C. & O. Vogt Institute for Brain Research, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Karl Zilles
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, 52425 Jülich, Germany.,C. & O. Vogt Institute for Brain Research, Heinrich-Heine-University, 40225 Düsseldorf, Germany.,JARA-BRAIN, Jülich-Aachen Research Alliance, 52425 Jülich, Germany
| | - Carmen Cavada
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Calle Arzobispo Morcillo 4, 28029 Madrid, Spain
| |
Collapse
|
21
|
Nguyen-Ky T, Tuan HD, Savkin A, Do MN, Van NTT. Real-Time EEG Signal Classification for Monitoring and Predicting the Transition Between Different Anaesthetic States. IEEE Trans Biomed Eng 2021; 68:1450-1458. [PMID: 33471747 DOI: 10.1109/tbme.2021.3053019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Quantitative identification of the transitions between anaesthetic states is very essential for optimizing patient safety and quality care during surgery but poses a very challenging task. The state-of-the-art monitors are still not capable of providing their manifest variables, so the practitioners must diagnose them based on their own experience. The present paper proposes a novel real-time method to identify these transitions. Firstly, the Hurst method is used to pre-process the de-noised electro-encephalograph (EEG) signals. The maximum of Hurst's ranges is then accepted as the EEG real-time response, which induces a new real-time feature under moving average framework. Its maximum power spectral density is found to be very differentiated into the distinct transitions of anaesthetic states and thus can be used as the quantitative index for their identification.
Collapse
|
22
|
Zheng W, Tan X, Liu T, Li X, Gao J, Hong L, Zhang X, Zhao Z, Yu Y, Zhang Y, Luo B, Wu D. Individualized Thalamic Parcellation Reveals Alterations in Shape and Microstructure of Thalamic Nuclei in Patients with Disorder of Consciousness. Cereb Cortex Commun 2021; 2:tgab024. [PMID: 34296169 PMCID: PMC8152869 DOI: 10.1093/texcom/tgab024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/25/2021] [Accepted: 03/28/2021] [Indexed: 12/02/2022] Open
Abstract
The thalamus plays crucial roles in consciousness generation and information processing. Previous evidence suggests that disorder of consciousness (DOC) caused by severe brain injury, is potentially related to thalamic abnormalities. However, how the morphology and microstructure change in thalamic subfields and thalamocortical fiber pathways in patients with DOC, and the relationships between these changes and the consciousness status remain unclear. Here, we generated the individual-specific thalamic parcellation in 10 DOC patients and 10 healthy controls (HC) via a novel thalamic segmentation framework based on the fiber orientation distribution (FOD) derived from 7-Tesla diffusion MRI, and investigated the shape deformation of thalamic nuclei as well as the microstructural changes associated with thalamic nuclei and thalamocortical pathways in patients with DOC. Enlargement of dorsal posterior nucleus and atrophy of anterior nucleus in the right thalamus were observed in DOC cohort relative to the HCs, and the former was closely linked to the consciousness level of the patients. We also found significant reductions of fiber density, but not fiber bundle cross-section, within several thalamic nuclei and most of the thalamocortical fiber pathways, suggesting that loss of axons might take primary responsibility for the impaired thalamocortical connections in patients with DOC rather than the change in fiber-bundle morphology. Furthermore, the individual-specific thalamic parcellation achieved 80% accuracy in classifying patients at the minimally conscious state from the vegetative state, compared with ~60% accuracy based on group-level parcellations. Our findings provide the first evidence for the shape deformation of thalamic nuclei in DOC patients and the microstructural basis of the disrupted thalamocortical connections.
Collapse
Affiliation(s)
- Weihao Zheng
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Xufei Tan
- Department of Clinical Medicine, School of Medicine, Zhejiang University City College, Hangzhou, 310015, P.R. China
| | - Tingting Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Xiaoxia Li
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Jian Gao
- Department of Rehabilitation, Hospital of Zhejiang Armed Police Corps, Hangzhou, 310051, P.R. China
| | - Lirong Hong
- Department of Rehabilitation, Hospital of Zhejiang Armed Police Corps, Hangzhou, 310051, P.R. China
| | - Xiaotong Zhang
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, 310029, P.R. China
| | - Zhiyong Zhao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Yamei Yu
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Benyan Luo
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Dan Wu
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| |
Collapse
|
23
|
Frohlich J, Toker D, Monti MM. Consciousness among delta waves: a paradox? Brain 2021; 144:2257-2277. [PMID: 33693596 DOI: 10.1093/brain/awab095] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/12/2021] [Accepted: 02/25/2021] [Indexed: 01/29/2023] Open
Abstract
A common observation in EEG research is that consciousness vanishes with the appearance of delta (1 - 4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are very frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalised epileptic seizures, and disorders of consciousness such as coma and vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the "down states" or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and nonconvulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalogram or MEG signals strongly relates to an individual's level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.
Collapse
Affiliation(s)
- Joel Frohlich
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Daniel Toker
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Martin M Monti
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA.,Department of Neurosurgery, UCLA Brain Injury Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
| |
Collapse
|
24
|
Schwerin S, Kopp C, Pircher E, Schneider G, Kreuzer M, Haseneder R, Kratzer S. Attenuation of Native Hyperpolarization-Activated, Cyclic Nucleotide-Gated Channel Function by the Volatile Anesthetic Sevoflurane in Mouse Thalamocortical Relay Neurons. Front Cell Neurosci 2021; 14:606687. [PMID: 33551750 PMCID: PMC7858256 DOI: 10.3389/fncel.2020.606687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/18/2020] [Indexed: 11/24/2022] Open
Abstract
As thalamocortical relay neurons are ascribed a crucial role in signal propagation and information processing, they have attracted considerable attention as potential targets for anesthetic modulation. In this study, we analyzed the effects of different concentrations of sevoflurane on the excitability of thalamocortical relay neurons and hyperpolarization-activated, cyclic-nucleotide gated (HCN) channels, which play a decisive role in regulating membrane properties and rhythmic oscillatory activity. The effects of sevoflurane on single-cell excitability and native HCN channels were investigated in acutely prepared brain slices from adult wild-type mice with the whole-cell patch-clamp technique, using voltage-clamp and current-clamp protocols. Sevoflurane dose-dependently depressed membrane biophysics and HCN-mediated parameters of neuronal excitability. Respective half-maximal inhibitory and effective concentrations ranged between 0.30 (95% CI, 0.18–0.50) mM and 0.88 (95% CI, 0.40–2.20) mM. We witnessed a pronounced reduction of HCN dependent Ih current amplitude starting at a concentration of 0.45 mM [relative change at −133 mV; 0.45 mM sevoflurane: 0.85 (interquartile range, 0.79–0.92), n = 12, p = 0.011; 1.47 mM sevoflurane: 0.37 (interquartile range, 0.34–0.62), n = 5, p < 0.001] with a half-maximal inhibitory concentration of 0.88 (95% CI, 0.40–2.20) mM. In contrast, effects on voltage-dependent channel gating were modest with significant changes only occurring at 1.47 mM [absolute change of half-maximal activation potential; 1.47 mM: −7.2 (interquartile range, −10.3 to −5.8) mV, n = 5, p = 0.020]. In this study, we demonstrate that sevoflurane inhibits the excitability of thalamocortical relay neurons in a concentration-dependent manner within a clinically relevant range. Especially concerning its effects on native HCN channel function, our findings indicate substance-specific differences in comparison to other anesthetic agents. Considering the importance of HCN channels, the observed effects might mechanistically contribute to the hypnotic properties of sevoflurane.
Collapse
Affiliation(s)
- Stefan Schwerin
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Claudia Kopp
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Elisabeth Pircher
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Gerhard Schneider
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Matthias Kreuzer
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Rainer Haseneder
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Stephan Kratzer
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| |
Collapse
|
25
|
Abstract
A novel, heuristic model based upon chaotic complex systems theory and quantum mechanics is proposed to overcome the dichotomy between mind and body. The mind-body interface represents a chaotic system, ruled by the probability principle, as shown in quantum mechanics. Neuronal activity shows many patterns of chaotic behavior, and applications of chaotic patterns seem to be relevant for research regarding the mind-body relationship and the process of trance. A quantum consciousness theory has been proposed, largely controversial, since quantum physics applies to subatomic world and not to macrostructures, such as the brain. Quantum cognition is an emerging field that applies the formalism of quantum theory to model cognitive phenomena such as information processing by the human brain; it overcomes limits and shortcomings of cartesian dualism as well as quantum general theory. As hypnosis is a state of consciousness, it applies to hypnotic cognitive functioning rather than hypnotic structure.
Collapse
|
26
|
Varley TF, Carhart-Harris R, Roseman L, Menon DK, Stamatakis EA. Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. Neuroimage 2020; 220:117049. [PMID: 32619708 DOI: 10.1016/j.neuroimage.2020.117049] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 05/12/2020] [Accepted: 06/09/2020] [Indexed: 12/19/2022] Open
Abstract
Psychedelic drugs, such as psilocybin and LSD, represent unique tools for researchers investigating the neural origins of consciousness. Currently, the most compelling theories of how psychedelics exert their effects is by increasing the complexity of brain activity and moving the system towards a critical point between order and disorder, creating more dynamic and complex patterns of neural activity. While the concept of criticality is of central importance to this theory, few of the published studies on psychedelics investigate it directly, testing instead related measures such as algorithmic complexity or Shannon entropy. We propose using the fractal dimension of functional activity in the brain as a measure of complexity since findings from physics suggest that as a system organizes towards criticality, it tends to take on a fractal structure. We tested two different measures of fractal dimension, one spatial and one temporal, using fMRI data from volunteers under the influence of both LSD and psilocybin. The first was the fractal dimension of cortical functional connectivity networks and the second was the fractal dimension of BOLD time-series. In addition to the fractal measures, we used a well-established, non-fractal measure of signal complexity and show that they behave similarly. We were able to show that both psychedelic drugs significantly increased the fractal dimension of functional connectivity networks, and that LSD significantly increased the fractal dimension of BOLD signals, with psilocybin showing a non-significant trend in the same direction. With both LSD and psilocybin, we were able to localize changes in the fractal dimension of BOLD signals to brain areas assigned to the dorsal-attenion network. These results show that psychedelic drugs increase the fractal dimension of activity in the brain and we see this as an indicator that the changes in consciousness triggered by psychedelics are associated with evolution towards a critical zone.
Collapse
Affiliation(s)
- Thomas F Varley
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, UK; Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA.
| | - Robin Carhart-Harris
- Centre for Neuropsychopharmacology, Department of Medicine, Imperial College London, London, UK
| | - Leor Roseman
- Centre for Neuropsychopharmacology, Department of Medicine, Imperial College London, London, UK; Computational, Cognitive and Clinical Neuroscience Laboratory, Department of Medicine, Imperial College London, London, UK
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, UK
| |
Collapse
|
27
|
Reimann HM, Niendorf T. The (Un)Conscious Mouse as a Model for Human Brain Functions: Key Principles of Anesthesia and Their Impact on Translational Neuroimaging. Front Syst Neurosci 2020; 14:8. [PMID: 32508601 PMCID: PMC7248373 DOI: 10.3389/fnsys.2020.00008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
In recent years, technical and procedural advances have brought functional magnetic resonance imaging (fMRI) to the field of murine neuroscience. Due to its unique capacity to measure functional activity non-invasively, across the entire brain, fMRI allows for the direct comparison of large-scale murine and human brain functions. This opens an avenue for bidirectional translational strategies to address fundamental questions ranging from neurological disorders to the nature of consciousness. The key challenges of murine fMRI are: (1) to generate and maintain functional brain states that approximate those of calm and relaxed human volunteers, while (2) preserving neurovascular coupling and physiological baseline conditions. Low-dose anesthetic protocols are commonly applied in murine functional brain studies to prevent stress and facilitate a calm and relaxed condition among animals. Yet, current mono-anesthesia has been shown to impair neural transmission and hemodynamic integrity. By linking the current state of murine electrophysiology, Ca2+ imaging and fMRI of anesthetic effects to findings from human studies, this systematic review proposes general principles to design, apply and monitor anesthetic protocols in a more sophisticated way. The further development of balanced multimodal anesthesia, combining two or more drugs with complementary modes of action helps to shape and maintain specific brain states and relevant aspects of murine physiology. Functional connectivity and its dynamic repertoire as assessed by fMRI can be used to make inferences about cortical states and provide additional information about whole-brain functional dynamics. Based on this, a simple and comprehensive functional neurosignature pattern can be determined for use in defining brain states and anesthetic depth in rest and in response to stimuli. Such a signature can be evaluated and shared between labs to indicate the brain state of a mouse during experiments, an important step toward translating findings across species.
Collapse
Affiliation(s)
- Henning M. Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
- Experimental and Clinical Research Center, A Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| |
Collapse
|
28
|
Tsurugizawa T, Tamada K, Ono N, Karakawa S, Kodama Y, Debacker C, Hata J, Okano H, Kitamura A, Zalesky A, Takumi T. Awake functional MRI detects neural circuit dysfunction in a mouse model of autism. SCIENCE ADVANCES 2020; 6:eaav4520. [PMID: 32076634 PMCID: PMC7002125 DOI: 10.1126/sciadv.aav4520] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/22/2019] [Indexed: 05/05/2023]
Abstract
MRI has potential as a translational approach from rodents to humans. However, given that mouse functional MRI (fMRI) uses anesthetics for suppression of motion, it has been difficult to directly compare the result of fMRI in "unconsciousness" disease model mice with that in "consciousness" patients. We develop awake fMRI to investigate brain function in 15q dup mice, a copy number variation model of autism. Compared to wild-type mice, we find that 15q dup is associated with whole-brain functional hypoconnectivity and diminished fMRI responses to odors of stranger mice. Ex vivo diffusion MRI reveals widespread anomalies in white matter ultrastructure in 15q dup mice, suggesting a putative anatomical substrate for these functional hypoconnectivity. We show that d-cycloserine (DCS) treatment partially normalizes these anormalies in the frontal cortex of 15q dup mice and rescues some social behaviors. Our results demonstrate the utility of awake rodent fMRI and provide a rationale for further investigation of DCS therapy.
Collapse
Affiliation(s)
- Tomokazu Tsurugizawa
- NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA Saclay, Gif-sur-Yvette 91191, France
- Corresponding author. (T.Ts.); (T.Ta.)
| | - Kota Tamada
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Nobukazu Ono
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Sachise Karakawa
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Yuko Kodama
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Clement Debacker
- NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA Saclay, Gif-sur-Yvette 91191, France
| | - Junichi Hata
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology, Keio University School of Medicine, Shinjuku, Tokyo 160-8585, Japan
| | - Hideyuki Okano
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology, Keio University School of Medicine, Shinjuku, Tokyo 160-8585, Japan
| | - Akihiko Kitamura
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Andrew Zalesky
- Melbourne Neuropsychiatry Centre and Department of Biomedical Engineering, University of Melbourne, Victoria 3010, Australia
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Chuo, Kobe 650-0017, Japan
- Corresponding author. (T.Ts.); (T.Ta.)
| |
Collapse
|
29
|
Propofol Anesthesia Alters Spatial and Topologic Organization of Rat Brain Metabolism. Anesthesiology 2020; 131:850-865. [PMID: 31343459 DOI: 10.1097/aln.0000000000002876] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Loss of consciousness during anesthesia reduces local and global rate of cerebral glucose metabolism. Despite this, the influence of gradual anesthetic-induced changes on consciousness across the entire brain metabolic network has barely been studied. The purpose of the present study was to identify specific cerebral metabolic patterns characteristic of different consciousness/anesthesia states induced by intravenous anesthetic propofol. METHODS At various times, 20 Sprague-Dawley adult rats were intravenously administered three different dosages of propofol to induce different anesthetic states: mild sedation (20 mg · kg · h), deep sedation (40 mg · kg · h), and deep anesthesia (80 mg · kg · h). Using [F]fluorodeoxyglucose positron emission tomography brain imaging, alterations in the spatial pattern of metabolic distribution and metabolic topography were investigated by applying voxel-based spatial covariance analysis and graph-theory analysis. RESULTS Evident reductions were found in baseline metabolism along with altered metabolic spatial distribution during propofol-induced anesthesia. Moreover, graph-theory analysis revealed a disruption in global and local efficiency of the metabolic brain network characterized by decreases in metabolic connectivity and energy efficiency during propofol-induced deep anesthesia (mild sedation global efficiency/local efficiency = 0.6985/0.7190, deep sedation global efficiency/local efficiency = 0.7444/0.7875, deep anesthesia global efficiency/local efficiency = 0.4498/0.6481; mild sedation vs. deep sedation, global efficiency: P = 0.356, local efficiency: P = 0.079; mild sedation vs. deep anesthesia, global efficiency: P < 0.0001, local efficiency: P < 0.0001; deep sedation vs. deep anesthesia, global efficiency: P < 0.0001, local efficiency: P < 0.0001). A strong spatial correlation was also found between cerebral metabolism and metabolic connectivity strength, which decreased significantly with deepening anesthesia level (correlation coefficients: mild sedation, r = 0.55, deep sedation, r = 0.47; deep anesthesia, r = 0.23; P < 0.0001 between the sedation and deep anesthesia groups). CONCLUSIONS The data revealed anesthesia-related alterations in spatial and topologic organization of metabolic brain network, as well as a close relationship between metabolic connectivity and cerebral metabolism during propofol anesthesia. These findings may provide novel insights into the metabolic mechanism of anesthetic-induced loss of consciousness.
Collapse
|
30
|
Wang S, Li Y, Qiu S, Zhang C, Wang G, Xian J, Li T, He H. Reorganization of rich-clubs in functional brain networks during propofol-induced unconsciousness and natural sleep. NEUROIMAGE-CLINICAL 2020; 25:102188. [PMID: 32018124 PMCID: PMC6997627 DOI: 10.1016/j.nicl.2020.102188] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 12/31/2019] [Accepted: 01/18/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND General anesthesia (GA) provides an invaluable experimental tool to understand the essential neural mechanisms underlying consciousness. Previous neuroimaging studies have shown the functional integration and segregation of brain functional networks during anesthetic-induced alteration of consciousness. However, the organization pattern of hubs in functional brain networks remains unclear. Moreover, comparisons with the well-characterized physiological unconsciousness can help us understand the neural mechanisms of anesthetic-induced unconsciousness. METHODS Resting-state functional magnetic resonance imaging was performed during wakefulness, mild propofol-induced sedation (m-PIS), and deep PIS (d-PIS) with clinical unconsciousness on 8 healthy volunteers and wakefulness and natural sleep on 9 age- and sex-matched healthy volunteers. Large-scale functional brain networks of each volunteer were constructed based on 160 regions of interest. Then, rich-club organizations in brain functional networks and nodal properties (nodal strength and efficiency) were assessed and analyzed among the different states and groups. RESULTS Rich-clubs in the functional brain networks were reorganized during alteration of consciousness induced by propofol. Firstly, rich-club nodes were switched from the posterior cingulate cortex (PCC), angular gyrus, and anterior and middle insula to the inferior parietal lobule (IPL), inferior parietal sulcus (IPS), and cerebellum. When sedation was deepened to unconsciousness, the rich-club nodes were switched to the occipital and angular gyrus. These results suggest that the rich-club nodes were switched among the high-order cognitive function networks (default mode network [DMN] and fronto-parietal network [FPN]), sensory networks (occipital network [ON]), and cerebellum network (CN) from consciousness (wakefulness) to propofol-induced unconsciousness. At the same time, compared with wakefulness, local connections were switched to rich-club connections during propofol-induced unconsciousness, suggesting a strengthening of the overall information commutation of networks. Nodal efficiency of the anterior and middle insula and ventral frontal cortex was significantly decreased. Additionally, from wakefulness to natural sleep, a similar pattern of rich-club reorganization with propofol-induced unconsciousness was observed: rich-club nodes were switched from the DMN (including precuneus and PCC) to the sensorimotor network (SMN, including part of the frontal and temporal gyrus). Compared with natural sleep, nodal efficiency of the insula, frontal gyrus, PCC, and cerebellum significantly decreased during propofol-induced unconsciousness. CONCLUSIONS Our study demonstrated that the rich-club reorganization in functional brain networks is characterized by switching of rich-club nodes between the high-order cognitive and sensory and motor networks during propofol-induced alteration of consciousness and natural sleep. These findings will help understand the common neurological mechanism of pharmacological and physiological unconsciousness.
Collapse
Affiliation(s)
- Shengpei Wang
- Research Center for Brain-inspired Intelligence and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yun Li
- Department of Anesthesia, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Shuang Qiu
- Research Center for Brain-inspired Intelligence and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Chuncheng Zhang
- Research Center for Brain-inspired Intelligence and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Guyan Wang
- Department of Anesthesia, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Junfang Xian
- Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Tianzuo Li
- Department of Anesthesia, Beijing Tongren Hospital, Capital Medical University, Beijing, China; Beijing Shijitan Hospital, Capital Medical University, Beijing, China.
| | - Huiguang He
- Research Center for Brain-inspired Intelligence and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
31
|
Zheng W, Woo CW, Yao Z, Goldstein P, Atlas LY, Roy M, Schmidt L, Krishnan A, Jepma M, Hu B, Wager TD. Pain-Evoked Reorganization in Functional Brain Networks. Cereb Cortex 2019; 30:2804-2822. [PMID: 31813959 DOI: 10.1093/cercor/bhz276] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/21/2019] [Accepted: 10/27/2019] [Indexed: 12/18/2022] Open
Abstract
Recent studies indicate that a significant reorganization of cerebral networks may occur in patients with chronic pain, but how immediate pain experience influences the organization of large-scale functional networks is not yet well characterized. To investigate this question, we used functional magnetic resonance imaging in 106 participants experiencing both noxious and innocuous heat. Painful stimulation caused network-level reorganization of cerebral connectivity that differed substantially from organization during innocuous stimulation and standard resting-state networks. Noxious stimuli increased somatosensory network connectivity with (a) frontoparietal networks involved in context representation, (b) "ventral attention network" regions involved in motivated action selection, and (c) basal ganglia and brainstem regions. This resulted in reduced "small-worldness," modularity (fewer networks), and global network efficiency and in the emergence of an integrated "pain supersystem" (PS) whose activity predicted individual differences in pain sensitivity across 5 participant cohorts. Network hubs were reorganized ("hub disruption") so that more hubs were localized in PS, and there was a shift from "connector" hubs linking disparate networks to "provincial" hubs connecting regions within PS. Our findings suggest that pain reorganizes the network structure of large-scale brain systems. These changes may prioritize responses to painful events and provide nociceptive systems privileged access to central control of cognition and action during pain.
Collapse
Affiliation(s)
- Weihao Zheng
- School of Information Science and Engineering, Lanzhou University, Lanzhou, 730000, P. R. China.,Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Choong-Wan Woo
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Zhijun Yao
- School of Information Science and Engineering, Lanzhou University, Lanzhou, 730000, P. R. China
| | - Pavel Goldstein
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA.,Institute of Cognitive Science, University of Colorado, Boulder, CO 80309, USA.,The School of Public Health, University of Haifa, Haifa, 3498838, Israel
| | - Lauren Y Atlas
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD 20892, USA.,National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.,National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Mathieu Roy
- Department of Psychology, McGill University, Montréal, Quebec H3A 0G4, Canada
| | - Liane Schmidt
- Control-Interoception-Attention (CIA) team, Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne University / CNRS / INSERM, 75013 Paris, France
| | - Anjali Krishnan
- Department of Psychology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, USA
| | - Marieke Jepma
- Department of Psychology, University of Amsterdam, Amsterdam, 1018 WS, The Netherlands
| | - Bin Hu
- School of Information Science and Engineering, Lanzhou University, Lanzhou, 730000, P. R. China
| | - Tor D Wager
- Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA.,Institute of Cognitive Science, University of Colorado, Boulder, CO 80309, USA.,Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
| |
Collapse
|
32
|
Modulation of the spontaneous hemodynamic response function across levels of consciousness. Neuroimage 2019; 200:450-459. [DOI: 10.1016/j.neuroimage.2019.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/03/2019] [Accepted: 07/04/2019] [Indexed: 01/06/2023] Open
|
33
|
Prefrontal neural dynamics in consciousness. Neuropsychologia 2019; 131:25-41. [DOI: 10.1016/j.neuropsychologia.2019.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 12/11/2022]
|
34
|
van Hateren JH. A theory of consciousness: computation, algorithm, and neurobiological realization. BIOLOGICAL CYBERNETICS 2019; 113:357-372. [PMID: 31289928 PMCID: PMC6658579 DOI: 10.1007/s00422-019-00803-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 07/03/2019] [Indexed: 06/09/2023]
Abstract
The most enigmatic aspect of consciousness is the fact that it is felt, as a subjective sensation. The theory proposed here aims to explain this particular aspect. The theory encompasses both the computation that is presumably involved and the way in which that computation may be realized in the brain's neurobiology. It is assumed that the brain makes an internal estimate of an individual's own evolutionary fitness, which can be shown to produce a special, distinct form of causation. Communicating components of the fitness estimate (either for external or for internal use) requires inverting them. Such inversion can be performed by the thalamocortical feedback loop in the mammalian brain, if that loop is operating in a switched, dual-stage mode. A first (nonconscious) stage produces forward estimates, whereas the second (conscious) stage inverts those estimates. It is argued that inversion produces another special, distinct form of causation, which is spatially localized and is plausibly sensed as the feeling of consciousness.
Collapse
Affiliation(s)
- J H van Hateren
- Johann Bernoulli Institute for Mathematics and Computer Science, University of Groningen, P.O. Box 407, 9700 AK, Groningen, The Netherlands.
| |
Collapse
|
35
|
Propofol inhibits the local activity and connectivity of nuclei in the cortico-reticulo-thalamic loop in rats. J Anesth 2019; 33:572-578. [DOI: 10.1007/s00540-019-02667-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 07/22/2019] [Indexed: 01/06/2023]
|
36
|
Cortico-Thalamic Circuit Model for Bottom-Up and Top-Down Mechanisms in General Anesthesia Involving the Reticular Activating System. ARCHIVES OF NEUROSCIENCE 2019. [DOI: 10.5812/ans.95498] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
37
|
Chen C, Zhang J, Sun L, Zhang Y, Gan WB, Tang P, Yang G. Long-term imaging of dorsal root ganglia in awake behaving mice. Nat Commun 2019; 10:3087. [PMID: 31300648 PMCID: PMC6625980 DOI: 10.1038/s41467-019-11158-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/26/2019] [Indexed: 01/26/2023] Open
Abstract
The dorsal root ganglia (DRG) contain the somas of first-order sensory neurons critical for somatosensation. Due to technical difficulties, DRG neuronal activity in awake behaving animals remains unknown. Here, we develop a method for imaging DRG at cellular and subcellular resolution over weeks in awake mice. The method involves the installation of an intervertebral fusion mount to reduce spinal movement, and the implantation of a vertebral glass window without interfering animals' motor and sensory functions. In vivo two-photon calcium imaging shows that DRG neuronal activity is higher in awake than anesthetized animals. Immediately after plantar formalin injection, DRG neuronal activity increases substantially and this activity upsurge correlates with animals' phasic pain behavior. Repeated imaging of DRG over 5 weeks after formalin injection reveals persistent neuronal hyperactivity associated with ongoing pain. The method described here provides an important means for in vivo studies of DRG functions in sensory perception and disorders.
Collapse
Affiliation(s)
- Chao Chen
- Department of Orthopaedics, Peking 301 Hospital, Beijing, 100853, China
| | - Jinhui Zhang
- Department of Orthopaedics, the Affiliated Southeast Hospital of Xiamen University, Zhangzhou 175 Hospital, Zhangzhou, 363000, China
| | - Linlin Sun
- Department of Anesthesiology, Columbia University, New York, 10032, NY, USA
| | - Yiling Zhang
- Department of Orthopaedics, Peking 301 Hospital, Beijing, 100853, China
| | - Wen-Biao Gan
- Department of Neuroscience and Physiology, Department of Anesthesiology, Skirball Institute, New York University School of Medicine, New York, 10016, NY, USA.
| | - Peifu Tang
- Department of Orthopaedics, Peking 301 Hospital, Beijing, 100853, China.
| | - Guang Yang
- Department of Anesthesiology, Columbia University, New York, 10032, NY, USA.
| |
Collapse
|
38
|
Brier LM, Landsness EC, Snyder AZ, Wright PW, Baxter GA, Bauer AQ, Lee JM, Culver JP. Separability of calcium slow waves and functional connectivity during wake, sleep, and anesthesia. NEUROPHOTONICS 2019; 6:035002. [PMID: 31930154 PMCID: PMC6952529 DOI: 10.1117/1.nph.6.3.035002] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/12/2019] [Indexed: 05/08/2023]
Abstract
Modulation of brain state, e.g., by anesthesia, alters the correlation structure of spontaneous activity, especially in the delta band. This effect has largely been attributed to the ∼ 1 Hz slow oscillation that is characteristic of anesthesia and nonrapid eye movement (NREM) sleep. However, the effect of the slow oscillation on correlation structures and the spectral content of spontaneous activity across brain states (including NREM) has not been comprehensively examined. Further, discrepancies between activity dynamics observed with hemoglobin versus calcium (GCaMP6) imaging have not been reconciled. Lastly, whether the slow oscillation replaces functional connectivity (FC) patterns typical of the alert state, or superimposes on them, remains unclear. Here, we use wide-field calcium imaging to study spontaneous cortical activity in awake, anesthetized, and naturally sleeping mice. We find modest brain state-dependent changes in infraslow correlations but larger changes in GCaMP6 delta correlations. Principal component analysis of GCaMP6 sleep/anesthesia data in the delta band revealed that the slow oscillation is largely confined to the first three components. Removal of these components revealed a correlation structure strikingly similar to that observed during wake. These results indicate that, during NREM sleep/anesthesia, the slow oscillation superimposes onto a canonical FC architecture.
Collapse
Affiliation(s)
- Lindsey M. Brier
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Address all correspondence to Lindsey M. Brier, E-mail:
| | - Eric C. Landsness
- Washington University School of Medicine, Department of Neurology, St. Louis, Missouri, United States
| | - Abraham Z. Snyder
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Washington University School of Medicine, Department of Neurology, St. Louis, Missouri, United States
| | - Patrick W. Wright
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Grant A. Baxter
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Adam Q. Bauer
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Jin-Moo Lee
- Washington University School of Medicine, Department of Neurology, St. Louis, Missouri, United States
| | - Joseph P. Culver
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
| |
Collapse
|
39
|
Voss LJ, García PS, Hentschke H, Banks MI. Understanding the Effects of General Anesthetics on Cortical Network Activity Using Ex Vivo Preparations. Anesthesiology 2019; 130:1049-1063. [PMID: 30694851 PMCID: PMC6520142 DOI: 10.1097/aln.0000000000002554] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
General anesthetics have been used to ablate consciousness during surgery for more than 150 yr. Despite significant advances in our understanding of their molecular-level pharmacologic effects, comparatively little is known about how anesthetics alter brain dynamics to cause unconsciousness. Consequently, while anesthesia practice is now routine and safe, there are many vagaries that remain unexplained. In this paper, the authors review the evidence that cortical network activity is particularly sensitive to general anesthetics, and suggest that disruption to communication in, and/or among, cortical brain regions is a common mechanism of anesthesia that ultimately produces loss of consciousness. The authors review data from acute brain slices and organotypic cultures showing that anesthetics with differing molecular mechanisms of action share in common the ability to impair neurophysiologic communication. While many questions remain, together, ex vivo and in vivo investigations suggest that a unified understanding of both clinical anesthesia and the neural basis of consciousness is attainable.
Collapse
Affiliation(s)
- Logan J Voss
- From the Department of Anaesthesia, Waikato District Health Board, Hamilton, New Zealand (L.J.V.) the Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia (P.S.G) Anesthesiology and Research Divisions, Atlanta Veterans Administration Medical Center, Atlanta, Georgia (P.S.G.) the Experimental Anesthesiology Section, Department of Anesthesiology, University Hospital of Tübingen, Tübingen, Germany (H.H.) rthe Department of Anesthesiology, University of Wisconsin, Madison, Wisconsin (M.I.B.)
| | | | | | | |
Collapse
|
40
|
Cavanna F, Vilas MG, Palmucci M, Tagliazucchi E. Dynamic functional connectivity and brain metastability during altered states of consciousness. Neuroimage 2018; 180:383-395. [DOI: 10.1016/j.neuroimage.2017.09.065] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/01/2017] [Accepted: 09/29/2017] [Indexed: 11/16/2022] Open
|
41
|
Fink SB. Commentary: The Concept of a Bewusstseinskultur. Front Psychol 2018; 9:732. [PMID: 30104986 PMCID: PMC6077227 DOI: 10.3389/fpsyg.2018.00732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/26/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sascha Benjamin Fink
- Program for Philosophy-Neurosciences-Cognition, Institute III: Philosophy, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,DFG Research Training Group 2386 "Extrospection", Humboldt-Universität zu Berlin, Charité Berlin, Otto-von-Guericke-Universität Magdeburg, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| |
Collapse
|
42
|
Hutt A, Lefebvre J, Hight D, Sleigh J. Suppression of underlying neuronal fluctuations mediates EEG slowing during general anaesthesia. Neuroimage 2018; 179:414-428. [PMID: 29920378 DOI: 10.1016/j.neuroimage.2018.06.043] [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] [Received: 03/02/2018] [Revised: 05/03/2018] [Accepted: 06/12/2018] [Indexed: 11/25/2022] Open
Abstract
The physiological mechanisms by which anaesthetic drugs modulate oscillatory brain activity remain poorly understood. Combining human data, mathematical and computational analysis of both spiking and mean-field models, we investigated the spectral dynamics of encephalographic (EEG) beta-alpha oscillations, observed in human patients undergoing general anaesthesia. The effect of anaesthetics can be modelled as a reduction of neural fluctuation intensity, and/or an increase in inhibitory synaptic gain in the thalamo-cortical circuit. Unlike previous work, which suggested the primary importance of gamma-amino-butryic-acid (GABA) augmentation in causing a shift to low EEG frequencies, our analysis demonstrates that a non-linear transition, triggered by a simple decrease in neural fluctuation intensity, is sufficient to explain the clinically-observed appearance - and subsequent slowing - of the beta-alpha narrowband EEG peak. In our model, increased synaptic inhibition alone, did not correlate with the clinically-observed encephalographic spectral changes, but did cause the anaesthetic-induced decrease in neuronal firing rate. Taken together, our results show that such a non-linear transition results in functional fragmentation of cortical and thalamic populations; highly correlated intra-population dynamics triggered by anaesthesia decouple and isolate neural populations. Our results are able to parsimoniously unify and replicate the observed anaesthetic effects on both the EEG spectra and inter-regional connectivity, and further highlight the importance of neural activity fluctuations in the genesis of altered brain states.
Collapse
Affiliation(s)
- Axel Hutt
- Department FE 12 - Data Assimilation, Deutscher Wetterdienst, 63067, Offenbach am Main, Germany; Department of Mathematics and Statistics, University of Reading, Reading, RG6 6AX, UK.
| | - Jérémie Lefebvre
- Krembil Research Institute, University Health Network, Toronto, Ontario, M5T 2S8, Canada; Department of Mathematics, University of Toronto, Toronto, Ontario, M5T 2S8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5T 2S8, Canada
| | - Darren Hight
- Department of Anaesthesiology, Waikato Clinical Campus, University of Auckland, Hamilton, 3240, New Zealand; Department of Anaesthesiology and Pain Therapy, University Hospital Bern, Inselspital, Bern, Switzerland
| | - Jamie Sleigh
- Department of Anaesthesiology, Waikato Clinical Campus, University of Auckland, Hamilton, 3240, New Zealand.
| |
Collapse
|
43
|
Facco E. Ipnosi ed esperienze di premorte nel continuum delle espressioni non ordinarie della mente. ACTA ACUST UNITED AC 2018. [DOI: 10.3280/ipn2018-001002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
44
|
Development and validation of brain target controlled infusion of propofol in mice. PLoS One 2018; 13:e0194949. [PMID: 29684039 PMCID: PMC5912730 DOI: 10.1371/journal.pone.0194949] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 03/13/2018] [Indexed: 12/25/2022] Open
Abstract
Mechanisms through which anesthetics disrupt neuronal activity are incompletely understood. In order to study anesthetic mechanisms in the intact brain, tight control over anesthetic pharmacology in a genetically and neurophysiologically accessible animal model is essential. Here, we developed a pharmacokinetic model that quantitatively describes propofol distribution into and elimination out of the brain. To develop the model, we used jugular venous catheters to infuse propofol in mice and measured propofol concentration in serial timed brain and blood samples using high performance liquid chromatography (HPLC). We then used adaptive fitting procedures to find parameters of a three compartment pharmacokinetic model such that all measurements collected in the blood and in the brain across different infusion schemes are fit by a single model. The purpose of the model was to develop target controlled infusion (TCI) capable of maintaining constant brain propofol concentration at the desired level. We validated the model for two different targeted concentrations in independent cohorts of experiments not used for model fitting. The predictions made by the model were unbiased, and the measured brain concentration was indistinguishable from the targeted concentration. We also verified that at the targeted concentration, state of anesthesia evidenced by slowing of the electroencephalogram and behavioral unresponsiveness was attained. Thus, we developed a useful tool for performing experiments necessitating use of anesthetics and for the investigation of mechanisms of action of propofol in mice.
Collapse
|
45
|
Moe HK, Moen KG, Skandsen T, Kvistad KA, Laureys S, Håberg A, Vik A. The Influence of Traumatic Axonal Injury in Thalamus and Brainstem on Level of Consciousness at Scene or Admission: A Clinical Magnetic Resonance Imaging Study. J Neurotrauma 2018; 35:975-984. [PMID: 29334825 PMCID: PMC5865618 DOI: 10.1089/neu.2017.5252] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to investigate how traumatic axonal injury (TAI) lesions in the thalamus, basal ganglia, and brainstem on clinical brain magnetic resonance imaging (MRI) are associated with level of consciousness in the acute phase in patients with moderate to severe traumatic brain injury (TBI). There were 158 patients with moderate to severe TBI (7-70 years) with early 1.5T MRI (median 7 days, range 0-35) without mass lesion included prospectively. Glasgow Coma Scale (GCS) scores were registered before intubation or at admission. The TAI lesions were identified in T2*gradient echo, fluid attenuated inversion recovery, and diffusion weighted imaging scans. In addition to registering TAI lesions in hemispheric white matter and the corpus callosum, TAI lesions in the thalamus, basal ganglia, and brainstem were classified as uni- or bilateral. Twenty percent of patients had TAI lesions in the thalamus (7% bilateral), 18% in basal ganglia (2% bilateral), and 29% in the brainstem (9% bilateral). One of 26 bilateral lesions in the thalamus or brainstem was found on computed tomography. The GCS scores were lower in patients with bilateral lesions in the thalamus (median four) and brainstem (median five) than in those with corresponding unilateral lesions (median six and eight, p = 0.002 and 0.022). The TAI locations most associated with low GCS scores in univariable ordinal regression analyses were bilateral TAI lesions in the thalamus (odds ratio [OR] 35.8; confidence interval [CI: 10.5-121.8], p < 0.001), followed by bilateral lesions in basal ganglia (OR 13.1 [CI: 2.0-88.2], p = 0.008) and bilateral lesions in the brainstem (OR 11.4 [CI: 4.0-32.2], p < 0.001). This Trondheim TBI study showed that patients with bilateral TAI lesions in the thalamus, basal ganglia, or brainstem had particularly low consciousness at admission. We suggest these bilateral lesions should be evaluated further as possible biomarkers in a new TAI-MRI classification as a worst grade, because they could explain low consciousness in patients without mass lesions.
Collapse
Affiliation(s)
- Hans Kristian Moe
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Kent Gøran Moen
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Medical Imaging, Levanger Hospital, Levanger, Norway
| | - Toril Skandsen
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Physical Medicine and Rehabilitation, St. Olavs University Hospital, Trondheim, Norway
| | - Kjell Arne Kvistad
- Department of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Center and University Hospital of Liège, University of Liège, Liège, Belgium
| | - Asta Håberg
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway
| | - Anne Vik
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Neurosurgery, St. Olavs University Hospital, Trondheim, Norway
| |
Collapse
|
46
|
Mitra A, Kraft A, Wright P, Acland B, Snyder AZ, Rosenthal Z, Czerniewski L, Bauer A, Snyder L, Culver J, Lee JM, Raichle ME. Spontaneous Infra-slow Brain Activity Has Unique Spatiotemporal Dynamics and Laminar Structure. Neuron 2018; 98:297-305.e6. [PMID: 29606579 DOI: 10.1016/j.neuron.2018.03.015] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 01/28/2018] [Accepted: 03/08/2018] [Indexed: 11/16/2022]
Abstract
Systems-level organization in spontaneous infra-slow (<0.1Hz) brain activity, measured using blood oxygen signals in fMRI and optical imaging, has become a major theme in the study of neural function in both humans and animal models. Yet the neurophysiological basis of infra-slow activity (ISA) remains unresolved. In particular, is ISA a distinct physiological process, or is it a low-frequency analog of faster neural activity? Here, using whole-cortex calcium/hemoglobin imaging in mice, we show that ISA in each of these modalities travels through the cortex along stereotypical spatiotemporal trajectories that are state dependent (wake versus anesthesia) and distinct from trajectories in delta (1-4 Hz) activity. Moreover, mouse laminar electrophysiology reveals that ISA travels through specific cortical layers and is organized into unique cross-laminar temporal dynamics that are different from higher frequency local field potential activity. These findings suggest that ISA is a distinct neurophysiological process that is reflected in fMRI blood oxygen signals.
Collapse
Affiliation(s)
- Anish Mitra
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA.
| | - Andrew Kraft
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Patrick Wright
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Benjamin Acland
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Zachary Rosenthal
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Leah Czerniewski
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Adam Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Lawrence Snyder
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Joseph Culver
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jin-Moo Lee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Marcus E Raichle
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
47
|
Scheinin H, Alkire EC, Scheinin A, Alkire MT, Kantonen O, Långsjö J. Using Positron Emission Tomography in Revealing the Mystery of General Anesthesia: Study Design Challenges and Opportunities. Methods Enzymol 2018; 603:279-303. [PMID: 29673531 DOI: 10.1016/bs.mie.2018.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Functional neuroimaging with positron emission tomography (PET) is one of the cornerstones for studying the central nervous system effects of general anesthetics and anesthesia mechanisms. General anesthesia offers a unique and safe way to directly manipulate consciousness, and can thus be used as a powerful research tool to study the neurobiology of human consciousness. In this chapter, we will address the possibilities of PET imaging in revealing the mysteries of general anesthesia and anesthetic induced unconsciousness and summarize some of the recent advancements in the field. Importantly, we will discuss possible ways to separate brain activity changes associated with the changing level of consciousness from the concentration or dose-dependent direct or indirect drug effects on the brain. We will try to demonstrate how state-of-the-art clinical pharmacology, use of specific anesthetic drugs, and innovative study design solutions could be utilized.
Collapse
Affiliation(s)
- Harry Scheinin
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Turku University Hospital, Turku, Finland; Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland.
| | - Emilee C Alkire
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Annalotta Scheinin
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Turku University Hospital, Turku, Finland
| | - Michael T Alkire
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States; VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Oskari Kantonen
- Turku University Hospital, Turku, Finland; The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Jaakko Långsjö
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Tampere University Hospital, Tampere, Finland
| |
Collapse
|
48
|
Riehl JR, Palanca BJ, Ching S. High-energy brain dynamics during anesthesia-induced unconsciousness. Netw Neurosci 2017; 1:431-445. [PMID: 30090873 PMCID: PMC6063715 DOI: 10.1162/netn_a_00023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/02/2017] [Indexed: 12/18/2022] Open
Abstract
Characterizing anesthesia-induced alterations to brain network dynamics provides a powerful framework to understand the neural mechanisms of unconsciousness. To this end, increased attention has been directed at how anesthetic drugs alter the functional connectivity between brain regions as defined through neuroimaging. However, the effects of anesthesia on temporal dynamics at functional network scales is less well understood. Here, we examine such dynamics in view of the free-energy principle, which postulates that brain dynamics tend to promote lower energy (more organized) states. We specifically engaged the hypothesis that such low-energy states play an important role in maintaining conscious awareness. To investigate this hypothesis, we analyzed resting-state BOLD fMRI data from human volunteers during wakefulness and under sevoflurane general anesthesia. Our approach, which extends an idea previously used in the characterization of neuron-scale populations, involves thresholding the BOLD time series and using a normalized Hamiltonian energy function derived from the Ising model. Our major finding is that the brain spends significantly more time in lower energy states during eyes-closed wakefulness than during general anesthesia. This effect is especially pronounced in networks thought to be critical for maintaining awareness, suggesting a crucial cognitive role for both the structure and the dynamical landscape of these networks. We show that activity in the human brain, as captured by functional magnetic resonance imaging (fMRI), is more organized during wakefulness than during general anesthesia. This increased organization corresponds to a decrease in a statistical-physics-inspired energy measure among brain regions of shared functional specialization (resting-state networks) that have putative roles in conscious awareness and attention. Characterizing the energy distributions in this way reveals significant changes in the dynamics of brain activity in different states of consciousness, insights that are not observable in the average functional connectivity data alone. Our results indicate that the ability of brain networks to sustain stable representations, via their dynamics, may be crucial for consciousness and cognition.
Collapse
Affiliation(s)
- James R Riehl
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Ben J Palanca
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.,Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - ShiNung Ching
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.,Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
49
|
Regional knockdown of NDUFS4 implicates a thalamocortical circuit mediating anesthetic sensitivity. PLoS One 2017; 12:e0188087. [PMID: 29136012 PMCID: PMC5685608 DOI: 10.1371/journal.pone.0188087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022] Open
Abstract
Knockout of the mitochondrial complex I protein, NDUFS4, profoundly increases sensitivity of mice to volatile anesthetics. In mice carrying an Ndufs4lox/lox gene, adeno-associated virus expressing Cre recombinase was injected into regions of the brain postulated to affect sensitivity to volatile anesthetics. These injections generated otherwise phenotypically wild type mice with region-specific, postnatal inactivation of Ndufs4, minimizing developmental effects of gene loss. Sensitivities to the volatile anesthetics isoflurane and halothane were measured using loss of righting reflex (LORR) and movement in response to tail clamp (TC) as endpoints. Knockdown (KD) of Ndufs4 in the vestibular nucleus produced resistance to both anesthetics for movement in response to TC. Ndufs4 loss in the central and dorsal medial thalami and in the parietal association cortex increased anesthetic sensitivity to both TC and LORR. Knockdown of Ndufs4 only in the parietal association cortex produced striking hypersensitivity for both endpoints, and accounted for half the total change seen in the global KO (Ndufs4(KO)). Excitatory synaptic transmission in the parietal association cortex in slices from Ndufs4(KO) animals was hypersensitive to isoflurane compared to control slices. We identified a direct neural circuit between the parietal association cortex and the central thalamus, consistent with a model in which isoflurane sensitivity is mediated by a thalamic signal relayed through excitatory synapses to the parietal association cortex. We postulate that the thalamocortical circuit is crucial for maintenance of consciousness and is disrupted by the inhibitory effects of isoflurane/halothane on mitochondria.
Collapse
|
50
|
Towards building a more complex view of the lateral geniculate nucleus: Recent advances in understanding its role. Prog Neurobiol 2017. [DOI: 10.1016/j.pneurobio.2017.06.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|