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Mashour GA, Lee U, Pal D, Li D. Consciousness and the Dying Brain. Anesthesiology 2024:140050. [PMID: 38603803 DOI: 10.1097/aln.0000000000004970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
The near-death experience has been reported since antiquity and is often characterized by the perception of light, interactions with other entities, and life recall. Near-death experiences can occur in a variety of situations, but they have been studied systematically after in-hospital cardiac arrest, with an incidence of 10 to 20%. Long attributed to metaphysical or supernatural causes, there have been recent advances in understanding the neurophysiologic basis of this unique category of conscious experience. This article reviews the epidemiology and neurobiology of near-death experiences, with a focus on clinical and laboratory evidence for a surge of neurophysiologic gamma oscillations and cortical connectivity after cardiac and respiratory arrest.
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Affiliation(s)
- George A Mashour
- Department of Anesthesiology, Center for Consciousness Science, Neuroscience Graduate Program, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan
| | - UnCheol Lee
- Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan
| | - Dinesh Pal
- Department of Anesthesiology, Center for Consciousness Science and Neuroscience Graduate Program, Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Duan Li
- Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan
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2
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Silverstein BH, Kolbman N, Nelson A, Liu T, Guzzo P, Gilligan J, Lee U, Mashour GA, Vanini G, Pal D. Psilocybin induces dose-dependent changes in functional network organization in rat cortex. bioRxiv 2024:2024.02.09.579718. [PMID: 38405722 PMCID: PMC10888735 DOI: 10.1101/2024.02.09.579718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Psilocybin produces an altered state of consciousness in humans and is associated with complex spatiotemporal changes in brain networks. Given the emphasis on rodent models for mechanistic studies, there is a need for characterization of the effect of psilocybin on brain-wide network dynamics. Previous rodent studies of psychedelics, using electroencephalogram, have primarily been done with sparse electrode arrays that offered limited spatial resolution precluding network level analysis, and have been restricted to lower gamma frequencies. Therefore, in the study, we used electroencephalographic recordings from 27 sites (electrodes) across rat cortex (n=6 male, 6 female) to characterize the effect of psilocybin (0.1 mg/kg, 1 mg/kg, and 10 mg/kg delivered over an hour) on network organization as inferred through changes in node degree (index of network density) and connection strength (weighted phase-lag index). The removal of aperiodic component from the electroencephalogram localized the primary oscillatory changes to theta (4-10 Hz), medium gamma (70-110 Hz), and high gamma (110-150 Hz) bands, which were used for the network analysis. Additionally, we determined the concurrent changes in theta-gamma phase-amplitude coupling. We report that psilocybin, in a dose-dependent manner, 1) disrupted theta-gamma coupling [p<0.05], 2) increased frontal high gamma connectivity [p<0.05] and posterior theta connectivity [p≤0.049], and 3) increased frontal high gamma [p<0.05] and posterior theta [p≤0.046] network density. The medium gamma frontoparietal connectivity showed a nonlinear relationship with psilocybin dose. Our results suggest that high-frequency network organization, decoupled from local theta-phase, may be an important signature of psilocybin-induced non-ordinary state of consciousness.
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Affiliation(s)
- Brian H Silverstein
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Nicholas Kolbman
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Amanda Nelson
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Tiecheng Liu
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Peter Guzzo
- Tryp Therapeutics, Kelowna, British Columbia, V1Y 7T2, Canada
| | - Jim Gilligan
- Tryp Therapeutics, Kelowna, British Columbia, V1Y 7T2, Canada
| | - UnCheol Lee
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Mondino A, González J, Li D, Mateos D, Osorio L, Cavelli M, Castro-Nin JP, Serantes D, Costa A, Vanini G, Mashour GA, Torterolo P. Urethane anaesthesia exhibits neurophysiological correlates of unconsciousness and is distinct from sleep. Eur J Neurosci 2024; 59:483-501. [PMID: 35545450 DOI: 10.1111/ejn.15690] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 04/13/2022] [Accepted: 05/06/2022] [Indexed: 11/27/2022]
Abstract
Urethane is a general anaesthetic widely used in animal research. The state of urethane anaesthesia is unique because it alternates between macroscopically distinct electrographic states: a slow-wave state that resembles non-rapid eye movement (NREM) sleep and an activated state with features of both REM sleep and wakefulness. Although it is assumed that urethane produces unconsciousness, this has been questioned because of states of cortical activation during drug exposure. Furthermore, the similarities and differences between urethane anaesthesia and physiological sleep are still unclear. In this study, we recorded the electroencephalogram (EEG) and electromyogram in chronically prepared rats during natural sleep-wake states and during urethane anaesthesia. We subsequently analysed the power, coherence, directed connectivity and complexity of brain oscillations and found that EEG under urethane anaesthesia has clear signatures of unconsciousness, with similarities to other general anaesthetics. In addition, the EEG profile under urethane is different in comparison with natural sleep states. These results suggest that consciousness is disrupted during urethane. Furthermore, despite similarities that have led others to conclude that urethane is a model of sleep, the electrocortical traits of depressed and activated states during urethane anaesthesia differ from physiological sleep states.
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Affiliation(s)
- Alejandra Mondino
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Joaquín González
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Duan Li
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Diego Mateos
- Institute of Applied Mathematics of the Coast-CONICET-UNL, CCT CONICET, Santa Fe, Argentina
- Faculty of Science and Technology, Autonomous University of Entre Ríos, Parana, Argentina
| | - Lucía Osorio
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Matías Cavelli
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
- Department of Psychiatry, University of Wisconsin, Madison, Wisconsin, USA
| | - Juan Pedro Castro-Nin
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Diego Serantes
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Alicia Costa
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Pablo Torterolo
- Department of Physiology, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
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Duan WY, Peng K, Qin HM, Li BM, Xu YX, Wang DJ, Yu L, Wang H, Hu J, Wang QX. Esketamine accelerates emergence from isoflurane general anaesthesia by activating the paraventricular thalamus glutamatergic neurones in mice. Br J Anaesth 2024; 132:334-342. [PMID: 38044237 DOI: 10.1016/j.bja.2023.10.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/02/2023] [Accepted: 10/18/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Delayed emergence from general anaesthesia poses a significant perioperative safety hazard. Subanaesthetic doses of ketamine not only deepen anaesthesia but also accelerate recovery from isoflurane anaesthesia; however, the mechanisms underlying this phenomenon remain elusive. Esketamine exhibits a more potent receptor affinity and fewer adverse effects than ketamine and exhibits shorter recovery times after brief periods of anaesthesia. As the paraventricular thalamus (PVT) plays a pivotal role in regulating wakefulness, we studied its role in the emergence process during combined esketamine and isoflurane anaesthesia. METHODS The righting reflex and cortical electroencephalography were used as measures of consciousness in mice during isoflurane anaesthesia with coadministration of esketamine. The expression of c-Fos was used to determine neuronal activity changes in PVT neurones after esketamine administration. The effect of esketamine combined with isoflurane anaesthesia on PVT glutamatergic (PVTGlu) neuronal activity was monitored by fibre photometry, and chemogenetic technology was used to manipulate PVTGlu neuronal activity. RESULTS A low dose of esketamine (5 mg kg-1) accelerated emergence from isoflurane general anaesthesia (474 [30] s vs 544 [39] s, P=0.001). Esketamine (5 mg kg-1) increased PVT c-Fos expression (508 [198] vs 258 [87], P=0.009) and enhanced the population activity of PVTGlu neurones (0.03 [1.7]% vs 6.9 [3.4]%, P=0.002) during isoflurane anaesthesia (1.9 [5.7]% vs -5.1 [5.3]%, P=0.016) and emergence (6.1 [6.2]% vs -1.1 [5.0]%, P=0.022). Chemogenetic suppression of PVTGlu neurones abolished the arousal-promoting effects of esketamine (459 [33] s vs 596 [33] s, P<0.001). CONCLUSIONS Our results suggest that esketamine promotes recovery from isoflurane anaesthesia by activating PVTGlu neurones. This mechanism could explain the rapid arousability exhibited upon treatment with a low dose of esketamine.
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Affiliation(s)
- Wen-Ying Duan
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Kang Peng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Hui-Min Qin
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Bai-Ming Li
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yun-Xin Xu
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dan-Jun Wang
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Le Yu
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hui Wang
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Qing-Xiu Wang
- Department of Anesthesiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
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Maarouf MM, Youssef AM, Amer AM. Evaluation of paradoxical effect of small dose ketamine as adjuvant in deep sedation for endoscopy patients. Egyptian Journal of Anaesthesia 2023. [DOI: 10.1080/11101849.2023.2166653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Affiliation(s)
- Mohammed M Maarouf
- Department of Anesthesiology, Intensive Care and Pain Management, Ain Shams University Faculty of Medicine, Cairo, Egypt
| | - Azza M Youssef
- Department of Anesthesiology, Intensive Care and Pain Management, Ain Shams University Faculty of Medicine, Cairo, Egypt
| | - Akram M Amer
- Department of Anesthesiology, Intensive Care and Pain Management, Ain Shams University Faculty of Medicine, Cairo, Egypt
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Masuda FK, Aery Jones EA, Sun Y, Giocomo LM. Ketamine evoked disruption of entorhinal and hippocampal spatial maps. Nat Commun 2023; 14:6285. [PMID: 37805575 PMCID: PMC10560293 DOI: 10.1038/s41467-023-41750-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/15/2023] [Indexed: 10/09/2023] Open
Abstract
Ketamine, a rapid-acting anesthetic and acute antidepressant, carries undesirable spatial cognition side effects including out-of-body experiences and spatial memory impairments. The neural substrates that underlie these alterations in spatial cognition however, remain incompletely understood. Here, we used electrophysiology and calcium imaging to examine ketamine's impacts on the medial entorhinal cortex and hippocampus, which contain neurons that encode an animal's spatial position, as mice navigated virtual reality and real world environments. Ketamine acutely increased firing rates, degraded cell-pair temporal firing-rate relationships, and altered oscillations, leading to longer-term remapping of spatial representations. In the reciprocally connected hippocampus, the activity of neurons that encode the position of the animal was suppressed after ketamine administration. Together, these findings demonstrate ketamine-induced dysfunction of the MEC-hippocampal circuit at the single cell, local-circuit population, and network levels, connecting previously demonstrated physiological effects of ketamine on spatial cognition to alterations in the spatial navigation circuit.
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Affiliation(s)
- Francis Kei Masuda
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Emily A Aery Jones
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Yanjun Sun
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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Zhou JS, Peng GF, Liang WD, Chen Z, Liu YY, Wang BY, Guo ML, Deng YL, Ye JM, Zhong ML, Wang LF. Recent advances in the study of anesthesia-and analgesia-related mechanisms of S-ketamine. Front Pharmacol 2023; 14:1228895. [PMID: 37781698 PMCID: PMC10539608 DOI: 10.3389/fphar.2023.1228895] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023] Open
Abstract
Ketamine is a racemic mixture of equal amounts of R-ketamine and S-ketamine and is well known to anesthesiologists for its unique dissociative anesthetic properties. The pharmacological properties of ketamine, namely, its sympathetic excitation, mild respiratory depression, and potent analgesia, are still highly valued in its use as an anesthetic for some patients. In particular, since its advent, S-ketamine has been widely used as an anesthetic in many countries due to its increased affinity for NMDA receptors and its enhanced anesthetic and analgesic effects. However, the anesthetic and analgesic mechanisms of S-ketamine are not fully understood. In addition to antagonizing NMDA receptors, a variety of other receptors or channels may be involved, but there are no relevant mechanistic summaries in the literature. Therefore, the purpose of this paper is to review the mechanisms of action of S-ketamine on relevant receptors and systems in the body that result in its pharmacological properties, such as anesthesia and analgesia, with the aim of providing a reference for its clinical applications and research.
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Affiliation(s)
- Jian-shun Zhou
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Guan-fa Peng
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Wei-dong Liang
- Department of Anesthesiology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Ganzhou Key Laboratory of Anesthesiology, Ganzhou, China
| | - Zhen Chen
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Ying-ying Liu
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Bing-yu Wang
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Ming-ling Guo
- The First Clinical Medical College of Gannan Medical University, Ganzhou, China
| | - Yun-ling Deng
- Department of Anesthesiology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Ganzhou Key Laboratory of Anesthesiology, Ganzhou, China
| | - Jun-ming Ye
- Department of Anesthesiology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Ganzhou Key Laboratory of Anesthesiology, Ganzhou, China
| | - Mao-lin Zhong
- Department of Anesthesiology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Ganzhou Key Laboratory of Anesthesiology, Ganzhou, China
| | - Li-feng Wang
- Department of Anesthesiology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
- Ganzhou Key Laboratory of Anesthesiology, Ganzhou, China
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Adama S, Bogdan M. Assessing consciousness in patients with disorders of consciousness using soft-clustering. Brain Inform 2023; 10:16. [PMID: 37450213 PMCID: PMC10348975 DOI: 10.1186/s40708-023-00197-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/25/2023] [Indexed: 07/18/2023] Open
Abstract
Consciousness is something we experience in our everyday life, more especially between the time we wake up in the morning and go to sleep at night, but also during the rapid eye movement (REM) sleep stage. Disorders of consciousness (DoC) are states in which a person's consciousness is damaged, possibly after a traumatic brain injury. Completely locked-in syndrome (CLIS) patients, on the other hand, display covert states of consciousness. Although they appear unconscious, their cognitive functions are mostly intact. Only, they cannot externally display it due to their quadriplegia and inability to speak. Determining these patients' states constitutes a challenging task. The ultimate goal of the approach presented in this paper is to assess these CLIS patients consciousness states. EEG data from DoC patients are used here first, under the assumption that if the proposed approach is able to accurately assess their consciousness states, it will assuredly do so on CLIS patients too. This method combines different sets of features consisting of spectral, complexity and connectivity measures in order to increase the probability of correctly estimating their consciousness levels. The obtained results showed that the proposed approach was able to correctly estimate several DoC patients' consciousness levels. This estimation is intended as a step prior attempting to communicate with them, in order to maximise the efficiency of brain-computer interfaces (BCI)-based communication systems.
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Affiliation(s)
- Sophie Adama
- Department of Neuromorphe Information Processing, Leipzig University, Augustusplatz 10, Leipzig, 04109 Germany
| | - Martin Bogdan
- Department of Neuromorphe Information Processing, Leipzig University, Augustusplatz 10, Leipzig, 04109 Germany
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Liu T, Zhang X, Li A, Liu T, Yang X, Zhang H, Lei Y, Yang Q, Dong H. Effects of intra-operative administration of subanesthetic s-ketamine on emergence from sevoflurane anesthesia: a randomized double-blind placebo-controlled study. BMC Anesthesiol 2023; 23:221. [PMID: 37353750 PMCID: PMC10288804 DOI: 10.1186/s12871-023-02170-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 06/09/2023] [Indexed: 06/25/2023] Open
Abstract
BACKGROUND Ketamine is administered in the perioperative period for its benefits in analgesia, anti-agitation and anti-depression when administered at a small dose. However, it is not clear whether the intra-operative administration of ketamine would affect emergence under sevoflurane anesthesia. To investigate this effect, we designed this trial. METHODS In this randomized, double-blind, placebo-controlled study, we enrolled 44 female patients aged 18-60 who were scheduled to elective laparoscopic gynecological surgeries. All patients were randomly assigned to saline or s-ketamine group. In s-ketamine group, patients received 0.125 mg/kg s-ketamine 30 min after the start of surgery. In saline group, patients were administered the same volume of saline. Sevoflurane and remifentanil were used to maintain general anesthesia. The primary outcome was emergence time. We also assessed postoperative agitation, cognitive function, and delirium. In addition, we collected and analyzed prefrontal electroencephalogram (EEG) during and after general anesthesia. RESULTS There were no significant differences in emergence time between s-ketamine group and saline group (10.80 ± 3.77 min vs. 10.00 ± 2.78 min, P = 0.457). Neither postoperative agitation (4 [3, 4] vs. 4 [3, 4], P = 0.835) nor cognitive function (25.84 ± 2.69 vs. 25.55 ± 2.19, P = 0.412) differed between groups. No postoperative delirium was observed in either group. Subanesthetic s-ketamine resulted in active EEG with decreased power of slow (-0.35 ± 1.13 dB vs. -1.63 ± 1.03 dB, P = 0.003), delta (-0.22 ± 1.11 dB vs. -1.32 ± 1.09 dB, P = 0.011) and alpha (-0.31 ± 0.71 dB vs. -1.71 ± 1.34 dB, P = 0.0003) waves and increased power of beta-gamma bands (-0.30 ± 0.89 dB vs. 4.20 ± 2.08 dB, P < 0.0001) during sevoflurane anesthesia, as well as an increased alpha peak frequency (-0.16 ± 0.48 Hz vs. 0.31 ± 0.73 Hz, P = 0.026). EEG patterns did not differ during the recovery period after emergence between groups. CONCLUSION Ketamine administered during sevoflurane anesthesia had no apparent influence on emergence time in young and middle-aged female patients undergoing laparoscopic surgery. Subanesthetic s-ketamine induced an active prefrontal EEG pattern during sevoflurane anesthesia but did not raise neurological side effects after surgery. TRIAL REGISTRATION Chinese Clinical Trial Registry, ChiCTR2100046479 (date: 16/05/2021).
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Affiliation(s)
- Tiantian Liu
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Xinxin Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Ao Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Tingting Liu
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Xue Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Huanhuan Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Yanling Lei
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Qianzi Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China.
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.
| | - Hailong Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China.
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10
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Romand R, Ehret G. Neuro-functional modeling of near-death experiences in contexts of altered states of consciousness. Front Psychol 2023; 13:846159. [PMID: 36743633 PMCID: PMC9891231 DOI: 10.3389/fpsyg.2022.846159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 11/23/2022] [Indexed: 01/19/2023] Open
Abstract
Near-death experiences (NDEs) including out-of-body experiences (OBEs) have been fascinating phenomena of perception both for affected persons and for communities in science and medicine. Modern progress in the recording of changing brain functions during the time between clinical death and brain death opened the perspective to address and understand the generation of NDEs in brain states of altered consciousness. Changes of consciousness can experimentally be induced in well-controlled clinical or laboratory settings. Reports of the persons having experienced the changes can inform about the similarity of the experiences with those from original NDEs. Thus, we collected neuro-functional models of NDEs including OBEs with experimental backgrounds of drug consumption, epilepsy, brain stimulation, and ischemic stress, and included so far largely unappreciated data from fighter pilot tests under gravitational stress generating cephalic nervous system ischemia. Since we found a large overlap of NDE themes or topics from original NDE reports with those from neuro-functional NDE models, we can state that, collectively, the models offer scientifically appropriate causal explanations for the occurrence of NDEs. The generation of OBEs, one of the NDE themes, can be localized in the temporo-parietal junction (TPJ) of the brain, a multimodal association area. The evaluated literature suggests that NDEs may emerge as hallucination-like phenomena from a brain in altered states of consciousness (ASCs).
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Affiliation(s)
- Raymond Romand
- Faculty of Medicine, University of Strasbourg, Strasbourg, France,*Correspondence: Raymond Romand,
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany,Günter Ehret,
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Adama S, Bogdan M. Application of Soft-Clustering to Assess Consciousness in a CLIS Patient. Brain Sci 2022; 13:brainsci13010065. [PMID: 36672046 PMCID: PMC9856569 DOI: 10.3390/brainsci13010065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 01/01/2023] Open
Abstract
Completely locked-in (CLIS) patients are characterized by sufficiently intact cognitive functions, but a complete paralysis that prevents them to interact with their surroundings. On one hand, studies have shown that the ability to communicate plays an important part in these patients' quality of life and prognosis. On the other hand, brain-computer interfaces (BCIs) provide a means for them to communicate using their brain signals. However, one major problem for such patients is the difficulty to determine if they are conscious or not at a specific time. This work aims to combine different sets of features consisting of spectral, complexity and connectivity measures, to increase the probability of correctly estimating CLIS patients' consciousness levels. The proposed approach was tested on data from one CLIS patient, which is particular in the sense that the experimenter was able to point out one time frame Δt during which he was undoubtedly conscious. Results showed that the method presented in this paper was able to detect increases and decreases of the patient's consciousness levels. More specifically, increases were observed during this Δt, corroborating the assertion of the experimenter reporting that the patient was definitely conscious then. Assessing the patients' consciousness is intended as a step prior attempting to communicate with them, in order to maximize the efficiency of BCI-based communication systems.
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12
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Kobayashi NHC, Farias SV, Luz DA, Machado-Ferraro KM, da Conceição BC, da Silveira CCM, Fernandes LMP, Cartágenes SDC, Ferreira VMM, Fontes-Júnior EA, Maia CDSF. Ketamine plus Alcohol: What We Know and What We Can Expect about This. Int J Mol Sci 2022; 23:ijms23147800. [PMID: 35887148 PMCID: PMC9323326 DOI: 10.3390/ijms23147800] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 01/02/2023] Open
Abstract
Drug abuse has become a public health concern. The misuse of ketamine, a psychedelic substance, has increased worldwide. In addition, the co-abuse with alcohol is frequently identified among misusers. Considering that ketamine and alcohol share several pharmacological targets, we hypothesize that the consumption of both psychoactive substances may synergically intensify the toxicological consequences, both under the effect of drugs available in body systems and during withdrawal. The aim of this review is to examine the toxicological mechanisms related to ketamine plus ethanol co-abuse, as well the consequences on cardiorespiratory, digestive, urinary, and central nervous systems. Furthermore, we provide a comprehensive discussion about the probable sites of shared molecular mechanisms that may elicit additional hazardous effects. Finally, we highlight the gaps of knowledge in this area, which deserves further research.
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Affiliation(s)
- Natalia Harumi Correa Kobayashi
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Sarah Viana Farias
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Diandra Araújo Luz
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Kissila Márvia Machado-Ferraro
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Brenda Costa da Conceição
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Cinthia Cristina Menezes da Silveira
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Luanna Melo Pereira Fernandes
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Sabrina de Carvalho Cartágenes
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Vânia Maria Moraes Ferreira
- Laboratory of Psychobiology, Psychology Institute, University of Brasília, Campus Universitário Darcy Ribeiro—Asa Norte, Brasília 70910900, DF, Brazil;
| | - Enéas Andrade Fontes-Júnior
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
| | - Cristiane do Socorro Ferraz Maia
- Laboratory of Pharmacology of Inflammation and Behavior, Faculty of Pharmacy, Institute of Health Science, Federal University of Pará, Belém 66075110, PA, Brazil; (N.H.C.K.); (S.V.F.); (D.A.L.); (K.M.M.-F.); (B.C.d.C.); (C.C.M.d.S.); (L.M.P.F.); (S.d.C.C.); (E.A.F.-J.)
- Correspondence: ; Tel.: +55-91-3201-7201
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13
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Leung LS, Ma J. Medial Septum Modulates Consciousness and Psychosis-Related Behaviors Through Hippocampal Gamma Activity. Front Neural Circuits 2022; 16:895000. [PMID: 35874429 PMCID: PMC9301478 DOI: 10.3389/fncir.2022.895000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Abnormally high-amplitude hippocampal gamma activity (30–100 Hz) in behaving animals is seen after a hippocampal seizure, following injection of phencyclidine (PCP) or ketamine, and transiently in a delirium stage during induction of general anesthesia. High-amplitude hippocampal gamma activity in behaving rats is associated with hyperactive behavior and impairment in sensorimotor gating and sensory gating. The medial septum is necessary for the high-amplitude gamma activity and abnormal behaviors observed following a hippocampal seizure or injection of PCP/ketamine. Glutamatergic projection of the hippocampus to the nucleus accumbens (NAC) and dopaminergic transmission in NAC is necessary for abnormal behaviors. Large hippocampal gamma waves are suggested to contribute to seizure-induced automatism following temporal lobe seizures, and the schizophrenia-like symptoms induced by PCP/ketamine. Low-amplitude gamma activity is found during general anesthesia, associated with loss of consciousness in humans and loss of righting reflex in animals. Local inactivation or lesion of the medial septum, NAC, and brain areas connected to the septohippocampal-NAC system attenuates the increase in hippocampal gamma and associated behavioral disruptions induced by hippocampal seizure or PCP/ketamine. Inactivation or lesion of the septohippocampal-NAC system decreases the dose of anesthetic necessary for gamma decrease and loss of consciousness in animals. Thus, it is proposed that the septohippocampal-NAC system serves to control consciousness and the behavioral hyperactivity and neural dysfunctions during psychosis.
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14
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Brito MA, Li D, Fields CW, Rybicki-Kler C, Dean JG, Liu T, Mashour GA, Pal D. Cortical Acetylcholine Levels Correlate With Neurophysiologic Complexity During Subanesthetic Ketamine and Nitrous Oxide Exposure in Rats. Anesth Analg 2022; 134:1126-1139. [PMID: 34928887 PMCID: PMC9093725 DOI: 10.1213/ane.0000000000005835] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Neurophysiologic complexity has been shown to decrease during states characterized by a depressed level of consciousness, such as sleep or anesthesia. Conversely, neurophysiologic complexity is increased during exposure to serotonergic psychedelics or subanesthetic doses of dissociative anesthetics. However, the neurochemical substrates underlying changes in neurophysiologic complexity are poorly characterized. Cortical acetylcholine appears to relate to cortical activation and changes in states of consciousness, but the relationship between cortical acetylcholine and complexity has not been formally studied. We addressed this gap by analyzing simultaneous changes in cortical acetylcholine (prefrontal and parietal) and neurophysiologic complexity before, during, and after subanesthetic ketamine (10 mg/kg/h) or 50% nitrous oxide. METHODS Under isoflurane anesthesia, adult Sprague Dawley rats (n = 24, 12 male and 12 female) were implanted with stainless-steel electrodes across the cortex to record monopolar electroencephalogram (0.5-175 Hz; 30 channels) and guide canulae in prefrontal and parietal cortices for local microdialysis quantification of acetylcholine levels. One subgroup of these rats was instrumented with a chronic catheter in jugular vein for ketamine infusion (n = 12, 6 male and 6 female). The electroencephalographic data were analyzed to determine subanesthetic ketamine or nitrous oxide-induced changes in Lempel-Ziv complexity and directed frontoparietal connectivity. Changes in complexity and connectivity were analyzed for correlation with concurrent changes in prefrontal and parietal acetylcholine. RESULTS Subanesthetic ketamine produced sustained increases in normalized Lempel-Ziv complexity (0.5-175 Hz; P < .001) and high gamma frontoparietal connectivity (125-175 Hz; P < .001). This was accompanied by progressive increases in prefrontal (104%; P < .001) and parietal (159%; P < .001) acetylcholine levels that peaked after 50 minutes of infusion. Nitrous oxide induction produced a transient increase in complexity (P < .05) and high gamma connectivity (P < .001), which was accompanied by increases (P < .001) in prefrontal (56%) and parietal (43%) acetylcholine levels. In contrast, the final 50 minutes of nitrous oxide administration were characterized by a decrease in prefrontal (38%; P < .001) and parietal (45%; P < .001) acetylcholine levels, reduced complexity (P < .001), and comparatively weaker frontoparietal high gamma connectivity (P < .001). Cortical acetylcholine and complexity were correlated with both subanesthetic ketamine (prefrontal: cluster-weighted marginal correlation [CW r] [144] = 0.42, P < .001; parietal: CW r[144] = 0.42, P < .001) and nitrous oxide (prefrontal: CW r[156] = 0.46, P < .001; parietal: CW r[156] = 0.56, P < .001) cohorts. CONCLUSIONS These data bridge changes in cortical acetylcholine with concurrent changes in neurophysiologic complexity, frontoparietal connectivity, and the level of consciousness.
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Affiliation(s)
- Michael A. Brito
- From the Department of Anesthesiology
- Neuroscience Graduate Program
- Center for Consciousness Science
| | - Duan Li
- From the Department of Anesthesiology
- Center for Consciousness Science
| | | | | | - Jon G. Dean
- From the Department of Anesthesiology
- Center for Consciousness Science
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | | | - George A. Mashour
- From the Department of Anesthesiology
- Neuroscience Graduate Program
- Center for Consciousness Science
| | - Dinesh Pal
- From the Department of Anesthesiology
- Neuroscience Graduate Program
- Center for Consciousness Science
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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15
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Wang Y, Zhang Y, Wang K, Zhu Z, Wang D, Yang Q, Dong H. Esketamine Increases Neurotransmitter Releases but Simplifies Neurotransmitter Networks in Mouse Prefrontal Cortex. J Neurophysiol 2022; 127:586-595. [PMID: 35080449 DOI: 10.1152/jn.00462.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
General anesthesia induces a profound but reversible unconscious state, which is accompanied by changes in various neurotransmitters in the cortex. Unlike the "brain silencing" effect of γ-aminobutyric acid (GABA) receptor potentiator anesthesia, ketamine anesthesia leads the brain to a paradoxical active state with higher cortical activity, which is manifested as dissociative anesthesia. However, how the overall neurotransmitter network evolves across conscious states after ketamine administration remains unclear. Using in vivo microdialysis, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, and electroencephalogram (EEG) recording technique, we continuously measured the concentrations of six neurotransmitters and the EEG signals during anesthesia with esketamine, an S-enantiomer of ketamine racemate. We found that there was an increase in the release of five cortical neurotransmitters after the administration of esketamine. The correlation of cortical neurotransmitters was dynamically simplified along with behavioral changes until full recovery after anesthesia. The esketamine-increased gamma oscillation power was positively correlated only with the concentration of 5-hydroxytryptamine (5-HT) in the medial prefrontal cortex. This study suggests that the transformation of the neurotransmitter network rather than the concentrations of neurotransmitters could be more indicative of the consciousness shift during esketamine anesthesia.
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Affiliation(s)
- Ye Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yunyun Zhang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Kai Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Zhenghua Zhu
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Dan Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Qianzi Yang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Hailong Dong
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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16
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Demchenko I, Tassone VK, Kennedy SH, Dunlop K, Bhat V. Intrinsic Connectivity Networks of Glutamate-Mediated Antidepressant Response: A Neuroimaging Review. Front Psychiatry 2022; 13:864902. [PMID: 35722550 PMCID: PMC9199367 DOI: 10.3389/fpsyt.2022.864902] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/12/2022] [Indexed: 11/23/2022] Open
Abstract
Conventional monoamine-based pharmacotherapy, considered the first-line treatment for major depressive disorder (MDD), has several challenges, including high rates of non-response. To address these challenges, preclinical and clinical studies have sought to characterize antidepressant response through monoamine-independent mechanisms. One striking example is glutamate, the brain's foremost excitatory neurotransmitter: since the 1990s, studies have consistently reported altered levels of glutamate in MDD, as well as antidepressant effects following molecular targeting of glutamatergic receptors. Therapeutically, this has led to advances in the discovery, testing, and clinical application of a wide array of glutamatergic agents, particularly ketamine. Notably, ketamine has been demonstrated to rapidly improve mood symptoms, unlike monoamine-based interventions, and the neurobiological basis behind this rapid antidepressant response is under active investigation. Advances in brain imaging techniques, including functional magnetic resonance imaging, magnetic resonance spectroscopy, and positron emission tomography, enable the identification of the brain network-based characteristics distinguishing rapid glutamatergic modulation from the effect of slow-acting conventional monoamine-based pharmacology. Here, we review brain imaging studies that examine brain connectivity features associated with rapid antidepressant response in MDD patients treated with glutamatergic pharmacotherapies in contrast with patients treated with slow-acting monoamine-based treatments. Trends in recent brain imaging literature suggest that the activity of brain regions is organized into coherent functionally distinct networks, termed intrinsic connectivity networks (ICNs). We provide an overview of major ICNs implicated in depression and explore how treatment response following glutamatergic modulation alters functional connectivity of limbic, cognitive, and executive nodes within ICNs, with well-characterized anti-anhedonic effects and the enhancement of "top-down" executive control. Alterations within and between the core ICNs could potentially exert downstream effects on the nodes within other brain networks of relevance to MDD that are structurally and functionally interconnected through glutamatergic synapses. Understanding similarities and differences in brain ICNs features underlying treatment response will positively impact the trajectory and outcomes for adults suffering from MDD and will facilitate the development of biomarkers to enable glutamate-based precision therapeutics.
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Affiliation(s)
- Ilya Demchenko
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Center for Depression and Suicide Studies, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Vanessa K Tassone
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Sidney H Kennedy
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Center for Depression and Suicide Studies, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Keenan Research Center for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Katharine Dunlop
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Center for Depression and Suicide Studies, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Keenan Research Center for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Venkat Bhat
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Center for Depression and Suicide Studies, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Keenan Research Center for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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17
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Willsey MS, Nu CS, Nason SR, Schroeder KE, Hutchison BC, Welle EJ, Patil PG, Mashour GA, Chestek CA. Neural Dynamics in Primate Cortex during Exposure to Subanesthetic Concentrations of Nitrous Oxide. eNeuro 2021; 8:ENEURO. [PMID: 34135005 DOI: 10.1523/ENEURO.0479-20.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 05/07/2021] [Accepted: 05/31/2021] [Indexed: 11/21/2022] Open
Abstract
Nitrous oxide (N2O) is a hypnotic gas with antidepressant and psychedelic properties at subanesthetic concentrations. Despite long-standing clinical use, there is insufficient understanding of its effect on neural dynamics and cortical processing, which is important for mechanistic understanding of its therapeutic effects. We administered subanesthetic (70%), inhaled N2O and studied the dynamic changes of spiking rate, spectral content, and somatosensory information representation in primary motor cortex (M1) in two male rhesus macaques implanted with Utah microelectrode arrays in the hand area of M1. The average sorted multiunit spiking rate in M1 increased from 8.1 ± 0.99 to 10.6 ± 1.3 Hz in Monkey W (p < 0.001) and from 5.6 ± 0.87 to 7.0 ± 1.1 Hz in Monkey N (p = 0.003). Power spectral densities increased in beta- and gamma-band power. To evaluate somatosensory content in M1 as a surrogate of information transfer, fingers were lightly brushed and classified using a naive Bayes classifier. In both monkeys, the proportion of correctly classified fingers dropped from 0.50 ± 0.06 before N2O inhalation to 0.34 ± 0.03 during N2O inhalation (p = 0.018), although some fingers continued to be correctly classified (p = 0.005). The decrease in correct classifications corresponded to decreased modulation depth for the population (p = 0.005) and fewer modulated units (p = 0.046). However, the increased single-unit firing rate was not correlated with its modulation depth (R2 < 0.001, p = 0.93). These data suggest that N2O degrades information transfer, although no clear relationship was found between neuronal tuning and N2O-induced changes in firing rate.
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18
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Huels ER, Groenhout T, Fields CW, Liu T, Mashour GA, Pal D. Inactivation of Prefrontal Cortex Delays Emergence From Sevoflurane Anesthesia. Front Syst Neurosci 2021; 15:690717. [PMID: 34305541 PMCID: PMC8299111 DOI: 10.3389/fnsys.2021.690717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/10/2021] [Indexed: 01/21/2023] Open
Abstract
Studies aimed at investigating brain regions involved in arousal state control have been traditionally limited to subcortical structures. In the current study, we tested the hypothesis that inactivation of prefrontal cortex, but not two subregions within parietal cortex—somatosensory barrel field and medial/lateral parietal association cortex—would suppress arousal, as measured by an increase in anesthetic sensitivity. Male and female Sprague Dawley rats were surgically prepared for recording electroencephalogram and bilateral infusion into prefrontal cortex (N = 13), somatosensory barrel field (N = 10), or medial/lateral parietal association cortex (N = 9). After at least 10 days of post-surgical recovery, 156 μM tetrodotoxin or saline was microinjected into one of the cortical sites. Ninety minutes after injection, rats were anesthetized with 2.5% sevoflurane and the time to loss of righting reflex, a surrogate for loss of consciousness, was measured. Sevoflurane was stopped after 45 min and the time to return of righting reflex, a surrogate for return of consciousness, was measured. Tetrodotoxin-mediated inactivation of all three cortical sites decreased (p < 0.05) the time to loss of righting reflex. By contrast, only inactivation of prefrontal cortex, but not somatosensory barrel field or medial/lateral parietal association cortex, increased (p < 0.001) the time to return of righting reflex. Burst suppression ratio was not altered following inactivation of any of the cortical sites, suggesting that there was no global effect due to pharmacologic lesion. These findings demonstrate that prefrontal cortex plays a causal role in emergence from anesthesia and behavioral arousal.
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Affiliation(s)
- Emma R Huels
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
| | - Trent Groenhout
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Christopher W Fields
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Tiecheng Liu
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
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19
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Tort-Colet N, Capone C, Sanchez-Vives MV, Mattia M. Attractor competition enriches cortical dynamics during awakening from anesthesia. Cell Rep 2021; 35:109270. [PMID: 34161772 DOI: 10.1016/j.celrep.2021.109270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 02/19/2021] [Accepted: 05/27/2021] [Indexed: 10/21/2022] Open
Abstract
Slow oscillations (≲ 1 Hz), a hallmark of slow-wave sleep and deep anesthesia across species, arise from spatiotemporal patterns of activity whose complexity increases as wakefulness is approached and cognitive functions emerge. The arousal process constitutes an open window to the unknown mechanisms underlying the emergence of such dynamical richness in awake cortical networks. Here, we investigate the changes in network dynamics as anesthesia fades out in the rat visual cortex. Starting from deep anesthesia, slow oscillations gradually increase their frequency, eventually expressing maximum regularity. This stage is followed by the abrupt onset of an infra-slow (~0.2 Hz) alternation between sleep-like oscillations and activated states. A population rate model reproduces this transition driven by an increased excitability that brings it to periodically cross a critical point. Based on our model, dynamical richness emerges as a competition between two metastable attractor states, a conclusion strongly supported by the data.
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Affiliation(s)
- Núria Tort-Colet
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Department of Integrative and Computational Neuroscience, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
| | - Cristiano Capone
- Physics Department, Sapienza University, Rome, Italy; Natl. Center for Radioprotection and Computational Physics, Istituto Superiore di Sanità, Rome, Italy; Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome, Italy
| | - Maria V Sanchez-Vives
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Maurizio Mattia
- Natl. Center for Radioprotection and Computational Physics, Istituto Superiore di Sanità, Rome, Italy
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20
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Leung LS, Chu L, Prado MAM, Prado VF. Forebrain Acetylcholine Modulates Isoflurane and Ketamine Anesthesia in Adult Mice. Anesthesiology 2021; 134:588-606. [PMID: 33635947 DOI: 10.1097/aln.0000000000003713] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cholinergic drugs are known to modulate general anesthesia, but anesthesia responses in acetylcholine-deficient mice have not been studied. It was hypothesized that mice with genetic deficiency of forebrain acetylcholine show increased anesthetic sensitivity to isoflurane and ketamine and decreased gamma-frequency brain activity. METHODS Male adult mice with heterozygous knockdown of vesicular acetylcholine transporter in the brain or homozygous knockout of the transporter in the basal forebrain were compared with wild-type mice. Hippocampal and frontal cortical electrographic activity and righting reflex were studied in response to isoflurane and ketamine doses. RESULTS The loss-of-righting-reflex dose for isoflurane was lower in knockout (mean ± SD, 0.76 ± 0.08%, n = 18, P = 0.005) but not knockdown (0.78 ± 0.07%, n = 24, P = 0.021), as compared to wild-type mice (0.83 ± 0.07%, n = 23), using a significance criterion of P = 0.017 for three planned comparisons. Loss-of-righting-reflex dose for ketamine was lower in knockout (144 ± 39 mg/kg, n = 14, P = 0.006) but not knockdown (162 ± 32 mg/kg, n = 20, P = 0.602) as compared to wild-type mice (168 ± 24 mg/kg, n = 21). Hippocampal high-gamma (63 to 100 Hz) power after isoflurane was significantly lower in knockout and knockdown mice compared to wild-type mice (isoflurane-dose and mouse-group interaction effect, F[8,56] = 2.87, P = 0.010; n = 5 to 6 mice per group). Hippocampal high-gamma power after ketamine was significantly lower in both knockout and knockdown mice when compared to wild-type mice (interaction effect F[2,13] = 6.06, P = 0.014). The change in frontal cortical gamma power with isoflurane or ketamine was not statistically different among knockout, knockdown, and wild-type mice. CONCLUSIONS These findings suggest that forebrain cholinergic neurons modulate behavioral sensitivity and hippocampal gamma activity during isoflurane and ketamine anesthesia. EDITOR’S PERSPECTIVE
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Średniawa W, Wróbel J, Kublik E, Wójcik DK, Whittington MA, Hunt MJ. Network and synaptic mechanisms underlying high frequency oscillations in the rat and cat olfactory bulb under ketamine-xylazine anesthesia. Sci Rep 2021; 11:6390. [PMID: 33737621 PMCID: PMC7973548 DOI: 10.1038/s41598-021-85705-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 02/25/2021] [Indexed: 11/09/2022] Open
Abstract
Wake-related ketamine-dependent high frequency oscillations (HFO) can be recorded in local field potentials (LFP) from cortical and subcortical regions in rodents. The mechanisms underlying their generation and occurrence in higher mammals are unclear. Unfortunately, anesthetic doses of pure ketamine attenuate HFO, which has precluded their investigation under anesthesia. Here, we show ketamine-xylazine (KX) anesthesia is associated with a prominent 80–130 Hz rhythm in the olfactory bulb (OB) of rats, whereas 30–65 Hz gamma power is diminished. Simultaneous LFP and thermocouple recordings revealed the 80–130 Hz rhythm was dependent on nasal respiration. This rhythm persisted despite surgical excision of the piriform cortex. Silicon probes spanning the dorsoventral aspect of the OB revealed this rhythm was strongest in ventral areas and associated with microcurrent sources about the mitral layer. Pharmacological microinfusion studies revealed dependency on excitatory-inhibitory synaptic activity, but not gap junctions. Finally, a similar rhythm occurred in the OB of KX-anesthetized cats, which shared key features with our rodent studies. We conclude that the activity we report here is driven by nasal airflow, local excitatory-inhibitory interactions, and conserved in higher mammals. Additionally, KX anesthesia is a convenient model to investigate further the mechanisms underlying wake-related ketamine-dependent HFO.
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Affiliation(s)
- Władysław Średniawa
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.,University of Warsaw, Faculty of Biology, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Jacek Wróbel
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Ewa Kublik
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Daniel Krzysztof Wójcik
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.,Faculty of Management and Social Communication, Jagiellonian University, 30-348, Cracow, Poland
| | | | - Mark Jeremy Hunt
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland. .,University of York, Heslington, NY, YO10 5DD, United Kingdom.
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Abstract
PURPOSE OF REVIEW Experimental preclinical models of recovery of consciousness (ROC) and anesthesia emergence are crucial for understanding the neuronal circuits restoring arousal during coma emergence. Such models can also potentially help to better understand how events during coma emergence facilitate or hinder recovery from brain injury. Here we provide an overview of current methods used to assess ROC/level of arousal in animal models. This exposes the need for objective approaches to calibrate arousal levels. We outline how correlation of measured behaviors and their reestablishment at multiple stages with cellular, local and broader neuronal networks, gives a fuller understanding of ROC. RECENT FINDINGS Animals emerging from diverse coma-like states share a dynamic process of cortical and behavioral recovery that reveals distinct states consistently sequenced from low-to-high arousal level and trackable in nonhuman primates and rodents. Neuronal activity modulation of layer V-pyramidal neurons and neuronal aggregates within the brainstem and thalamic nuclei play critical roles at specific stages to promote restoration of a conscious state. SUMMARY A comprehensive, graded calibration of cortical, physiological, and behavioral changes in animal models is undoubtedly needed to establish an integrative framework. This approach reveals the contribution of local and systemic neuronal circuits to the underlying mechanisms for recovering consciousness.
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Affiliation(s)
| | - Nicholas D Schiff
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
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Mondino A, Cavelli M, González J, Osorio L, Castro-Zaballa S, Costa A, Vanini G, Torterolo P. Power and Coherence in the EEG of the Rat: Impact of Behavioral States, Cortical Area, Lateralization and Light/Dark Phases. Clocks Sleep 2020; 2:536-556. [PMID: 33317018 PMCID: PMC7768537 DOI: 10.3390/clockssleep2040039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/28/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
The sleep-wake cycle is constituted by three behavioral states: wakefulness (W), non-REM (NREM) and REM sleep. These states are associated with drastic changes in cognitive capacities, mostly determined by the function of the thalamo-cortical system, whose activity can be examined by means of intra-cranial electroencephalogram (iEEG). With the purpose to study in depth the basal activity of the iEEG in adult rats, we analyzed the spectral power and coherence of the iEEG during W and sleep in the paleocortex (olfactory bulb), and in neocortical areas. We also analyzed the laterality of the signals, as well as the influence of the light and dark phases. We found that the iEEG power and coherence of the whole spectrum were largely affected by behavioral states and highly dependent on the cortical areas recorded. We also determined that there are night/day differences in power and coherence during sleep, but not in W. Finally, we observed that, during REM sleep, intra-hemispheric coherence differs between right and left hemispheres. We conclude that the iEEG dynamics are highly dependent on the cortical area and behavioral states. Moreover, there are light/dark phases disparities in the iEEG during sleep, and intra-hemispheric connectivity differs between both hemispheres during REM sleep.
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Affiliation(s)
- Alejandra Mondino
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5615, USA;
| | - Matías Cavelli
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
- Department of Psychiatry, University of Wisconsin, 6001 Research Park Blvd, Madison, WI 53719, USA
| | - Joaquín González
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
| | - Lucía Osorio
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
| | - Santiago Castro-Zaballa
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
| | - Alicia Costa
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5615, USA;
| | - Pablo Torterolo
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay; (A.M.); (M.C.); (J.G.); (L.O.); (S.C.-Z.); (A.C.)
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Parkar A, Fedrigon DC, Alam F, Vanini G, Mashour GA, Pal D. Carbachol and Nicotine in Prefrontal Cortex Have Differential Effects on Sleep-Wake States. Front Neurosci 2020; 14:567849. [PMID: 33328847 PMCID: PMC7714754 DOI: 10.3389/fnins.2020.567849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 10/16/2020] [Indexed: 11/13/2022] Open
Abstract
The role of the brainstem cholinergic system in the regulation of sleep-wake states has been studied extensively but relatively little is known about the role of cholinergic mechanisms in prefrontal cortex in the regulation of sleep-wake states. In a recent study, we showed that prefrontal cholinergic stimulation in anesthetized rat can reverse the traits associated with anesthesia and restore a wake-like state, thereby providing evidence for a causal role for prefrontal cholinergic mechanisms in modulating level of arousal. However, the effect of increase in prefrontal cholinergic tone on spontaneous sleep-wake states has yet to be demonstrated. Therefore, in this study, we tested the hypothesis that delivery of cholinergic agonists - carbachol or nicotine - into prefrontal cortex of rat during slow wave sleep (SWS) would produce behavioral arousal and increase the time spent in wake state. We show that unilateral microinjection (200 nL) of carbachol (1 mM) or nicotine (100 mM) into prefrontal cortex during SWS decreased the latency to the onset of wake state (p = 0.03 for carbachol, p = 0.03 for nicotine) and increased the latency to the onset of rapid eye movement sleep (p = 0.008 for carbachol, p = 0.006 for nicotine). Although the infusion of 1 mM carbachol increased the time spent in wake state (p = 0.01) and decreased the time spent in SWS (p = 0.01), infusion of 10 or 100 mM nicotine did not produce any statistically significant change in sleep-wake architecture. These data demonstrate a differential role of prefrontal cholinergic receptors in modulating spontaneous sleep-wake states.
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Affiliation(s)
- Anjum Parkar
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Donald C Fedrigon
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Farah Alam
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
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Abstract
The righting reflex (RR) is frequently used to assess level of arousal and applied to animal models of a range of neurological disorders. RR produces a binary result that, when positive, is used to infer restoration of consciousness, often without further behavioral corroboration. We find that RR is an unreliable metric for arousal/recovery of consciousness. Instead, cortical activity and motor behavior that accompany RR are a non-binary, superior criterion that accurately calibrates and establishes level of arousal in rodents.
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Affiliation(s)
- Sijia Gao
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, 10065, USA
- School of Electrical and Computer Engineering, Cornell University, New York, NY, 10044, USA
| | - Diany Paola Calderon
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, 10065, USA.
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Pang L, Cui M, Dai W, Kong J, Chen H, Wu S. Can Intraoperative Low-Dose R, S-Ketamine Prevent Depressive Symptoms After Surgery? The First Meta-Analysis of Clinical Trials. Front Pharmacol 2020; 11:586104. [PMID: 33192527 PMCID: PMC7604489 DOI: 10.3389/fphar.2020.586104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/18/2020] [Indexed: 12/23/2022] Open
Abstract
Background: Postoperative depression is a common complication after surgery that profoundly affects recovery and prognosis. New research indicates that (R,S)-ketamine is a potent antidepressant that exerts a rapid and sustained antidepressive effect. However, there is no consensus on whether intraoperative low-dose (R,S)-ketamine prevents postoperative depression. Objectives: This study aimed to investigate the safety, feasibility, and short-term complications of intraoperative low-dose (R,S)-ketamine in preventing postoperative depressive symptoms. Methods: The Web of Science, Cochrane, PubMed, and CNKI databases were systematically searched (last search February 28, 2020) to identify studies involving ketamine. Sensitivity and metaregression analyses were performed to identify potential confounders. The meta-analysis was performed using Review Manager 5.3. Results: A total of 13 studies (seven in Chinese and six in English) representing 1,148 cases of patients who were treated with (R,S)-ketamine and 874 cases of patients who received other treatments were included in the meta-analysis. Anesthesia duration and blood loss did not significantly differ between the two groups, demonstrating that (R,S)-ketamine was safe (odds ratio,OR: 0.27; 95% CI: -1.14 to 1.68; P = 0.71) for prophylactic treatment of postoperative depression. Blood loss (OR: -1.83; 95% CI: -8.34 to 4.68; P = 0.58), the number of postoperative depressive patients (95% CI: 0.8-1.07; P = 0.08; (R,S)-ketamine: control = 12.9%:15.8%), and postoperative complications (OR: 0.83, 95% CI: 0.44-1.58; P = 0.57; (R,S)-ketamine: control = 19.3%:19.3%) were all similar across groups. Intra-operative low-dose (R,S)-ketamine reduced extubation time (OR: -2.84; 95% CI: -5.48 to -0.21; P = 0.03). Conclusions: The prophylactic anti-depressant effect of (R,S)-ketamine did not significantly differ between the (R,S)-ketamine and control groups in patients undergoing general or spinal anesthesia. However, (R,S)-ketamine use led to a higher incidence of adverse reactions in patients under 40 years of age who underwent a Cesarean section under spinal anesthesia.
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Affiliation(s)
- Liwei Pang
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, China
| | - Meiying Cui
- Department of Anesthesiology, Shengjing Hospital, China Medical University, Shenyang, China
| | - Wanling Dai
- Innovation Institute of China Medical University, Shenyang, China
| | - Jing Kong
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, China
| | - Hongzhi Chen
- Department of Anesthesiology, Shengjing Hospital, China Medical University, Shenyang, China
| | - Shuodong Wu
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, China
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Brito MA, Li D, Mashour GA, Pal D. State-Dependent and Bandwidth-Specific Effects of Ketamine and Propofol on Electroencephalographic Complexity in Rats. Front Syst Neurosci 2020; 14:50. [PMID: 32848642 PMCID: PMC7431468 DOI: 10.3389/fnsys.2020.00050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/02/2020] [Indexed: 12/20/2022] Open
Abstract
There is an ongoing debate as to whether ketamine anesthesia suppresses neurophysiologic complexity at doses sufficient for surgical anesthesia, with previous human studies reporting surrogates of both suppressed and preserved levels of cortical complexity. However, these studies have not assessed cortical dynamics in higher gamma frequencies, which have previously been demonstrated to correlate with the level of consciousness during anesthesia. In this study, we used Lempel-Ziv complexity (LZc) to characterize frontal and parietal electroencephalographic complexity (0.5–175 Hz, 0.5–55 Hz, 65–175 Hz) before, during, and after ketamine or propofol anesthesia in the rat. To control for the potential influence of spectral changes in complexity estimation, LZc was normalized with phase-shuffled surrogate data. We demonstrate that ketamine and propofol anesthesia were characterized by a significant reduction in broadband (0.5–175 Hz) LZc. Further analysis showed that while the reduction of LZc during ketamine anesthesia was significant in 65–175 Hz range, during propofol anesthesia, a significant decrease was observed in 0.5–55 Hz bandwidth. LZc in broadband and 0.5–55 Hz range showed a significant increase during emergence from ketamine anesthesia. Phase-shuffled normalized LZc revealed that (1) decrease in complexity during ketamine and propofol anesthesia—not increase in complexity during emergence—were dissociable from the influence of spectral changes, and (2) reduced LZc during ketamine anesthesia was present across all three bandwidths. Ketamine anesthesia was characterized by reduced complexity in high gamma bandwidth, as reflected in both raw and phase-shuffled normalized LZc, which suggests that reduced high gamma complexity is a neurophysiological feature of ketamine anesthesia.
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Affiliation(s)
- Michael A Brito
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Duan Li
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
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Lendner JD, Helfrich RF, Mander BA, Romundstad L, Lin JJ, Walker MP, Larsson PG, Knight RT. An electrophysiological marker of arousal level in humans. eLife 2020; 9:e55092. [PMID: 32720644 PMCID: PMC7394547 DOI: 10.7554/elife.55092] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 07/06/2020] [Indexed: 12/13/2022] Open
Abstract
Deep non-rapid eye movement sleep (NREM) and general anesthesia with propofol are prominent states of reduced arousal linked to the occurrence of synchronized oscillations in the electroencephalogram (EEG). Although rapid eye movement (REM) sleep is also associated with diminished arousal levels, it is characterized by a desynchronized, 'wake-like' EEG. This observation implies that reduced arousal states are not necessarily only defined by synchronous oscillatory activity. Using intracranial and surface EEG recordings in four independent data sets, we demonstrate that the 1/f spectral slope of the electrophysiological power spectrum, which reflects the non-oscillatory, scale-free component of neural activity, delineates wakefulness from propofol anesthesia, NREM and REM sleep. Critically, the spectral slope discriminates wakefulness from REM sleep solely based on the neurophysiological brain state. Taken together, our findings describe a common electrophysiological marker that tracks states of reduced arousal, including different sleep stages as well as anesthesia in humans.
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Affiliation(s)
- Janna D Lendner
- Helen Wills Neuroscience Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center TuebingenTuebingenGermany
| | - Randolph F Helfrich
- Hertie-Institute for Clinical Brain ResearchTuebingenGermany
- Department of Neurology and Epileptology, University Medical Center TuebingenTuebingenGermany
| | - Bryce A Mander
- Department of Psychiatry and Human Behavior, University of California, IrvineIrvineUnited States
| | - Luis Romundstad
- Department of Anesthesiology, University of Oslo Medical CenterOsloNorway
| | - Jack J Lin
- Department of Neurology, University of California, IrvineIrvineUnited States
| | - Matthew P Walker
- Helen Wills Neuroscience Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Psychology, University of California, BerkeleyBerkeleyUnited States
| | - Pal G Larsson
- Department of Neurosurgery, University of Oslo Medical CenterOsloNorway
| | - Robert T Knight
- Helen Wills Neuroscience Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Psychology, University of California, BerkeleyBerkeleyUnited States
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Abstract
AbstractThe drug ketamine has been extensively studied due to its use in anaesthesia, as a model of psychosis and, most recently, its antidepressant properties. Understanding the physiology of ketamine is complex due to its rich pharmacology with multiple potential sites at clinically relevant doses. In this review of the neurophysiology of ketamine, we focus on the acute effects of ketamine in the resting brain. We ascend through spatial scales starting with a complete review of the pharmacology of ketamine and then cover its effects on in vitro and in vivo electrophysiology. We then summarise and critically evaluate studies using EEG/MEG and neuroimaging measures (MRI and PET), integrating across scales where possible. While a complicated and, at times, confusing picture of ketamine’s effects are revealed, we stress that much of this might be caused by use of different species, doses, and analytical methodologies and suggest strategies that future work could use to answer these problems.
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Affiliation(s)
- Rebecca McMillan
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Suresh D. Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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31
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Malekmohammadi M, Price CM, Hudson AE, DiCesare JAT, Pouratian N. Propofol-induced loss of consciousness is associated with a decrease in thalamocortical connectivity in humans. Brain 2020; 142:2288-2302. [PMID: 31236577 DOI: 10.1093/brain/awz169] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 03/25/2019] [Accepted: 04/18/2019] [Indexed: 11/14/2022] Open
Abstract
Although the molecular effects of many anaesthetics have been well characterized, a network-level explanation for how these changes lead to loss of consciousness remains unclear. Studies using electroencephalography have characterized changes in neural oscillations in the cortex at specific frequency bands during propofol-induced anaesthesia and modelling work suggests these changes result from changes in thalamocortical functional connectivity. However, it is unclear if the neurophysiological changes seen at the cortex are due to enhanced or disrupted thalamocortical communication. Direct recordings from these sites during anaesthesia that could be used to confirm such models are rare. We recorded local field potentials from the ventral intermediate nucleus of the thalamus and electrocorticography signals from the ipsilateral sensorimotor cortex in 10 patients undergoing deep brain stimulation surgery. Signals were acquired during induction of propofol anaesthesia while subjects were resting. After confirming direct structural connectivity between the thalamus and the cortical recording site, we investigated propofol-associated changes in thalamic and cortical local power as well as thalamocortical functional connectivity, as measured with coherence, debiased weighted phase lag index, and phase amplitude coupling. Propofol anaesthesia resulted in local power increases at α frequencies (8-12 Hz) across both thalamic and cortical areas. At sensorimotor cortices, there was a broadband power increase (12-100 Hz), while the power of this same broad frequency band was suppressed within the thalamus. Despite the increase in local α power both within the thalamus and cortex, thalamocortical coherence and debiased weighted phase lag index in the α/low β frequencies (8-16 Hz, which was present in the awake state) significantly decreased with propofol administration (P < 0.05, two group test of coherence). Likewise, propofol administration resulted in decreased phase amplitude coupling between the phase of α/low β in the thalamus and the amplitude of broadband gamma (50-200 Hz) in the cortex (P = 0.031, Wilcoxon signed-rank test). We also report phase amplitude coupling between the phase of slow wave oscillations (0.1-1 Hz) and amplitude of broadband frequencies (8-200 Hz) within the cortex and across thalamocortical connections, during anaesthesia, both following a peak-max pattern. While confirming α-power increases with propofol administration both in thalamus and cortex, we observed decreased thalamocortical connectivity, contradicting models that suggest increasing cortical low frequency power is necessarily related to increased thalamocortical coherence but in support of the theory that propofol-induced loss of consciousness is associated with disrupted thalamocortical communication.
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Affiliation(s)
| | - Collin M Price
- Department of Neurosurgery, University of California, Los Angeles, CA, USA
| | - Andrew E Hudson
- Department of Anaesthesiology, University of California, Los Angeles, CA, USA
| | | | - Nader Pouratian
- Department of Neurosurgery, University of California, Los Angeles, CA, USA
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32
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Reimann HM, Niendorf T. The (Un)Conscious Mouse as a Model for Human Brain Functions: Key Principles of Anesthesia and Their Impact on Translational Neuroimaging. Front Syst Neurosci 2020; 14:8. [PMID: 32508601 PMCID: PMC7248373 DOI: 10.3389/fnsys.2020.00008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
In recent years, technical and procedural advances have brought functional magnetic resonance imaging (fMRI) to the field of murine neuroscience. Due to its unique capacity to measure functional activity non-invasively, across the entire brain, fMRI allows for the direct comparison of large-scale murine and human brain functions. This opens an avenue for bidirectional translational strategies to address fundamental questions ranging from neurological disorders to the nature of consciousness. The key challenges of murine fMRI are: (1) to generate and maintain functional brain states that approximate those of calm and relaxed human volunteers, while (2) preserving neurovascular coupling and physiological baseline conditions. Low-dose anesthetic protocols are commonly applied in murine functional brain studies to prevent stress and facilitate a calm and relaxed condition among animals. Yet, current mono-anesthesia has been shown to impair neural transmission and hemodynamic integrity. By linking the current state of murine electrophysiology, Ca2+ imaging and fMRI of anesthetic effects to findings from human studies, this systematic review proposes general principles to design, apply and monitor anesthetic protocols in a more sophisticated way. The further development of balanced multimodal anesthesia, combining two or more drugs with complementary modes of action helps to shape and maintain specific brain states and relevant aspects of murine physiology. Functional connectivity and its dynamic repertoire as assessed by fMRI can be used to make inferences about cortical states and provide additional information about whole-brain functional dynamics. Based on this, a simple and comprehensive functional neurosignature pattern can be determined for use in defining brain states and anesthetic depth in rest and in response to stimuli. Such a signature can be evaluated and shared between labs to indicate the brain state of a mouse during experiments, an important step toward translating findings across species.
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Affiliation(s)
- Henning M. Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
- Experimental and Clinical Research Center, A Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
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Manduca JD, Thériault RK, Williams OOF, Rasmussen DJ, Perreault ML. Transient Dose-dependent Effects of Ketamine on Neural Oscillatory Activity in Wistar-Kyoto Rats. Neuroscience 2020; 441:161-175. [PMID: 32417341 DOI: 10.1016/j.neuroscience.2020.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/16/2020] [Accepted: 05/07/2020] [Indexed: 12/15/2022]
Abstract
Ketamine is a promising therapeutic for treatment-resistant depression (TRD) but is associated with an array of short-term psychomimetic side-effects. These disparate drug effects may be elicited through the modulation of neural circuit activity. The purpose of this study was to therefore delineate dose- and time-dependent changes in ketamine-induced neural oscillatory patterns in regions of the brain implicated in depression. Wistar-Kyoto rats were used as a model system to study these aspects of TRD neuropathology whereas Wistar rats were used as a control strain. Animals received a low (10 mg/kg) or high (30 mg/kg) dose of ketamine and temporal changes in neural oscillatory activity recorded from the prefrontal cortex (PFC), cingulate cortex (Cg), and nucleus accumbens (NAc) for ninety minutes. Effects of each dose of ketamine on immobility in the forced swim test were also evaluated. High dose ketamine induced a transient increase in theta power in the PFC and Cg, as well as a dose-dependent increase in gamma power in these regions 10-min, but not 90-min, post-administration. In contrast, only low dose ketamine normalized innate deficits in fast gamma coherence between the NAc-Cg and PFC-Cg, an effect that persisted at 90-min post-injection. These low dose ketamine-induced oscillatory alterations were accompanied by a reduction in immobility time in the forced swim test. These results show that ketamine induces time-dependent effects on neural oscillations at specific frequencies. These drug-induced changes may differentially contribute to the psychomimetic and therapeutic effects of the drug.
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Affiliation(s)
- Joshua D Manduca
- Department of Molecular and Cellular Biology, University of Guelph (ON), Canada
| | - Rachel-Karson Thériault
- Department of Molecular and Cellular Biology, University of Guelph (ON), Canada; Collaborative Neuroscience Program, University of Guelph (ON), Canada
| | - Olivia O F Williams
- Department of Molecular and Cellular Biology, University of Guelph (ON), Canada
| | - Duncan J Rasmussen
- Department of Molecular and Cellular Biology, University of Guelph (ON), Canada
| | - Melissa L Perreault
- Department of Molecular and Cellular Biology, University of Guelph (ON), Canada; Collaborative Neuroscience Program, University of Guelph (ON), Canada.
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Abstract
The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. Emergence is driven by mechanisms that can be distinct from entry to the anesthetized state. In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.
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Pal D, Li D, Dean JG, Brito MA, Liu T, Fryzel AM, Hudetz AG, Mashour GA. Level of Consciousness Is Dissociable from Electroencephalographic Measures of Cortical Connectivity, Slow Oscillations, and Complexity. J Neurosci 2020; 40:605-18. [PMID: 31776211 DOI: 10.1523/JNEUROSCI.1910-19.2019] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/05/2019] [Accepted: 11/22/2019] [Indexed: 12/19/2022] Open
Abstract
Leading neuroscientific theories posit a central role for the functional integration of cortical areas in conscious states. Considerable evidence supporting this hypothesis is based on network changes during anesthesia, but it is unclear whether these changes represent state-related (conscious vs unconscious) or drug-related (anesthetic vs no anesthetic) effects. We recently demonstrated that carbachol delivery to prefrontal cortex (PFC) restored wakefulness despite continuous administration of the general anesthetic sevoflurane. By contrast, carbachol delivery to parietal cortex, or noradrenaline delivery to either prefrontal or parietal cortices, failed to restore wakefulness. Thus, carbachol-induced reversal of sevoflurane anesthesia represents a unique state that combines wakefulness with clinically relevant anesthetic concentrations in the brain. To differentiate the state-related and drug-related associations of cortical connectivity and dynamics, we analyzed the electroencephalographic data gathered from adult male Sprague Dawley rats during the aforementioned experiments for changes in functional cortical gamma connectivity (25–155 Hz), slow oscillations (0.5–1 Hz), and complexity (<175 Hz). We show that higher gamma (85–155 Hz) connectivity is decreased (p ≤ 0.02) during sevoflurane anesthesia, an expected finding, but was not restored during wakefulness induced by carbachol delivery to PFC. Conversely, for rats in which wakefulness was not restored, the functional gamma connectivity remained reduced, but there was a significant decrease (p < 0.001) in the power of slow oscillations and increase (p < 0.001) in cortical complexity, which was similar to that observed during wakefulness induced after carbachol delivery to PFC. We conclude that the level of consciousness can be dissociated from cortical connectivity, oscillations, and dynamics. SIGNIFICANCE STATEMENT Numerous theories of consciousness suggest that functional connectivity across the cortex is characteristic of the conscious state and is reduced during anesthesia. However, it is unknown whether the observed changes are state-related (conscious vs unconscious) or drug-related (drug vs no drug). We used a novel rat model in which cholinergic stimulation of PFC produced wakefulness despite continuous exposure to a general anesthetic. We demonstrate that, as expected, general anesthesia reduces connectivity. Surprisingly, the connectivity remains suppressed despite pharmacologically induced wakefulness in the presence of anesthetic, with restoration occurring only after the anesthetic is discontinued. Thus, whether an animal exhibits wakefulness or not can be dissociated from cortical connectivity, prompting a reevaluation of the role of connectivity in level of consciousness.
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Esteves M, Almeida AM, Silva J, Silva Moreira P, Carvalho E, Pêgo JM, Almeida A, Sotiropoulos I, Sousa N, Leite-Almeida H. MORPhA Scale: Behavioral and electroencephalographic validation of a rodent anesthesia scale. J Neurosci Methods 2019; 324:108304. [DOI: 10.1016/j.jneumeth.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 10/26/2022]
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Hofmann JI, Schwarz C, Rudolph U, Antkowiak B. Effects of Diazepam on Low-Frequency and High-Frequency Electrocortical γ-Power Mediated by α1- and α2-GABA A Receptors. Int J Mol Sci 2019; 20:E3486. [PMID: 31315211 DOI: 10.3390/ijms20143486] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 07/06/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
Patterns of spontaneous electric activity in the cerebral cortex change upon administration of benzodiazepines. Here we are testing the hypothesis that the prototypical benzodiazepine, diazepam, affects spectral power density in the low (20-50 Hz) and high (50-90 Hz) γ-band by targeting GABAA receptors harboring α1- and α2-subunits. Local field potentials (LFPs) and action potentials were recorded in the barrel cortex of wild type mice and two mutant strains in which the drug exclusively acted via GABAA receptors containing either α1- (DZα1-mice) or α2-subunits (DZα2-mice). In wild type mice, diazepam enhanced low γ-power. This effect was also evident in DZα2-mice, while diazepam decreased low γ-power in DZα1-mice. Diazepam increased correlated local LFP-activity in wild type animals and DZα2- but not in DZα1-mice. In all genotypes, spectral power density in the high γ-range and multi-unit action potential activity declined upon diazepam administration. We conclude that diazepam modifies low γ-power in opposing ways via α1- and α2-GABAA receptors. The drug's boosting effect involves α2-receptors and an increase in local intra-cortical synchrony. Furthermore, it is important to make a distinction between high- and low γ-power when evaluating the effects of drugs that target GABAA receptors.
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Fekete T, Omer DB, O'hashi K, Grinvald A, van Leeuwen C, Shriki O. Critical dynamics, anesthesia and information integration: Lessons from multi-scale criticality analysis of voltage imaging data. Neuroimage 2018; 183:919-33. [DOI: 10.1016/j.neuroimage.2018.08.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 08/10/2018] [Accepted: 08/11/2018] [Indexed: 10/28/2022] Open
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Darracq M, Funk CM, Polyakov D, Riedner B, Gosseries O, Nieminen JO, Bonhomme V, Brichant JF, Boly M, Laureys S, Tononi G, Sanders RD. Evoked Alpha Power is Reduced in Disconnected Consciousness During Sleep and Anesthesia. Sci Rep 2018; 8:16664. [PMID: 30413741 DOI: 10.1038/s41598-018-34957-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/22/2018] [Indexed: 12/17/2022] Open
Abstract
Sleep and anesthesia entail alterations in conscious experience. Conscious experience may be absent (unconsciousness) or take the form of dreaming, a state in which sensory stimuli are not incorporated into conscious experience (disconnected consciousness). Recent work has identified features of cortical activity that distinguish conscious from unconscious states; however, less is known about how cortical activity differs between disconnected states and normal wakefulness. We employed transcranial magnetic stimulation–electroencephalography (TMS–EEG) over parietal regions across states of anesthesia and sleep to assess whether evoked oscillatory activity differed in disconnected states. We hypothesized that alpha activity, which may regulate perception of sensory stimuli, is altered in the disconnected states of rapid eye movement (REM) sleep and ketamine anesthesia. Compared to wakefulness, evoked alpha power (8–12 Hz) was decreased during disconnected consciousness. In contrast, in unconscious states of propofol anesthesia and non-REM (NREM) sleep, evoked low-gamma power (30–40 Hz) was decreased compared to wakefulness or states of disconnected consciousness. These findings were confirmed in subjects in which dream reports were obtained following serial awakenings from NREM sleep. By examining signatures of evoked cortical activity across conscious states, we identified novel evidence that suppression of evoked alpha activity may represent a promising marker of sensory disconnection.
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Mashour GA, Ben Abdallah A, Pryor KO, El-Gabalawy R, Vlisides PE, Jacobsohn E, Lenze E, Maybrier HR, Veselis RA, Avidan MS. Intraoperative ketamine for prevention of depressive symptoms after major surgery in older adults: an international, multicentre, double-blind, randomised clinical trial. Br J Anaesth 2018; 121:1075-1083. [PMID: 30336852 DOI: 10.1016/j.bja.2018.03.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/14/2018] [Accepted: 03/06/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Ketamine is a general anaesthetic with anti-depressant effects at subanaesthetic doses. We hypothesised that intraoperative administration of ketamine would prevent or mitigate postoperative depressive symptoms in surgical patients. METHODS We conducted an international, randomised clinical trial testing the effects of intraoperative administration of ketamine [0.5 mg kg-1 (Lo-K) or 1.0 mg kg-1 (Hi-K)] vs control [saline placebo (P)] in patients ≥60 yr old undergoing major surgery with general anaesthesia. We administered the Patient Health Questionnaire-8 before the operation, on postoperative day (POD) 3 (primary outcome), and on POD30 to assess depressive symptoms, a secondary outcome of the original trial. RESULTS There was no significant difference on POD3 in the proportion of patients with symptoms suggestive of depression between the placebo [23/156 (14.7%)] and combined ketamine (Lo-K plus Hi-K) [61/349 (17.5%)] groups [difference = -2.7%; 95% confidence interval (CI), 5.0% to -9.4%; P=0.446]. Of the total cohort, 9.6% (64/670; 95% CI, 7.6-12.0%) had symptoms suggestive of depression before operation, which increased to 16.6% (84/505; 95% CI, 13.6-20.1%) on POD3, and decreased to 11.9% (47/395; 95% CI, 9.1-15.5%) on POD30. Of the patients with depressive symptoms on POD3 and POD30, 51% and 49%, respectively, had no prior history of depression or depressive symptoms. CONCLUSIONS Major surgery is associated with new-onset symptoms suggestive of depression in patients ≥60 yr old. Intraoperative administration of subanaesthetic ketamine does not appear to prevent or improve depressive symptoms. CLINICAL TRIALS REGISTRATION NCT01690988.
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Affiliation(s)
- G A Mashour
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - A Ben Abdallah
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
| | - K O Pryor
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - R El-Gabalawy
- Department of Clinical Health Psychology, University of Manitoba, Winnipeg, MB, Canada; Department of Anesthesia and Perioperative Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - P E Vlisides
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - E Jacobsohn
- Department of Anesthesia, University of Manitoba, Winnipeg, MB, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - E Lenze
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, USA
| | - H R Maybrier
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
| | - R A Veselis
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Neuroanesthesiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - M S Avidan
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
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Pal D, Dean JG, Liu T, Li D, Watson CJ, Hudetz AG, Mashour GA. Differential Role of Prefrontal and Parietal Cortices in Controlling Level of Consciousness. Curr Biol 2018; 28:2145-2152.e5. [PMID: 29937348 DOI: 10.1016/j.cub.2018.05.025] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/29/2018] [Accepted: 05/09/2018] [Indexed: 12/23/2022]
Abstract
Consciousness is determined both by level (e.g., being awake versus being anesthetized) and content (i.e., the qualitative aspects of experience). Subcortical areas are known to play a causal role in regulating the level of consciousness [1-9], but the role of the cortex is less well understood. Clinical and correlative data have been used both to support and refute a role for prefrontal and posterior cortices in the level of consciousness [10-22]. The prefrontal cortex has extensive reciprocal connections to wake-promoting centers in the brainstem and diencephalon [23, 24], and hence is in a unique position to modulate level of consciousness. Furthermore, a recent study suggested that the prefrontal cortex might be important in regulating level of consciousness [25] but causal evidence, and a comparison with more posterior cortical sites, is lacking. Therefore, to test the hypothesis that prefrontal cortex plays a role in regulating level of consciousness, we attempted to reverse sevoflurane anesthesia by cholinergic or noradrenergic stimulation of the prefrontal prelimbic cortex and two areas of parietal cortex in rat. General anesthesia was defined by loss of the righting reflex, a widely used surrogate measure in rodents. We demonstrate that cholinergic stimulation of prefrontal cortex, but not parietal cortex, restored wake-like behavior, despite continuous exposure to clinically relevant concentrations of sevoflurane anesthesia. Noradrenergic stimulation of the prefrontal and parietal areas resulted in electroencephalographic activation but failed to produce any signs of wake-like behavior. We conclude that cholinergic mechanisms in prefrontal cortex can regulate the level of consciousness.
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Castro-Zaballa S, Cavelli ML, Gonzalez J, Nardi AE, Machado S, Scorza C, Torterolo P. EEG 40 Hz Coherence Decreases in REM Sleep and Ketamine Model of Psychosis. Front Psychiatry 2018; 9:766. [PMID: 30705645 PMCID: PMC6345101 DOI: 10.3389/fpsyt.2018.00766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 12/21/2018] [Indexed: 01/04/2023] Open
Abstract
Cognitive processes are carried out during wakefulness by means of extensive interactions between cortical and subcortical areas. In psychiatric conditions, such as psychosis, these processes are altered. Interestingly, REM sleep where most dreams occurs, shares electrophysiological, pharmacological, and neurochemical features with psychosis. Because of this fact, REM sleep is considered a natural model of psychosis. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that at sub-anesthetic dose induces psychotomimetic-like effects in humans and animals, and is employed as a pharmacological model of psychosis. Oscillations in the gamma frequency band of the electroencephalogram (EEG), mainly at about 40 Hz, have been involved in cognitive functions. Hence, the present study was conducted to analyze the EEG low gamma (30-45 Hz) band power and coherence of the cat, in natural (REM sleep) and pharmacological (sub-anesthetic doses of ketamine) models of psychosis. These results were compared with the gamma activity during alert (AW) and quiet wakefulness (QW), as well as during non-REM (NREM) sleep. Five cats were chronically prepared for polysomnographic recordings, with electrodes in different cortical areas. Basal recordings were obtained and ketamine (5, 10, and 15 mg/kg, i.m.) was administrated. Gamma activity (power and coherence) was analyzed in the abovementioned conditions. Compared to wakefulness and NREM sleep, following ketamine administration gamma coherence decreased among all cortical regions studied; the same coherence profile was observed during REM sleep. On the contrary, gamma power was relatively high under ketamine, and similar to QW and REM sleep. We conclude that functional interactions between cortical areas in the gamma frequency band decrease in both experimental models of psychosis. This uncoupling of gamma frequency activity may be involved in the cognitive features shared by dreaming and psychosis.
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Affiliation(s)
- Santiago Castro-Zaballa
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Matías Lorenzo Cavelli
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Joaquin Gonzalez
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Antonio Egidio Nardi
- Laboratório de Pânico e Respiração, Instituto de Psiquiatria da Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratório de Neurociência da Atividade Física, Universidade Salgado de Oliveira, Rio de Janeiro, Brazil
| | - Sergio Machado
- Laboratório de Pânico e Respiração, Instituto de Psiquiatria da Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratório de Neurociência da Atividade Física, Universidade Salgado de Oliveira, Rio de Janeiro, Brazil.,The Intercontinental Neuroscience Research Group, Merida, Mexico
| | - Cecilia Scorza
- Departamento de Neurofarmacología Experimental, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Pablo Torterolo
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.,The Intercontinental Neuroscience Research Group, Merida, Mexico
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Kadam SD, D'Ambrosio R, Duveau V, Roucard C, Garcia-Cairasco N, Ikeda A, de Curtis M, Galanopoulou AS, Kelly KM. Methodological standards and interpretation of video-electroencephalography in adult control rodents. A TASK1-WG1 report of the AES/ILAE Translational Task Force of the ILAE. Epilepsia 2017; 58 Suppl 4:10-27. [PMID: 29105073 DOI: 10.1111/epi.13903] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2017] [Indexed: 01/13/2023]
Abstract
In vivo electrophysiological recordings are widely used in neuroscience research, and video-electroencephalography (vEEG) has become a mainstay of preclinical neuroscience research, including studies of epilepsy and cognition. Studies utilizing vEEG typically involve comparison of measurements obtained from different experimental groups, or from the same experimental group at different times, in which one set of measurements serves as "control" and the others as "test" of the variables of interest. Thus, controls provide mainly a reference measurement for the experimental test. Control rodents represent an undiagnosed population, and cannot be assumed to be "normal" in the sense of being "healthy." Certain physiological EEG patterns seen in humans are also seen in control rodents. However, interpretation of rodent vEEG studies relies on documented differences in frequency, morphology, type, location, behavioral state dependence, reactivity, and functional or structural correlates of specific EEG patterns and features between control and test groups. This paper will focus on the vEEG of standard laboratory rodent strains with the aim of developing a small set of practical guidelines that can assist researchers in the design, reporting, and interpretation of future vEEG studies. To this end, we will: (1) discuss advantages and pitfalls of common vEEG techniques in rodents and propose a set of recommended practices and (2) present EEG patterns and associated behaviors recorded from adult rats of a variety of strains. We will describe the defining features of selected vEEG patterns (brain-generated or artifactual) and note similarities to vEEG patterns seen in adult humans. We will note similarities to normal variants or pathological human EEG patterns and defer their interpretation to a future report focusing on rodent seizure patterns.
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Affiliation(s)
- Shilpa D Kadam
- Department of Neurology, Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A
| | - Raimondo D'Ambrosio
- Department of Neurological Surgery and Regional Epilepsy Center, University of Washington, Seattle, Washington, U.S.A
| | | | | | - Norberto Garcia-Cairasco
- Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders, and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Marco de Curtis
- Epileptology and Experimental Neurophysiology Unit, Institutes of Hospitality and Care of a Scientific Nature (IRCCS) Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Aristea S Galanopoulou
- Laboratory of Developmental Epilepsy, Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A
| | - Kevin M Kelly
- Brain Injury and Epilepsy Research Laboratory, Allegheny Health Network Research Institute, Allegheny General Hospital, Pittsburgh, Pennsylvania, U.S.A
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Ion BF, Wells MM, Chen Q, Xu Y, Tang P. Ketamine Inhibition of the Pentameric Ligand-Gated Ion Channel GLIC. Biophys J 2017; 113:605-612. [PMID: 28793215 DOI: 10.1016/j.bpj.2017.06.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/14/2017] [Accepted: 06/22/2017] [Indexed: 12/11/2022] Open
Abstract
Ketamine inhibits pentameric ligand-gated ion channels (pLGICs), including the bacterial pLGIC from Gloeobacter violaceus (GLIC). The crystal structure of GLIC shows R-ketamine bound to an extracellular intersubunit cavity. Here, we performed molecular dynamics simulations of GLIC in the absence and presence of R- or S-ketamine. No stable binding of S-ketamine in the original cavity was observed in the simulations, largely due to its unfavorable access to residue D154, which provides important electrostatic interactions to stabilize R-ketamine binding. Contrary to the symmetric binding shown in the crystal structure, R-ketamine moved away from some of the binding sites and was bound to GLIC asymmetrically at the end of simulations. The asymmetric binding is consistent with the experimentally measured negative cooperativity of ketamine binding to GLIC. In the presence of R-ketamine, all subunits showed changes in structure and dynamics, irrespective of binding stability; the extracellular intersubunit cavity expanded and intersubunit electrostatic interactions involved in channel activation were altered. R-ketamine binding promoted a conformational shift toward closed GLIC. Conformational changes near the ketamine-binding site were propagated to the interface between the extracellular and transmembrane domains, and further to the pore-lining TM2 through two pathways: pre-TM1 and the β1-β2 loop. Both signaling pathways have been predicted previously using the perturbation-based Markovian transmission model. The study provides a structural and dynamics basis for the inhibitory modulation of ketamine on pLGICs.
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Affiliation(s)
- Bogdan F Ion
- Departments of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Marta M Wells
- Departments of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Qiang Chen
- Departments of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Yan Xu
- Departments of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Pei Tang
- Departments of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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Abstract
A quest for a systems-level neuroscientific basis of anesthetic-induced loss and return of consciousness has been in the forefront of research for the past 2 decades. Recent advances toward the discovery of underlying mechanisms have been achieved using experimental electrophysiology, multichannel electroencephalography, magnetoencephalography, and functional magnetic resonance imaging. By the careful dosing of various volatile and IV anesthetic agents to the level of behavioral unresponsiveness, both specific and common changes in functional and effective connectivity across large-scale brain networks have been discovered and interpreted in the context of how the synthesis of neural information might be affected during anesthesia. The results of most investigations to date converge toward the conclusion that a common neural correlate of anesthetic-induced unresponsiveness is a consistent depression or functional disconnection of lateral frontoparietal networks, which are thought to be critical for consciousness of the environment. A reduction in the repertoire of brain states may contribute to the anesthetic disruption of large-scale information integration leading to unconsciousness. In future investigations, a systematic delineation of connectivity changes with multiple anesthetics using the same experimental design, and the same analytical method will be desirable. The critical neural events that account for the transition between responsive and unresponsive states should be assessed at similar anesthetic doses just below and above the loss or return of responsiveness. There will also be a need to identify a robust, sensitive, and reliable measure of information transfer. Ultimately, finding a behavior-independent measure of subjective experience that can track covert cognition in unresponsive subjects and a delineation of causal factors versus correlated events will be essential to understand the neuronal basis of human consciousness and unconsciousness.
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Mashour GA, Hudetz AG. Bottom-Up and Top-Down Mechanisms of General Anesthetics Modulate Different Dimensions of Consciousness. Front Neural Circuits 2017; 11:44. [PMID: 28676745 PMCID: PMC5476707 DOI: 10.3389/fncir.2017.00044] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 06/07/2017] [Indexed: 11/29/2022] Open
Abstract
There has been controversy regarding the precise mechanisms of anesthetic-induced unconsciousness, with two salient approaches that have emerged within systems neuroscience. One prominent approach is the “bottom up” paradigm, which argues that anesthetics suppress consciousness by modulating sleep-wake nuclei and neural circuits in the brainstem and diencephalon that have evolved to control arousal states. Another approach is the “top-down” paradigm, which argues that anesthetics suppress consciousness by modulating the cortical and thalamocortical circuits involved in the integration of neural information. In this article, we synthesize these approaches by mapping bottom-up and top-down mechanisms of general anesthetics to two distinct but inter-related dimensions of consciousness: level and content. We show how this explains certain empirical observations regarding the diversity of anesthetic drug effects. We conclude with a more nuanced discussion of how levels and contents of consciousness interact to generate subjective experience and what this implies for the mechanisms of anesthetic-induced unconsciousness.
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Affiliation(s)
- George A Mashour
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center of Consciousness Science, University of MichiganAnn Arbor, MI, United States.,Neuroscience Graduate Program, University of MichiganAnn Arbor, MI, United States
| | - Anthony G Hudetz
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center of Consciousness Science, University of MichiganAnn Arbor, MI, United States.,Neuroscience Graduate Program, University of MichiganAnn Arbor, MI, United States
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Pal D, Silverstein BH, Sharba L, Li D, Hambrecht-Wiedbusch VS, Hudetz AG, Mashour GA. Propofol, Sevoflurane, and Ketamine Induce a Reversible Increase in Delta-Gamma and Theta-Gamma Phase-Amplitude Coupling in Frontal Cortex of Rat. Front Syst Neurosci 2017; 11:41. [PMID: 28659769 PMCID: PMC5468385 DOI: 10.3389/fnsys.2017.00041] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/12/2017] [Indexed: 01/12/2023] Open
Abstract
Studies from human and non-human species have demonstrated a breakdown of functional corticocortical connectivity during general anesthesia induced by anesthetics with diverse molecular, neurophysiological, and pharmacological profiles. Recent studies have demonstrated that changes in long-range neural communication, and by corollary, functional connectivity, might be influenced by cross-frequency coupling (CFC) between the phase of slow oscillations and the amplitude of local fast oscillations. Phase-amplitude coupling (PAC) between slow oscillations and alpha rhythm during general anesthesia reveal distinct patterns depending on the anesthetic. In this study, we analyzed the effect of three clinically used anesthetics (propofol: n = 6, sevoflurane: n = 10, and ketamine: n = 8) with distinct molecular mechanisms on changes in PAC in the frontal cortex of rat. The loss of righting reflex was used as a surrogate for unconsciousness. PAC was calculated using the modulation index (MI) algorithm between delta (1–4 Hz), theta (4–10 Hz), low gamma (25–55 Hz), and high gamma (65–125 Hz) bands. A linear mixed model with fixed effects was used for statistical comparisons between waking, anesthetized, and post-anesthesia recovery epochs. All three anesthetics increased the coupling between delta and low gamma (p < 0.0001) as well as between theta and low gamma (p < 0.0001) oscillations, which returned to baseline waking levels during the post-anesthetic recovery period. In addition, a reversible reduction in high gamma power (p < 0.0001) was a consistent change during anesthesia induced by all three agents. The changes in delta-high gamma and theta-high gamma PAC as well as power spectral changes in delta, theta, and low gamma bandwidths did not show a uniform response across the three anesthetics. These results encourage the study of alternative PAC patterns as drug-invariant markers of general anesthesia in humans.
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Affiliation(s)
- Dinesh Pal
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States
| | - Brian H Silverstein
- Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States.,Translational Neuroscience Program, Wayne State University School of MedicineDetroit, MI, United States
| | - Lana Sharba
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States
| | - Duan Li
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States
| | - Viviane S Hambrecht-Wiedbusch
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States
| | - Anthony G Hudetz
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States.,Neuroscience Graduate Program, University of MichiganAnn Arbor, MI, United States
| | - George A Mashour
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States.,Center for Consciousness Science, University of MichiganAnn Arbor, MI, United States.,Neuroscience Graduate Program, University of MichiganAnn Arbor, MI, United States
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Pal D, Silverstein BH, Lee H, Mashour GA. Neural Correlates of Wakefulness, Sleep, and General Anesthesia: An Experimental Study in Rat. Anesthesiology 2016; 125:929-42. [PMID: 27617688 DOI: 10.1097/ALN.0000000000001342] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Significant advances have been made in our understanding of subcortical processes related to anesthetic- and sleep-induced unconsciousness, but the associated changes in cortical connectivity and cortical neurochemistry have yet to be fully clarified. METHODS Male Sprague-Dawley rats were instrumented for simultaneous measurement of cortical acetylcholine and electroencephalographic indices of corticocortical connectivity-coherence and symbolic transfer entropy-before, during, and after general anesthesia (propofol, n = 11; sevoflurane, n = 13). In another group of rats (n = 7), these electroencephalographic indices were analyzed during wakefulness, slow wave sleep (SWS), and rapid eye movement (REM) sleep. RESULTS Compared to wakefulness, anesthetic-induced unconsciousness was characterized by a significant decrease in cortical acetylcholine that recovered to preanesthesia levels during recovery wakefulness. Corticocortical coherence and frontal-parietal symbolic transfer entropy in high γ band (85 to 155 Hz) were decreased during anesthetic-induced unconsciousness and returned to preanesthesia levels during recovery wakefulness. Sleep-wake states showed a state-dependent change in coherence and transfer entropy in high γ bandwidth, which correlated with behavioral arousal: high during wakefulness, low during SWS, and lowest during REM sleep. By contrast, frontal-parietal θ connectivity during sleep-wake states was not correlated with behavioral arousal but showed an association with well-established changes in cortical acetylcholine: high during wakefulness and REM sleep and low during SWS. CONCLUSIONS Corticocortical coherence and frontal-parietal connectivity in high γ bandwidth correlates with behavioral arousal and is not mediated by cholinergic mechanisms, while θ connectivity correlates with cortical acetylcholine levels.
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Akeju O, Brown EN. Neural oscillations demonstrate that general anesthesia and sedative states are neurophysiologically distinct from sleep. Curr Opin Neurobiol 2017; 44:178-185. [PMID: 28544930 PMCID: PMC5520989 DOI: 10.1016/j.conb.2017.04.011] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 11/19/2022]
Abstract
General anesthesia is a man-made neurophysiological state comprised of unconsciousness, amnesia, analgesia, and immobility along with maintenance of physiological stability. Growing evidence suggests that anesthetic-induced neural oscillations are a primary mechanism of anesthetic action. Each anesthetic drug class produces distinct oscillatory dynamics that can be related to the circuit mechanisms of drug action. Sleep is a naturally occurring state of decreased arousal that is essential for normal health. Physiological measurements (electrooculogram, electromyogram) and neural oscillatory (electroencephalogram) dynamics are used to empirically characterize sleep into rapid eye movement sleep and the three stages of non-rapid eye movement sleep. In this review, we discuss the differences between anesthesia- and sleep-induced altered states from the perspective of neural oscillations.
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Affiliation(s)
- Oluwaseun Akeju
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
| | - Emery N Brown
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States.
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Safavynia SA, Keating G, Speigel I, Fidler JA, Kreuzer M, Rye DB, Jenkins A, García PS. Effects of γ-Aminobutyric Acid Type A Receptor Modulation by Flumazenil on Emergence from General Anesthesia. Anesthesiology 2016; 125:147-58. [PMID: 27111534 DOI: 10.1097/ALN.0000000000001134] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Transitions into conscious states are partially mediated by inactivation of sleep networks and activation of arousal networks. Pharmacologic hastening of emergence from general anesthesia has largely focused on activating subcortical monoaminergic networks, with little attention on antagonizing the γ-aminobutyric acid type A receptor (GABAAR). As the GABAAR mediates the clinical effects of many common general anesthetics, the authors hypothesized that negative GABAAR modulators would hasten emergence, possibly via cortical networks involved in sleep. METHODS The authors investigated the capacity of the benzodiazepine rescue agent, flumazenil, which had been recently shown to promote wakefulness in hypersomnia patients, to alter emergence. Using an in vivo rodent model and an in vitro GABAAR heterologous expression system, they measured flumazenil's effects on behavioral, neurophysiologic, and electrophysiologic correlates of emergence from isoflurane anesthesia. RESULTS Animals administered intravenous flumazenil (0.4 mg/kg, n = 8) exhibited hastened emergence compared to saline-treated animals (n = 8) at cessation of isoflurane anesthesia. Wake-like electroencephalographic patterns occurred sooner and exhibited more high-frequency electroencephalography power after flumazenil administration (median latency ± median absolute deviation: 290 ± 34 s) compared to saline administration (473 ± 186 s; P = 0.042). Moreover, in flumazenil-treated animals, there was a decreased impact on postanesthesia sleep. In vitro experiments in human embryonic kidney-293T cells demonstrated that flumazenil inhibited isoflurane-mediated GABA current enhancement (n = 34 cells, 88.7 ± 2.42% potentiation at 3 μM). Moreover, flumazenil exhibited weak agonist activity on the GABAAR (n = 10 cells, 10.3 ± 3.96% peak GABA EC20 current at 1 μM). CONCLUSIONS Flumazenil can modulate emergence from isoflurane anesthesia. The authors highlight the complex role GABAARs play in mediating consciousness and provide mechanistic links between emergence from anesthesia and arousal.
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