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1.
Artigo em Russo | MEDLINE | ID: mdl-38881020

RESUMO

BACKGROUND: Treatment of patients with prolonged and permanent disturbance of consciousness is still an extremely difficult problem. Nowadays, management is based on pathophysiological and molecular mechanisms of impaired consciousness. Several electrophysiological and pharmacological methods were proposed to restore consciousness in appropriate patients. OBJECTIVE: We present recovery of clear consciousness under therapy with phenazepam and literature review devoted to therapy of these disorders. RESULTS AND CONCLUSION: This case confirms available data on drug neuromodulation in complex treatment of patients with prolonged impairment of consciousness and substantiates the need for individual multimodal assessment of structural and functional disorders in prolonged and chronic impairment of consciousness for adequate therapy.


Assuntos
Benzodiazepinas , Humanos , Benzodiazepinas/uso terapêutico , Benzodiazepinas/administração & dosagem , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Transtornos da Consciência/fisiopatologia , Transtornos da Consciência/tratamento farmacológico , Transtornos da Consciência/terapia , Masculino
2.
Biomed Pharmacother ; 176: 116937, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38870632

RESUMO

The advent of general anesthesia (GA) has significant implications for clinical practice. However, the exact mechanisms underlying GA-induced transitions in consciousness remain elusive. Given some similarities between GA and sleep, the sleep-arousal neural nuclei and circuits involved in sleep-arousal, including the 5-HTergic system, could be implicated in GA. Herein, we utilized pharmacology, optogenetics, chemogenetics, fiber photometry, and retrograde tracing to demonstrate that both endogenous and exogenous activation of the 5-HTergic neural circuit between the dorsal raphe nucleus (DR) and basolateral amygdala (BLA) promotes arousal and facilitates recovery of consciousness from sevoflurane anesthesia. Notably, the 5-HT1A receptor within this pathway holds a pivotal role. Our findings will be conducive to substantially expanding our comprehension of the neural circuit mechanisms underlying sevoflurane anesthesia and provide a potential target for modulating consciousness, ultimately leading to a reduction in anesthetic dose requirements and side effects.


Assuntos
Anestésicos Inalatórios , Complexo Nuclear Basolateral da Amígdala , Estado de Consciência , Núcleo Dorsal da Rafe , Sevoflurano , Sevoflurano/farmacologia , Animais , Núcleo Dorsal da Rafe/efeitos dos fármacos , Núcleo Dorsal da Rafe/metabolismo , Estado de Consciência/efeitos dos fármacos , Anestésicos Inalatórios/farmacologia , Complexo Nuclear Basolateral da Amígdala/efeitos dos fármacos , Complexo Nuclear Basolateral da Amígdala/metabolismo , Complexo Nuclear Basolateral da Amígdala/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Serotonina/metabolismo , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Receptor 5-HT1A de Serotonina/metabolismo , Optogenética
3.
CNS Neurosci Ther ; 30(6): e14782, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38828651

RESUMO

BACKGROUND: The thalamus system plays critical roles in the regulation of reversible unconsciousness induced by general anesthetics, especially the arousal stage of general anesthesia (GA). But the function of thalamus in GA-induced loss of consciousness (LOC) is little known. The thalamic reticular nucleus (TRN) is the only GABAergic neurons-composed nucleus in the thalamus, which is composed of parvalbumin (PV) and somatostatin (SST)-expressing GABAergic neurons. The anterior sector of TRN (aTRN) is indicated to participate in the induction of anesthesia, but the roles remain unclear. This study aimed to reveal the role of the aTRN in propofol and isoflurane anesthesia. METHODS: We first set up c-Fos straining to monitor the activity variation of aTRNPV and aTRNSST neurons during propofol and isoflurane anesthesia. Subsequently, optogenetic tools were utilized to activate aTRNPV and aTRNSST neurons to elucidate the roles of aTRNPV and aTRNSST neurons in propofol and isoflurane anesthesia. Electroencephalogram (EEG) recordings and behavioral tests were recorded and analyzed. Lastly, chemogenetic activation of the aTRNPV neurons was applied to confirm the function of the aTRN neurons in propofol and isoflurane anesthesia. RESULTS: c-Fos straining showed that both aTRNPV and aTRNSST neurons are activated during the LOC period of propofol and isoflurane anesthesia. Optogenetic activation of aTRNPV and aTRNSST neurons promoted isoflurane induction and delayed the recovery of consciousness (ROC) after propofol and isoflurane anesthesia, meanwhile chemogenetic activation of the aTRNPV neurons displayed the similar effects. Moreover, optogenetic and chemogenetic activation of the aTRN neurons resulted in the accumulated burst suppression ratio (BSR) during propofol and isoflurane GA, although they represented different effects on the power distribution of EEG frequency. CONCLUSION: Our findings reveal that the aTRN GABAergic neurons play a critical role in promoting the induction of propofol- and isoflurane-mediated GA.


Assuntos
Anestesia Geral , Estado de Consciência , Neurônios GABAérgicos , Isoflurano , Propofol , Propofol/farmacologia , Isoflurano/farmacologia , Animais , Neurônios GABAérgicos/efeitos dos fármacos , Neurônios GABAérgicos/fisiologia , Camundongos , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Masculino , Eletroencefalografia , Anestésicos Inalatórios/farmacologia , Núcleos Anteriores do Tálamo/efeitos dos fármacos , Núcleos Anteriores do Tálamo/fisiologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Anestésicos Intravenosos/farmacologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Optogenética
4.
Commun Biol ; 7(1): 716, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38858589

RESUMO

The awake mammalian brain is functionally organized in terms of large-scale distributed networks that are constantly interacting. Loss of consciousness might disrupt this temporal organization leaving patients unresponsive. We hypothesize that characterizing brain activity in terms of transient events may provide a signature of consciousness. For this, we analyze temporal dynamics of spatiotemporally overlapping functional networks obtained from fMRI transient activity across different anesthetics and levels of anesthesia. We first show a striking homology in spatial organization of networks between monkeys and humans, indicating cross-species similarities in resting-state fMRI structure. We then track how network organization shifts under different anesthesia conditions in macaque monkeys. While the spatial aspect of the networks is preserved, their temporal dynamics are highly affected by anesthesia. Networks express for longer durations and co-activate in an anesthetic-specific configuration. Additionally, hierarchical brain organization is disrupted with a consciousness-level-signature role of the default mode network. In conclusion, large-scale brain network temporal dynamics capture differences in anesthetic-specific consciousness-level, paving the way towards a clinical translation of these cortical signature.


Assuntos
Encéfalo , Estado de Consciência , Imageamento por Ressonância Magnética , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Animais , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem , Humanos , Anestesia , Masculino , Macaca mulatta , Adulto , Rede Nervosa/fisiologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Feminino , Mapeamento Encefálico/métodos
5.
Brain Stimul ; 17(3): 687-697, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38821397

RESUMO

BACKGROUND: Dopaminergic neurons in the ventral tegmental area (VTA) are crucially involved in regulating arousal, making them a potential target for reversing general anesthesia. Electrical deep brain stimulation (DBS) of the VTA restores consciousness in animals anesthetized with drugs that primarily enhance GABAA receptors. However, it is unknown if VTA DBS restores consciousness in animals anesthetized with drugs that target other receptors. OBJECTIVE: To evaluate the efficacy of VTA DBS in restoring consciousness after exposure to four anesthetics with distinct receptor targets. METHODS: Sixteen adult Sprague-Dawley rats (8 female, 8 male) with bipolar electrodes implanted in the VTA were exposed to dexmedetomidine, fentanyl, ketamine, or sevoflurane to produce loss of righting, a proxy for unconsciousness. After receiving the dopamine D1 receptor antagonist, SCH-23390, or saline (vehicle), DBS was initiated at 30 µA and increased by 10 µA until reaching a maximum of 100 µA. The current that evoked behavioral arousal and restored righting was recorded for each anesthetic and compared across drug (saline/SCH-23390) condition. Electroencephalogram, heart rate and pulse oximetry were recorded continuously. RESULTS: VTA DBS restored righting after sevoflurane, dexmedetomidine, and fentanyl-induced unconsciousness, but not ketamine-induced unconsciousness. D1 receptor antagonism diminished the efficacy of VTA stimulation following sevoflurane and fentanyl, but not dexmedetomidine. CONCLUSIONS: Electrical DBS of the VTA restores consciousness in animals anesthetized with mechanistically distinct drugs, excluding ketamine. The involvement of the D1 receptor in mediating this effect is anesthetic-specific.


Assuntos
Estimulação Encefálica Profunda , Dexmedetomidina , Fentanila , Ratos Sprague-Dawley , Sevoflurano , Inconsciência , Área Tegmentar Ventral , Animais , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/fisiologia , Sevoflurano/farmacologia , Dexmedetomidina/farmacologia , Masculino , Fentanila/farmacologia , Ratos , Feminino , Inconsciência/induzido quimicamente , Inconsciência/terapia , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Ketamina/farmacologia , Anestésicos Inalatórios/farmacologia
6.
J Pharmacol Toxicol Methods ; 127: 107510, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38705245

RESUMO

Cardiovascular safety pharmacology and toxicology studies include vehicle control animals in most studies. Electrocardiogram data on common vehicles is accumulated relatively quickly. In the interests of the 3Rs principles it may be useful to use this historical information to reduce the use of animals or to refine the sensitivity of studies. We used implanted telemetry data from a large nonhuman primate (NHP) cardiovascular study (n = 48) evaluating the effect of moxifloxacin. We extracted 24 animals to conduct a n = 3/sex/group analysis. The remaining 24 animals were used to generate 1000 unique combinations of 3 male and 3 female NHP to act as control groups for the three treated groups in the n = 3/sex/group analysis. The distribution of treatment effects, median minimum detectable difference (MDD) values were gathered from the 1000 studies. These represent contemporary controls. Data were available from 42 NHP from 3 other studies in the same laboratory using the same technology. These were used to generate 1000 unique combinations of 6, 12, 18, 24 and 36 NHP to act as historical control animals for the 18 animals in the treated groups of the moxifloxacin study. Data from an additional laboratory were also available for 20 NHP. The QT, RR and QT-RR data from the three sources were comparable. However, differences in the time course of QTc effect in the vehicle data from the two laboratories meant that it was not possible to use cross-lab controls. In the case of historical controls from the same laboratory, these could be used in place of the contemporary controls in determining a treatment's effect. There appeared to be an advantage in using larger (≥18) group sizes for historical controls. These data support the opportunity of using historical controls to reduce the number of animals used in new cardiovascular studies.


Assuntos
Eletrocardiografia , Fluoroquinolonas , Moxifloxacina , Telemetria , Animais , Feminino , Eletrocardiografia/métodos , Eletrocardiografia/efeitos dos fármacos , Masculino , Telemetria/métodos , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/fisiopatologia , Grupos Controle , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Estado de Consciência/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos
7.
Eur J Neurosci ; 59(12): 3151-3161, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38752321

RESUMO

Regarding the stage of arousal level required for working memory to function properly, limited studies have been conducted on changes in working memory performance when the arousal level of consciousness decreases. This study aimed to experimentally clarify the stages of consciousness necessary for optimal working memory function. In this experiment, the sedation levels were changed step-by-step using anaesthesia, and the performance accuracy during the execution of working memory was assessed using a dual-task paradigm. Participants were required to categorize and remember words in a specific target category. Categorization performance was measured across four different sedative phases: before anaesthesia (baseline), and deep, moderate and light stages of sedation. Short-delay recognition tasks were performed under these four sedative stages, followed by long-delay recognition tasks after participants recovered from sedation. The results of the short-delay recognition task showed that the performance was lowest at the deep stage. The performance of the moderate stage was lower than the baseline. In the long-delay recognition task, the performance under moderate sedation was lower than that under baseline and light sedation. In addition, the performance under light sedation was lower than that under baseline. These results suggest that task performance becomes difficult under half sedation and that transferring information to long-term memory is difficult even under one-quarter sedation.


Assuntos
Nível de Alerta , Estado de Consciência , Memória de Curto Prazo , Humanos , Memória de Curto Prazo/fisiologia , Memória de Curto Prazo/efeitos dos fármacos , Masculino , Feminino , Estado de Consciência/fisiologia , Estado de Consciência/efeitos dos fármacos , Nível de Alerta/fisiologia , Adulto Jovem , Adulto , Hipnóticos e Sedativos/farmacologia , Hipnóticos e Sedativos/administração & dosagem , Reconhecimento Psicológico/fisiologia
8.
Artigo em Inglês | MEDLINE | ID: mdl-38588855

RESUMO

BACKGROUND: Psilocybin is a widely studied psychedelic substance that leads to the psychedelic state, a specific altered state of consciousness. To date, the relationship between the psychedelic state's neurobiological and experiential patterns remains undercharacterized because they are often analyzed separately. We investigated the relationship between neurobiological and experiential patterns after psilocybin by focusing on the link between dynamic cerebral connectivity and retrospective questionnaire assessment. METHODS: Healthy participants were randomized to receive either psilocybin (n = 22) or placebo (n = 27) and scanned for 6 minutes in an eyes-open resting state during the peak subjective drug effect (102 minutes posttreatment) in ultrahigh field 7T magnetic resonance imaging. The 5-Dimensional Altered States of Consciousness Rating Scale was administered 360 minutes after drug intake. RESULTS: Under psilocybin, there were alterations across all dimensions of the 5-Dimensional Altered States of Consciousness Rating Scale and widespread increases in averaged brain functional connectivity. Time-varying functional connectivity analysis unveiled a recurrent hyperconnected pattern characterized by low blood oxygen level-dependent signal amplitude, suggesting heightened cortical arousal. In terms of neuroexperiential links, canonical correlation analysis showed higher transition probabilities to the hyperconnected pattern with feelings of oceanic boundlessness and secondly with visionary restructuralization. CONCLUSIONS: Psilocybin generates profound alterations at both the brain and the experiential levels. We suggest that the brain's tendency to enter a hyperconnected-hyperarousal pattern under psilocybin represents the potential to entertain variant mental associations. These findings illuminate the intricate interplay between brain dynamics and subjective experience under psilocybin, thereby providing insights into the neurophysiology and neuroexperiential qualities of the psychedelic state.


Assuntos
Conectoma , Alucinógenos , Imageamento por Ressonância Magnética , Psilocibina , Humanos , Psilocibina/farmacologia , Psilocibina/administração & dosagem , Alucinógenos/administração & dosagem , Alucinógenos/farmacologia , Masculino , Adulto , Feminino , Adulto Jovem , Encéfalo/efeitos dos fármacos , Encéfalo/diagnóstico por imagem , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia
9.
Psychopathology ; 57(3): 248-258, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38631303

RESUMO

BACKGROUND: The state of twilight consciousness is marked by a focused narrowing of awareness, maintaining vigilance and attention while simultaneously experiencing perceptual shifts in the surrounding environment. It is crucial to recognize that this twilight state represents not just a contraction but also an expansion of conscious experience. SUMMARY: Substances of abuse, particularly new psychoactive substances, play a significant role in inducing this twilight state. They achieve this by deconstructing essential components of consciousness, such as the perception of time and space. KEY MESSAGE: This paper aimed to explore the phenomenon of the twilight state of consciousness and shed light on how new psychoactive substances can alter the perception of time and space during this twilight phase, potentially triggering exogenous psychosis. This comprehensive inquiry employs a phenomenological approach to the study of consciousness, recognizing it as the primary tool for ascribing significance to this intricate yet often overlooked aspect of psychopathology.


Assuntos
Estado de Consciência , Psicoses Induzidas por Substâncias , Psicotrópicos , Humanos , Estado de Consciência/efeitos dos fármacos , Psicoses Induzidas por Substâncias/etiologia , Psicotrópicos/efeitos adversos , Percepção Espacial , Percepção do Tempo , Conscientização/fisiologia , Transtornos Relacionados ao Uso de Substâncias/psicologia
10.
Neuron ; 112(10): 1553-1567, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38579714

RESUMO

In the 19th century, the discovery of general anesthesia revolutionized medical care. In the 21st century, anesthetics have become indispensable tools to study consciousness. Here, I review key aspects of the relationship between anesthesia and the neurobiology of consciousness, including interfaces of sleep and anesthetic mechanisms, anesthesia and primary sensory processing, the effects of anesthetics on large-scale functional brain networks, and mechanisms of arousal from anesthesia. I discuss the implications of the data derived from the anesthetized state for the science of consciousness and then conclude with outstanding questions, reflections, and future directions.


Assuntos
Encéfalo , Estado de Consciência , Neurobiologia , Humanos , Estado de Consciência/fisiologia , Estado de Consciência/efeitos dos fármacos , Encéfalo/fisiologia , Encéfalo/efeitos dos fármacos , Animais , Anestesia , Sono/fisiologia , Sono/efeitos dos fármacos , Anestésicos/farmacologia , Nível de Alerta/fisiologia , Nível de Alerta/efeitos dos fármacos
11.
Perspect Biol Med ; 67(1): 117-142, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38662068

RESUMO

Psychedelics have again become a subject of widespread interest, owing to the reinvigoration of research into their traditional uses, possible medical applications, and social implications. As evidence for psychedelics' clinical potential mounts, the field has increasingly focused on searching for mechanisms to explain the effects of psychedelics and therapeutic efficacy of psychedelic-assisted therapy (PAT). This paper reviews three general frameworks that encompass several prominent models for understanding psychedelics' effects-specifically, neurobiological, psychological, and spiritual frameworks. Following our review, the implications of each framework for ethics and professional competencies in the implementation of psychedelics as medicines are explored. We suggest that interdisciplinary education may be necessary to improve communication between researchers, develop models that effectively incorporate multiple levels of analysis, and facilitate collaboration between professionals with diverse backgrounds in the implementation of psychedelic medicines. We also address pitfalls associated with overemphasis on neuro-mechanisms, risks associated with instigating vulnerable states of consciousness, and hurdles associated with the integration of spiritual frameworks in medicine. Ultimately, as psychedelics push the boundaries of explanatory frameworks focused on one level of analysis, developing new and more useful models to reflect knowledge being produced in this field should be a central aim of psychedelic science going forward.


Assuntos
Alucinógenos , Alucinógenos/uso terapêutico , Humanos , Espiritualidade , Estado de Consciência/efeitos dos fármacos
12.
Perspect Biol Med ; 67(1): 155-165, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38662070

RESUMO

Psychedelics, including psilocybin, and other consciousness-altering compounds such as 3,4-methylenedioxymethamphetamine (MDMA), currently are being scientifically investigated for their potential therapeutic uses, with a primary focus on measurable outcomes: for example, alleviation of symptoms or increases in self-reported well-being. Accordingly, much recent discussion about the possible value of these substances has turned on estimates of the magnitude and duration of persisting positive effects in comparison to harms. However, many have described the value of a psychedelic experience with little or no reference to such therapeutic benefits, instead seeming to find the experience valuable in its own right. How can we make sense of such testimony? Could a psychedelic experience be valuable even if there were no persisting beneficial effects? If so, how? Using the concept of psychological richness, combined with insights from the philosophy of aesthetics and the enhancement literature, this essay explores potential sources of value in the acute subjective experience, apart from the value derived from persisting beneficial effects.


Assuntos
Alucinógenos , Humanos , Alucinógenos/uso terapêutico , Estado de Consciência/efeitos dos fármacos , Psilocibina/uso terapêutico , N-Metil-3,4-Metilenodioxianfetamina
13.
Trends Neurosci ; 47(5): 355-366, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38490858

RESUMO

The suppression of consciousness by anesthetics and the emergence of the brain from anesthesia are complex and elusive processes. Anesthetics may exert their inhibitory effects by binding to specific protein targets or through membrane-mediated targets, disrupting neural activity and the integrity and function of neural circuits responsible for signal transmission and conscious perception/subjective experience. Emergence from anesthesia was generally thought to depend on the elimination of the anesthetic from the body. Recently, studies have suggested that emergence from anesthesia is a dynamic and active process that can be partially controlled and is independent of the specific molecular targets of anesthetics. This article summarizes the fundamentals of anesthetics' actions in the brain and the mechanisms of emergence from anesthesia that have been recently revealed in animal studies.


Assuntos
Anestésicos , Encéfalo , Humanos , Animais , Encéfalo/fisiologia , Encéfalo/efeitos dos fármacos , Anestésicos/farmacologia , Anestesia/métodos , Estado de Consciência/fisiologia , Estado de Consciência/efeitos dos fármacos , Período de Recuperação da Anestesia
14.
Nature ; 618(7966): 790-798, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37316665

RESUMO

Psychedelics are a broad class of drugs defined by their ability to induce an altered state of consciousness1,2. These drugs have been used for millennia in both spiritual and medicinal contexts, and a number of recent clinical successes have spurred a renewed interest in developing psychedelic therapies3-9. Nevertheless, a unifying mechanism that can account for these shared phenomenological and therapeutic properties remains unknown. Here we demonstrate in mice that the ability to reopen the social reward learning critical period is a shared property across psychedelic drugs. Notably, the time course of critical period reopening is proportional to the duration of acute subjective effects reported in humans. Furthermore, the ability to reinstate social reward learning in adulthood is paralleled by metaplastic restoration of oxytocin-mediated long-term depression in the nucleus accumbens. Finally, identification of differentially expressed genes in the 'open state' versus the 'closed state' provides evidence that reorganization of the extracellular matrix is a common downstream mechanism underlying psychedelic drug-mediated critical period reopening. Together these results have important implications for the implementation of psychedelics in clinical practice, as well as the design of novel compounds for the treatment of neuropsychiatric disease.


Assuntos
Período Crítico Psicológico , Alucinógenos , Aprendizagem , Recompensa , Animais , Humanos , Camundongos , Estado de Consciência/efeitos dos fármacos , Alucinógenos/farmacologia , Alucinógenos/uso terapêutico , Aprendizagem/efeitos dos fármacos , Fatores de Tempo , Ocitocina/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Depressão Sináptica de Longo Prazo/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos
15.
Neuroimage ; 249: 118891, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35007718

RESUMO

Recent neuroimaging studies have demonstrated that spontaneous brain activity exhibits rich spatiotemporal structure that can be characterized as the exploration of a repertoire of spatially distributed patterns that recur over time. The repertoire of brain states may reflect the capacity for consciousness, since general anesthetics suppress and psychedelic drugs enhance such dynamics. However, the modulation of brain activity repertoire across varying states of consciousness has not yet been studied in a systematic and unified framework. As a unique drug that has both psychedelic and anesthetic properties depending on the dose, ketamine offers an opportunity to examine brain reconfiguration dynamics along a continuum of consciousness. Here we investigated the dynamic organization of cortical activity during wakefulness and during altered states of consciousness induced by different doses of ketamine. Through k-means clustering analysis of the envelope data of source-localized electroencephalographic (EEG) signals, we identified a set of recurring states that represent frequency-specific spatial coactivation patterns. We quantified the effect of ketamine on individual brain states in terms of fractional occupancy and transition probabilities and found that ketamine anesthesia tends to shift the configuration toward brain states with low spatial variability. Furthermore, by assessing the temporal dynamics of the occurrence and transitions of brain states, we showed that subanesthetic ketamine is associated with a richer repertoire, while anesthetic ketamine induces dynamic changes in brain state organization, with the repertoire richness evolving from a reduced level to one comparable to that of normal wakefulness before recovery of consciousness. These results provide a novel description of ketamine's modulation of the dynamic configuration of cortical activity and advance understanding of the neurophysiological mechanism of ketamine in terms of the spatial, temporal, and spectral structures of underlying whole-brain dynamics.


Assuntos
Anestésicos Dissociativos/farmacologia , Ondas Encefálicas/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Eletroencefalografia/métodos , Ketamina/farmacologia , Vigília/efeitos dos fármacos , Adulto , Anestesia Geral , Anestésicos Dissociativos/administração & dosagem , Humanos , Ketamina/administração & dosagem
16.
Am J Respir Crit Care Med ; 205(2): 171-182, 2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34748722

RESUMO

Rationale: Predicting recovery of consciousness in unresponsive, brain-injured individuals has crucial implications for clinical decision-making. Propofol induces distinctive brain network reconfiguration in the healthy brain as it loses consciousness. In patients with disorders of consciousness, the brain network's reconfiguration to propofol may reveal the patient's underlying capacity for consciousness. Objectives: To design and test a new metric for the prognostication of consciousness recovery in disorders of consciousness. Methods: Using a within-subject design, we conducted an anesthetic protocol with concomitant high-density EEG in 12 patients with a disorder of consciousness after a brain injury. We quantified the reconfiguration of EEG network hubs and directed functional connectivity before, during, and after propofol exposure and obtained an index of propofol-induced network reconfiguration: the adaptive reconfiguration index. We compared the index of patients who recovered consciousness 3 months after EEG (n = 3) to that of patients who did not recover or remained in a chronic disorder of consciousness (n = 7) and conducted a logistic regression to assess prognostic accuracy. Measurements and Main Results: The adaptive reconfiguration index was significantly higher in patients who later recovered full consciousness (U value = 21, P = 0.008) and able to discriminate with 100% accuracy whether the patient recovered consciousness. Conclusions: The adaptive reconfiguration index of patients who recovered from a disorder of consciousness at 3-month follow-up was linearly separable from that of patients who did not recover or remained in a chronic disorder of consciousness on the single-subject level. EEG and propofol can be administered at the bedside with few contraindications, affording the adaptive reconfiguration index tremendous translational potential as a prognostic measure of consciousness recovery in acute clinical settings.


Assuntos
Lesões Encefálicas/induzido quimicamente , Lesões Encefálicas/fisiopatologia , Coma/induzido quimicamente , Coma/fisiopatologia , Transtornos da Consciência/induzido quimicamente , Transtornos da Consciência/fisiopatologia , Estado de Consciência/efeitos dos fármacos , Propofol/efeitos adversos , Adolescente , Adulto , Idoso , Período de Recuperação da Anestesia , Feminino , Previsões , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Recuperação de Função Fisiológica/efeitos dos fármacos , Adulto Jovem
17.
Behav Brain Res ; 419: 113685, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34838931

RESUMO

Consciousness is supported by rich neuronal dynamics to orchestrate behaviors and conscious processing can be disrupted by general anesthetics. Previous studies suggested that dynamic reconfiguration of large-scale functional network is critical for learning and higher-order cognitive function. During altered states of consciousness, how brain functional networks are dynamically changed and reconfigured at the whole-brain level is still unclear. To fill this gap, using multilayer network approach and functional magnetic resonance imaging (fMRI) data of 21 healthy subjects, we investigated the dynamic network reconfiguration in three different states of consciousness: wakefulness, dexmedetomidine-induced sedation, and recovery. Applying time-varying community detection algorithm, we constructed multilayer modularity networks to track and quantify dynamic interactions among brain areas that span time and space. We compared four high-level network features (i.e., switching, promiscuity, integration, and recruitment) derived from multilayer modularity across the three conditions. We found that sedation state is primarily characterized by increased switching rates as well as decreased integration, representing a whole-brain pattern with higher modular dynamics and more fragmented communication; such alteration can be mostly reversed after the recovery of consciousness. Thus, our work can provide additional insights to understand the modular network reconfiguration across different states of consciousness and may provide some clinical implications for disorders of consciousness.


Assuntos
Encéfalo/fisiologia , Conectoma , Estado de Consciência/fisiologia , Dexmedetomidina/farmacologia , Hipnóticos e Sedativos/farmacologia , Rede Nervosa/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Dexmedetomidina/administração & dosagem , Humanos , Hipnóticos e Sedativos/administração & dosagem , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Adulto Jovem
18.
Neuroimage ; 245: 118659, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34767940

RESUMO

Studying changes in cortical oscillations can help elucidate the mechanistic link between receptor physiology and the clinical effects of anaesthetic drugs. Propofol, a GABA-ergic drug produces divergent effects on visual cortical activity: increasing induced gamma-band responses (GBR) while decreasing evoked responses. Dexmedetomidine, an α2- adrenergic agonist, differs from GABA-ergic sedatives both mechanistically and clinically as it allows easy arousability from deep sedation with less cognitive side-effects. Here we use magnetoencephalography (MEG) to characterize and compare the effects of GABA-ergic (propofol) and non-GABA-ergic (dexmedetomidine) sedation, on visual and motor cortical oscillations. Sixteen male participants received target-controlled infusions of propofol and dexmedetomidine, producing mild-sedation, in a placebo-controlled, cross-over study. MEG data was collected during a combined visuomotor task. The key findings were that propofol significantly enhanced visual stimulus induced GBR (44% increase in amplitude) while dexmedetomidine decreased it (40%). Propofol also decreased the amplitudes of the Mv100 (visual M100) (27%) and Mv150 (52%) visual evoked fields (VEF), whilst dexmedetomidine had no effect on these. During the motor task, neither drug had any significant effect on movement related gamma synchrony (MRGS), movement related beta de-synchronisation (MRBD) or Mm100 (movement-related M100) movement-related evoked fields (MEF), although dexmedetomidine slowed the Mm300. Dexmedetomidine increased (92%) post-movement beta synchronisation/rebound (PMBR) power while propofol reduced it (70%, statistically non- significant). Overall, dexmedetomidine and propofol, at equi-sedative doses, produce contrasting effects on visual induced GBR, VEF, PMBR and MEF. These findings provide a mechanistic link between the known receptor physiology of these sedative drugs with their known clinical effects and may be used to explore mechanisms of other anaesthetic drugs on human consciousness.


Assuntos
Ondas Encefálicas/efeitos dos fármacos , Dexmedetomidina/farmacologia , Hipnóticos e Sedativos/farmacologia , Magnetoencefalografia/métodos , Córtex Motor/efeitos dos fármacos , Propofol/farmacologia , Adulto , Sedação Consciente , Estado de Consciência/efeitos dos fármacos , Estudos Cross-Over , Humanos , Masculino , Movimento/fisiologia , Vigília , Adulto Jovem
19.
PLoS One ; 16(9): e0256198, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495973

RESUMO

There is lack of research on effects of red wine on consciousness when drank in wine bars designed to enhance the pleasurableness of the wine drinking experience. Effects of a moderate dose of red wine (≈ 40.98 g of ethanol) on consciousness were examined in a naturalistic study taking place in a wine bar located in one of the most touristic areas of Lisbon, Portugal. One hundred two participants drank in one of three conditions: alone, in dyad, or in groups up to six people. Red wine increased pleasure and arousal, decreased the awareness of time, slowed the subjective passage of time, increased the attentional focus on the present moment, decreased body awareness, slowed thought speed, turned imagination more vivid, and made the environment become more fascinating. Red wine increased insightfulness and originality of thoughts, increased sensations of oneness with the environment, spiritual feelings, all-encompassing love, and profound peace. All changes in consciousness occurred regardless of volunteers drinking alone, in dyad or in group. Men and women did not report different changes in consciousness. Older age correlated with greater increases in pleasure. Younger age correlated with greater increases in fascination with the environment of the wine bar. Drinking wine in a contemporaneous Western environment designed to enhance the pleasurableness of the wine drinking experience may trigger changes in consciousness commonly associated with mystical-type states.


Assuntos
Bebidas Alcoólicas , Nível de Alerta/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Etanol/farmacologia , Vinho , Adulto , Depressores do Sistema Nervoso Central/farmacologia , Feminino , Humanos , Masculino , Satisfação Pessoal , Portugal , Inquéritos e Questionários
20.
J Neurophysiol ; 126(4): 1265-1275, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34469699

RESUMO

The electroencephalogram (EEG) provides an objective, neural correlate of consciousness. Opioid receptors modulate mammalian neuronal excitability, and this fact was used to characterize how opioids administered to mice alter EEG power and states of consciousness. The present study tested the hypothesis that antinociceptive doses of fentanyl, morphine, or buprenorphine differentially alter the EEG and states of sleep and wakefulness in adult, male C57BL/6J mice. Mice were anesthetized and implanted with telemeters that enabled wireless recordings of cortical EEG and electromyogram (EMG). After surgical recovery, EEG and EMG were used to objectively score states of consciousness as wakefulness, rapid eye movement (REM) sleep, or non-REM (NREM) sleep. Measures of EEG power (dB) were quantified as δ (0.5-4 Hz), θ (4-8 Hz), α (8-13 Hz), σ (12-15 Hz), ß (13-30 Hz), and γ (30-60 Hz). Compared with saline (control), fentanyl and morphine decreased NREM sleep, morphine eliminated REM sleep, and buprenorphine eliminated NREM sleep and REM sleep. Opioids significantly and differentially disrupted the temporal organization of sleep/wake states, altered specific EEG frequency bands, and caused dissociated states of consciousness. The results are discussed relative to the fact that opioids, pain, and sleep modulate interacting states of consciousness.NEW & NOTEWORTHY This study discovered that antinociceptive doses of fentanyl, morphine, and buprenorphine significantly and differentially disrupt EEG-defined states of consciousness in C57BL/6J mice. These data are noteworthy because: 1) buprenorphine is commonly used in medication-assisted therapy for opioid addiction, and 2) there is evidence that disordered sleep can promote addiction relapse. The results contribute to community phenotyping efforts by making publicly available all descriptive and inferential statistics from this study (Supplemental Tables S1-S8).


Assuntos
Analgésicos Opioides/farmacologia , Analgésicos/farmacologia , Ondas Encefálicas/efeitos dos fármacos , Buprenorfina/farmacologia , Estado de Consciência/efeitos dos fármacos , Transtornos Dissociativos/induzido quimicamente , Eletrocorticografia/efeitos dos fármacos , Fentanila/farmacologia , Morfina/farmacologia , Fases do Sono/efeitos dos fármacos , Vigília/efeitos dos fármacos , Analgésicos/administração & dosagem , Analgésicos Opioides/administração & dosagem , Animais , Buprenorfina/administração & dosagem , Modelos Animais de Doenças , Eletroencefalografia , Eletromiografia , Fentanila/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Morfina/administração & dosagem
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