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 , OptogenéticaRESUMO
Objective.Deep brain stimulation (DBS) is a potential treatment that promotes the recovery of patients with disorders of consciousness (DOC). This study quantified the changes in consciousness and the neuromodulation effect of DBS on patients with DOC.Approach.Eleven patients were recruited for this study which consists of three conditions: 'Pre' (two days before DBS surgery), 'Post-On' (one month after surgery with stimulation), and 'Post-Off' (one month after surgery without stimulation). Functional near-infrared spectroscopy (fNIRS) was recorded from the frontal lobe, parietal lobe, and occipital lobe of patients during the experiment of auditory stimuli paradigm, in parallel with the coma recovery scale-revised (CRS-R) assessment. The brain hemodynamic states were defined and state transition acceleration was taken to quantify the information transmission strength of the brain network. Linear regression analysis was conducted between the changes in regional and global indicators and the changes in the CRS-R index.Main results.Significant correlation was observed between the changes in the global transition acceleration indicator and the changes in the CRS-R index (slope = 55.910,p< 0.001,R2= 0.732). For the regional indicators, similar correlations were found between the changes in the frontal lobe and parietal lobe indicators and the changes in the CRS-R index (slope = 46.612,p< 0.01,R2= 0.694; slope = 47.491,p< 0.01,R2= 0.676).Significance.Our study suggests that fNIRS-based brain hemodynamics transition analysis can signify the neuromodulation effect of DBS treatment on patients with DOC, and the transition acceleration indicator is a promising brain functional marker for DOC.
Assuntos
Encéfalo , Transtornos da Consciência , Humanos , Transtornos da Consciência/terapia , Encéfalo/diagnóstico por imagem , Estado de Consciência/fisiologia , Análise Espectral , Resultado do TratamentoRESUMO
BACKGROUND: Recent studies have demonstrated that changes in brain information processing during anesthetic-induced loss of consciousness (LOC) might be influenced by phase-amplitude coupling (PAC) in electroencephalogram (EEG). However, most anesthesia research on PAC typically focuses on delta and alpha oscillations. Studies of spatial-frequency characteristics by PAC for EEG may yield additional insights into understanding the impaired information processing under anesthesia unconsciousness and provide potential improvements in anesthesia monitoring. OBJECTIVE: Considering different frequency bands of EEG represent neural activities on different spatial scales, we hypothesized that functional coupling simultaneously appears in multiple frequency bands and specific brain regions during anesthesia unconsciousness. In this paper, PAC analysis on whole-brain EEG besides delta and alpha oscillations was investigated to understand the influence of multiple cross-frequency coordination coupling on information processing during the loss and recovery of consciousness. METHOD: EEG data from fifteen patients without cognitive diseases (7 males/8 females, aged 43.8 ± 13.4 years, weighing 63.3 ± 14.9 kilograms) undergoing lower limb surgery and sevoflurane anesthesia was recorded. To investigate the spatial-frequency characteristics of EEG source signals during loss and recovery of consciousness, the time-resolved PAC (tPAC) was calculated to reflect cross-frequency coordination in different frequency bands (delta, theta, alpha, beta, gamma) and different functional regions (Visual, Limbic, Dorsal attention, Ventral attention, Default, Somatomotor, Control, Salience networks). Furthermore, different patterns (peak-max and trough-max) of PAC were examined by constructing phase-amplitude histograms using phase bins to investigate the different information processing during LOC. The multivariate analysis of variance (MANOVA) and trend analysis were used for statistical analysis. RESULTS: Theta-alpha and alpha-beta PAC were observed during sevoflurane-induced LOC, which significantly changed during loss and recovery of consciousness (F4,70 = 16.553, p < 0.001 for theta-alpha PAC and F4,70 = 12.446, p < 0.001 for alpha-beta PAC, MANOVA test). Simultaneously, PAC was distributed in specific functional regions, i.e., Visual, Limbic, Default, Somatomotor, etc. Furthermore, peak-max patterns of theta-alpha PAC were observed while alpha-beta PAC showed trough-max patterns and vice versa. CONCLUSION: Theta-alpha and alpha-beta PAC observed in specific brain regions represent information processing on multiple spatial scales, and the opposite patterns of PAC indicate opposite information processing on multiple spatial scales during LOC. Our study demonstrates the regulation of local-global information processing during sevoflurane-induced LOC. It suggests the utility of evaluating the balance of functional integration and segregation in monitoring anesthetized states.
Assuntos
Estado de Consciência , Inconsciência , Encéfalo/fisiologia , Estado de Consciência/fisiologia , Eletroencefalografia , Feminino , Humanos , Masculino , Sevoflurano/efeitos adversos , Inconsciência/induzido quimicamenteRESUMO
INTRODUCTION: Doxorubicin (DOX), an anticancer drug used in chemotherapy, causes significant cardiotoxicity. This study aimed to investigate the effects of DOX on mouse cardiac electrophysiology, in conscious versus anesthetized state. METHODS: Male and female C57BL/6 mice were injected with saline, 20 or 30 mg/kg DOX. ECGs were recorded 5 days post-injection in conscious and isoflurane anesthetized states. ECGs were analyzed using a custom MATLAB software to determine P, PR, QRS, QTc, and RR intervals as well as heart rate variability (HRV). RESULTS: ECGs from the same mouse demonstrated P wave and QTc shortening as well as PR and RR interval prolongation in anesthetized versus conscious saline-treated mice. ECG response to DOX was also modulated by anesthesia. DOX treatment induced significant ECG modulation in female mice alone. While DOX20 treatment caused decrease in P and QRS durations, DOX30 treatment-induced QTc and RR interval prolongation in anesthetized but not in conscious female mice. These data suggest significant sex differences and anesthesia-induced differences in ECG response to DOX. HRV measured in time and frequency domains, a metric of arrhythmia susceptibility, was increased in DOX20-treated mice compared to saline. CONCLUSIONS: This study for the first time identifies that the ECG response to DOX is modulated by anesthesia. Furthermore, this response demonstrated stark sex differences. These findings could have significant implications in clinical diagnosis of DOX cardiotoxicity.
Assuntos
Anestesia/métodos , Antibióticos Antineoplásicos/toxicidade , Cardiotoxicidade/patologia , Estado de Consciência/fisiologia , Doxorrubicina/toxicidade , Eletrocardiografia/métodos , Animais , Cardiotoxicidade/etiologia , Feminino , Frequência Cardíaca , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fatores SexuaisRESUMO
Blood pressure (BP) and heart rate (HR) are both controlled by the autonomic nervous system (ANS) and are closely intertwined due to reflex mechanisms. The baroreflex is a key homeostatic mechanism to counteract acute, short-term changes in arterial BP and to maintain BP in a relatively narrow physiological range. BP is sensed by baroreceptors located in the aortic arch and carotid sinus. When BP changes, signals are transmitted to the central nervous system and are then communicated to the parasympathetic and sympathetic branches of the autonomic nervous system to adjust HR. A rise in BP causes a reflex decrease in HR, a drop in BP causes a reflex increase in HR. Baroreflex sensitivity (BRS) is the quantitative relationship between changes in arterial BP and corresponding changes in HR. Cardiovascular diseases are often associated with impaired baroreflex function. In various studies reduced BRS has been reported in e.g., heart failure, myocardial infarction, or coronary artery disease. Determination of BRS requires information from both BP and HR, which can be recorded simultaneously using telemetric devices. The surgical procedure is described beginning with the insertion of the pressure sensor into the left carotid artery and positioning of its tip in the aortic arch to monitor arterial pressure followed by the subcutaneous placement of the transmitter and ECG electrodes. We also describe postoperative intensive care and analgesic management. After a two-week period of post-surgery recovery long-term ECG and BP recordings are performed in conscious and unrestrained mice. Finally, we include examples of high-quality recordings and the analysis of spontaneous baroreceptor sensitivity using the sequence method.
Assuntos
Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Estado de Consciência/fisiologia , Eletrocardiografia , Telemetria , Animais , Artérias Carótidas/fisiologia , Ritmo Circadiano/fisiologia , Eletrodos Implantados , Frequência Cardíaca/fisiologia , Humanos , Masculino , Camundongos Endogâmicos C57BL , Processamento de Sinais Assistido por Computador , SoftwareRESUMO
OBJECTIVES: Falls can have catastrophic consequences, especially for older adults. This study examined whether personality traits predict the incidence of falls in older age. METHOD: Participants were older adults aged from 65 to 99 years (N = 4,759) drawn from the Health and Retirement Study. Personality traits and demographic factors were assessed at baseline. Falls were tracked for up to 11 years. RESULTS: Over the follow-up period, 2,811 individuals reported falls. Cox regression analyses that included demographic covariates indicated that lower conscientiousness and higher neuroticism increased the risk of falling. Disease burden, depressive symptoms, and physical inactivity mediated the associations between both traits and falls incidence, whereas smoking status and handgrip strength mediated the neuroticism-falls incidence association. DISCUSSION: This study provides new prospective evidence that personality predicts the incidence of falls in older adults and suggest that personality assessment may help identifying individuals at higher risk of falling.
Assuntos
Acidentes por Quedas , Estado de Consciência/fisiologia , Depressão , Força da Mão , Neuroticismo/fisiologia , Determinação da Personalidade/estatística & dados numéricos , Personalidade , Acidentes por Quedas/prevenção & controle , Acidentes por Quedas/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Correlação de Dados , Depressão/diagnóstico , Depressão/fisiopatologia , Feminino , Humanos , Incidência , Masculino , Medição de Risco/métodos , Medição de Risco/estatística & dados numéricos , Fatores de Risco , Comportamento Sedentário , Fumar/epidemiologia , Fumar/psicologia , Estados Unidos/epidemiologiaRESUMO
Recent demonstrations of human brain organoid transplantation in rodents have accentuated ethical concerns associated with these entities, especially as they relate to potential "humanization" of host animals. Consideration of established scientific principles can help define the realistic range of expected outcomes in such transplantation studies. This practical approach suggests that augmentation of discrete brain functions in transplant hosts is a more relevant ethical question in the near term than the possibility of "conscious" chimeric animals. We hope that this framework contributes to a balanced approach for proceeding with studies involving brain organoid transplantation and other forms of human-animal brain chimeras.
Assuntos
Transplante de Tecido Encefálico/ética , Encéfalo/fisiologia , Quimera/fisiologia , Estado de Consciência/fisiologia , Organoides/transplante , Animais , Modelos Animais de Doenças , Ética em Pesquisa , Humanos , Camundongos , Organoides/fisiologia , Guias de Prática Clínica como Assunto , Ratos , Transplante HeterólogoRESUMO
BACKGROUND: Functional brain connectivity studies can provide important information about changes in brain-state dynamics during general anesthesia. In adults, γ-aminobutyric acid-mediated agents disrupt integration of information from local to the whole-brain scale. Beginning around 3 to 4 months postnatal age, γ-aminobutyric acid-mediated anesthetics such as sevoflurane generate α-electroencephalography oscillations. In previous studies of sevoflurane-anesthetized infants 0 to 3.9 months of age, α-oscillations were absent, and power spectra did not distinguish between anesthetized and emergence from anesthesia conditions. Few studies detailing functional connectivity during general anesthesia in infants exist. This study's aim was to identify changes in functional connectivity of the infant brain during anesthesia. METHODS: A retrospective cohort study was performed using multichannel electroencephalograph recordings of 20 infants aged 0 to 3.9 months old who underwent sevoflurane anesthesia for elective surgery. Whole-brain functional connectivity was evaluated during maintenance of a surgical state of anesthesia and during emergence from anesthesia. Functional connectivity was represented as networks, and network efficiency indices (including complexity and modularity) were computed at the sensor and source levels. RESULTS: Sevoflurane decreased functional connectivity at the δ-frequency (1 to 4 Hz) in infants 0 to 3.9 months old when comparing anesthesia with emergence. At the sensor level, complexity decreased during anesthesia, showing less whole-brain integration with prominent alterations in the connectivity of frontal and parietal sensors (median difference, 0.0293; 95% CI, -0.0016 to 0.0397). At the source level, similar results were observed (median difference, 0.0201; 95% CI, -0.0025 to 0.0482) with prominent alterations in the connectivity between default-mode and frontoparietal regions. Anesthesia resulted in fragmented modules as modularity increased at the sensor (median difference, 0.0562; 95% CI, 0.0048 to 0.1298) and source (median difference, 0.0548; 95% CI, -0.0040 to 0.1074) levels. CONCLUSIONS: Sevoflurane is associated with decreased capacity for efficient information transfer in the infant brain. Such findings strengthen the hypothesis that conscious processing relies on an efficient system of integrated information transfer across the whole brain.
Assuntos
Anestésicos Inalatórios/administração & dosagem , Encéfalo/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Ritmo Delta/efeitos dos fármacos , Rede Nervosa/efeitos dos fármacos , Sevoflurano/administração & dosagem , Encéfalo/fisiologia , Estudos de Coortes , Estado de Consciência/fisiologia , Ritmo Delta/fisiologia , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/métodos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Rede Nervosa/fisiologia , Estudos Retrospectivos , Inconsciência/induzido quimicamente , Inconsciência/fisiopatologiaRESUMO
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.
Assuntos
Anestesia Geral , Anestésicos Gerais/efeitos adversos , Anestésicos Gerais/farmacologia , Encéfalo/efeitos dos fármacos , Neurônios/fisiologia , Vigília/efeitos dos fármacos , Acetilcolina/metabolismo , Adenosina/metabolismo , Período de Recuperação da Anestesia , Animais , Nível de Alerta/efeitos dos fármacos , Encéfalo/fisiologia , Estado de Consciência/fisiologia , Dopamina/metabolismo , Humanos , Neurotransmissores/metabolismo , Norepinefrina/metabolismo , Orexinas/metabolismo , Sono/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismoRESUMO
We are conscious and verbally report some of the information reaching our senses, although a big amount of information is processed unconsciously. There is no agreement about the neural correlates of consciousness, with low-level theories proposing that neural processing on primary sensory brain regions is the most important neural correlate of consciousness, while high-level theories propose that activity within the fronto-parietal network is the key component of conscious processing (Block, 2009). Contrary to the proposal of high-level theories, patients with prefrontal lobe damage do not present clinical symptoms associated to consciousness deficits. In the present study, we explored the conscious perception of near-threshold stimuli in a group of patients with right prefrontal damage and a group of matched healthy controls. Results demonstrated that perceptual contrast to perceive the near-threshold targets was related to damage to the right dorsolateral prefrontal cortex, and with reduced integrity of the ventral branch of the right superior longitudinal fascicule (SLF III). These results suggest a causal role of the prefrontal lobe in conscious processing.
Assuntos
Lesões Encefálicas Traumáticas/fisiopatologia , Estado de Consciência/fisiologia , Córtex Pré-Frontal/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Percepção Visual/fisiologia , Adulto , Idoso , Atenção , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Neoplasias Meníngeas/cirurgia , Meningioma/cirurgia , Pessoa de Meia-Idade , Vias Neurais , Testes Neuropsicológicos , Procedimentos Neurocirúrgicos , Percepção , Córtex Pré-Frontal/lesões , Limiar SensorialRESUMO
Wakefulness and sleep arise from global changes in brain physiology that may also govern the flow of neural activity between cortical regions responsible for perceptual processing versus planning and action. To test whether and how the sleep/wake cycle affects the overall propagation of neural activity in large-scale brain networks, we applied single-pulse electrical stimulation (SPES) in patients implanted with intracranial EEG electrodes for epilepsy surgery. SPES elicited cortico-cortical spectral responses at high-gamma frequencies (CCSRHG, 80-150 Hz), which indexes changes in neuronal population firing rates. Using event-related causality (ERC) analysis, we found that the overall patterns of neural propagation among sites with CCSRHG were different during wakefulness and different sleep stages. For example, stimulation of frontal lobe elicited greater propagation toward parietal lobe during slow-wave sleep than during wakefulness. During REM sleep, we observed a decrease in propagation within frontal lobe, and an increase in propagation within parietal lobe, elicited by frontal and parietal stimulation, respectively. These biases in the directionality of large-scale cortical network dynamics during REM sleep could potentially account for some of the unique experiential aspects of this sleep stage. Together these findings suggest that the regulation of conscious awareness and sleep is associated with differences in the balance of neural propagation across large-scale frontal-parietal networks.
Assuntos
Estado de Consciência/fisiologia , Estimulação Elétrica/métodos , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Sono REM/fisiologia , Sono de Ondas Lentas/fisiologia , Adulto , Eletrocorticografia/métodos , Eletroencefalografia/métodos , Epilepsia , Frequência Cardíaca , Humanos , Masculino , Neurônios , Vigília/fisiologiaRESUMO
The aim of this study is to describe the imaging features, the relevant anatomy, and the fractional anisotropy (FA) values in diffusion tensor tractography (DTT) of the ascending reticular activating system (ARAS) fiber tracts in 2 patients who recovered from initial altered consciousness after presenting with a brainstem cavernous malformation (BSCM) hemorrhage. A DTT was performed in 2 patients with impaired consciousness after a brainstem cavernous malformation hemorrhage. A 1.5â¯T scanner was used to obtain the axial tensors. Post-processing was performed and the mean FA values were recorded. The FA maps were used to seed the following regions of interest: the ventromedial midbrain, the anterior thalamus bilaterally, and the hypothalamus bilaterally. The first case presented with posterior displacement of the dorsal raphè fiber tracts, with preservation of all the ascending reticular activating fiber tracts and spontaneous recovery of consciousness after 20â¯days. The second case presented with no destruction but also had posterior displacement of the inferior dorsal raphè fiber tracts, with recovery of consciousness 1â¯month after resection surgery. Described in this study are affected fibers of the ARAS, as well as the FA value abnormalities in 2 patients, with recovery of a transient disorder of consciousness after a BSCM hemorrhage.
Assuntos
Tronco Encefálico/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Estado de Consciência/fisiologia , Imagem de Tensor de Difusão/métodos , Recuperação de Função Fisiológica/fisiologia , Formação Reticular/diagnóstico por imagem , Adulto , Tronco Encefálico/anormalidades , Tronco Encefálico/fisiopatologia , Hemorragia Cerebral/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeAssuntos
Monitores de Consciência , Monitorização Intraoperatória/métodos , Procedimentos Ortopédicos/efeitos adversos , Porencefalia/complicações , Adolescente , Anestesia Geral/efeitos adversos , Anestesia Geral/métodos , Estado de Consciência/fisiologia , Eletroencefalografia , Feminino , Humanos , Extremidade Inferior/cirurgia , Monitorização Intraoperatória/instrumentação , Paresia/complicações , Porencefalia/fisiopatologiaRESUMO
Objective: The mind-brain problem (MBP) has marked implications for psychiatry, but has been poorly discussed in the psychiatric literature. This paper evaluates the presentation of the MBP in the three leading general psychiatry journals during the last 20 years. Methods: Systematic review of articles on the MBP published in the three general psychiatry journals with the highest impact factor from 1995 to 2015. The content of these articles was analyzed and discussed in the light of contemporary debates on the MBP. Results: Twenty-three papers, usually written by prestigious authors, explicitly discussed the MBP and received many citations (mean = 130). The two main categories were critiques of dualism and defenses of physicalism (mind as a brain product). These papers revealed several misrepresentations of theoretical positions and lacked relevant contemporary literature. Without further discussion or evidence, they presented the MBP as solved, dualism as an old-fashioned or superstitious idea, and physicalism as the only rational and empirically confirmed option. Conclusion: The MBP has not been properly presented and discussed in the three leading psychiatric journals in the last 20 years. The few articles on the topic have been highly cited, but reveal misrepresentations and lack of careful philosophical discussion, as well as a strong bias against dualism and toward a materialist/physicalist approach to psychiatry.
Assuntos
Humanos , Psiquiatria/estatística & dados numéricos , Psicofisiologia , Publicações/estatística & dados numéricos , Encéfalo/fisiologia , Neurociências , Estado de Consciência/fisiologia , Fator de Impacto de RevistasRESUMO
Desde la etapa neonatal, la detección temprana de marcadores conductuales de alteraciones sutiles en el neurodesarrollo, es un campo todavía en crecimiento. El objetivo de esta revisión es describir los mecanismos que subyacen a la conducta del neonato durante la aplicación de la subescala de habituación que forma parte de la Neonatal Behavioral Assessment Scale (NBAS), con especial énfasis en la vía visual. Se destacan el papel de la habituación y la regulación de los estados de conciencia como los mecanismos fundamentales durante el primer estímulo y del segundo al décimo estímulo, en dicha escala. Estos procesos representan una capacidad fundamental para la adaptación del recién nacido y se discuten sus posibles implicaciones en el desempeño cognitivo posterior.
Since the neonatal stage, early detection of behavioral markers of subtle impairments in neurodevelopment is a field still under growth. The objective of this review is to describe the mechanisms underlying neonatal behavior during the habituation scale of NBAS, that emphasizes the visual pathway. The role of habituation and the regulation of behavioral states are highlighted during the first stimuli and the second to ten stimuli, during performance of NBAS. Those processes represent a fundamental capacity for newborns´ adaptation and are discussed in line to later cognitive performance.
Assuntos
Humanos , Animais , Recém-Nascido , Desenvolvimento Infantil/fisiologia , Estado de Consciência/fisiologia , Técnicas de Observação do Comportamento , Habituação PsicofisiológicaAssuntos
Anestesia Geral/métodos , Anestésicos Gerais/uso terapêutico , Dor/prevenção & controle , Anestesia Geral/história , Anestésicos Gerais/química , Anestésicos Gerais/história , Estado de Consciência/fisiologia , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Optogenética/instrumentação , Optogenética/métodos , Dor/história , Procedimentos Cirúrgicos OperatóriosRESUMO
AIM: To identify effective treatments and risk factors associated with death rattle in adults at the end of life. BACKGROUND: The presence of noisy, pooled respiratory tract secretions is among the most common symptoms in dying patients around the world. It is unknown if "death rattle" distresses patients, but it can distress relatives and clinicians. Treatments appear unsatisfactory, so prophylaxis would be ideal if possible. DESIGN: Quantitative systematic review and narrative summary following Cochrane Collaboration guidelines. DATA SOURCES: CINAHL, MEDLINE, Health Source Nursing and Web of Science were searched for international literature in any language published from 1993 - 2016 using MeSH headings and iterative interchangeable terms for "death rattle". REVIEW METHODS: Randomized controlled trials were appraised using the Cochrane Collaboration's tool for assessing risk of bias. Non-randomized studies were assessed using ROBINS-I tool for assessing risk of bias in non-randomized studies of interventions. Instances of treatment and risk were extracted and relevant key findings extracted in line with Cochrane methods. RESULTS: Five randomized trials and 23 non-randomized studies were analysed. No pharmacological or non-pharmacological treatment was found superior to placebo. There was a weak association between lung or brain metastases and presence of death rattle, but otherwise inconsistent empirical support for a range of potential risk factors. CONCLUSIONS: Clinicians have no clear evidence to follow in either treating death rattle or preventing it occurring. However, several risk factors look promising candidates for prospective analysis, so this review concludes with clear recommendations for further research.
Assuntos
Sons Respiratórios/fisiologia , Doente Terminal , Adulto , Fatores Etários , Antagonistas Colinérgicos/metabolismo , Antagonistas Colinérgicos/uso terapêutico , Estado de Consciência/fisiologia , Tosse/fisiopatologia , Transtornos de Deglutição/diagnóstico , Feminino , Humanos , Tempo de Internação , Masculino , Posicionamento do Paciente/métodos , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Sistema Respiratório/metabolismo , Medicamentos para o Sistema Respiratório/uso terapêutico , Infecções Respiratórias/fisiopatologia , Fatores de Risco , Fatores Sexuais , Assistência Terminal/métodos , Equilíbrio Hidroeletrolítico/fisiologiaRESUMO
Increasing evidence implicates brain ghrelin in a wide variety of physiological functions. Among its gastrointestinal functions, ghrelin is known to act centrally to regulate gastrointestinal motility. Visceral sensation is one of the key gastrointestinal functions controlled by the central nervous system. Little is, however, known about the role of central ghrelin in visceral sensation. The present study thus aimed to clarify whether brain ghrelin is involved in visceral sensation. Visceral sensation was evaluated by the colonic distension-induced abdominal withdrawal reflex (AWR) in conscious rats. Intracisternally administered ghrelin increased the threshold volume of colonic distension-induced AWR in a dose-dependent manner. By contrast, neither intraperitoneal injection of ghrelin nor intracisternal des-acyl-ghrelin altered the threshold volume. Pretreatment with subcutaneous injection of either naloxone hydrochloride or sulpiride, a dopamine D2 receptor antagonist, significantly blocked ghrelin-induced visceral antinociception; furthermore, neither subcutaneous injection of naloxone methiodide, a peripheral selective opioid antagonist, SCH23390, a dopamine D1 receptor antagonist, nor DPCPX, an adenosine A1 receptor antagonist, blocked antinociception. Although intracisternal SB334867, an orexin 1 receptor antagonist, alone failed to change the threshold volume, centrally injected SB334867 potently blocked ghrelin-induced antinociceptive action during colonic distension. These results provide the first evidence that ghrelin acts centrally in the brain to enhance antinociceptive response to colonic distension through the central opioid system, dopamine D2 signaling, and the orexinergic pathway.
Assuntos
Analgésicos Opioides/farmacologia , Dopamina/metabolismo , Grelina/farmacologia , Dor Visceral/tratamento farmacológico , Analgésicos/farmacologia , Animais , Benzoxazóis/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Estado de Consciência/efeitos dos fármacos , Estado de Consciência/fisiologia , Masculino , Naftiridinas , Orexinas/metabolismo , Ratos Sprague-Dawley , Receptores de Dopamina D1/metabolismo , Ureia/análogos & derivados , Ureia/farmacologiaRESUMO
The location of neurons in the gustatory cortex (GC) activated by intra-oral infusion of solutions in conscious rats was mapped using Fos immunohistochemistry. Groups of adult male Wistar rats (N'sâ¯=â¯5) received an infusion of one of the following: dH2O, 0.1 or 1.0â¯M NaCl, 0.1 or 1.0â¯M sucrose, 0.32â¯M MSG (with 100⯵M amiloride and 2.5â¯M inosine 5'-monophosphate), 0.03â¯M HCl, or 0.003â¯M QHCl delivered via an intra-oral cannula (0.233â¯ml/min for 5â¯min). Unstimulated control rats received no infusion. Taste reactivity (TR) behaviors were videotaped and scored. The number of Fos-immunoreactive (Fos-IR) neurons was counted in eight sections throughout the anterior-posterior extent of the GC in the medial and lateral halves of the granular (GI), dysgranular (DI), and dorsal (AID) and ventral (AIV) agranular insular cortices. Intra-oral infusion of dH2O, NaCl, or sucrose altered the number of Fos-IR neurons in only specific subareas of the GC and the effects of these tastants were concentration-dependent. For example, 1.0â¯M NaCl increased Fos-IR neurons in the posterior lateral AID and DI and elicited more aversive TR responses than 0.1â¯M NaCl. Compared to dH2O, infusions of HCl or QHCl increased the total number of Fos-IR neurons in many subareas of the GC throughout its anterior-posterior extent and increased aversive TR behaviors. Linear regression analyses suggested that neurons in the medial AID of the posterior GC may influence aversive behavioral responses to HCl and QHCl while neurons in the posterior lateral AID and DI may play a role in aversive TR responses to 1.0â¯M NaCl.
Assuntos
Córtex Cerebral/metabolismo , Lobo Parietal/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Quinina/farmacologia , Animais , Córtex Cerebral/patologia , Estado de Consciência/fisiologia , Masculino , Neurônios/efeitos dos fármacos , Neurônios/patologia , Quinina/administração & dosagem , Ratos Wistar , Paladar/efeitos dos fármacos , Paladar/fisiologiaRESUMO
Agreeing with Damasio's statement defining the "process" of consciousness, we propose the self as created by mind-based knowledge and a combination of images of an organism's intentional motor responses interacting with its environment. The lemniscal system, with plastic capabilities, manages gravity in voluntary movement. The spinal segment motor reflex represents the schema of gravity-managing neuronal activity, and it can become "nested" in cortical areas participating in consciousness-building, allowing consideration of the brain as a hyper-evolved nervous system segment harboring atavic spinal organization. Consciousness' capability to change itself makes humans co-participants in their own mental and consciousness evolution.