Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 11.552
Filtrar
2.
Nat Commun ; 11(1): 6109, 2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-33257683

RESUMO

Our daily behavior is dynamically influenced by conscious and unconscious processes. Although the neural bases of conscious experience have been extensively investigated over the past several decades, how unconscious information impacts neural circuitry and behavior remains unknown. Here, we recorded populations of neurons in macaque primary visual cortex (V1) to find that perceptually unidentifiable stimuli repeatedly presented in the absence of awareness are encoded by neural populations in a way that facilitates their future processing in the context of a behavioral task. Such exposure increases stimulus sensitivity and information encoded in cell populations, even though animals are unaware of stimulus identity. This phenomenon is consistent with a Hebbian mechanism underlying an increase in functional connectivity specifically for the neurons activated by subthreshold stimuli. This form of unsupervised adaptation may constitute a vestigial pre-attention system using the mere frequency of stimulus occurrence to change stimulus representations even when sensory inputs are perceptually invisible.


Assuntos
Comportamento/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adaptação Fisiológica , Animais , Estado de Consciência , Fenômenos Eletrofisiológicos , Humanos , Macaca mulatta , Masculino , Neurônios/fisiologia , Estimulação Luminosa
3.
Diving Hyperb Med ; 50(4): 421-423, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33325026

RESUMO

INTRODUCTION: Drowning is likely to result from impairment of consciousness when scuba diving. Causes include toxic effects of breathing gas, including nitrogen narcosis and oxygen toxicity, and arterial gas embolism. METHODS: Review of the medical records of scuba divers who had impaired consciousness underwater that could not be attributed to toxic effects of breathing gas or arterial gas embolism. RESULTS: Four scuba divers had episodes of impaired consciousness when at shallow depths (8-18 m) underwater. The descriptions of the episodes were very similar. Three had histories of recurrent episodes of vasovagal syncope on land. CONLCUSIONS: Absence of other causes for their impaired consciousness underwater leads to the conclusion that the probable cause was vasovagal syncope.


Assuntos
Mergulho , Embolia Aérea , Narcose por Gás Inerte , Síncope Vasovagal , Estado de Consciência , Mergulho/efeitos adversos , Embolia Aérea/etiologia , Humanos , Síncope Vasovagal/etiologia
4.
Gan To Kagaku Ryoho ; 47(10): 1521-1523, 2020 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-33130755

RESUMO

Oral transmucosal fentanyl has been indicated for the management of breakthrough pain in patients with cancer. Fentanyl sublingual tablets(FST)have been approved for use in Japan since 2013. However, the optimal use of FSTs has not been well-elucidated. In this case, a 73-year-old man with rectal cancer and third lumbar vertebral metastasis was treated with 100 µg FST and 12.5 µg/h fentanyl patch every day for the management of cancer-related breakthrough pain. After receiving the fourth dose of FST, the patient was unconscious for 2 days. However, his respiration was stable. This case shows that due care should be taken while administering FSTs to patients, specifically geriatric patients with bone metastasis and hypoalbuminemia.


Assuntos
Dor Irruptiva , Neoplasias , Administração Sublingual , Idoso , Analgésicos Opioides/efeitos adversos , Dor Irruptiva/tratamento farmacológico , Estado de Consciência , Fentanila/uso terapêutico , Humanos , Japão , Masculino , Neoplasias/tratamento farmacológico , Comprimidos/uso terapêutico
6.
Lancet Haematol ; 7(11): e789-e797, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33091354

RESUMO

BACKGROUND: Infection with Plasmodium falciparum leads to severe malaria and death in approximately 400 000 children each year in sub-Saharan Africa. Blood transfusion might benefit some patients with malaria but could potentially harm others. The aim of this study was to estimate the association between transfusion and death among children admitted to hospital with P falciparum malaria. METHODS: In this prospective, multicentre observational study, we analysed admissions to six tertiary care hospitals in The Gambia, Malawi, Gabon, Kenya, and Ghana that participated in the Severe Malaria in African Children network. Patients were enrolled if they were younger than 180 months and had a Giemsa-stained thick blood smear that was positive for P falciparum. Blood transfusion (whole blood at a target volume of 20 mL per kg) was administered at the discretion of the responsible physicians who were aware of local and international transfusion guidelines. The primary endpoint was death associated with transfusion, which was estimated using models adjusted for site and disease severity. We also aimed to identify factors associated with the decision to transfuse. The exploratory objective was to estimate optimal haemoglobin transfusion thresholds using generalised additive models. FINDINGS: Between Dec 19, 2000, and March 8, 2005, 26 106 patients were enrolled in the study, 25 893 of whom had their transfusion status recorded and were included in the primary analysis. 8513 (32·8%) patients received a blood transfusion. Patients were followed-up until discharge from hospital for a median of 2 days (IQR 1-4). 405 (4·8%) of 8513 patients who received a transfusion died compared with 689 (4·0%) of 17 380 patients who did not receive a transfusion. Transfusion was associated with decreased odds of death in site-adjusted analysis (odds ratio [OR] 0·82 [95% CI 0·71-0·94]) and after adjusting for the increased disease severity of patients who received a transfusion (0·50 [0·42-0·60]). Severe anaemia, elevated lactate concentration, respiratory distress, and parasite density were associated with greater odds of receiving a transfusion. Among all study participants, transfusion was associated with improved survival when the admission haemoglobin concentration was up to 77 g/L (95% CI 65-110). Among those with impaired consciousness (Blantyre Coma Score ≤4), transfusion was associated with improved survival at haemoglobin concentrations up to 105 g/L (95% CI 71-115). Among those with hyperlactataemia (blood lactate ≥5·0 mmol/L), transfusion was not significantly associated with harm at any haemoglobin concentration-ie, the OR of death comparing transfused versus not transfused was less than 1 at all haemoglobin concentrations (lower bound of the 95% CI for the haemoglobin concentration at which the OR of death equals 1: 90 g/L; no upper bound). INTERPRETATION: Our findings suggest that whole blood transfusion was associated with improved survival among children hospitalised with P falciparum malaria. Among those with impaired consciousness or hyperlactataemia, transfusion was associated with improved survival at haemoglobin concentrations above the currently recommended transfusion threshold. These findings highlight the need to do randomised controlled trials to test higher transfusion thresholds among African children with severe malaria complicated by these factors. FUNDING: US National Institute of Allergy and Infectious Diseases.


Assuntos
Transfusão de Sangue , Malária Falciparum/mortalidade , Anemia/complicações , Antimaláricos/uso terapêutico , Pré-Escolar , Estado de Consciência , Hemoglobinas/análise , Hospitalização , Humanos , Hiperlactatemia/complicações , Lactente , Quênia , Malária Falciparum/complicações , Malária Falciparum/tratamento farmacológico , Malária Falciparum/patologia , Razão de Chances , Estudos Prospectivos , Quinina/uso terapêutico , Índice de Gravidade de Doença , Taxa de Sobrevida , Centros de Atenção Terciária , Resultado do Tratamento
7.
Nature ; 586(7831): 658-661, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33110258
8.
Zh Nevrol Psikhiatr Im S S Korsakova ; 120(9. Vyp. 2): 13-21, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33076640

RESUMO

In this paper, the authors review experimental data on the ability to perceive the passage of time during wakefulness and sleep. The evolutionary significance of the sense of time and its role in cognitive functions is discussed. Recent findings on neural mechanisms underlying perception and estimation of time as well as temporal order judgments are described. Similarities and differences of the awareness of time in wakefulness, REM, and NREM sleep are analyzed.


Assuntos
Estado de Consciência , Vigília , Sono
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 134-137, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33017948

RESUMO

Neuroscience has generated a number of recent advances in the search for the neural correlates of consciousness, but these have yet to find valuable real-world applications. Electroencephalography under anesthesia provides a powerful experimental setup to identify electrophysiological signatures of altered states of consciousness, as well as a testbed for developing systems for automatic diagnosis and prognosis of awareness in clinical settings. In this work, we use deep convolutional neural networks to automatically differentiate sub-anesthetic states and depths of anesthesia, solely from one second of raw EEG signal. Our results with leave-one-participant-out-cross-validation show that behavioral measures, such as the Ramsay score, can be used to learn generalizable neural networks that reliably predict levels of unconsciousness in unseen transitional anesthetic states, as well as in unseen experimental setups and behaviors. Our findings highlight the potential of deep learning to detect progressive changes in anesthetic-induced unconsciousness with higher granularity than behavioral or pharmacological markers. This work has broader significance for identifying generalized patterns of brain activity that index states of consciousness.Clinical Relevance- In the United States alone, over 100,000 people receive general anesthesia every day, from which up to 1% is affected by unintended intraoperative awareness [1]. Despite this, brain-based monitoring of consciousness is not common in the clinic, and has had mixed success [2]. Given this context, our aim is to develop and explore an automated deep learning model that accurately predicts and interprets the depth and quality of anesthesia from the raw EEG signal.


Assuntos
Anestésicos , Propofol , Estado de Consciência , Humanos , Redes Neurais de Computação , Inconsciência/induzido quimicamente
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 824-827, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018112

RESUMO

We have traditionally defined `loss of consciousness' (LOC) and `regain of consciousness' (ROC) during general anesthesia in terms of behavioral correlates. We are starting to understand the dynamics in brain activity that may help define those events; however, we have not yet explored the possible autonomic correlates of LOC and ROC. In this study, we investigated the autonomic dynamics immediately surrounding loss and regain of consciousness in nine healthy volunteers under controlled propofol sedation. We used multimodal autonomic indices generated from physiologically accurate models and found that just before and after LOC and ROC could be differentiated with an AUC of 0.80. In addition, we saw that some of the autonomic changes accompanying LOC and ROC verify known information about the mechanism of action of propofol, while others indicate new avenues for exploration of propofol's effect on the autonomic nervous system. Overall, our work suggests that the autonomic dynamics surrounding the events of loss and regain of consciousness are worthy of further investigation.Clinical Relevance-This introduces the possibility of autonomic biomarkers for loss and regain of consciousness during general anesthesia that are more precise than behavioral tracking alone.


Assuntos
Propofol , Anestésicos Intravenosos , Sistema Nervoso Autônomo , Estado de Consciência , Humanos , Inconsciência/induzido quimicamente
13.
Crit Care Resusc ; 22(3): 245-252, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32900331

RESUMO

OBJECTIVE: The degree of sedation or agitation in critically ill patients is typically assessed with the Richmond Agitation and Sedation Scale (RASS). However, this approach is intermittent and subject to unrecognised variation between assessments. High frequency accelerometry may assist in achieving a quantitative and continuous assessment of sedation while heralding imminent agitation. DESIGN: We undertook a prospective, observational pilot study. SETTING: An adult tertiary intensive care unit in Melbourne, Australia. PARTICIPANTS: 20 patients with an admission diagnosis of trauma. MAIN OUTCOME MEASURES: Accelerometers were applied to patients' wrists and used to continuously record patient movement. Video data of patient behaviour were simultaneously collected, and observers blinded to accelerometry data were adjudicated the RASS score every 30 seconds. Exploratory analyses were undertaken. RESULTS: Patients were enrolled for a median duration of 9.7 hours (interquartile range [IQR], 0-22.8) and a total of 160 hours. These patients had a median RASS score of 0 (IQR, -4 to 0). A 2-minute moving window of amplitude variance was seen to reflect contemporaneous fluctuations in motor activity and was proportional to the RASS score. Furthermore, the moving window of amplitude variance was observed to spike immediately before ≥ 2 point increases in the RASS score. CONCLUSIONS: We describe a novel approach to the analysis of wrist accelerometry data in critically ill patients. This technique not only appears to provide novel and continuous information about the depth of sedation or degree of agitation, it is also notable in its aptitude to anticipate impending transitions to higher RASS values.


Assuntos
Acelerometria/estatística & dados numéricos , Estado de Consciência , Estado Terminal , Agitação Psicomotora , Adulto , Austrália , Cuidados Críticos , Humanos , Projetos Piloto , Estudos Prospectivos
14.
Nat Commun ; 11(1): 4525, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913209

RESUMO

To date we know little about natural emotion word repertoires, and whether or how they are associated with emotional functioning. Principles from linguistics suggest that the richness or diversity of individuals' actively used emotion vocabularies may correspond with their typical emotion experiences. The current investigation measures active emotion vocabularies in participant-generated natural speech and examined their relationships to individual differences in mood, personality, and physical and emotional well-being. Study 1 analyzes stream-of-consciousness essays by 1,567 college students. Study 2 analyzes public blogs written by over 35,000 individuals. The studies yield consistent findings that emotion vocabulary richness corresponds broadly with experience. Larger negative emotion vocabularies correlate with more psychological distress and poorer physical health. Larger positive emotion vocabularies correlate with higher well-being and better physical health. Findings support theories linking language use and development with lived experience and may have future clinical implications pending further research.


Assuntos
Emoções , Saúde Mental , Estudantes/psicologia , Vocabulário , Adolescente , Estado de Consciência , Feminino , Humanos , Masculino , Fatores Sexuais , Fala , Estudantes/estatística & dados numéricos , Redação , Adulto Jovem
15.
Am J Physiol Heart Circ Physiol ; 319(4): H893-H905, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32886003

RESUMO

Heart rate variability (HRV) is a measure of variation in time interval between heartbeats and reflects the influence of autonomic nervous system and circulating/locally released factors on sinoatrial node discharge. Here, we tested whether electrocardiograms (ECGs) obtained in conscious, restrained mice, a condition that affects sympathovagal balance, reveal alterations of heart rhythm dynamics with aging. Moreover, based on emergence of sodium channels as modulators of pacemaker activity, we addressed consequences of altered sodium channels on heart rhythm. C57Bl/6 mice and mice with enhanced late sodium current due to Nav1.5 mutation at Ser571 (S571E) at ~4 to ~24 mo of age, were studied. HRV was assessed using time- and frequency-domain and nonlinear parameters. For C57Bl/6 and S571E mice, standard deviation of RR intervals (SDRR), total power of RR interval variation, and nonlinear standard deviation 2 (SD2) were maximal at ~4 mo and decreased at ~18 and ~24 mo, together with attenuation of indexes of sympathovagal balance. Modulation of sympathetic and/or parasympathetic divisions revealed attenuation of autonomic tone at ~24 mo. At ~4 mo, S571E mice presented lower heart rate and higher SDRR, total power, and SD2 with respect to C57Bl/6, properties reversed by late sodium current inhibition. At ~24 mo, heart rate decreased in C57Bl/6 but increased in S571E, a condition preserved after autonomic blockade. Collectively, our data indicate that aging is associated with reduced HRV. Moreover, sodium channel function conditions heart rate and its age-related adaptations, but does not interfere with HRV decline occurring with age.NEW & NOTEWORTHY We have investigated age-associated alterations of heart rate properties in mice using conscious electrocardiographic recordings. Our findings support the notion that aging is coupled with altered sympathovagal balance with consequences on heart rate variability. Moreover, by using a genetically engineered mouse line, we provide evidence that sodium channels modulate heart rate and its age-related adaptations.


Assuntos
Envelhecimento , Frequência Cardíaca , Coração/inervação , Periodicidade , Sistema Nervoso Simpático/fisiologia , Nervo Vago/fisiologia , Fatores Etários , Animais , Relógios Biológicos , Estado de Consciência , Eletrocardiografia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Mutação , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Restrição Física , Nó Sinoatrial/inervação , Nó Sinoatrial/metabolismo , Fatores de Tempo
16.
Sci Rep ; 10(1): 15789, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978423

RESUMO

The field of neuropharmacology has not yet achieved a full understanding of how the brain transitions between states of consciousness and drug-induced unconsciousness, or anesthesia. Many small molecules are used to alter human consciousness, but the repertoire of underlying molecular targets, and thereby the genes, are incompletely understood. Here we describe a robust larval zebrafish model of anesthetic action, from sedation to general anesthesia. We use loss of movement under three different conditions, spontaneous movement, electrical stimulation or a tap, as a surrogate for sedation and general anesthesia, respectively. Using these behavioral patterns, we find that larval zebrafish respond to inhalational and IV anesthetics at concentrations similar to mammals. Additionally, known sedative drugs cause loss of spontaneous larval movement but not to the tap response. This robust, highly tractable vertebrate model can be used in the detection of genes and neural substrates involved in the transition from consciousness to unconsciousness.


Assuntos
Anestésicos/farmacologia , Comportamento Animal/efeitos dos fármacos , Encéfalo/fisiologia , Estado de Consciência/efeitos dos fármacos , Inconsciência/fisiopatologia , Animais , Encéfalo/efeitos dos fármacos , Modelos Animais , Inconsciência/psicologia , Peixe-Zebra
17.
BMC Neurol ; 20(1): 343, 2020 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-32919461

RESUMO

BACKGROUND: Previous studies have shown that a single Coma-Recovery Scale-Revision (CRS-R) assessment can identify high rates of misdiagnosis by clinical consensus. The aim of this study was to investigate the proportion of misdiagnosis by clinical consensus compared to repeated behavior-scale assessments in patients with prolonged disorders of consciousness (DOC). METHODS: Patients with prolonged DOC during hospitalization were screened by clinicians, and the clinicians formed a clinical-consensus diagnosis. Trained professionals used the CRS-R to evaluate the consciousness levels of the enrolled patients repeatedly (≥5 times) within a week. Based on the repeated evaluation results, the enrolled patients with prolonged DOC were divided into unresponsive wakefulness syndrome (UWS), minimally conscious state (MCS), and emergence from MCS (EMCS). Finally, the relationship between the results of the CRS-R and the clinical consensus were analyzed. RESULTS: In this study, 137 patients with a clinical-consensus diagnosis of prolonged DOC were enrolled. It was found that 24.7% of patients with clinical UWS were actually in MCS after a single CRS-R behavior evaluation, while the repeated CRS-R evaluation results showed that the proportion of misdiagnosis of MCS was 38.2%. A total of 16.7% of EMCS patients were misdiagnosed with clinical MCS, and 1.1% of EMCS patients were misdiagnosed with clinical UWS. CONCLUSIONS: The rate of the misdiagnosis by clinical consensus is still relatively high. Therefore, clinicians should be aware of the importance of the bedside CRS-R behavior assessment and should apply the CRS-R tool in daily procedures. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04139239 ; Registered 24 October 2019 - Retrospectively registered.


Assuntos
Transtornos da Consciência/diagnóstico , Estado de Consciência/fisiologia , Estado Vegetativo Persistente/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Consenso , Erros de Diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vigília , Adulto Jovem
18.
J Opioid Manag ; 16(4): 237-238, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886349

RESUMO

The COVID-19 ARDS appears to have worse outcomes than ARDS from other causes. It is a predictable serious complication and the key strategy is to maintain oxygenation. Adopting the prone position for conscious COVID-19 patients requiring basic respiratory support, is shown to benefit patients in terms of improving oxygenation, reducing the need for invasive ventilation and potentially even reducing mortality. Cough and myalgia are the common and most distressing symptoms seen in conscious COVID-19 patients which can impair tolerance to awake proning. Modified awake proning with application of transdermal fentanyl patch (TFP) can improve the compliance to conscious proning in COVID-19 patients.


Assuntos
Analgésicos Opioides/administração & dosagem , Estado de Consciência , Infecções por Coronavirus/terapia , Fentanila/administração & dosagem , Pneumonia Viral/terapia , Decúbito Ventral , Betacoronavirus , Humanos , Pandemias , /virologia , Adesivo Transdérmico
19.
Science ; 369(6511): 1567-1568, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32973020
20.
Rev Infirm ; 69(263): 32-33, 2020.
Artigo em Francês | MEDLINE | ID: mdl-32993903

RESUMO

Consciousness and the body. Life is expressed in the body through physical, chemical and biological processes as well as through the emergence of immaterial dimensions such as consciousness and subjectivity. These material and immaterial dimensions, connected and interdependent, form the basis of our humanity and should be considered together in the case of a global and personalised approach to the care practice.


Assuntos
Estado de Consciência , Corpo Humano , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA