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1.
Medicine (Baltimore) ; 100(33): e27001, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34414988

RESUMO

ABSTRACT: This study aimed to investigate evidence of gray matter brain lesions in multiple sclerosis (MS) patients by evaluating the resting state alpha rhythm of brain electrical activity.The study included 50 patients diagnosed with MS recruited from the MS clinic with 50 age and gender-matched control participants. The study investigated parameters of posterior dominant rhythm (PDR) in the electroencephalography (EEG) recordings including wave frequency and amplitude. Functional disability among the patients was evaluated according to the expanded disability status scale. Univariate statistical analysis was completed using one-way analysis of variance and t test with a P value of less than .05 to indicate statistical significance.Patients with MS had significantly lower PDR frequency and amplitude values compared to the controls (P value < .01) and 34% of the MS patients had a PDR frequency of less than 8.5 Hz. The PDR frequency was negatively associated with the level of functional disability among the patients (P value <.001) and 4% of the patients had abnormal epileptiform discharges.Background slowing of resting alpha rhythms and epileptiform discharges are suggestive of gray matter degeneration and may help in the prediction and follow-up of cortical damage and functional disabilities among MS patients. Therefore, electroencephalography monitoring of the PDR spectrum may serve as an alternative or complementary tool with other imaging techniques to detect and monitor cerebral cortical lesions.


Assuntos
Eletroencefalografia/estatística & dados numéricos , Substância Cinzenta/anormalidades , Esclerose Múltipla/complicações , Adulto , Estudos de Casos e Controles , Eletroencefalografia/métodos , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Iraque , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia
2.
Nat Commun ; 12(1): 4646, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34330901

RESUMO

Microglia are important for brain homeostasis and immunity, but their role in regulating vigilance remains unclear. We employed genetic, physiological, and metabolomic methods to examine microglial involvement in the regulation of wakefulness and sleep. Microglial depletion decreased stable nighttime wakefulness in mice by increasing transitions between wakefulness and non-rapid eye movement (NREM) sleep. Metabolomic analysis revealed that the sleep-wake behavior closely correlated with diurnal variation of the brain ceramide, which disappeared in microglia-depleted mice. Ceramide preferentially influenced microglia in the thalamic reticular nucleus (TRN), and local depletion of TRN microglia produced similar impaired wakefulness. Chemogenetic manipulations of anterior TRN neurons showed that they regulated transitions between wakefulness and NREM sleep. Their firing capacity was suppressed by both microglial depletion and added ceramide. In microglia-depleted mice, activating anterior TRN neurons or inhibiting ceramide production both restored stable wakefulness. These findings demonstrate that microglia can modulate stable wakefulness through anterior TRN neurons via ceramide signaling.


Assuntos
Potenciais de Ação/fisiologia , Neurônios GABAérgicos/fisiologia , Microglia/fisiologia , Sono/fisiologia , Núcleos Talâmicos/fisiologia , Vigília/fisiologia , Algoritmos , Animais , Eletroencefalografia/métodos , Eletromiografia/métodos , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Modelos Neurológicos , Núcleos Talâmicos/citologia
3.
Clin Neurophysiol ; 132(9): 2248-2250, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34275732

RESUMO

Restructuring of healthcare services during the COVID-19 pandemic has led to lockdown of Epilepsy Monitoring Units (EMUs) in many hospitals. The ad-hoc taskforce of the International League Against Epilepsy (ILAE) and the International Federation of Clinical Neurophysiology (IFCN) highlights the detrimental effect of postponing video-EEG monitoring of patients with epilepsy and other paroxysmal events. The taskforce calls for action to continue functioning of Epilepsy Monitoring Units during emergency situations, such as the COVID-19 pandemic. Long-term video-EEG monitoring is an essential diagnostic service. Access to video-EEG monitoring of the patients in the EMUs must be given high priority. Patients should be screened for COVID-19, before admission, according to the local regulations. Local policies for COVID-19 infection control should be adhered to during the video-EEG monitoring. In cases of differential diagnosis where reduction of antiseizure medication is not required, consider home video-EEG monitoring as an alternative in selected patients.


Assuntos
COVID-19/prevenção & controle , Controle de Doenças Transmissíveis/normas , Eletroencefalografia/normas , Epilepsia/diagnóstico , Acesso aos Serviços de Saúde/normas , Neurofisiologia/normas , COVID-19/epidemiologia , Controle de Doenças Transmissíveis/métodos , Consenso , Eletroencefalografia/métodos , Epilepsia/epidemiologia , Epilepsia/fisiopatologia , Humanos , Internacionalidade , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Neurofisiologia/métodos
4.
J Clin Neurosci ; 90: 351-358, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34275574

RESUMO

Autism spectrum disorder (ASD) is a very serious neurodevelopmental disorder and diagnosis mainly depends on the clinical scale, which has a certain degree of subjectivity. It is necessary to make accurate evaluation by objective indicators. In this study, we enrolled 96 children aged from 3 to 6 years: 48 low-function autistic children (38 males and 10 females; mean±SD age: 4.9±1.1 years) and 48 typically developing (TD) children (38 males and 10 females; mean±SD age: 4.9 ± 1.2 years) to participate in our experiment. We investigated to fuse multi-features (entropy, relative power, coherence and bicoherence) to distinguish low-function autistic children and TD children accurately. Minimum redundancy maximum correlation algorithm was used to choose the features and support vector machine was used for classification. Ten-fold cross validation was used to test the accuracy of the model. Better classification result was obtained. We tried to provide a reliable basis for clinical evaluation and diagnosis for ASD.


Assuntos
Transtorno Autístico/classificação , Transtorno Autístico/diagnóstico , Eletroencefalografia/métodos , Algoritmos , Transtorno do Espectro Autista/classificação , Transtorno do Espectro Autista/diagnóstico por imagem , Criança , Pré-Escolar , Entropia , Feminino , Humanos , Masculino , Valores de Referência , Máquina de Vetores de Suporte
5.
Commun Biol ; 4(1): 854, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244598

RESUMO

Current state-of-the-art functional magnetic resonance imaging (fMRI) offers remarkable imaging quality and resolution, yet, the intrinsic dimensionality of brain dynamics in different states (wakefulness, light and deep sleep) remains unknown. Here we present a method to reveal the low dimensional intrinsic manifold underlying human brain dynamics, which is invariant of the high dimensional spatio-temporal representation of the neuroimaging technology. By applying this intrinsic manifold framework to fMRI data acquired in wakefulness and sleep, we reveal the nonlinear differences between wakefulness and three different sleep stages, and successfully decode these different brain states with a mean accuracy across participants of 96%. Remarkably, a further group analysis shows that the intrinsic manifolds of all participants share a common topology. Overall, our results reveal the intrinsic manifold underlying the spatiotemporal dynamics of brain activity and demonstrate how this manifold enables the decoding of different brain states such as wakefulness and various sleep stages.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Sono/fisiologia , Vigília/fisiologia , Algoritmos , Encéfalo/diagnóstico por imagem , Eletroencefalografia/métodos , Humanos , Modelos Neurológicos , Rede Nervosa/diagnóstico por imagem , Neuroimagem/métodos , Fases do Sono/fisiologia
6.
Mayo Clin Proc ; 96(7): 2005-2007, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34218872
7.
Nat Commun ; 12(1): 4533, 2021 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-34312388

RESUMO

Successful listening crucially depends on intact attentional filters that separate relevant from irrelevant information. Research into their neurobiological implementation has focused on two potential auditory filter strategies: the lateralization of alpha power and selective neural speech tracking. However, the functional interplay of the two neural filter strategies and their potency to index listening success in an ageing population remains unclear. Using electroencephalography and a dual-talker task in a representative sample of listeners (N = 155; age=39-80 years), we here demonstrate an often-missed link from single-trial behavioural outcomes back to trial-by-trial changes in neural attentional filtering. First, we observe preserved attentional-cue-driven modulation of both neural filters across chronological age and hearing levels. Second, neural filter states vary independently of one another, demonstrating complementary neurobiological solutions of spatial selective attention. Stronger neural speech tracking but not alpha lateralization boosts trial-to-trial behavioural performance. Our results highlight the translational potential of neural speech tracking as an individualized neural marker of adaptive listening behaviour.


Assuntos
Envelhecimento/fisiologia , Atenção/fisiologia , Percepção Auditiva/fisiologia , Perda Auditiva/fisiopatologia , Audição/fisiologia , Vias Neurais/fisiologia , Estimulação Acústica/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Eletroencefalografia/métodos , Feminino , Perda Auditiva/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Percepção da Fala/fisiologia
8.
Neurology ; 97(6): e587-e596, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34078719

RESUMO

OBJECTIVE: To determine whether screening continuous EEG monitoring (cEEG) is associated with greater odds of treatment success for neonatal seizures. METHODS: We included term neonates with acute symptomatic seizures enrolled in the Neonatal Seizure Registry (NSR), a prospective, multicenter cohort of neonates with seizures. We compared 2 cEEG approaches: (1) screening cEEG, initiated for indications of encephalopathy or paralysis without suspected clinical seizures; and (2) confirmatory cEEG, initiated for the indication of clinical events suspicious for seizures, either alone or in addition to other indications. The primary outcome was successful response to initial seizure treatment, defined as seizures resolved without recurrence within 30 minutes after initial loading dose of antiseizure medicine. Multivariable logistic regression analyses assessed the association between cEEG approach and successful seizure treatment. RESULTS: Among 514 neonates included, 161 (31%) had screening cEEG and 353 (69%) had confirmatory cEEG. Neonates with screening cEEG had a higher proportion of successful initial seizure treatment than neonates with confirmatory cEEG (39% vs 18%; p < 0.0001). After adjusting for covariates, there remained a greater odds ratio (OR) for successful initial seizure treatment in the screening vs confirmatory cEEG groups (adjusted OR 2.44, 95% confidence interval 1.45-4.11, p = 0.0008). CONCLUSIONS: These findings provide evidence from a large, contemporary cohort of neonates that a screening cEEG approach may improve odds of successful treatment of acute seizures. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for neonates a screening cEEG approach, compared to a confirmatory EEG approach, increases the probability of successful treatment of acute seizures.


Assuntos
Anticonvulsivantes/administração & dosagem , Eletroencefalografia , Monitorização Neurofisiológica , Avaliação de Resultados em Cuidados de Saúde , Sistema de Registros , Convulsões/diagnóstico , Convulsões/tratamento farmacológico , Estudos de Coortes , Eletroencefalografia/métodos , Eletroencefalografia/normas , Feminino , Humanos , Recém-Nascido , Doenças do Recém-Nascido , Masculino , Monitorização Neurofisiológica/métodos , Monitorização Neurofisiológica/normas
9.
Br J Anaesth ; 127(2): 254-263, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34099242

RESUMO

BACKGROUND: Brain activity complexity is a promising correlate of states of consciousness. Previous studies have shown higher complexity for awake compared with deep anaesthesia states. However, little attention has been paid to complexity in intermediate states of sedation. METHODS: We analysed the Lempel-Ziv complexity of EEG signals from subjects undergoing moderate propofol sedation, from an open access database, and related it to behavioural performance as a continuous marker of the level of sedation and to plasma propofol concentrations. We explored its relation to spectral properties, to propofol susceptibility, and its topographical distribution. RESULTS: Subjects who retained behavioural performance despite propofol sedation showed increased brain activity complexity compared with baseline (M=13.9%, 95% confidence interval=7.5-20.3). This was not the case for subjects who lost behavioural performance. The increase was most prominent in frontal electrodes, and correlated with behavioural performance and propofol susceptibility. This effect was positively correlated with high-frequency activity. However, abolishing specific frequency ranges (e.g. alpha or gamma) did not reduce the propofol-induced increase in Lempel-Ziv complexity. CONCLUSIONS: Brain activity complexity can increase in response to propofol, particularly during low-dose sedation. Propofol-mediated Lempel-Ziv complexity increase was independent of frequency-specific spectral power manipulations, and most prominent in frontal areas. Taken together, these results advance our understanding of brain activity complexity and anaesthetics. They do not support models of consciousness that propose a direct relation between brain activity complexity and states of consciousness.


Assuntos
Encéfalo/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Hipnóticos e Sedativos/farmacologia , Propofol/farmacologia , Relação Dose-Resposta a Droga , Eletroencefalografia/métodos , Humanos
10.
Best Pract Res Clin Anaesthesiol ; 35(2): 159-169, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030801

RESUMO

With the widespread use of electroencephalogram [EEG] monitoring during surgery or in the Intensive Care Unit [ICU], clinicians can sometimes face the pattern of burst suppression [BS]. The BS pattern corresponds to the continuous quasi-periodic alternation between high-voltage slow waves [the bursts] and periods of low voltage or even isoelectricity of the EEG signal [the suppression] and is extremely rare outside ICU and the operative room. BS can be secondary to increased anesthetic depth or a marker of cerebral damage, as a therapeutic endpoint [i.e., refractory status epilepticus or refractory intracranial hypertension]. In this review, we report the neurophysiological features of BS to better define its role during intraoperative and critical care settings.


Assuntos
Anestésicos/administração & dosagem , Eletroencefalografia/métodos , Monitorização Intraoperatória/métodos , Assistência Perioperatória/métodos , Complicações Pós-Operatórias/prevenção & controle , Complicações Pós-Operatórias/fisiopatologia , Anestésicos/efeitos adversos , Eletroencefalografia/efeitos dos fármacos , Humanos , Complicações Pós-Operatórias/etiologia
11.
Clin Pediatr (Phila) ; 60(8): 363-369, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34014115

RESUMO

Children with complex febrile seizure (CFS) are often hospitalized for concerns for serious bacterial infection (SBI) or seizure recurrence. We describe the yield of diagnostic studies and seizure recurrence during hospitalization in CFS children. We performed a retrospective review of 372 visits in 350 developmentally normal children aged 6 to 60 months between 2011 and 2016 for CFS. Majority of patients were male (200; 57.1%), with a mean age of 19.8 ± 11.3 months. Active seizures were noted in 42 (11.3%), status epilepticus in 35 (9.4%) while 97 (26.1%) had a seizure in the pediatric emergency department. The distribution of SBI was as follows: bacteremia (3; 1.1%), urinary tract infection (7; 3.7%), pneumonia (15; 6.8%), and bacterial meningitis (0; 0%). Electroencephalography (EEG) abnormality was rare (7/158; 4.4%). Seizure recurrence during hospitalization was uncommon (19; 5.1%). Logistic regression analysis did not reveal any predictors for seizure recurrence. The seizure recurrence rate during hospitalization, EEG yield, and SBI incidence was low in children with CFS.


Assuntos
Infecções Bacterianas/epidemiologia , Eletroencefalografia/métodos , Hospitalização/estatística & dados numéricos , Convulsões Febris/diagnóstico , Convulsões Febris/epidemiologia , Pré-Escolar , Estudos de Coortes , Comorbidade , Feminino , Humanos , Incidência , Lactente , Masculino , Estudos Retrospectivos
12.
Best Pract Res Clin Anaesthesiol ; 35(2): 191-206, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030804

RESUMO

Delirium is a frequent and serious complication after surgery. It has a variable incidence between 20% and 40% with the highest incidence in elderly people undergoing major or cardiac surgery. The development of postoperative delirium (POD) is associated with increased hospital stay lengths, morbidity, the need for home care, and mortality. Studies have appeared in the last decade that evaluate the use of noninvasive monitoring to prevent its development. The evaluation of the depth of anesthesia with processed EEG allows to avoid awareness and burst suppression events. The cessation of brain activity is associated with the development of delirium. Another noninvasive monitoring technique is NIRS for cerebral tissue hypoxia detection by measuring regional oxygen saturation. The reduction of this parameter does not seem to be associated with the development of POD but with postoperative cognitive dysfunction. There are few studies in the literature and with conflicting results on the use of the pupillometer and transcranial Doppler in predicting the development of postoperative delirium.


Assuntos
Delírio/prevenção & controle , Eletroencefalografia/métodos , Monitorização Neurofisiológica Intraoperatória/métodos , Salas Cirúrgicas/métodos , Complicações Cognitivas Pós-Operatórias/prevenção & controle , Delírio/diagnóstico , Delírio/fisiopatologia , Humanos , Complicações Cognitivas Pós-Operatórias/diagnóstico , Complicações Cognitivas Pós-Operatórias/fisiopatologia
13.
Best Pract Res Clin Anaesthesiol ; 35(2): 255-266, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030809

RESUMO

Cerebral complications are common in perioperative settings even in non-neurosurgical procedures. These include postoperative cognitive dysfunction or delirium as well as cerebrovascular accidents. During surgery, it is essential to ensure an adequate degree of sedation and analgesia, and at the same time, to provide hemodynamic and respiratory stability in order to minimize neurological complications. In this context, the role of neuromonitoring in the operating room is gaining interest, even in the non-neurolosurgical population. The use of multimodal neuromonitoring can potentially reduce the occurrence of adverse effects during and after surgery, and optimize the administration of anesthetic drugs. In addition to the traditional focus on monitoring hemodynamic and respiratory systems during general anesthesia, the ability to constantly monitor the activity and maintenance of brain homeostasis, creating evidence-based protocols, should also become part of the standard of care: in this challenge, neuromonitoring comes to our aid. In this review, we aim to describe the role of the main types of noninvasive neuromonitoring such as those based on electroencephalography (EEG) waves (EEG, Entropy module, Bispectral Index, Narcotrend Monitor), near-infrared spectroscopy (NIRS) based on noninvasive measurement of cerebral regional oxygenation, and Transcranial Doppler used in the perioperative settings in non-neurosurgical intervention. We also describe the advantages, disadvantage, and limitation of each monitoring technique.


Assuntos
Anestesia Geral/métodos , Eletroencefalografia/métodos , Monitorização Neurofisiológica Intraoperatória/métodos , Complicações Pós-Operatórias/prevenção & controle , Anestesia Geral/efeitos adversos , Humanos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Ultrassonografia Doppler Transcraniana/métodos
14.
Epilepsia Open ; 6(2): 437-442, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34033234

RESUMO

OBJECTIVE: Hyperventilation (HV) is one of the main and basic activation methods during ambulatory electroencephalogram (EEG), unless medical reasons contraindicate it. During the COVID-19 pandemic, with the high risk of human-to-human infection, local guidelines and recommendations have been developed that suggest not to perform the HV maneuver routinely. Our objective was to characterize patients who present positive HV in an epilepsy center. METHODS: We analyzed retrospectively all the ambulatory EEGs performed during one year in our specialized ambulatory child and adolescent epilepsy center, and describe patients with positive maneuver. RESULTS: A total of 305 EEGs were performed. Patients under 3 years and 11 months were excluded as well as all patients that did not fill up the criteria for epilepsy diagnosis. From the 252 EEGs that were included in the study, 194 EEGs (77%) were classified as abnormal and 58 (23%) as normal. From these same 252 EEGs, 150 EEG finished correctly the HV maneuver. Physiological slowing response was found in 54 EEGs (36%), no changes (negative) in 83 (55%), and abnormal response (positive) in 13 EEGs (9%). The 13 HV-positive EEGs showed 4 patients with an increase of epileptiform activity, 3 patients experienced an increase of basal preregistered abnormal slowing, and 6 EEGs showed trigger of bilaterally synchronous and symmetric 2-4 Hz spike-and-slow wave discharges and absences. None of these last 6 patients needed more than 3 minutes to elicit the paroxysmal discharge. SIGNIFICANCE: Based on these findings and according with other studies, the low positivity and high specificity of the HV maneuver support the idea that HV could be excluded during the COVID-19 pandemic situation, and also reevaluate whether it could be changed to a complementary maneuver, restricted only for cases where absence epilepsy is suspected. Larger studies will be needed to reaffirm this proposal.


Assuntos
Assistência Ambulatorial , COVID-19 , Eletroencefalografia/métodos , Epilepsia Tipo Ausência , Adolescente , Assistência Ambulatorial/métodos , Assistência Ambulatorial/estatística & dados numéricos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Criança , Chile/epidemiologia , Técnicas de Diagnóstico Neurológico/normas , Técnicas de Diagnóstico Neurológico/tendências , Epilepsia Tipo Ausência/diagnóstico , Epilepsia Tipo Ausência/epidemiologia , Epilepsia Tipo Ausência/fisiopatologia , Feminino , Humanos , Hiperventilação , Masculino , Estudos Retrospectivos , SARS-CoV-2 , Convulsões/diagnóstico , Convulsões/fisiopatologia , Sensibilidade e Especificidade
15.
Epilepsia Open ; 6(2): 331-338, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34033243

RESUMO

OBJECTIVE: To determine whether the portable Ceribell® electroencephalograph (EEG) (Mountain View, CA) used for suspected status epilepticus (SE) can reduce time to diagnosis and on-call workforce demands and whether it can be applied to patients in respiratory isolation. METHODS: A multidisciplinary team developed a protocol for the use of the Ceribell EEG. The staff deploying the device, the attending physician, and the interpreting neurologist completed evaluation tools for each patient. Data maintained for quality and resource planning of 18-channel electroencephalography ordered for suspected SE were used as controls. Times to diagnosis were compared by application of Welch-Satterthwaite tests and workforce call-in demands by Fisher's exact t test. We evaluated qualitative data related to the use of the EEG in COVID-19 isolation rooms and on its technical aspects and acceptance by staff members. RESULTS: The Ceribell EEG reduced diagnosis time (P = .0000006) and on-call workforce demand (P = .02). The device can be used at any time of day in any hospital care area and has advantages in respiratory isolation rooms. SIGNIFICANCE: Compared with a standard 18-channel EEG, the Ceribell device allowed earlier diagnosis of SE and non-SE conditions and reduced workforce demands. Due to the ease of its use and its simple components, which can be readily disinfected, it is advantageous for COVID-19 patients in isolation.


Assuntos
COVID-19 , Eletroencefalografia , Serviços Médicos de Emergência , Controle de Infecções , Estado Epiléptico/diagnóstico , Tempo para o Tratamento/normas , Serviços de Atendimento/instrumentação , COVID-19/epidemiologia , COVID-19/prevenção & controle , COVID-19/terapia , Diagnóstico Precoce , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Serviços Médicos de Emergência/métodos , Serviços Médicos de Emergência/organização & administração , Serviços Médicos de Emergência/normas , Pesquisa sobre Serviços de Saúde , Mão de Obra em Saúde , Hospitalização , Humanos , Controle de Infecções/métodos , Controle de Infecções/organização & administração , Estudo de Prova de Conceito , Melhoria de Qualidade , SARS-CoV-2 , Gestão da Segurança , Estado Epiléptico/terapia
16.
Nat Commun ; 12(1): 3112, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035303

RESUMO

Sleep is thought to support memory consolidation via reactivation of prior experiences, with particular electrophysiological sleep signatures (slow oscillations (SOs) and sleep spindles) gating the information flow between relevant brain areas. However, empirical evidence for a role of endogenous memory reactivation (i.e., without experimentally delivered memory cues) for consolidation in humans is lacking. Here, we devised a paradigm in which participants acquired associative memories before taking a nap. Multivariate decoding was then used to capture endogenous memory reactivation during non-rapid eye movement (NREM) sleep in surface EEG recordings. Our results reveal reactivation of learning material during SO-spindle complexes, with the precision of SO-spindle coupling predicting reactivation strength. Critically, reactivation strength (i.e. classifier evidence in favor of the previously studied stimulus category) in turn predicts the level of consolidation across participants. These results elucidate the memory function of sleep in humans and emphasize the importance of SOs and spindles in clocking endogenous consolidation processes.


Assuntos
Encéfalo/fisiologia , Aprendizagem/fisiologia , Consolidação da Memória/fisiologia , Memória/fisiologia , Sono/fisiologia , Sinais (Psicologia) , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Estimulação Luminosa , Polissonografia/métodos , Desempenho Psicomotor/fisiologia , Adulto Jovem
17.
Oxid Med Cell Longev ; 2021: 6640108, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33953833

RESUMO

Criticality is considered a dynamic signature of healthy brain activity that can be measured on the short-term timescale with neural avalanches and long-term timescale with long-range temporal correlation (LRTC). It is unclear how the brain dynamics change in adult moyamoya disease (MMD). We used BOLD-fMRI for LRTC analysis from 16 hemorrhagic (H MMD) and 34 ischemic (I MMD) patients and 25 healthy controls. Afterwards, they were examined by EEG recordings in the eyes-closed (EC), eyes-open (EO), and working memory (WM) states. The EEG data of 11 H MMD and 13 I MMD patients and 21 healthy controls were in good quality for analysis. Regarding the 4 metrics of neural avalanches (e.g., size (α), duration (ß), κ value, and branching parameter (σ)), both MMD subtypes exhibited subcritical states in the EC state. When switching to the WM state, H MMD remained inactive, while I MMD surpassed controls and became supercritical (p < 0.05). Regarding LRTC, the amplitude envelope in the EC state was more analogous to random noise in the MMD patients than in controls. During state transitions, LRTC decreased sharply in the controls but remained chaotic in the MMD individuals (p < 0.05). The spatial LRTC reduction distribution based on both EEG and fMRI in the EC state implied that, compared with controls, the two MMD subtypes might exhibit mutually independent but partially overlapping patterns. The regions showing decreased LRTC in both EEG and fMRI were the left supplemental motor area of H MMD and right pre-/postcentral gyrus and right inferior temporal gyrus of I MMD. This study not only sheds light on the decayed critical dynamics of MMD in both the resting and task states for the first time but also proposes several EEG and fMRI features to identify its two subtypes.


Assuntos
Eletroencefalografia/métodos , Imageamento por Ressonância Magnética/métodos , Doença de Moyamoya/diagnóstico por imagem , Adulto , Feminino , Humanos , Masculino
18.
J Neuroeng Rehabil ; 18(1): 74, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947410

RESUMO

BACKGROUND: The key challenge to constructing functional corticomuscular coupling (FCMC) is to accurately identify the direction and strength of the information flow between scalp electroencephalography (EEG) and surface electromyography (SEMG). Traditional TE and TDMI methods have difficulty in identifying the information interaction for short time series as they tend to rely on long and stable data, so we propose a time-delayed maximal information coefficient (TDMIC) method. With this method, we aim to investigate the directional specificity of bidirectional total and nonlinear information flow on FCMC, and to explore the neural mechanisms underlying motor dysfunction in stroke patients. METHODS: We introduced a time-delayed parameter in the maximal information coefficient to capture the direction of information interaction between two time series. We employed the linear and non-linear system model based on short data to verify the validity of our algorithm. We then used the TDMIC method to study the characteristics of total and nonlinear information flow in FCMC during a dorsiflexion task for healthy controls and stroke patients. RESULTS: The simulation results showed that the TDMIC method can better detect the direction of information interaction compared with TE and TDMI methods. For healthy controls, the beta band (14-30 Hz) had higher information flow in FCMC than the gamma band (31-45 Hz). Furthermore, the beta-band total and nonlinear information flow in the descending direction (EEG to EMG) was significantly higher than that in the ascending direction (EMG to EEG), whereas in the gamma band the ascending direction had significantly higher information flow than the descending direction. Additionally, we found that the strong bidirectional information flow mainly acted on Cz, C3, CP3, P3 and CPz. Compared to controls, both the beta-and gamma-band bidirectional total and nonlinear information flows of the stroke group were significantly weaker. There is no significant difference in the direction of beta- and gamma-band information flow in stroke group. CONCLUSIONS: The proposed method could effectively identify the information interaction between short time series. According to our experiment, the beta band mainly passes downward motor control information while the gamma band features upward sensory feedback information delivery. Our observation demonstrate that the center and contralateral sensorimotor cortex play a major role in lower limb motor control. The study further demonstrates that brain damage caused by stroke disrupts the bidirectional information interaction between cortex and effector muscles in the sensorimotor system, leading to motor dysfunction.


Assuntos
Algoritmos , Eletroencefalografia/métodos , Eletromiografia/métodos , Acidente Vascular Cerebral/fisiopatologia , Interface Usuário-Computador , Idoso , Simulação por Computador , Retroalimentação Sensorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiologia , Músculo Esquelético/fisiologia , Projetos Piloto
19.
PLoS Comput Biol ; 17(4): e1008893, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33798190

RESUMO

The electroencephalogram (EEG) is a major tool for non-invasively studying brain function and dysfunction. Comparing experimentally recorded EEGs with neural network models is important to better interpret EEGs in terms of neural mechanisms. Most current neural network models use networks of simple point neurons. They capture important properties of cortical dynamics, and are numerically or analytically tractable. However, point neurons cannot generate an EEG, as EEG generation requires spatially separated transmembrane currents. Here, we explored how to compute an accurate approximation of a rodent's EEG with quantities defined in point-neuron network models. We constructed different approximations (or proxies) of the EEG signal that can be computed from networks of leaky integrate-and-fire (LIF) point neurons, such as firing rates, membrane potentials, and combinations of synaptic currents. We then evaluated how well each proxy reconstructed a ground-truth EEG obtained when the synaptic currents of the LIF model network were fed into a three-dimensional network model of multicompartmental neurons with realistic morphologies. Proxies based on linear combinations of AMPA and GABA currents performed better than proxies based on firing rates or membrane potentials. A new class of proxies, based on an optimized linear combination of time-shifted AMPA and GABA currents, provided the most accurate estimate of the EEG over a wide range of network states. The new linear proxies explained 85-95% of the variance of the ground-truth EEG for a wide range of network configurations including different cell morphologies, distributions of presynaptic inputs, positions of the recording electrode, and spatial extensions of the network. Non-linear EEG proxies using a convolutional neural network (CNN) on synaptic currents increased proxy performance by a further 2-8%. Our proxies can be used to easily calculate a biologically realistic EEG signal directly from point-neuron simulations thus facilitating a quantitative comparison between computational models and experimental EEG recordings.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia/métodos , Modelos Neurológicos , Neurônios/fisiologia , Encéfalo/citologia , Eletrodos , Humanos , Neurônios/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/metabolismo , Ácido gama-Aminobutírico/metabolismo
20.
Arch Dis Child Fetal Neonatal Ed ; 106(5): 535-541, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33875522

RESUMO

OBJECTIVE: Establish if serial, multichannel video electroencephalography (EEG) in preterm infants can accurately predict 2-year neurodevelopmental outcome. DESIGN AND PATIENTS: EEGs were recorded at three time points over the neonatal course for infants <32 weeks' gestational age (GA). Monitoring commenced soon after birth and continued over the first 3 days. EEGs were repeated at approximately 32 and 35 weeks' postmenstrual age (PMA). EEG scores were based on an age-specific grading scheme. Clinical score of neonatal morbidity risk and cranial ultrasound imaging were completed. SETTING: Neonatal intensive care unit at Cork University Maternity Hospital, Ireland. MAIN OUTCOME MEASURES: Bayley Scales of Infant Development III at 2 years' corrected age. RESULTS: Sixty-seven infants were prospectively enrolled in the study and 57 had follow-up available (median GA 28.9 weeks (IQR 26.5-30.4)). Forty had normal outcome, 17 had abnormal outcome/died. All EEG time points were individually predictive of abnormal outcome; however, the 35-week EEG performed best. The area under the receiver operating characteristic curve (AUC) for this time point was 0.91 (95% CI 0.83 to 1), p<0.001. Comparatively, the clinical course AUC was 0.68 (95% CI 0.54 to 0.80, p=0.015), while abnormal cranial ultrasound was 0.58 (95% CI 0.41 to 0.75, p=0.342). CONCLUSION: Multichannel EEG is a strong predictor of 2-year outcome in preterm infants particularly when recorded around 35 weeks' PMA. Infants at high risk of brain injury may benefit from early postnatal EEG recording which, if normal, is reassuring. Postnatal clinical complications can contribute to poor outcome; therefore, we state that a later EEG around 35 weeks has a role to play in prognostication.


Assuntos
Deficiências do Desenvolvimento/diagnóstico , Eletroencefalografia/métodos , Recém-Nascido Prematuro/fisiologia , Pré-Escolar , Seguimentos , Humanos , Recém-Nascido , Terapia Intensiva Neonatal , Prognóstico , Estudos Prospectivos , Fatores de Tempo
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