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1.
Gigascience ; 112022 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-35254424

RESUMO

BACKGROUND: One of the goals of neuropsychology is to understand the brain mechanisms underlying aspects of attention and cognitive control. Several tasks have been developed as a part of this body of research, however their results are not always consistent. A reliable comparison of the data and a synthesis of study conclusions has been precluded by multiple methodological differences. Here, we describe a publicly available, high-density electroencephalography (EEG) dataset obtained from 42 healthy young adults while they performed 3 cognitive tasks: (i) an extended multi-source interference task; (ii) a 3-stimuli oddball task; (iii) a control, simple reaction task; and (iv) a resting-state protocol. Demographic and psychometric information are included within the dataset. DATASET VALIDATION: First, data validation confirmed acceptable quality of the obtained EEG signals. Typical event-related potential (ERP) waveforms were obtained, as expected for attention and cognitive control tasks (i.e., N200, P300, N450). Behavioral results showed the expected progression of reaction times and error rates, which confirmed the effectiveness of the applied paradigms. CONCLUSIONS: This dataset is well suited for neuropsychological research regarding common and distinct mechanisms involved in different cognitive tasks. Using this dataset, researchers can compare a wide range of classical EEG/ERP features across tasks for any selected subset of electrodes. At the same time, 128-channel EEG recording allows for source localization and detailed connectivity studies. Neurophysiological measures can be correlated with additional psychometric data obtained from the same participants. This dataset can also be used to develop and verify novel analytical and classification approaches that can advance the field of deep/machine learning algorithms, recognition of single-trial ERP responses to different task conditions, and detection of EEG/ERP features for use in brain-computer interface applications.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Encéfalo/fisiologia , Cognição/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Humanos , Adulto Jovem
2.
Behav Neurosci ; 136(2): 195-205, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34941318

RESUMO

Although the interrupting effect of chronic pain on voluntary-directed attention is well-documented, research on the impact of chronic pain on involuntary-directed attention remains incomplete. This study aimed to investigate the influence of chronic pain on involuntary as well as voluntary allocation of attention as, respectively, indexed by the P3a and P3b components in the event-related potential derived from the electroencephalogram. Both involuntary and voluntary captures of attention were compared between 33 patients with chronic pain and 33 healthy controls using an auditory three-stimulus oddball task (with standard, target, and unexpected distractor tones). The results revealed a reduced P3a amplitude as well as a reduced P3b amplitude in patients with chronic pain compared to healthy controls, indicating a detrimental effect of chronic pain on involuntary and voluntary attention, respectively. This study extends the picture of the impairing effects of chronic pain on attentional allocation to a current task and attentional allocation to information outside the focus of attention. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Dor Crônica , Atenção , Eletroencefalografia , Potenciais Evocados , Humanos
3.
Transl Psychiatry ; 12(1): 77, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35197453

RESUMO

Serotonergic psychedelic drugs, such as psilocin (4-hydroxy-N,N-dimethyltryptamine), profoundly alter the quality of consciousness through mechanisms which are incompletely understood. Growing evidence suggests that a single psychedelic experience can positively impact long-term psychological well-being, with relevance for the treatment of psychiatric disorders, including depression. A prominent factor associated with psychiatric disorders is disturbed sleep, and the sleep-wake cycle is implicated in the homeostatic regulation of neuronal activity and synaptic plasticity. However, it remains largely unknown to what extent psychedelic agents directly affect sleep, in terms of both acute arousal and homeostatic sleep regulation. Here, chronic electrophysiological recordings were obtained in mice to track sleep-wake architecture and cortical activity after psilocin injection. Administration of psilocin led to delayed REM sleep onset and reduced NREM sleep maintenance for up to approximately 3 h after dosing, and the acute EEG response was associated primarily with an enhanced oscillation around 4 Hz. No long-term changes in sleep-wake quantity were found. When combined with sleep deprivation, psilocin did not alter the dynamics of homeostatic sleep rebound during the subsequent recovery period, as reflected in both sleep amount and EEG slow-wave activity. However, psilocin decreased the recovery rate of sleep slow-wave activity following sleep deprivation in the local field potentials of electrodes targeting the medial prefrontal and surrounding cortex. It is concluded that psilocin affects both global vigilance state control and local sleep homeostasis, an effect which may be relevant for its antidepressant efficacy.


Assuntos
Eletroencefalografia , Sono , Animais , Encéfalo/fisiologia , Humanos , Camundongos , Psilocibina/análogos & derivados , Sono/fisiologia , Privação do Sono , Vigília
4.
Comput Biol Med ; 146: 105594, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35659118

RESUMO

Sleep contributes to more than a third of a person's life, making sleep monitoring essential for overall well-being. Cyclic alternating patterns (CAP) are crucial in monitoring sleep quality and associated illnesses such as insomnia, nocturnal frontal lobe epilepsy (NFLE), narcolepsy, etc. However, traditionally medical specialists practice manual division techniques of CAP phases which are sensitive to human weariness and inaccuracies. This might result in a false sleep stage diagnosis. This study proposes an automated approach using a deep learning model based on a 1-dimensional convolutional neural network for classifying CAP phases (A and B). The proposed model uses single-channel standardized electroencephalogram (EEG) recordings provided by the CAP sleep database. The model was created with the help of healthy participants and patients suffering from five distinct sleep disorders, which includes narcolepsy, rapid eye movement behaviour disorder (RBD), periodic leg movement disorder (PLM), NFLE, and insomnia. The developed model has achieved the highest automated classification accuracy of 78.84% for the healthy dataset and 82.21%, 79.48%, 78.73%, 76.68%, and 70.88% for narcolepsy, RBD, PLM, NFLE, and insomnia subjects, respectively in categorizing phases A and B. The proposed approach can help medical professionals monitor sleep and examine a person's brain stability.


Assuntos
Narcolepsia , Distúrbios do Início e da Manutenção do Sono , Transtornos do Sono-Vigília , Eletroencefalografia , Humanos , Redes Neurais de Computação , Polissonografia , Sono , Fases do Sono
5.
J Neural Eng ; 19(3)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35688127

RESUMO

Objective. This study analyzed detection (movement vs. non-movement) and classification (different types of movements) to decode upper-limb movement volitions in a pseudo-online fashion.Approach. Nine healthy subjects executed four self-initiated movements: left wrist extension, right wrist extension, left index finger extension, and right index finger extension. For detection, we investigated the performance of three individual classifiers (support vector machine (SVM), EEGNET, and Riemannian geometry featured SVM) on three frequency bands (0.05-5 Hz, 5-40 Hz, 0.05-40 Hz). The best frequency band and the best classifier combinations were constructed to realize an ensemble processing pipeline using majority voting. For classification, we used adaptive boosted Riemannian geometry model to differentiate contra-lateral and ipsilateral movements.Main results. The ensemble model achieved 79.6 ± 8.8% true positive rate and 3.1 ± 1.2 false positives per minute with 75.3 ± 112.6 ms latency on a pseudo-online detection task. The following classification gave around 67% accuracy to differentiate contralateral movements.Significance. The newly proposed ensemble method and pseudo-online testing procedure could provide a robust brain-computer interface design for movement decoding.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Eletroencefalografia/métodos , Humanos , Movimento , Processamento de Sinais Assistido por Computador , Extremidade Superior
6.
Dev Cogn Neurosci ; 55: 101118, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35653919

RESUMO

Reward is deemed a performance reinforcer. The current study investigated how social and monetary reward anticipation affected cognitive control in 39 children, 40 adolescents, and 40 adults. We found that cognitive control performance improved with age in a Simon task, and the reaction time (RT) was modulated by the reward magnitude. The conflict monitoring process (target N2 amplitudes) of adolescents and the attentional control processes (target P3 amplitudes) of adolescents and adults could be adjusted by reward magnitude, suggesting that adolescents were more sensitive to rewards compared to children. Reward magnitudes influenced the neural process of attentional control with larger P3 in congruent trails than that in incongruent trials only in low reward condition. The result of hierarchical drift-diffusion model indicated that children had slower drift rates, higher decision threshold, and longer non-decision time than adolescents and adults. Adolescents had faster drift rates in monetary task than in social task under the high reward condition, and they had faster drift rates under high reward condition than no reward condition only in the monetary task. The correlation analysis further showed that adults' non-decision time and decision threshold correlated with conflict monitoring process (N2 responses) and attentional control process on conflicts (P3 responses). Adolescents' drift rates associated with neural process of attentional control. The current study reveals that reward magnitude and reward type can modulate cognitive control process, especially in adolescents.


Assuntos
Eletroencefalografia , Potenciais Evocados , Adolescente , Adulto , Atenção , Criança , Potenciais Evocados/fisiologia , Humanos , Tempo de Reação/fisiologia , Recompensa
7.
Neuropsychologia ; 172: 108284, 2022 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-35667495

RESUMO

Statistical learning, the process of tracking distributional information and discovering embedded patterns, is traditionally regarded as a form of implicit learning. However, recent studies proposed that both implicit (attention-independent) and explicit (attention-dependent) learning systems are involved in statistical learning. To understand the role of attention in statistical learning, the current study investigates the cortical processing of distributional patterns in speech across local and global contexts. We then ask how these cortical responses relate to statistical learning behavior in a word segmentation task. We found Event-Related Potential (ERP) evidence of pre-attentive processing of both the local (mismatching negativity) and global distributional information (late discriminative negativity). However, as speech elements became less frequent and more surprising, some participants showed an involuntary attentional shift, reflected in a P3a response. Individuals who displayed attentive neural tracking of distributional information showed faster learning in a speech statistical learning task. These results suggest that an involuntary attentional shift might play a facilitatory, but not essential, role in statistical learning.


Assuntos
Atenção , Eletroencefalografia , Estimulação Acústica/métodos , Atenção/fisiologia , Potenciais Evocados/fisiologia , Humanos , Aprendizagem , Fala
8.
Artigo em Inglês | MEDLINE | ID: mdl-35657833

RESUMO

The hybrid brain-computer interface (hBCI) combining motor imagery (MI) and steady-state visual evoked potential (SSVEP) has been proven to have better performance than a pure MI- or SSVEP-based brain-computer interface (BCI). In most studies on hBCIs, subjects have been required to focus their attention on flickering light-emitting diodes (LEDs) or blocks while imagining body movements. However, these two classical tasks performed concurrently have a poor correlation. Therefore, it is necessary to reduce the task complexity of such a system and improve its user-friendliness. Aiming to achieve this goal, this study proposes a novel hybrid BCI that combines MI and intermodulation SSVEPs. In the proposed system, images of both hands flicker at the same frequency (i.e., 30 Hz) but at different grasp frequencies (i.e., 1 Hz for the left hand, and 1.5 Hz for the right hand), resulting in different intermodulation frequencies for encoding targets. Additionally, movement observation for subjects can help to perform the MI task better. In this study, two types of brain signals are classified independently and then fused by a scoring mechanism based on the probability distribution of relevant parameters. The online verification results showed that the average accuracies of 12 healthy subjects and 11 stroke patients were 92.40 ± 7.45% and 73.07 ± 9.07%, respectively. The average accuracies of 10 healthy subjects in the MI, SSVEP, and hybrid tasks were 84.00 ± 12.81%, 80.75 ± 8.08%, and 89.00 ± 9.94%, respectively. The high recognition accuracy verifies the feasibility and robustness of the proposed system. This study provides a novel and natural paradigm for a hybrid BCI based on MI and SSVEP.


Assuntos
Interfaces Cérebro-Computador , Potenciais Evocados Visuais , Atenção , Encéfalo/fisiologia , Eletroencefalografia/métodos , Humanos , Movimento/fisiologia , Estimulação Luminosa/métodos
9.
Artigo em Inglês | MEDLINE | ID: mdl-35657835

RESUMO

Deep learning (DL) methods have been widely used in the field of seizure prediction from electroencephalogram (EEG) in recent years. However, DL methods usually have numerous multiplication operations resulting in high computational complexity. In addtion, most of the current approaches in this field focus on designing models with special architectures to learn representations, ignoring the use of intrinsic patterns in the data. In this study, we propose a simple and effective end-to-end adder network and supervised contrastive learning (AddNet-SCL). The method uses addition instead of the massive multiplication in the convolution process to reduce the computational cost. Besides, contrastive learning is employed to effectively use label information, points of the same class are clustered together in the projection space, and points of different class are pushed apart at the same time. Moreover, the proposed model is trained by combining the supervised contrastive loss from the projection layer and the cross-entropy loss from the classification layer. Since the adder networks uses the l1 -norm distance as the similarity measure between the input feature and the filters, the gradient function of the network changes, an adaptive learning rate strategy is employed to ensure the convergence of AddNet-CL. Experimental results show that the proposed method achieves 94.9% sensitivity, an area under curve (AUC) of 94.2%, and a false positive rate of (FPR) 0.077/h on 19 patients in the CHB-MIT database and 89.1% sensitivity, an AUC of 83.1%, and an FPR of 0.120/h in the Kaggle database. Competitive results show that this method has broad prospects in clinical practice.


Assuntos
Eletroencefalografia , Convulsões , Bases de Dados Factuais , Eletroencefalografia/métodos , Humanos , Convulsões/diagnóstico
11.
Sensors (Basel) ; 22(11)2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35684685

RESUMO

The neural correlates of intentional emotion transfer by the music performer are not well investigated as the present-day research mainly focuses on the assessment of emotions evoked by music. In this study, we aim to determine whether EEG connectivity patterns can reflect differences in information exchange during emotional playing. The EEG data were recorded while subjects were performing a simple piano score with contrasting emotional intentions and evaluated the subjectively experienced success of emotion transfer. The brain connectivity patterns were assessed from the EEG data using the Granger Causality approach. The effective connectivity was analyzed in different frequency bands-delta, theta, alpha, beta, and gamma. The features that (1) were able to discriminate between the neutral baseline and the emotional playing and (2) were shared across conditions, were used for further comparison. The low frequency bands-delta, theta, alpha-showed a limited number of connections (4 to 6) contributing to the discrimination between the emotional playing conditions. In contrast, a dense pattern of connections between regions that was able to discriminate between conditions (30 to 38) was observed in beta and gamma frequency ranges. The current study demonstrates that EEG-based connectivity in beta and gamma frequency ranges can effectively reflect the state of the networks involved in the emotional transfer through musical performance, whereas utility of the low frequency bands (delta, theta, alpha) remains questionable.


Assuntos
Música , Encéfalo/fisiologia , Mapeamento Encefálico , Eletroencefalografia , Emoções/fisiologia , Humanos , Música/psicologia
12.
Sensors (Basel) ; 22(11)2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35684700

RESUMO

Nowadays, more people tend to go to bed late and spend their sleep time with various electronic devices. At the same time, the BCI (brain-computer interface) rehabilitation equipment uses a visual display, thus it is necessary to evaluate the problem of visual fatigue to avoid the impact on the training effect. Therefore, it is very important to understand the impact of using electronic devices in a dark environment at night on human visual fatigue. This paper uses Matlab to write different color paradigm stimulations, uses a 4K display with an adjustable screen brightness to jointly design the experiment, uses eye tracker and g.tec Electroencephalogram (EEG) equipment to collect the signal, and then carries out data processing and analysis, finally obtaining the influence of the combination of different colors and different screen brightness on human visual fatigue in a dark environment. In this study, subjects were asked to evaluate their subjective (Likert scale) perception, and objective signals (pupil diameter, θ + α frequency band data) were collected in a dark environment (<3 lx). The Likert scale showed that a low screen brightness in the dark environment could reduce the visual fatigue of the subjects, and participants preferred blue to red. The pupil data revealed that visual perception sensitivity was more vulnerable to stimulation at a medium and high screen brightness, which is easier to deepen visual fatigue. EEG frequency band data concluded that there was no significant difference between paradigm colors and screen brightness on visual fatigue. On this basis, this paper puts forward a new index-the visual anti-fatigue index, which provides a valuable reference for the optimization of the indoor living environment, the improvement of satisfaction with the use of electronic equipment and BCI rehabilitation equipment, and the protection of human eyes.


Assuntos
Astenopia , Interfaces Cérebro-Computador , Eletroencefalografia , Humanos , Pupila/fisiologia , Percepção Visual
13.
Brain Lang ; 230: 105138, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35644106

RESUMO

The purpose of this study was to test the effects of concreteness and relationship type (similarity vs. association) on semantic processing using event-related potentials (ERP). Neurophysiological evidence has been found for the concreteness effect and for an effect of relationship type. This study replicated and extended these findings by investigating the interaction of concreteness and relationship type. Twenty-four neurologically healthy young adults performed lexical decision and semantic relatedness tasks while continuous scalp EEG was recorded. Larger N400 effects were found for concrete words in associative relationships than for concrete words in similarity relationships and abstract words in either type of relationship. The results are discussed in relation to the different representational frameworks account for abstract and concrete word processing.


Assuntos
Eletroencefalografia , Potenciais Evocados , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Tempo de Reação/fisiologia , Semântica , Adulto Jovem
14.
Neurologia (Engl Ed) ; 37(5): 334-345, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35672120

RESUMO

OBJECTIVE: Stereoelectroencephalography (SEEG) is a technique for preoperative evaluation of patients with difficult-to-localise refractory focal epilepsy (DLRFE), enabling the study of deep cortical structures. The procedure, which is increasingly used in international epilepsy centres, has not been fully developed in Spain. We describe our experience with SEEG in the preoperative evaluation of DLRFE. MATERIAL AND METHODS: In the last 8 years, 71 patients with DLRFE were evaluated with SEEG in our epilepsy centre. We prospectively analysed our results in terms of localisation of the epileptogenic zone (EZ), surgical outcomes, and complications associated with the procedure. RESULTS: The median age of the sample was 30 years (range, 4-59 years); 27 patients (38%) were women. Forty-five patients (63.4%) showed no abnormalities on brain MR images. A total of 627 electrodes were implanted (median, 9 electrodes per patient; range, 1-17), and 50% of implantations were multilobar. The EZ was identified in 64 patients (90.1%), and was extratemporal or temporal plus in 66% of the cases. Follow-up was over one year in 55 of the 61 patients undergoing surgery: in the last year of follow-up, 58.2% were seizure-free (Engel Epilepsy Surgery Outcome Scale class I) and 76.4% had good outcomes (Engel I-II). Three patients (4.2%) presented brain haemorrhages. CONCLUSION: SEEG enables localisation of the EZ in patients in whom this was previously impossible, offering better surgical outcomes than other invasive techniques while having a relatively low rate of complications.


Assuntos
Epilepsia Resistente a Medicamentos , Epilepsias Parciais , Epilepsia , Adolescente , Adulto , Criança , Pré-Escolar , Epilepsia Resistente a Medicamentos/cirurgia , Eletrodos Implantados , Eletroencefalografia/métodos , Epilepsias Parciais/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas Estereotáxicas , Adulto Jovem
15.
Sci Data ; 9(1): 333, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35701407

RESUMO

In neuroscience, electroencephalography (EEG) data is often used to extract features (biomarkers) to identify neurological or psychiatric dysfunction or to predict treatment response. At the same time neuroscience is becoming more data-driven, made possible by computational advances. In support of biomarker development and methodologies such as training Artificial Intelligent (AI) networks we present the extensive Two Decades-Brainclinics Research Archive for Insights in Neurophysiology (TDBRAIN) EEG database. This clinical lifespan database (5-89 years) contains resting-state, raw EEG-data complemented with relevant clinical and demographic data of a heterogenous collection of 1274 psychiatric patients collected between 2001 to 2021. Main indications included are Major Depressive Disorder (MDD; N = 426), attention deficit hyperactivity disorder (ADHD; N = 271), Subjective Memory Complaints (SMC: N = 119) and obsessive-compulsive disorder (OCD; N = 75). Demographic-, personality- and day of measurement data are included in the database. Thirty percent of clinical and treatment outcome data will remain blinded for prospective validation and replication purposes. The TDBRAIN database and code are available on the Brainclinics Foundation website at www.brainclinics.com/resources and on Synapse at www.synapse.org/TDBRAIN .


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Transtorno Depressivo Maior , Transtorno Obsessivo-Compulsivo , Biomarcadores , Bases de Dados Factuais , Eletroencefalografia , Humanos , Neurofisiologia
16.
Neurodiagn J ; 62(2): 81-86, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35709518

RESUMO

This case report details lateralized periodic discharges (LPDs) detected and described via intraoperative neuromonitoring during tumor resection. Descriptions and quantifications were made according to the American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology: 2021 Version. Further, this case illustrates quantitative changes to the LPDs observed in real time as the tumor was removed.


Assuntos
Eletroencefalografia , Monitoração Neuromuscular , Humanos
17.
Artigo em Inglês | MEDLINE | ID: mdl-35696466

RESUMO

Monitoring the consciousness states of patients and ensuring the appropriate depth of anesthesia (DOA) is critical for the safe implementation of surgery. In this study, a high-density electroencephalogram (EEG) combined with blood drug concentration and behavioral response indicators was used to monitor propofol-induced sedation and evaluate the alterations in consciousness states. Microstate analysis, which can reflect the semi-stable state of the sub-second activation of the brain functional network, can be used to assess the brain's consciousness states. In this research, the EEG microstate sequences were constructed to compare the characteristics of corresponding sequences. Compared with the baseline (BS) state, the microstate sequences in the moderate sedation (MD) state exhibited higher complexity indexes of the multiscale sample entropy. With respect to the transition probability (TP) of microstates, most microstates tended to be converted into microstate C in the BS state. In contrast, they tended to be converted into microstate F in the MD state. The significant difference between the expected TP and observed TP could lead to the conclusion that hidden layers were present when there were changes in the consciousness states. According to the hidden Markov model, the accuracy of distinguishing the BS and MD states was 80.16%. The characteristics of microstate sequence revealed the variations in the brain states caused by alterations in consciousness states during anesthesia from a new perspective and presented a new idea for monitoring the DOA.


Assuntos
Propofol , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Estado de Consciência , Eletroencefalografia/métodos , Humanos , Propofol/farmacologia
18.
Sci Data ; 9(1): 325, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715429

RESUMO

This dataset consists of raw 64-channel EEG, cardiovascular (electrocardiography and photoplethysmography), and pupillometry data from 86 human participants recorded during 4 minutes of eyes-closed resting and during performance of a classic working memory task - digit span task with serial recall. The participants either memorized or just listened to sequences of 5, 9, or 13 digits presented auditorily every 2 seconds. The dataset can be used for (1) developing algorithms for cognitive load discrimination and detection of cognitive overload; (2) studying neural (event-related potentials and brain oscillations) and peripheral (electrocardiography, photoplethysmography, and pupillometry) physiological signals during encoding and maintenance of each sequentially presented memory item; (3) correlating cognitive load and individual differences in working memory to neural and peripheral physiology, and studying the relationship between the physiological signals; (4) integration of the physiological findings with the vast knowledge coming from behavioral studies of verbal working memory in simple span paradigms. The data are shared in Brain Imaging Data Structure (BIDS) format and freely available on OpenNeuro ( https://openneuro.org/datasets/ds003838 ).


Assuntos
Encéfalo , Eletroencefalografia , Memória de Curto Prazo , Encéfalo/fisiologia , Potenciais Evocados/fisiologia , Humanos , Memória de Curto Prazo/fisiologia , Rememoração Mental
19.
Math Biosci Eng ; 19(7): 6907-6922, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35730288

RESUMO

Motor Imagery EEG (MI-EEG) classification plays an important role in different Brain-Computer Interface (BCI) systems. Recently, deep learning has been widely used in the MI-EEG classification tasks, however this technology requires a large number of labeled training samples which are difficult to obtain, and insufficient labeled training samples will result in a degradation of the classification performance. To address the degradation problem, we investigate a Self-Supervised Learning (SSL) based MI-EEG classification method to reduce the dependence on a large number of labeled training samples. The proposed method includes a pretext task and a downstream classification one. In the pretext task, each MI-EEG is rearranged according to the temporal characteristic. A network is pre-trained using the original and rearranged MI-EEGs. In the downstream task, a MI-EEG classification network is firstly initialized by the network learned in the pretext task and then trained using a small number of the labeled training samples. A series of experiments are conducted on Data sets 1 and 2b of BCI competition IV and IVa of BCI competition III. In the case of one third of the labeled training samples, the proposed method can obtain an obvious improvement compared to the baseline network without using SSL. In the experiments under different percentages of the labeled training samples, the results show that the designed SSL strategy is effective and beneficial to improving the classification performance.


Assuntos
Interfaces Cérebro-Computador , Algoritmos , Eletroencefalografia , Aprendizado de Máquina Supervisionado
20.
Cochrane Database Syst Rev ; 6: CD000190, 2022 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-35731671

RESUMO

BACKGROUND: Temporary interruption of cerebral blood flow during carotid endarterectomy can be avoided by using a shunt across the clamped section of the carotid artery. The shunt may improve the outcome. This is an update of a Cochrane review originally published in 1996 and previously updated in 2002, 2009, and 2014. OBJECTIVES: To assess the effect of routine versus selective or no shunting, and to assess the best method for selective shunting on death, stroke, and other complications in people undergoing carotid endarterectomy under general anaesthesia. SEARCH METHODS: We searched the Cochrane Stroke Group Trials Register (last searched April 2021), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2021, Issue 4), MEDLINE (1966 to April 2021), Embase (1980 to April 2021), and the Science Citation Index Expanded (SCI-EXPANDED) (1980 to April 2021). We also searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform, and handsearched relevant journals, conference proceedings, and reference lists. SELECTION CRITERIA: Randomised and quasi-randomised trials of routine shunting compared with no shunting or selective shunting, and trials that compared different shunting policies in people undergoing carotid endarterectomy. DATA COLLECTION AND ANALYSIS: Three independent review authors performed data extraction, selection, and analysis. A pooled Peto odds ratio (OR) and 95% confidence interval (CI) were computed for all outcomes of interest. Best and worse case scenarios were also calculated in case of unavailable data. Two authors independently assessed risk of bias, and quality of evidence using GRADE. MAIN RESULTS: No new trials were found for this updated review. Thus, six trials involving 1270 participants are included in this latest review: three trials involving 686 participants compared routine shunting with no shunting, one trial involving 200 participants compared routine shunting with selective shunting, one trial involving 253 participants compared selective shunting with and without near-infrared refractory spectroscopy monitoring, and the other trial involving 131 participants compared shunting with a combination of electroencephalographic and carotid pressure measurement with shunting by carotid pressure measurement alone. Only three trials comparing routine shunting and no shunting were eligible for meta-analysis. Major findings of this comparison found that the routine shunting had less risk of stroke-related death within 30 days of surgery (best case) than no shunting (Peto odds ratio (OR) 0.13, 95% confidence interval (CI) 0.02 to 0.96, I2 not applicable, P = 0.05, low-quality evidence), the routine shunting group had a lower stroke rate within 24 hours of surgery (Peto odds ratio (OR) 0.15, 95% CI 0.03 to 0.78, I2 = not applicable, P = 0.02, low-quality evidence), and ipsilateral stroke within 30 days of surgery (best case) (Peto OR 0.41, 95% CI 0.18 to 0.97, I2 = 52%, P = 0.04, low-quality evidence) than the no shunting group. No difference was found between the groups in terms of postoperative neurological deficit between selective shunting with and without near-infrared refractory spectroscopy monitoring. However, this analysis was inadequately powered to reliably detect the effect. There was no difference between the risk of ipsilateral stroke in participants selected for shunting with the combination of electroencephalographic and carotid pressure assessment compared with pressure assessment alone, although again the data were limited. AUTHORS' CONCLUSIONS: This review concluded that the data available were too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy when performed under general anaesthesia. Large-scale randomised trials of routine shunting versus selective shunting are required. No method of monitoring in selective shunting has been shown to produce better outcomes.


Assuntos
Endarterectomia das Carótidas , Acidente Vascular Cerebral , Anestesia Geral/efeitos adversos , Artérias Carótidas/cirurgia , Eletroencefalografia/efeitos adversos , Endarterectomia das Carótidas/efeitos adversos , Endarterectomia das Carótidas/métodos , Humanos , Acidente Vascular Cerebral/etiologia
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