Phase and amplitude analysis in time–frequency space—application to voluntary finger movement

Ginter, J.; Blinowska, Katarzyna J.; Kamiński, Maciej; Durka, P.J.

doi:10.1016/s0165-0270(01)00424-1

Cited by 80 publications

(67 citation statements)

References 26 publications

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“…An alternative approach proposed in [31] involves calculation of covariance matrix of MVAR model for short data windows and ensemble averaging over trials. Short-time directed transfer function (SDTF) [16,19,20,26] based on this concept applies a sliding window for estimating the time-dependence of directed connectivity.…”

mentioning

confidence: 99%

Application of directed transfer function and network formalism for the assessment of functional connectivity in working memory task

Blinowska

Kamiński

Brzezicka

et al. 2013

Phil. Trans. R. Soc. A.

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The dynamic pattern of functional connectivity during a working memory task was investigated by means of the short-time directed transfer function. A clear-cut picture of transmissions was observed with the main centres of propagation located in the frontal and parietal regions, in agreement with imaging studies and neurophysiological hypotheses concerning the mechanisms of working memory. The study of the time evolution revealed that most of the time short-range interactions prevailed, whereas the communication between the main centres of activity occurred more sparsely and changed dynamically in time. The patterns of connectivity were quantified by means of a network formalism based on assortative mixing-an approach novel in the field of brain networks study. By means of application of the above method, we have demonstrated the existence of a modular structure of brain networks. The strength of interaction inside the modules was higher than between modules. The obtained results are compatible with theories concerning metabolic energy saving and efficient wiring in the brain, which showed that preferred organization includes modular structure with dense connectivity inside the modules and more sparse connections between the modules.

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mentioning

confidence: 99%

Application of directed transfer function and network formalism for the assessment of functional connectivity in working memory task

Blinowska

Kamiński

Brzezicka

et al. 2013

Phil. Trans. R. Soc. A.

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“…A escolha por esta banda se justifica pelo fato de beta estar particularmente associada a processos de integração sensório-motora 11 . o sistema 10-20 é sempre utilizado como um todo, porém, os eletrodos localizados em áreas frontais, centrais e parietais foram selecionados por estarem de acordo com os objetivos do projeto.…”

Section: Análise De Dados E Cálculo Da Variável Dependente -unclassified

Os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica

Ecard

Silva

Neto

et al. 2007

Arq. Neuro-Psiquiatr.

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Resumo -o objetivo do presente estudo foi avaliar os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica. Para tal, simultaneamente ao registro da atividade eletroencefalográfi-ca, realizou-se eletroestimulação no antebraço direito para estimulação da extensão do indicador. A amostra consistiu de 45 sujeitos randomizados em 3 grupos de 15 sujeitos cada: grupo controle (submetido a 24 blocos de estimulação com intensidade de corrente zero), grupo 1 (24 blocos) e grupo 2 (36 blocos). A assimetria entre os pares de eletrodos F3-F4, C3-C4 e P3-P4 foi analisada ao longo dos grupos através de uma Anova. os resultados apontaram para uma interação grupo x eletrodo e uma tendência de diminuição da assimetria inter-hemisférica após a eletroestimulação.PAlAvRAs-ChAve: Fes, eeG, eeGq, assimetria Inter-hemisférica.the effects of functional electrical stimulation on cortical interhemispheric asymmetry AbstRACt -the aim of the present study was to assess the effects of functional electrical stimulation (Fes) on cortical interhemispheric asymmetry. electrostimulation was performed on the right forearm to stimulate the extension of the index finger. eeG activity was recorded simultaneously. the sample included 45 subjects randomly divided into 3 groups of 15 subjects each: control group (submitted to 24 blocks of stimulation at a null intensity current), group 1 (24 blocks) and group 2 (36 blocks). Interhemispheric asymmetry between F3-F4, C3-C4 and P3-P4 was analyzed through an Anova. Results pointed out to a group x electrode interaction and a general tendency of asymmetry decrease after stimulation. os estudos na área do comportamento motor têm evoluído ao longo dos tempos e novos padrões têm surgido com o objetivo de ampliar o entendimento sobre as interações neuromusculares na produção de uma ação motora [1][2][3] . existem inúmeras possibilidades de aplicação do aprendizado motor no processo de reabilitação motora-funcional. A partir de tais argumentos, torna-se essencial o entendimento de como se processa esse aprendizado, quer seja em condições normais, bem como em circunstâncias patológi-cas, para que se desenvolvam estratégias eficazes de tratamento. Com relação às técnicas que são utilizadas a fim de gerar a reabilitação funcional daqueles que necessitam de cuidados, pode-se citar a estimulação elétrica funcional (Fes) como um importante aliado para a potencialização terapêutica 4 ; entretanto, os efeitos de sua aplicação na dinâmica cerebral são ainda muito pouco explorados. outra técnica utilizada é o exame eletrencefalográfico (eeG), que permite mapear não só a região cerebral ativada durante a execução de uma tarefa, como também quantificar o nível de atividade elétrica neuronal nestas regiões. Através de métodos de análises quantitativas (eeGq) torna-se possível, por exemplo, observar assimetrias inter e intra-hemisféricas geradas durante o aprendizado de uma tarefa motora [5][6] .

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“…Therefore an ideal BCI system should consider space-time-frequency (s-t-f) features at the same time by adopting the physio-anotomical differences between the subjects. Recently time-frequency (t-f) analysis methods have been used to classify and visualize MI and ME related activities [6][7][8][9]. In contrast to conventional methods where the classification is implemented with fixed windows or predefined frequency index, the main use of t-f methods in a BCI system is that they can account for multiple time-frequency indexes in the classification stage.…”

Section: Introductionmentioning

confidence: 99%

A Space-time-Frequency Analysis Approach for the Classification Motor Imagery EEG Recordings in a Brain Computer Interface Task

Ince¹,

Tewfik²,

Arıca³

2006

2006 International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-We introduce an adaptive space time frequency analysis to extract and classify subject specific brain oscillations induced by motor imagery in a Brain Computer Interface task. The introduced method requires no prior knowledge of the reactive frequency bands, their temporal behavior or cortical locations. The algorithm implements an arbitrary time-frequency segmentation procedure by using a flexible local discriminant base algorithm for given multichannel brain activity recordings to extract subject specific ERD and ERS patterns. Extracted time-frequency features are processed by principal component analysis to reduce the feature set which is highly correlated due to volume conduction and the neighbor cortical regions. The reduced feature set is then fed to a linear discriminant analysis for classification. We give experimental results for 9 subjects to show the superior performance of the proposed method where the classification accuracy varied between 76.4% and 96.8% and the average classification accuracy was 84.9%.

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Phase and amplitude analysis in time–frequency space—application to voluntary finger movement

Cited by 80 publications

References 26 publications

Application of directed transfer function and network formalism for the assessment of functional connectivity in working memory task

Application of directed transfer function and network formalism for the assessment of functional connectivity in working memory task

Os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica

A Space-time-Frequency Analysis Approach for the Classification Motor Imagery EEG Recordings in a Brain Computer Interface Task

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