Origin of wavelets in the visual evoked potentials

Whittaker, Stephen G.; Siegfried, John B.

doi:10.1016/0013-4694(83)90151-7

Cited by 55 publications

(14 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Several early studies of brain signals evoked by simple visual stimuli (light flashes, gratings or reversing checkerboards) reported multi-cycled high-frequency oscillations, superimposed on the broad-band visual evoked potential (VEP; Cracco and Cracco, 1978;Sannita et al, 1995;Whittaker and Siegfried, 1983). These so-called "wavelets" -not to be confused with the wavelet-method for spectral analysis -were extracted by high-pass filtering the broad-band signal in the gamma-band range.…”

Section: Evoked Gba As a Correlate Of Bottom-up Stimulus Processingmentioning

confidence: 99%

High frequency oscillations as a correlate of visual perception

Martinović

Busch

2011

International Journal of Psychophysiology

View full text Add to dashboard Cite

Cortical oscillatory activity in the gamma-band range (>30Hz) is a fundamental mechanism of neural coding that arises during a range of cognitive processes in both animals and humans. Since the first report on high frequency oscillatory synchrony between V1 neurons belonging to the same orientation column (Gray and Singer, 1989, PNAS, 86, 1698-1702), the role of such oscillations in visual perception has been extensively researched. Visual stimuli elicit an early, evoked gamma-band response and a later, induced (neither time nor phase-locked) response. An abundance of experimental evidence now links both evoked and induced high frequency oscillations to a range of visual stimulus properties. On the basis of early studies into gamma-band oscillations in vision, induced high frequency oscillatory activity has been proposed as a putative cortical mechanism of coherent percept formation and object representation while evoked high frequency activity was related to the processing of image features. Recent studies demonstrate that both evoked and induced gamma-band activity are correlated with the speed and accuracy of visual detection and discrimination. Furthermore, induced gamma-band oscillations in the visual cortex are also correlated with fixational eye movement patterns. These direct relations between gamma-band activity and the efficacy of visual perception strongly suggest that cortical high frequency synchronisations constitute a neural mechanism that subserves processes essential for the organised intake and analysis of visual information.

show abstract

Section: Evoked Gba As a Correlate Of Bottom-up Stimulus Processingmentioning

confidence: 99%

High frequency oscillations as a correlate of visual perception

Martinović

Busch

2011

International Journal of Psychophysiology

View full text Add to dashboard Cite

show abstract

“…O potencial provocado visual ou VEP (Visual Evoked Potential) consiste da combinação de potenciais pós-sinápticos de neurônios localizados principalmente no córtex visual primário (V1), gerados durante a ocorrência de estí-mulos visuais (Whittaker & Siegfried, 1983). O VEP refl ete em grande medida o registro da atividade da região retiniana central, pois o mapa retinotópico da projeção dessa região em V1 sofre enorme magnifi cação devido à sua grande densidade neuronal (e.g.…”

Section: O Potencial Provocado Visualunclassified

Estimativa da sensibilidade ao contraste espacial de luminância e discriminação de cores por meio do potencial provocado visual transiente

et al. 2006

View full text Add to dashboard Cite

O potencial provocado visual (VEP) é uma resposta cortical registrável na superfície do couro cabeludo, que refl ete a atividade dos neurônios de V1. É classifi cado, a partir da freqüência temporal de estimulação, em transiente ou de estado estacionário. Outras propriedades do estímulo parecem provocar uma atividade seletiva dos diversos grupos de neurônios existentes em V1. Desse modo, o VEP vem sendo usado para estudar a visão humana acromática e cromática. Diversos trabalhos usaram o VEP para estimar a sensibilidade ao contraste de luminância no domínio das freqüências espaciais. Mais recentemente, há estudos que empregaram o VEP para medir os limiares de discriminação de cores. O VEP transiente pode complementar as medidas psicofísicas de sensibilidade ao contraste espacial de luminância e de discriminação cromática, e constitui um método não invasivo para estudar a visão de indivíduos com difi culdades de realizar testes psicofísicos. Descritores: Discriminação de cores. Sensibilidade de contraste (visão).Potenciais visuais provocados. Estimulação visual. 64B. D. Gomes, G. S. Souza, A. R. Rodrigues, C. A. Saito, M. Silva-Filho e L. C. L. Silveira O potencial provocado visualO potencial provocado visual ou VEP (Visual Evoked Potential) consiste da combinação de potenciais pós-sinápticos de neurônios localizados principalmente no córtex visual primário (V1), gerados durante a ocorrência de estí-mulos visuais (Whittaker & Siegfried, 1983). O VEP refl ete em grande medida o registro da atividade da região retiniana central, pois o mapa retinotópico da projeção dessa região em V1 sofre enorme magnifi cação devido à sua grande densidade neuronal (e.g. Silveira, Picanço-Diniz, Sampaio, & Oswaldo-Cruz, 1989). Nessa região retiniana, as chamadas "linhas privadas" compreendem conexões entre fotorreceptores, células bipolares e células ganglionares na proporção de 1:1:1. Com isso, mais de 50% das células de V1 têm campos receptivos localizados nos 10 o centrais do campo visual. Além de ser um método de escolha para estudar a região central da visão, aquela de grande importância oftalmológica, o VEP tem ainda a vantagem de ser um método não invasivo para o estudo das vias retino-tálamo-corticais (Regan & Spekreijse, 1986).O VEP tem amplitude da ordem de milivolt quando registrado diretamente no córtex cerebral, mas é reduzido à escala de microvolt quando captado por eléctrodos de superfície posicionados sobre o couro cabeludo. Essa queda de tensão ocorre entre os diversos meios (meninges, osso, músculo, pele) que se interpõem entre a origem do potencial e o local de registro, atenuando a amplitude do sinal.O registro eletrofi siológico do VEP em seres humanos é uma variação da eletroencefalografi a (EEG), chamada de encefalografi a relacionada a eventos, e é realizado usando-se eletródios de superfície com resistência de contato entre 3 e 5 KOhm, colocados em pontos estratégicos na superfície do crânio (Odom, et al., 2004). A diferença de potencial entre os eletródios é captada por amplifi cadores diferenciais de...

show abstract

“…1981;Gambi et al. 1981;Pratt et al, 1982;Whittaker and Siegfried. 1983] and it has been hypothe sized that they may correspond to the subcortical visual oscillating potentials observed in animals [Cracco and Cracco, 1978;Rubinstein.…”

Section: Introductionmentioning

confidence: 99%

“…1980, 1982]. Several types of recording procedures, electrode posi tioning and signal filtering have been proposed in order to discriminate short-latency oscillating components of visual evoked potentials (VEPs) which are supposed to be subcortical in origin from those generated in the retina and in the visual cortex [Hughes, 1964;Rubinstein and Harding, 1981;Whittaker and Siegfried, 1983], How ever, the widespread application of oscillating VEP wave lets analysis in clinical practice has been limited by the lack of a clear definition of their generator sources. In an attempt to clarify this point, we have utilized multichan nel recordings from corneal, scalp and nasopharyngeal electrodes both in healthy and in diseased volunteers; the latter either suffered from a primary retinal dysfunction (retinitis pigmentosa, RP) or from an optic nerve disease (retrobulbar neuritis, RBN).…”

Section: Introductionmentioning

confidence: 99%

Short-Latency Sinusoidal Wavelets to Bright Flashed Stimuli: Studies with Corneal Lens, Nasopharyngeal, Retrobulbar and Scalp Recordings

Sanarelli

Rossini²,

Rizzo³

et al. 1989

Eur Neurol

View full text Add to dashboard Cite

Short-latency flash visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded in 30 healthy volunteers and 14 patients (7 with retrobulbar neuritis and 7 with retinitis pigmentosa). Simultaneous recordings were performed by corneal, scalp, nasopharyngeal and retrobulbar (5 patients) electrodes. In 18 out of 30 healthy controls a brief sequence of oscillating wavelets was recorded between 15 and 40 ms on the scalp sites behind the vertex. In retrobulbar neuritis (RBN) patients normal responses were recorded by lens, retrobulbar, nasopharyngeal and frontal scalp electrodes. On the contrary none of these patients displayed short-latency activity behind the Cz scalp position. In 5 out of the 7 patients with retinitis pigmentosa, corneal, nasopharyngeal and scalp electrodes failed to detect any reliable waveform time-locked to the flash onset. In the remaining 2, a small lens ERG was recorded, while all other electrodes recorded a sequence of low-volted wavelets initiating 30 ms after the stimulus onset. In these patients an occipital VEP reduced in amplitude and with prolonged latency was also recorded. It is concluded that in presence of a normal corneal ERG because of the presence of volume spread oscillating retinal activity, it is hard to define while part of the scalp recorded, short latency, oscillating potentials is generated in subcortical visual structures.

show abstract

Origin of wavelets in the visual evoked potentials

Cited by 55 publications

References 7 publications

High frequency oscillations as a correlate of visual perception

High frequency oscillations as a correlate of visual perception

Estimativa da sensibilidade ao contraste espacial de luminância e discriminação de cores por meio do potencial provocado visual transiente

Short-Latency Sinusoidal Wavelets to Bright Flashed Stimuli: Studies with Corneal Lens, Nasopharyngeal, Retrobulbar and Scalp Recordings

Contact Info

Product

Resources

About