Visual evoked potentials in three-dimensional color space: Correlates of spatio-chromatic processing

Rabin, Jeff; Switkes, Eugene; Crognale, Michael A.; Schneck, Marilyn E.; Adams, Anthony J.

doi:10.1016/0042-6989(94)90222-4

Cited by 174 publications

(184 citation statements)

References 63 publications

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“…1A) generated artifactual transient potentials and resulted in band-pass temporal frequency tuning. This finding serves as a caution against reports which claim to obtain tritan occipital potentials with band-pass properties (Rabin et al 1994). The ability of human observers to discriminate small changes in the orientation of a visual stimulus depends on its chromatic content and its contrast.…”

Section: Wavelength Discrimination At Detection Thresholds Reveals Hucontrasting

confidence: 39%

Sensory Functions

1995

The Journal of Physiology

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Learning-related changes in synaptic organization occur in the intermediate and medial part of hyperstriatum ventrale (IMHV) after imprinting (Horn, 1990). NCAMs are implicated in synaptic plasticity (Edelman & Crossin, 1991). Are they implicated in imprinting?Dark-reared chicks (n = 132) were exposed for 1 h to an imprinting stimulus (a rotating red box) and their preferences for it determined to provide a measure of learning (preference score). Chicks with low preference scores were classed as poor learners (PL), those with high preference scores as good learners (GL). A further 66 chicks remained in darkness throughout as dark controls (DC). Chicks were killed by decapitation 9-5 or 24 h after training and tissue removed from IMHV, hyperstriatum accessorium (HA) and posterior neostriatum (PNS), separately from each hemisphere. Tissue from three chicks in each group was pooled. The amounts of three major NCAM isoforms (180, 140 and 120 kDa) in the P2 fraction were measured using SDS electrophoresis-immunoblotting (antibodies from K. Crossin) and '25I-labelled secondary antibodies. For IMHV, differences occurred only 24 h after traininga. There were more NCAMs (for each isoform) in GLs than PLsb or DCsb; PLs did not differ significantly from DCs. Effects reached significance only in left IMHVC. In HA, there was more NCAM 180 kDa in GLs than in DCs 9 5 h after trainingd, but no significant difference between the two trained groups. There were no training-or learning-related effects in PNS.The change in HA could be a consequence of non-specific effects of training. The effects in the left IMHV cannot be accounted for in this way: GLs and PLs were matched for locomotor activity, and both groups had similar training experience, yet PLs differed significantly from GLs, but did not differ significantly from DCs. The results show that in the left IMHV learning is associated with increased expression of NCAMs, implicating enhanced cell-to-cell adhesion in long-term memory. One eye was removed on the day of birth (P0) under ether anaesthesia. Paired injections of red and green fluorescent latex microspheres, spaced mediolaterally, were made into area 17 on both sides (Saffan 2 ml kg-1 I.M.). After injections at P2, a discrete cortical injection labelled cells throughout the dLGN. Using two different tracers, the overlap of the two populations was complete and the percentage of doublelabelled cells low. The pattern of labelling was similar on both sides of the brain. At P6, the geniculo-cortical topography contralateral to the remaining eye was adultlike. Ipsilaterally, although a single injection labelled neurons in a confined area of the dLGN, the double injections revealed greater scatter than contralaterally. Although not apparent at P6, a double focus of geniculate labelling from a single cortical injection ipsilateral to the remaining eye was seen at P12. Recordings were made in area 17 of adults enucleated at birth. The hamsters were paralysed with gallamine triethiodide (35 mg kg-' h-1 i.v.) and anaesthetized wit...

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Section: Wavelength Discrimination At Detection Thresholds Reveals Hucontrasting

confidence: 39%

Sensory Functions

1995

The Journal of Physiology

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“…Visual stimuli were reversing horizontal sine-wave gratings generated by a widely used board and displayed on a colour monitor [20][21][22].…”

Section: Visual Stimulimentioning

confidence: 99%

Chromatic pattern-reversal electroretinograms (ChPERGs) are spared in multiple system atrophy compared with Parkinson’s disease

et al. 2006

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Idiopathic Parkinson's disease (IPD) patients have abnormal visual evoked potentials (VEPs) and pattern electroretinograms (PERGs), attributed to dopaminergic transmission deficiency in visual pathway, probably the retina. VEP abnormalities are not reported in multiple system atrophy (MSA). The aim of this study was to investigate and compare chromatic (Ch) red-green (R-G) and blueyellow (B-Y), and luminance yellow-black (Y-Bk) PERGs in patients with MSA and IPD. We investigated 6 MSA patients (mean age: 62±7.4 years) not undergoing any pharmacological treatment, as well as 12 early IPD patients (mean age: 60.1±8.3 years) and 12 age-matched normal observers. ChPERGs were recorded monocularly in response to full-field equiluminant R-G, B-Y and Y-Bk horizontal gratings. In MSA only responses to R-G stimuli showed minimal insignificant changes (slight but not significant amplitude reduction without any significant latency delay); no significant abnormality was detected for B-Y and luminance Y-Bk stimuli. By contrast, in IPD all responses were reduced in amplitude and delayed in latency, above all for B-Y stimuli. Present data indicate that both chromatic and achromatic PERGs are virtually unaffected in MSA, whereas in early IPD they are clearly impaired, suggesting different pathogenic retinal mechanisms and a useful simple tool for distinguishing MSA from IPD.

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“…Com estimulação onset / offset por redes acromáticas o VEP é predominantemente de polaridade positiva e, além disso, outros perfi s temporais de estimulação, como a reversão de fase, também originam respostas caracteristicamente positivas, não importando se o estímulo é cromático ou acromático. Essa polaridade da resposta à redes isoluminantes é interpretado como uma ativação seletiva das vias de oponên-cia de cores (Baseler & Sutter, 1997;Berninger, Arden, Hogg, & Frumkes, 1989a, 1989bGomes, 2005;Gomes et al, 2006;Kulikowski, Murray, & Parry, 1989;Kulikowski, Robson, & McKeefry, 1996;Murray, Parry, Carden, & Kulikowski, 1987;Porciatti, Di Bartolo, Nardi, & Fiorentini, 1997;Porciatti & Sartucci, 1999;Rabin, Switkes, Crognale, Schnek, & Adams, 1994;Suttle, Anderson, & Harding, 1999). Essa resposta relaciona-se com muitos fenôme-nos psicofísicos, tal como a degradação do VEP quando se usa estímulos de alta freqüência espacial.…”

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

et al. 2006

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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...

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Visual evoked potentials in three-dimensional color space: Correlates of spatio-chromatic processing

Cited by 174 publications

References 63 publications

Sensory Functions

Sensory Functions

Chromatic pattern-reversal electroretinograms (ChPERGs) are spared in multiple system atrophy compared with Parkinson’s disease

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

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