Contrast sensitivity of pattern transient VEP components: contribution from M and P pathways

dc.creatorSOUZA, Givago da Silva
dc.creatorGOMES, Bruno Duarte
dc.creatorLACERDA, Eliza Maria da Costa Brito
dc.creatorSAITO, Cézar Akiyoshi
dc.creatorSILVA FILHO, Manoel da
dc.creatorSILVEIRA, Luiz Carlos de Lima
dc.date.accessioned2014-06-30T12:59:55Z
dc.date.available2014-06-30T12:59:55Z
dc.date.issued2013-12
dc.description.abstractThe purpose of this study was to compare contrast sensitivity estimated from transient visual evoked potentials (VEPs) elicited by achromatic pattern-reversal and pattern-onset/offset modes. The stimuli were 2-cpd, achromatic horizontal gratings presented either as a 1 Hz pattern reversal or a 300 ms onset/700 ms offset stimulus. Contrast thresholds were estimated by linear regression to amplitudes of VEP components vs. the logarithm of the stimulus contrasts, and these regressions were extrapolated to the zero amplitude level. Contrast sensitivity was defined as the inverse of contrast threshold. For pattern reversal, the relation between the P100 amplitude and log of the stimulus contrast was best described by two separate linear regressions. For the N135 component, a single straight line was sufficient. In the case of pattern onset/offset for both the C1 and C2 components, single straight lines described their amplitude vs. log contrast relations in the medium-to-low contrast range. Some saturation was observed for C2 components. The contrast sensitivity estimated from the low-contrast limb of the P100, from the N135, and from the C2 were all similar but higher than those obtained from the high-contrast limb of the P100 and C1 data, which were also similar to each other. With 2 cpd stimuli, a mechanism possibly driven by the M pathway appeared to contribute to the P100 component at medium-to-low contrasts and to the N135 and C2 components at all contrast levels, whereas another mechanism, possibly driven by the P and M pathways, appeared to contribute to the P100 component at high contrast and C1 component at all contrast levels.pt_BR
dc.identifier.citationSOUZA, Givago S. et al. Contrast sensitivity of pattern transient VEP components: contribution from M and P pathways. Psychology & Neuroscience, Rio de Janeiro, v. 6, n. 2, p. 191-198, jul./dez. 2013. Disponível em: <http://www.scielo.br/pdf/pn/v6n2/v6n2a07.pdf>. Acesso em: 12 fev. 2014. <http://dx.doi.org/10.3922/j.psns.2013.2.07>.pt_BR
dc.identifier.issn1983-3288
dc.identifier.urihttps://repositorio.ufpa.br/handle/2011/5182
dc.language.isoengpt_BR
dc.rightsAcesso Aberto
dc.subjectSensibilidade ao contrastept_BR
dc.subjectVisão espacialpt_BR
dc.subjectVias visuais paralelaspt_BR
dc.subjectVEPpt_BR
dc.titleContrast sensitivity of pattern transient VEP components: contribution from M and P pathwayspt_BR
dc.typeArtigo de Periódicopt_BR

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