Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

dc.creatorBARBONI, Mirella Telles Salgueiro
dc.creatorGOMES, Bruno Duarte
dc.creatorSOUZA, Givago da Silva
dc.creatorRODRIGUES, Anderson Raiol
dc.creatorVENTURA, Dora Selma Fix
dc.creatorSILVEIRA, Luiz Carlos de Lima
dc.date2014-08-11T18:01:02Z
dc.date2014-08-11T18:01:02Z
dc.date2013-02
dc.date.accessioned2023-09-28T15:41:23Z
dc.date.available2023-09-28T15:41:23Z
dc.identifierBARBONI, M.T.S. et al. Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics. Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v. 46, n. 2, p. 154-163, fev. 2013. Disponível em: <http://www.scielo.br/pdf/bjmbr/v46n2/bjb2428.pdf>. Acesso em: 12 fev. 2014. <http://dx.doi.org/10.1590/1414-431X20122428>.
dc.identifier1414-431X
dc.identifierhttp://repositorio.ufpa.br/jspui/handle/2011/5428
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/9019310
dc.descriptionThe purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus.
dc.formatapplication/pdf
dc.languageeng
dc.rightsAcesso Aberto
dc.subjectSensibilidade ao contraste
dc.subjectVisão de cores
dc.subjectVisão espacial
dc.subjectPsicofísica visual
dc.subjectTestes de avaliação da visão de cores
dc.subjectLimiares visual
dc.titleChromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
dc.typeArtigo de Periódico


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