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

BARBONI, Mirella Telles Salgueiro; GOMES, Bruno Duarte; SOUZA, Givago da Silva; RODRIGUES, Anderson Raiol; VENTURA, Dora Selma Fix; SILVEIRA, Luiz Carlos de Lima

Artigo

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

The 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 horizon...

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Autor principal:	BARBONI, Mirella Telles Salgueiro
Outros Autores:	GOMES, Bruno Duarte, SOUZA, Givago da Silva, RODRIGUES, Anderson Raiol, VENTURA, Dora Selma Fix, SILVEIRA, Luiz Carlos de Lima
Grau:	Artigo
Idioma:	eng
Publicado em:	2014
Assuntos:	Sensibilidade ao contraste Visão de cores Visão espacial Psicofísica visual Testes de avaliação da visão de cores Limiares visual
Acesso em linha:	http://repositorio.ufpa.br/jspui/handle/2011/5428

id	ir-2011-5428
recordtype	dspace
spelling	ir-2011-54282018-01-08T14:02:34Z Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics BARBONI, Mirella Telles Salgueiro GOMES, Bruno Duarte SOUZA, Givago da Silva RODRIGUES, Anderson Raiol VENTURA, Dora Selma Fix SILVEIRA, Luiz Carlos de Lima Sensibilidade ao contraste Visão de cores Visão espacial Psicofísica visual Testes de avaliação da visão de cores Limiares visual The 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. 2014-08-11T18:01:02Z 2014-08-11T18:01:02Z 2013-02 Artigo de Periódico BARBONI, 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>. 1414-431X http://repositorio.ufpa.br/jspui/handle/2011/5428 eng Acesso Aberto application/pdf
institution	Repositório Institucional - Universidade Federal do Pará
collection	RI-UFPA
language	eng
topic	Sensibilidade ao contraste Visão de cores Visão espacial Psicofísica visual Testes de avaliação da visão de cores Limiares visual
spellingShingle	Sensibilidade ao contraste Visão de cores Visão espacial Psicofísica visual Testes de avaliação da visão de cores Limiares visual BARBONI, Mirella Telles Salgueiro Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
topic_facet	Sensibilidade ao contraste Visão de cores Visão espacial Psicofísica visual Testes de avaliação da visão de cores Limiares visual
description	The 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.
format	Artigo
author	BARBONI, Mirella Telles Salgueiro
author2	GOMES, Bruno Duarte SOUZA, Givago da Silva RODRIGUES, Anderson Raiol VENTURA, Dora Selma Fix SILVEIRA, Luiz Carlos de Lima
author2Str	GOMES, Bruno Duarte SOUZA, Givago da Silva RODRIGUES, Anderson Raiol VENTURA, Dora Selma Fix SILVEIRA, Luiz Carlos de Lima
title	Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
title_short	Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
title_full	Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
title_fullStr	Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
title_full_unstemmed	Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
title_sort	chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics
publishDate	2014
url	http://repositorio.ufpa.br/jspui/handle/2011/5428
_version_	1832604102908968960
score	11.755432

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

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