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Comparing the spatial-frequency response of first-order and second-order lateral visual interactions: grating induction and contrast-contrast.

Mark E McCourt
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Abstract

The magnitudes of two suprathreshold lateral spatial-interaction effects--grating induction and contrast--contrast--were compared with regard to their dependence upon inducing-grating spatial frequency. Both effects cause the contrast of target stimuli embedded in surrounding patterns to be matched nonveridically. The magnitudes of each effect were measured in a common unit that indexed the degree of nonveridical contrast matching across a large range of target-grating contrasts (+/- 0.80). Grating induction was a low-pass effect with respect to spatial frequency, whereas contrast-contrast was bandpass, peaking at approximately 4.0 cycles deg(-1). The magnitude of grating induction exceeded that of contrast--contrast, both overall and at their optimal frequencies (0.03125 and 4.0 cycles deg(-1), respectively); the two effects are equipotent at an inducing-grating spatial frequency of 1.0 cycle deg(-1). A significant negative correlation between the magnitudes of the two effects suggests a link whereby activation of second-order normalization mechanisms may inhibit first-order mechanisms.

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Contrast SensitivityHumansLightPhotic StimulationPsychological TestsSensory ThresholdsSpace PerceptionJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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Mark E McCourt. 2005. Comparing the spatial-frequency response of first-order and second-order lateral visual interactions: grating induction and contrast-contrast.. https://doi.org/10.1068/p5348

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