| The effect of chromatic and luminance information on reaction times. | |
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MedLine Citation:
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PMID: 20594382 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We present a series of experiments exploring the effect of chromaticity on reaction time (RT) for a variety of stimulus conditions, including chromatic and luminance contrast, luminance, and size. The chromaticity of these stimuli was varied along a series of vectors in color space that included the two chromatic-opponent-cone axes, a red-green (L-M) axis and a blue-yellow [S - (L + M)] axis, and intermediate noncardinal orientations, as well as the luminance axis (L + M). For Weber luminance contrasts above 10-20%, RTs tend to the same asymptote, irrespective of chromatic direction. At lower luminance contrast, the addition of chromatic information shortens the RT. RTs are strongly influenced by stimulus size when the chromatic stimulus is modulated along the [S - (L + M)] pathway and by stimulus size and adaptation luminance for the (L-M) pathway. RTs are independent of stimulus size for stimuli larger than 0.5 deg. Data are modeled with a modified version of Pieron's formula with an exponent close to 2, in which the stimulus intensity term is replaced by a factor that considers the relative effects of chromatic and achromatic information, as indexed by the RMS (square-root of the cone contrast) value at isoluminance and the Weber luminance contrast, respectively. The parameters of the model reveal how RT is linked to stimulus size, chromatic channels, and adaptation luminance and how they can be interpreted in terms of two chromatic mechanisms. This equation predicts that, for isoluminance, RTs for a stimulus lying on the S-cone pathway are higher than those for a stimulus lying on the L-M-cone pathway, for a given RMS cone contrast. The equation also predicts an asymptotic trend to the RT for an achromatic stimulus when the luminance contrast is sufficiently large. |
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Authors:
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Beatriz M O'Donell; Jose F Barraza; Elisa M Colombo |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-07-01 |
Journal Detail:
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Title: Visual neuroscience Volume: 27 ISSN: 1469-8714 ISO Abbreviation: Vis. Neurosci. Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-08-27 Completed Date: 2010-12-10 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8809466 Medline TA: Vis Neurosci Country: England |
Other Details:
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Languages: eng Pagination: 119-29 Citation Subset: IM |
Affiliation:
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Departamento de Luminotecnia Luz y Visión Ing. Herberto C. Bühler, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina. bodonell@herrera.unt.edu.ar |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological
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physiology Adult Analysis of Variance Color* Color Perception / physiology* Contrast Sensitivity / physiology* Female Humans Male Middle Aged Models, Statistical Photic Stimulation / methods Psychophysics / methods Reaction Time / physiology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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