Colour thresholds in dichromats and normals
| Autor: | Thomas Kuyk, S.C. Mangel, J.F. Shows, Michael S. Loop |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Adult
Male genetic structures Color vision Color Vision Defects Stimulus (physiology) Optics medicine Psychophysics Humans Dichromacy Short duration Mathematics business.industry Detection threshold Middle Aged medicine.disease Bright-white Sensory Systems Ophthalmology Colour vision sensitivity Case-Control Studies Sensory Thresholds Female business Color Perception |
| Zdroj: | Vision Research. 43(9):983-992 |
| ISSN: | 0042-6989 |
| DOI: | 10.1016/s0042-6989(03)00074-9 |
| Popis: | Studies indicate dichromats detect large, long duration spectral increments presented on bright white backgrounds with a blue-yellow colour opponent mechanism. Since opponent processes signal colour, we hypothesized that under these viewing conditions dichromats should perceive spectral increments as coloured at detection threshold. Psychophysical detection and colour discrimination thresholds were determined for normal and dichromatic humans. Test stimuli were 2 degrees, 200 ms increments presented upon a white, 1000 td, spatially coincident background. As expected, normal observers were able to discriminate between white and spectral flashes at intensities near detection threshold intensities. Dichromatic observers required suprathreshold ( approximately 0.30 log units) stimulus intensities to discriminate between the white and spectral flashes. The results do not support our hypothesis and alternative explanations for the elevated colour discrimination thresholds in dichromats are discussed. |
| Databáze: | OpenAIRE |
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