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S‐cone excitation ratios for reaction times to blue‐yellow suprathreshold changes at isoluminance
Author(s) -
Medina José M.,
Díaz José A.
Publication year - 2010
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.2010.00745.x
Subject(s) - confusion , luminance , scaling , cone (formal languages) , contrast (vision) , optics , mathematics , excitation , stimulus (psychology) , power law , power function , physics , psychology , mathematical analysis , statistics , geometry , cognitive psychology , algorithm , quantum mechanics , psychoanalysis
We examined different contrast metrics to scale visual latencies for suprathreshold stimuli modulated along tritan confusion lines. S‐cone increments (‘blue’) and decrements (‘yellow’) were isolated along two different tritan confusion lines, each one having a different luminance value. Reaction times (RT) were evaluated as a function of the Weber contrast and the S‐cone excitation ratio between the test stimulus and the background. RTs were described using a model that generalizes Piéron’s law and incorporates the notion of threshold units and power law scaling. Our results show that RTs for S‐cone increments and decrements equate better when using the S‐cone excitation ratio. However, a single function did not describe all RT data. S‐cone RTs are better described by separate functions. We conclude that S‐cone increments and decrements do not scale in the same manner. Both Weber contrast and the S‐cone excitation ratio are plausible metrics at isoluminance. The implications for the S‐cone pathways are discussed.