Rod-cone interaction in form detection.
Using a Wright colorimeter, absolute threshold, absolute form threshold and specific form threshold were measured during long-term dark adaptation in the extrafoveal retina. The specific form threshold was found to fall markedly at about the cone-rod break but thereafter rose steeply. Furthermore, during the rod phase of the dark adaptation the form percept of the small, slender rectangular test field changed qualitatively from a line or rectangle to a circular field at all mesopic intensities. The results indicate that light signals from rods may both facilitate and suppress cone-mediated information about form, and that the rod system may completely dominate the perception of form several log units above the absolute dark-adapted cone threshold when the eye is dark adapted.
Stabell
B
B
Department of Psychology, University of Oslo, Norway.
Stabell
U
U
D003623:Dark Adaptation / Q000502:physiology; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D010786:Photoreceptor Cells / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology*; D013997:Time Factors