Simulated bipolar cells in fovea of human retina. III. Effects of chromatic adaptation in bipolar cell spectral responses.
Effects of chromatic adaptation on C-type bipolar cells (BC) in human retinal fovea are studied. Adaptation of the r-g channel is linear for both central fovea and parafovea. Adaptation of the parafovea bl-y channel, on the other hand, is nonlinear, which is accounted for by the slower adaptation rate of blue-sensitive cones with white light intensity as compared to rates of red- and green-sensitive cones. Achromatic adaptation of red- and green-center BCs produces uniform response decreases but without unique yellow loci shifts. Achromatic adaptation of blue-center BCs, on the other hand, does cause shifts of the unique green locus. Shifts of the crossover points for the BC response spectra occur with chromatic adaptation; the unique yellow loci shifts to shorter wavelengths with adapting wavelengths shorter than 550 nm and longer wave-lengths with longer adapting wavelengths than 550 nm. Chromatic adaptation is sufficient to explain the Bezold-Brüke effects; but to fully account for these shifts a novel hypothesis is proposed. For the green and red spectrum regions Bezold-Brücke shifts are due to r-g channel chromatic adaptation, while for the blue spectrum region bl-y channel chromatic adaptation accounts for Bezold-Brücke shifts. The two channels function independently in an either/or manner. The bl-y channel, besides having a unique green locus at 517.7 nm, has a crossover point at about 670 nm. Chromatic adaptation of the bl-y channel produces shifts of the unique red locus, which may account for extraspectral hue shifts.
Siminoff
R
R
Institut für Arbeitsphysiologie, Universität Dortmund, Federal Republic of Germany.
D000064:Acclimatization; D003118:Color Perception; D005584:Fovea Centralis / Q000166:cytology / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000166:cytology / Q000502:physiology*; D012160:Retina / Q000502:physiology*