Receptoral and postreceptoral visual processes in recovery from chromatic adaptation.
AUTOR(ES)
Jameson, D
RESUMO
The time course of recovery from chromatic adaptation in human vision was tracked by determining the wavelength of light that appears uniquely yellow (neither red nor green) both before and after exposure to yellowish green and yellowish red adapting lights. Recovery is complete within 5 min after steady light exposure. After exposure to the alternating repeated sequence 10-sec light/10-sec dark, the initial magnitude of the aftereffect is reduced but recovery is retarded. The results are interpreted in terms of two processes located at different levels in the hierarchical organization of the visual system. One is a change in the balance of cone receptor sensitivities; the second is a shift in the equilibrium baseline between opposite-signed responses of the red/green channel at the opponent-process neural level. The baseline-shift mechanism is effective in the condition in which repeated input signals originating at the receptors are of sufficient strength to activate the system effectively. Hence, this process is revealed in the alternating adaptation condition when the receptors undergo partial recovery after each light exposure, but receptor adaptation during continued steady light exposure effectively protects the subsequent neural systems from continued strong activation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=383747Documentos Relacionados
- Suppression of mutants aberrant in light intensity responses of complementary chromatic adaptation.
- Spectral sensitivity functions of post-receptoral responses in human vision.
- Human photopic vision with only short wavelength cones: post-receptoral properties.
- Endorphins may function in heat adaptation.
- Cultural versus genetic adaptation.