title: A molecular basis for Weber's law.
abstract: A mathematical model is presented that obeys a strong form of Weber's law--over a range of adapting and stimulus intensities, equal contrast stimuli evoke identical responses. To account for the strong Weber's law, the adaptive stage in the proposed model employs a "delayed" reverse reaction along with a power-law input. It is suggested that this Weber's law mechanism is responsible for a slow, voltage-uncorrelated component of adaptation in the vertebrate photoreceptor. A plausible biochemical mechanism is the G-protein cycle with phosphorylation of photoactivated photopigment (and binding of arrestin to the phosphorylated photopigment) as the adaptive process. In an Appendix, features of the general model and implications of a specific biochemical model are examined by computer simulation.
authors.affiliation: Laboratory of Biophysics, Rockefeller University, New York, NY 10021-6399.
authors.forename: S M
authors.initials: SM
authors.lastname: Dawis
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology; D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D008027:Light; D008433:Mathematics; D008954:Models, Biological; D012160:Retina / Q000502:physiology*; D012684:Sensory Thresholds; D015398:Signal Transduction / Q000502:physiology
chemical_list: D019204:GTP-Binding Proteins