Step response of mouse rod photoreceptors modeled in terms of elemental photic signals.
The process of light adaptation in rod photoreceptors enables these sensory cells of the retina to remain responsive to photic stimuli over a broad range of light intensity. Recent studies have employed the technique of paired-flash electroretinography to determine properties of phototransduction, and of light and dark adaptation, in rod photoreceptors in the living eye. Building on these studies, we have developed a theoretical model aimed at explaining the rod electrical response to a step of light based on known physiology. The central feature of the model is its description of the macroscopic (i.e., measured) response in terms of a time-evolving, weighted sum of elemental responses determined under dark-adapted and near fully light-adapted conditions. The model yields a time-dependent function that describes the course of desensitization and putatively represents the cumulative dynamics of underlying biochemical processes involved in light adaptation of the rod.
Silva
Gabriel A
GA
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA. gsilva@ucsd.edu
Pepperberg
David R
DR
D000200:Action Potentials / Q000502:physiology; D000221:Adaptation, Ocular / Q000502:physiology* / Q000528:radiation effects*; D000222:Adaptation, Physiological / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D003198:Computer Simulation; D003624:Darkness; D004596:Electroretinography / Q000379:methods; D006706:Homeostasis / Q000502:physiology; D008027:Light; D051379:Mice; D008954:Models, Biological; D010775:Photic Stimulation / Q000379:methods*; D015203:Reproducibility of Results; D017948:Retinal Rod Photoreceptor Cells / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000502:physiology* / Q000528:radiation effects*