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.
['Gabriel De Andrade E Silva', 'David R. Pepperberg']
Step response of mouse rod photoreceptors modeled in terms of elemental photic signals