Abstract
Purpose::
To introduce and test a model for rod flicker electroretinogram (ERG) intensity and frequency series in mice.
Methods::
Based on the functionally cone-deficient Cnga3-/- knockout mice, a model for rod flicker ERG was developed that incorporates flash intensity and frequency, background intensity, and integration time. In addition, fine-tuning parameters like absolute position on the intensity scale and maximum amplitude were added to allow the use of the model with different recording setups.The performance of the model was then tested in a variety of conditions and with a number of genetically altered mouse lines whose defects were expected to specifically change one or more components of the model, and the model predictions were then compared to the actual recordings.All functional testing was performed in dark-adapted animals with a Ganzfeld system (Multiliner Vision, Viasys, Germany) under scotopic conditions. The study was performed in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Visual Research.
Results::
The model was found to fit real rod flicker data fairly well, both when recorded in form of an intensity or a frequency series, and with or without a static background. Mutant mice were used to validate model predictions for the alterations expected to be caused by the respective genetic deficiencies. Intriguingly, the results were again in good agreement with the model predictions, even in additional recordings on static backgrounds and/or with different flash frequencies.Known limitations of the model in the current form concerned mainly the very low intensity range (towards single photoreceptor responses), and the very low frequency range (towards single flash responses).
Conclusions::
A model for rod flicker electroretinograms was introduced and tested. It provides an excellent fit to real data, both in normal and genetically altered mice, over a wide range of intensities and frequencies.
Keywords: electroretinography: non-clinical • signal transduction: pharmacology/physiology • retina: distal (photoreceptors, horizontal cells, bipolar cells)