Computational modeling of the secondary rod pathway contribution to the retinal output

In the retina, signals originating from rod and cone photoreceptors can reach retinal ganglion cells (RGCs) through different pathways. The secondary rod pathway is functionally important under mesopic light, such as at dawn or dusk. Electrical synapses (gap junctions) between rods and cones form the entry to the secondary rod pathway. Recent experimental observations indicate that these gap junctions are plastic, changing with the time of day and/or light/dark adaptation. However, the impact of this plasticity on the contribution of the secondary rod pathway to RGC activity remains elusive. Here, we model the spatial topology and connectivity of the secondary rod pathway of the mouse retina and test the light responses of OFF RGCs to dim light stimuli. Our results corroborate previously published electrical recordings thereby establishing the validity of the model and its suitability to further study rod/cone coupling plasticity.