Sustained ON alpha retinal ganglion cells in the temporal retina exhibit task-specific regional adaptions in dendritic signal integration

Abstract

Various retinal ganglion cells (RGCs) show regional adaptations, for instance, to increase visual acuity. However, for many RGC types, it is not known how they vary in their signalprocessing properties across the retina. In the mouse retina, sustained ON alpha (sONα) RGCs were found to have differences in morphology and receptive field sizes along the nasotemporal axis, and temporal sONα RGCs are likely to play a role in visually guided hunting. Thus, we hypothesised that this cell type also exhibits regional adaptations on the level of dendritic signal processing and that these adaptations are advantageous for prey capture. Here, we measured dendritic signals from individual sONα RGCs at different locations in theexvivowhole-mount mouse retina using two-photon microscopy. We measured both postsynaptic Ca2+signals at the dendrites of individual RGCs and presynaptic glutamate signals from bipolar cells (BCs). We found that temporal sONα RGC dendrites exhibit, in addition to the expected sustained-ON signals with only weak surrounds, signals with strong surround suppression, which were not present in nasal sONα RGCs. This difference was also present in the excitatory presynaptic inputs from BCs, suggesting a presynaptic origin. Finally, using population models in an encoder-decoder paradigm, we showed that these adaptations might be beneficial for detecting crickets in hunting behaviour.