Abstract
In the nervous system, the properties of neurons must be matched to their role within the network1. In vision, this begins with light detection by photoreceptors2–5. Because different behaviourally critical visual stimuli tend to appear in different parts of visual space, photoreceptors should be adjusted depending on their location in the eye6–12. However, a direct link between an animal’s specific visual requirements13, a corresponding regional tuning of photoreceptors, and their underlying cellular and molecular mechanisms has not been made. Here we show that UV-cones in the larval zebrafish area temporalis14 are specifically tuned for UV-bright prey capture in their upper frontal visual field, which uses the signal from a single cone at a time. For this, UV-detection efficiency is regionally boosted 42-fold. Next, in vivo 2-photon imaging, transcriptomics and computational modelling reveal that these cones use an elevated baseline of synaptic calcium to facilitate the encoding of bright objects, which in turn results from expressional tuning of phototransduction genes3,15,16. Finally, this signal is further accentuated at the level of glutamate release driving retinal networks. Our results demonstrate how same-type photoreceptors can be regionally tuned at the level of cellular anatomy, biochemical pathways and synaptic function to support specific tasks within the eye. These regional differences tally with variations between peripheral and foveal cones in primates10,12,17,18 and hint at a common mechanistic origin. Together, our results highlight a rich mechanistic toolkit for the tuning of neurons.
