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Perinatal correlated retinal activity is required for the wiring of visual axons in non-image forming nuclei

The formation of the visual system is a complex multistep process that includes proper assembly between retinal ganglion cell (RGC) axon terminals and their relay neurons in the different visual nuclei of the brain. RGC axons reach the main image-forming nuclei (IFN) —the superior colliculus and the lateral geniculate nucleus— at perinatal stages and extensively arborize to then refine throughout the first postnatal weeks. Spontaneous activity generated in the immature retina plays an essential role in the fine-tune refinement of exhuberant axonal arborizations but the molecular mechanisms underlying this activity-dependent remodeling process remain poorly characterized. RGC axons, in addition to innervate IFN, target non-image forming nuclei (NIFN), but the impact of spontaneous retinal activity in the development of these accessory nuclei has not yet been described. Here, by genetically altering spontaneous activity in the RGCs of mice we demonstrate that correlated retinal activity also shapes the connectivity of the non-image forming circuit and identify the transcriptional programs modulating this process. Together, our data contribute to a better understanding of the molecular mechanisms ruling activity-dependent axon refining in the building of visual circuits.