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

ABSTRACT The development of the visual system is an intricate and multi-step process involving the precise connection of retinal ganglion cell (RGC) axon terminals with their corresponding neurons in the visual nuclei of the brain. Upon reaching primary image-forming nuclei (IFN), such as the superior colliculus and the lateral geniculate nucleus, RGC axons undergo extensive arborization that refines over the first few postnatal weeks. The molecular mechanisms driving this activity-dependent remodeling process, which is influenced by spontaneous activity in the developing retina, are still not well understood. In this study, by manipulating the activity of RGCs in mice and analyzing their transcriptomic profiles before eye opening, we have identified gene programs involved in activity-dependent refinement. Furthermore, while RGC axons also target non-image forming nuclei (NIFN), the impact of spontaneous retinal activity on the development of these accessory nuclei, has not yet been elucidated. The analysis of visual terminals from mice with altered retinal activity revealed that spontaneous retinal waves occurring prior to visual experience also play a role in shaping the connectivity of the non-image forming circuit. Overall, these findings contribute to a deeper understanding of the mechanisms governing activity-dependent axon refinement during the establishment of the visual circuit.