We have investigated the ontogeny of light-driven responses in mouse retinal ganglion cells (RGCs).Using a large-scale, high-density multielectrode array, we recorded from hundreds to thousands of RGCs simultaneously at pan-retinal level, including dorsal and ventral locations. Responses to different contrasts not only revealed a complex developmental profile for ON, OFF and ON-OFF responses, but also unveiled differences between dorsal and ventral RGC responses. At eye-opening, dorsal RGCs of all types were more responsive to light, perhaps indicating an environmental priority to nest viewing for pre-weaning pups. The developmental profile of ON and OFF responses exhibited antagonistic behaviour, with the strongest ON responses shortly after eye-opening, followed by an increase in the strength of OFF responses later on. Further, we found that with maturation receptive field (RF) center sizes decrease, spike-triggered averaged responses to white noise become stronger, and centers become more circular while maintaining differences between RGC types. We conclude that the maturation of retinal functionality is not spatially homogeneous, likely reflecting ecological requirements that favour earlier maturation of the dorsal retina.The onset of visual experience in mouse occurs around postnatal day (P) 12, at eye opening. Although the retina cannot experience patterned vision beforehand, it is remarkable that RGCs are already capable of encoding information originating from photoreceptors and transmit it to retinal central targets as soon as eyes open. However, these early light responses are far from mature, and they progressively acquire their adult features while the retina develops [1][2][3][4] . In mouse, RGC dendritic stratification in the ON and OFF layers of the inner plexiform layer matures after eye opening 5 and light-driven activity guides the refinement of synaptic connectivity 6,7 . Consequently, RF sizes 8,9 and complex RF properties such as direction and orientation selectivity 10-12 keep maturing after the onset of visual experience. Yet, despite ongoing maturation after eye opening, longitudinal studies of RF properties have never been fully documented 3 . One important often neglected issue is that the retina is not uniformly organised from a functional perspective. Indeed, dorsal, ventral, nasal and temporal domains have evolved to enable optimal encoding of specific features in the visual scene. For example, mouse cones co-express medium wavelength and short wavelength opsins (M-opsin and S-opsin), with a dorsal-to-ventral increasing gradient in S-opsin (and opposite for M-opsin) [13][14][15][16][17][18][19] . These dorso-ventral gradients affect RGC responses in adult animals with respect to their spectral tuning [20][21][22] , improving encoding of achromatic contrasts 20,21 and providing evolutionary advantages for visual tasks 23,24 . The topographical organisation of some RGC subtypes also exhibits dorsal, ventral, nasal, and temporal non-uniformity [25][26][27][28] . However, nothing is know...