Subtype-Dependent Postnatal Development of Direction- and Orientation-Selective

19 The direction-selective ganglion cells (DSGCs) and orientation-selective ganglion 20 cells (OSGCs) encode the directional and the orientational information of a moving 21 object, respectively. It is unclear how DSGCs and OSGCs mature in the mouse retina 22 during postnatal development. Here we investigated the development of DSGCs and 23 OSGCs after eye-opening. We show that (1) DSGCs and OSGCs are present at postnatal 24 day 12 (P12), just before eye-opening; (2) the fractions of both DSGCs and OSGCs 25 increase from P12 to P30; (3) the development of DSGCs and OSGCs are subtype26 dependent; and (4) directionand orientationselectivity are two separate features of 27 retinal ganglion cells (RGCs) in the mouse retina. We classified RGCs into different 28 functional subtypes based on their light response properties. Compared to P12, the 29 directionand orientationselectivity of ON-OFF RGCs but not ON RGCs became 30 stronger at P30. The tuning width of DSGCs for both ON and ON-OFF subtypes 31 decreased with age. For OSGCs, we divided them into non-DS OSGCs and DS&OSGCs. 32 For DS&OSGCs, we found that there was no correlation between the directionand 33 orientationselectivity and that the tuning width of both ON and ON-OFF subtypes 34 remained unchanged with age. For non-DS OSGCs, the tuning width of ON but not ON35 OFF subtype decreased with development. These findings provide a foundation to reveal 36 the molecular and synaptic mechanisms underlying the development of the directionand 37 orientationselectivity in the retina. 38