Subtype-dependent postnatal development of direction- and orientation-selective retinal ganglion cells in mice.

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