The visual system consists of a hierarchy of distinct brain areas, each responsible for processing different aspects of visual features. To better understand how signals from an upstream area contribute to visual processing in the downstream area, this project will focus on a specific type of computation broadly found in the visual system: i.e., selectivity to motion direction. Many neurons in the mouse superior colliculus, a direct target of the retina, preferentially respond to stimuli moving in one direction, but not the opposite, with diverse direction preferences across populations. Such direction-selective responses can be found already in the retina, but biased to the four cardinal directions: up, down, left, and right. This raises a question: Is direction-selectivity in the superior colliculus fully dependent on the retinal inputs, or (re-)computed de novo? Preliminary results from two photon calcium imaging show stronger direction selectivity responses to moving gratings with various spatial frequencies in comparison to retinal ganglion cell axons. Interestingly, retinal ganglion cell axons seem to respond to a specific range of spatial frequencies, suggesting a distinctive transformation from retinal ganglion cell axons to the superior colliculus. To further address direction selectivity mechanisms in the superior colliculus, I plan to block direction selective retinal ganglion cell input to the superior colliculus using chemogenetic tools in CART cre mice. The outcome of this project will clarify the mechanisms underlying direction selectivity in the superior colliculus and give further insight into how visual motion is computed in the brain.