Direction selectivity in the retina and brain

Visual motion tells us how objects are moving in the world, and how we are moving within that world. Our work has recently transformed the understanding of this system’s architecture in the context of the whole animal. We studied how the global geometry of retinal direction selectivity relates to optic flow induced by self-motion. By intensive global mapping using two-photon calcium imaging, electrophysiology, and retrograde tracing, we revealed a surprising spherical geometry of retinal direction selectivity. We identified four subtypes of direction-selective ganglion cells, each of which aligned its directional preferences with optic flow produced by the mouse’s movement along either the body or gravitational axis. This has fascinating implications for all the perceptual and visuomotor functions supported by these cells, including image stabilization, cortical motion perception, and gaze shifts to moving targets. Now a days, we study how signals from the various subtypes of direction-selective ganglion cells interact in the brain to generate an estimate of the direction of motion and trigger compensatory eye movements. We also study the mechanistic basis of retinal direction selectivity, and specifically, the asymmetry of input to direction-selective retinal ganglion cells from presynaptic cells.