The retina contains an important class of neurons called Direction Selective Ganglion Cells (DSGCs) that enable animals to determine the direction an object is moving across its visual field. Mature DSGCs respond strongly to objects moving in one of several preferred directions that lie along cardinal axes – up, down, left, or right. In their paper in Current Biology, Rémi Bos, Christian Gainer, and Marla Feller show that visual experience is necessary for populations of DSGCs to become tuned to movement along the cardinal axes.
By stimulating the retina with drifting bars and simultaneously monitoring the neuronal activity of a large population of ganglion cells with two-photon calcium imaging, Bos et al. were able to identify DSGCs and determine their preferred direction. Though individual DSGCs only responded to movement in one direction at eye opening, the population of DSGCs were responsive to movement in all directions. Over the course of a few weeks of visual experience, distinct populations of DSGCs became most responsive to movement along one of the cardinal axes. This was found to be due to realignment of directional tuning based on visual experience. When animals were deprived of visual experience by being reared in the dark, the population of DSGCs remained responsive to movement in all directions.
