An ON-type direction selective ganglion cell in primate retina

To maintain a stable and clear image of the world, our eyes reflexively follow the direction in which a visual scene is moving. Such gaze stabilisation mechanisms reduce image blur as we move in the environment. In non-primate mammals, this behaviour is initiated by retinal output neurons called ON-type direction-selective ganglion cells (ON-DSGCs), which detect the direction of image motion and transmit signals to brainstem nuclei that drive compensatory eye movements. However, in primates, ON-DSGCs have not yet been identified in the retina, raising the possibility that this reflex is mediated by cortical visual areas. Here, we mined single-cell RNA transcriptomic data from primate retina to identify a candidate ON-DSGC. We then combined two-photon calcium imaging, molecular identification, and morphological analysis, to reveal a population of ON-DSGCs in the macaque retina. The morphology, molecular signature, and GABAergic mechanisms that underlie direction selectivity in primate ON-DSGCs are highly conserved with lower mammals. We further show that the human retina contains a homologous cell type.  The presence of ON-DSGCs in primates highlights the need to examine the contribution of subcortical retinal mechanisms to normal and aberrant gaze stabilisation in the developing and mature visual system.