Contextual tuning of direction-selective retinal ganglion cells

A direction-selective (DS) retinal ganglion cell responds well to a small object moving within its receptive field center, but less well when there is also a moving stimulus in the surrounding area; this has been described as tuning for local motion. We show here an additional selectivity, such that the surround has less effect if there is a discontinuity-that is, a difference in spatial phase, spatial frequency or velocity-between the center stimulus and that present in the surround.