SPATIAL-ORGANIZATION OF RETINAL INFORMATION ABOUT THE DIRECTION OF IMAGE MOTION

The visual stimuli that elicit neural activity differ for different re tinal ganglion cells and these cells have been categorized by the visu al information that they transmit. If specific visual information is c onveyed exclusively of primarily by a particular set of ganglion cells , one might expect the cells to be organized spatially so that their s ampling of information from the visual field is complete but not redun dant, In other words, the laterally spreading dendrites of the ganglio n cells should completely cover the retinal plane without gaps or sign ificant overlap. The first evidence for this sort of arrangement, whic h has been called a tiling or tessellation, was for the two types of ' 'alpha'' ganglion cells in cat retina. Other reports of tiling by gang lion cells have been made subsequently. We have found evidence of a pa rticularly rigorous tiling for the four types of ganglion cells in rab bit retina that convey information about the direction of retinal imag e motion (the ON-OFF direction-selective cells). Although individual c ells in the four groups are morphologically indistinguishable, they ar e organized as four overlaid tilings, each tiling consisting of like t ype cells that respond preferentially to a particular direction of ret inal image motion. These observations lend support to the hypothesis t hat tiling is a general feature of the organization of information out flow from the retina and clearly implicate mechanisms for recognition of like-type cells and establishment of mutually acceptable territorie s during retinal development.