Properties of X- and Y-cells in the rabbit retina.

Bevelled glass microelectrodes were used to record spike potentials extracellularly from the ganglion cells of the rabbit retina. Good responses were obtained from the isolated retina or eye-cup preparation for at least 12 hr. Using a contrast reversal stimulus, 63.8% (67/105) of the units showed linear spatial summation (X-cells), and 21.0% (22/105) showed nonlinear spatial summation (Y-cells). The X- and Y-cells in the rabbit retina had physiological properties which were similar to those in cat retina. Directionally selective cells (15.2%) were found to respond poorly, if at all, to the contrast reversal stimulus.