Figure 5.

Suppression of spontaneous firing activity of ON RGCs in normal retinas to subsurface glutamate ejection. Suppression (arrowheads) of firing followed by excitation was readily observed in response to a 50-ms ejection of 5 mM glutamate in a spontaneously active RGC (A). In another ON RGC with a low of spontaneous firing, an initial suppression of firing after glutamate application was also detected after summation of responses to 100 pairs of applications (B). Note that responses to glutamate were consistent over long recording periods, which lasted up to 98 minutes.