Fig. 7

HEPES attenuates parasol ganglion cell (GC) surround. A An ON parasol GC in macaque monkey retina was illuminated to a 300-μm-diameter spot light (stimulus trace below) and its ON responses in the absence (left) and presence (right) of 20 mM HEPES were obtained by intracellular recording. The responses were similar in both conditions. B Responses of a parasol GC to a larger 2,000-μm-diameter spot (stimulus trace below) were obtained in the absence (left) and presence (right) of HEPES. The control response was small and transient because of surround antagonism. The response in HEPES was larger and more sustained, indicating diminished surround antagonism (from Davenport et al. [64])