Fig. 3: Weak surround suppression of ON alpha excitatory conductances does not depend on glutamate receptor saturation or desensitization.

a Theoretical model hypothesizing how the saturation or desensitization of glutamate receptors could lead to decreased surround suppression of postsynaptic RGC excitatory conductances. Blue indicates a BC whose glutamate release has strong surround suppression. Purple indicates an RGC with glutamate receptors that do not undergo saturation or desensitization and thus responds with excitatory conductances that exhibit strong surround suppression inherited from the BC glutamate response. Brown indicates an RGC with glutamate receptors that do undergo saturation or desensitization; thus, the preferred size excitatory response is decreased relative to the full-field excitatory response. b Example ON alpha excitatory conductances evoked by a preferred spot size in control conditions (brown) or during subsaturating bath application of NBQX (red). c Same as (b), but red indicates bath application of kynurenic acid (KYN). d Proportion of ON alpha excitatory response (averaged across 1 s stimulus) evoked in NBQX (n = 3) or KYN (n = 3) compared to control conditions. e ON alpha excitatory conductances evoked by a preferred (red) or full-field (pink) spot size during bath application of NBQX. f Same as (e), but during bath application of KYN. g Surround suppression of ON alpha excitatory conductances in the presence of NBQX (n = 3) or KYN (n = 3). a, b, c, e, f Gray horizontal bar indicates a 1-second presentation of the stimulus. d, g Dots indicate data from individual cells. Bar plots indicate average ± s.e.m., *p < 0.05, paired, two-sided, two-sample Student’s t test. Source data are provided as a Source Data file.