Fig. 4: A BC receptive field model of RGC excitation suggests differing BC receptive fields are necessary to evoke the differing level of surround suppression observed.
a Schematic illustrating the BC receptive field model of RGC excitation. The RGC receptive field (RGC RF) is constructed from BC receptive fields (Bipolar RF) randomly sampled across its dendritic arbor. RGC excitation is modeled as the summation of the RGC receptive field within a virtual stimulus. b Two example PixON dendritic arbors (top) and their corresponding excitatory conductances (bottom, solid line). Dotted lines indicate the model-predicted excitatory responses when using the BC RF in (c). c The BC RF that minimized the absolute error between measured and model-predicted excitatory responses from (a) (see “Methods” for details). Fitting was performed simultaneously on 6 PixON RGCs. d Experimentally measured surround suppression from PixON (n = 14) and ON alpha (n = 8) RGCs plotted against the average surround suppression predicted by the model when cross-validating against a new set of PixON and ON alpha RGCs. Note: Alignment to unity indicates perfectly accurate model prediction. e–g Same as (b–d), but fitting to 6 ON alpha RGCs. h–j Same as (b–d), but simultaneously fitting to 3 PixON RGCs and 3 ON alpha RGCs. Source data are provided as a Source Data file.
