Fig. 2: Bipolar cell receptive fields exhibit differing radial direction selectivity.

a Top: iGluSnFR is ubiquitously expressed in the IPL, which was vertically scanned using an electrically-tunable lens. Middle: “1D noise” stimulus consisting of twenty 20 × 50 μm rectangles switching randomly between black and white at 20 Hz. The relative scale of the FOV is shown. Bottom: average of a scan with example regions of interest (ROIs, black regions in b). b Example RFs from the ROIs in (a). Dotted box: the cropped RF used for clustering. c Top: the cropped RF from the dotted box in (b), with the same aspect ratio as the principal components (PCs) in (d). Bottom: RFs were aligned to the RF center and then all RFs were flattened to 1 dimension and cropped to exclude missing space-time. Sample size is 3,233 ROIs/ 4 fields/ 3 mice. d Top: feature weights for the 4 components from PCA. The fifth feature was the IPL depth of the ROI. Bottom, reconstructed components of the sparse PCA. e Mixture of Gaussian clustering was performed and the Bayesian information criterion (BIC) was used to select the number of clusters. f Clusters plotted against IPL depth. Gray regions: approximate ChAT bands as IPL landmarks. g Average RF of each cluster. “c” and “s” show the regions used to calculate the spatial average of the center and surround in (h). h Average temporal RFs taken from center (“c”) and surround (“s”) regions indicated in (g), normalized to the peak of the center response. i Example cropped RFs (“half” vs. “full”) convolved with the motion stimuli (“originates”, “terminates”, “left”, “right”) to measure the rDS of each cluster. j Modeled responses to motion (velocity 1000 μm/s) for each cluster for stimuli originating (“O”, green) or terminating (“T”, cyan) in the RF center or passing through the RF (“L”, black; “R”, gray). k Stimulus preference as a function of velocity for each cluster for the originating vs. terminating (black) or passing through to the left or right (gray) conditions. See also Supplementary Figs. 3–6.