Fig. S2.

Temporal stability of gradient sensing. (A–C) Angular histograms of branch directions for new branches appearing during (A) day 1 (total 145 branches), (B) day 2 (total 157 branches), and (C) day 3 (total 132 branches) of continual exposure of organoids to a 0.5-nM/mm EGF gradient. Branch angles are plotted irrespective of the organoid from which each branch originates. The gradient of EGF is in the 0° direction. Plots are noncumulative, in that B shows only branches that form during day 2 (and not day 1), and C shows only branches that form during day 3 (and not days 1 and 2). The number of branches changes because the organoids change their morphology with time, but there is clearly no evidence of an improving accuracy of branch formation angle and hence no evidence of temporal integration. Bias is measured by measure B from Fig. 2 in the main text (but for individual branches, as in Fig. S3).