Manipulations with chemical labels, which lead to shifts in the bifurcation point A. The endogenous receptor gradient is made steeper compared to Figure 5B. The single-valued part of the map expands caudally. B. Density of ligand is reduced by 25%. Similar expansion of the single-valued part of the map is evident. C. The ligand gradient is made steeper. This is to reproduce the possible effect of ligand dimerization. The bifurcation point is moved slightly rostrally, expanding the double-valued part of the map. In all three columns the vertical arrangement of panels is similar to Figure 5.