Fig. 7. The over-activation of chemoattraction led to similar results with mathematical simulation and organotypic culture. (A-C) Simulation of a local pulse of activator led to the formation of an accumulation of cells, surrounded by a ring of inhibition. The size of this ring was proportional to the activator concentration. (D-F) Patterns resulting from the local application of BMP7-coated beads. The maximal area of inhibition (red circle) was obtained with the maximal concentration of BMP7. p_u(x,0)=c^*exp(-(x²+(y-0.5)²)^*500) with c=4, 8 or 24. Scale bars: 250 µm.