Schematic representation of the Cellular Potts Model [43]. Cells are represented on a numerical grid as domains of pixels with identical index (shown as a specific shade of gray), while the extracellular matrix is the set of the remaining pixels (white pixels) having by convention. Connections between neighboring lattice sites of unlike index (some of them are indicated with double-headed arrows) represent membrane bonds, with a characteristic bond energy , which depends on the pair of objects in contact and determine the strength of their adhesion. Furthermore, because biological cells generally have a fixed range of sizes and shapes, additional elastic energy terms are considered whenever deviations from a target volume or elongation occur. All these contributions lead to (2.1), representing the βenergyβ of the system at each time instant. Cytoskeletally driven membrane fluctuations can be mimicked by randomly choosing a lattice site and copying its index into a randomly chosen neighboring lattice site (single-head arrow).
