Percolation model of axon guidance

In the developing brain neurons interconnect via the action of molecules that guide the axon to its targets, thus allowing the proper wiring scheme to emerge. It is not fully understood whether the underlying mechanism is wholly deterministic or not. The existence of “choice-points” and “decision-regions” suggests that options are available to the growth cone. The guidance mechanism is here simulated by equating the axonal trajectory to that of a trickle of ground water sipping through a bed of sand. Decision regions are implemented by assigning each site of the percolation lattice a set of probabilities ruling the possible moves.