Possible model for interaction of young neurons with topography for polarization and axon formation.

<p>(<b>A</b>) When a neuron is located on the interface between a pillar array and a flat area (step 1) the N-cadherin patch is accumulated at the topographical contact, also F-actin is located at pillar contact via an unknown mechanism (step 2). After first sprout formation (step 3), the Golgi and centrosome are also recruited to the interface (step 4), from which at a later time point the axon starts to form (step 5). (<b>B</b>) Pillar contact gives rise to growth signaling, if this is repeated frequently enough during outgrowth of the neurite this leads to an overall growth encouragement. On the other hand if the pillars are spaced further apart, this neurite will not be able to exploit its full growth potential.