Fig. 5.

Polar Distribution of Axonal Outgrowth: Varying P, Fixed L/P Axonal outgrowth direction observed when varying P while holding L/P fixed (L/P = 0.5, or equivalently, L/G = 1). In addition to values of P seen previously, P = 1.7 μm is now also included. Angles are indicated around each plot. Data are grouped in 1° bins, where the length of a line indicates the relative number of axons for a given direction, normalized for each value of P. All data are overlaid upon representative micropatterns. For each pattern dimension, n ≥ 509 (number of counted axons) obtained from at least six independent samples. Guidance dramatically varies from predominantly parallel (P = 8.3 μm) to perpendicular (P = 1.7 μm). In fact, obvious parallel guidance entirely vanishes on the smallest periodicity. As can be seen in the data, the distribution of parallel growth tends to be very narrow, while the distribution of perpendicular growth is much wider.