Sholl analysis of neurons cultured at different initial plating densities. (A) Initial plating density had no effect on dendrites when neurons were cultured on soft gels. (B) When plated at the lowest density (50,000 cells/cm2), neurons cultured on stiff gels had the most proximal dendrites (See Table S4 for p values). (C) Sholl analysis of neurons cultured on soft and stiff gels with the same final number of cells. (See Table S5 for p values). Bar indicates significance. Data were averaged across four experiments. All data are represented as mean ± SEM. Numbers of cells for each condition are listed for 50,000, 80,000, and 100,000 cells/cm2, respectively. Soft gels: n= 28; 37; 34. Stiff gels: 35; 30; 33.