Fig. 3

Neuronal activity induces growth on permissive but not inhibitory substrates. A Neurite outgrowth was significantly increased in optogeneticallty stimulated DRG neurons over growth-permissive substrates (0; laminin), but not over different concentrations (5, 10, 20 μg/ml) of non-permissive substrates (CSPGs). Average neurite length per neuron was determined at 24 h in vitro. Data are expressed as mean neurite length per cell ± s.e.m (n = 7–12 images). **p < 0.01 denotes significant differences in ANOVA followed by Bonferroni test. B Neurite branching is increased dose-dependently by CSPGs but is not affected by neuronal stimulation. Average number of branches for each 100 µm was determined at 24 h in vitro. Data are expressed as mean ± s.e.m (n = 7–12 images; *p < 0.05; ***p < 0.005 denote significant differences vs respective 0 µg/ml condition in ANOVA followed by Bonferroni test). C Representative images of Tuj-1 staining used to analyze neurite length. Scale bar: 200 μm