Effect of laser light irradiation on neurite elongation. The figure illustrates the effect of laser light irradiation on neurite elongation in PC12 cells cultured on laminin and collagen. A. The continuous black line delineates the cell body, whereas the dotted lines mark the processes (see text for details and inclusion/exclusion criteria). B. Neurite length of non-irradiated, MOD1 and MOD2 irradiated cells at 1, 2, 3 and 4 days in vitro. NGF stimulates neurite outgrowth for 3–4 days; MOD1, but not MOD2, further extends neurite outgrowth. Statistical analysis: two-way ANOVA and post-hoc test, *p < 0.05.