Figure 3

Acute BDNF treatment induces maturation of the dendritic spine population. 11 DIV hippocampal neurons were transfected with a vector expressing Lifeact-ruby, and 24 hrs later, the neurons were treated with vehicle or 100 ng/ml BDNF followed by time-lapse imaging every 5 minutes for 1 hr. Each protrusion was tracked across time and measured using the automated method. (a) Head volume was plotted as the percent change from the initial time point (T₀). Statistical analyses were performed to compare protrusion head volume at T₀ and T₆₀ (N = 105 - 135 spines; Kruskal Wallis test with repeated measures; Control: P = 0.548; BDNF: P = 0.001). (b) Neck width was plotted and analyzed as above (Control: P = 0.91; BDNF: P = 0.0002). (c) Dendritic protrusion length was plotted and analyzed as above (Control: P = 0.648; BDNF: P = 0.017). (d) Dendritic protrusions were classified as stubby, mushroom, or thin at each time point. The percentages of total protrusions within each class are presented for T₀ and T₆₀ (*P = 0.038, ^‡P = 0.044, ^#P = 0.015). (e) The number of protrusions within a dendritic region was determined using Imaris Filament Tracer and compared between T₀ and T₆₀ (N = 25 - 30 neurons; repeated measures ANOVA, post-hoc Tukey's test [Control: P = 0.219; BDNF: P = 0.014]).