BDNF triggers the formation of nascent growth cone adhesions. (A) Representative confocal images of dual immunolabeled growth cones showing β1-integrin (red) and known cytoplasmic adhesion components (green: FAK; PY; vinculin; talin; α-actinin) after BDNF treatment (50 ng/mL; 20 min). Arrowheads in the merged images denote spots of co-localization. Scale bar, 5 μm. (B) Quantification of the percentage of total immunostaining for adhesion components, α5-integrin, and TrkB receptors that overlapped with β1-integrin clusters. Data are the mean ± standard error of the mean. (n > 40, n/s P > 0.05, **P < 0.001, ANOVA with Tukey's post hoc analysis.) BDNF: brain-derived neurotrophic factor; FAK: focal adhesion kinase; PY: phosphotyrosine.