Fig. 3

Differential expression of singing-driven IEGs during the fall and spring. a Examples of singing-driven induction of IEG mRNAs (Egr1, c-fos, Nr4a1, Sik1, Dusp6, and Gadd45β) in RA in first fall, second spring, and second fall. All images in columns are from the same bird. Total cumulative singing duration before brain sampling is shown at the bottom of the panels. White dots: mRNA expression. Red: cresyl violet counterstain. Scale bar = 200 μm. b Induction response of the six singing-driven IEGs in song nuclei in first fall, second spring, and second fall. Two-way ANOVA with Scheffe’s F test. *p < 0.05, **p < 0.01