Fig. 4.
Mean numbers of ZENK-labeled cells counted in (A) POM, (B) LSc.vl, (C) BSTm(v), (D) GCt, and (E) VTA. Black bars are breeding condition males with nestboxes; gray bars, breeding condition males without nestboxes; white bars, non-breeding condition males. Asterisk indicates significant differences between breeding condition males with nestboxes and those without nestboxes (p<0.05; Student’s t-tests). Data from non-breeding condition males were not statistically compared to breeding condition males due to methodological differences.