Figure 3

Testosterone stimulated the expression of neurofilament in the song control nuclei of female European robins. Photomicrographs are shown for the HVC (A, B, E, F), the RA (D, H) and for the caudal forebrain (C, G) after anti-neurofilament immunofluorescence staining. Scale bars represent 100 μm (A for A and E; C for C and G) and 250 μm (D, H), respectively. Sagittal cryostat sections were obtained from control (left panels) and testosterone (right panels) female robins. Please note an expansion of circumcellular, neurofilament-immunopositive structures after testosterone treatment.