Cntnap2 expression outside the song system in developing and adult male zebra finch brain. High levels of Cntnap2 were detected early in development, in both anterior (B) and posterior (F) hatchling (1d) brain, highlighting robust expression in HA, N, NC, St (including MSt and StL), DTZ and TeO. A similar Cntnap2 expression pattern was conserved in anterior (D) and posterior (H) male brain at 6d. The same structures were labeled by Cntnap2 probe in female brain (not shown). In the adult, Cntnap2 hybridization signals were enriched in NC, MSt, StL, SpL (J), Hb, DTZ and SpM (L), TeO and IM/IPc (J,L). Inverted darkfield images of emulsion autoradiograhy of posterior male brain revealed robust labeling of TeO layers 6, 8–10 and 13 and tectal nuclei IM and IPc (O), as well as in the Purkinje cell layer of Cb (R). Arrowheads in P and R point to the Purkinje cell layer. More attenuated emulsion grain signals were detected in the midbrain nuclei ICo/MLd (O). For abbreviations, see Table 1. Scale bars = 1 mm.