Figure 6Figure 6
A) Nissl stain of sagittal section of the male zebra finch brain at the level of the cerebellum and Area X (dotted white circle). B) Nissl stain of the zebra finch telencephalon at the level of striatal Area X (dotted white circle) which is visible bilaterally. C-F) Photomicrographs show immunostain signals for DNA (DAPI-blue), FoxP2 (green) and CASK (red) as well as a merged image (far right panel in each row). C) As expected, cerebellar Purkinje neurons do not show strong DAPI signals (left panel; white arrowheads) but do co-stain for FoxP2 and CASK D). Striatal neurons from an adult male zebra finch housed with a female show co-localization of FoxP2 and CASK signals (white arrowheads). In striking contrast, those from a male who sang alone (E) show undetectable FoxP2 signals and strong CASK signals whereas those from a non-singer (F) show robust FoxP2 signals and undetectable CASK. Abbreviations: A=Anterior, D=Dorsal, L=lateral