Event:

In songbirds, testosterone and its estrogenic metabolites are involved in both the developmental and seasonal acquisition of song. In a well-studied model system, male canaries (Serinus canaria) sing seasonally in a testosterone-dependent manner in order to attract females. Female canaries do not sing at all during the breeding season, but may produce a relatively primitive song, known as subsong outside of the breeding season. When treated with testosterone, female canaries can develop highly structured songs that contain features similar to sexy songs of males. Singing of songbirds such as the canary is controlled by brain areas interconnected in the song control system. A” key” song area is the HVC (letter based name) that controls the sequential appearance of song motor units. The canonical idea is that the hormone induced singing correlates with hormone induced plasticity of the song system, in particular of the morphology and neuron numbers of HVC.
Further, testosterone and its estrogenic metabolites induce changes in the transcriptome of HVC. I discuss if and how hormone-induced singing, HVC-transcriptomes, and HVC-morphology are related. Then I show that one hormone induced gene, the neurotrophin BDNF is a central player in song development.