Norepinephrine inhibition in juvenile male zebra finches modulates adult song quality.

During development, male zebra finches learn a song that they eventually use in courtship and defense of nest sites. Norepinephrine (NE) is important for learning and memory in vertebrates, and this neuromodulator and its receptors are present throughout the brain regions that control song learning and production. The present study used the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP4) to reduce brain levels of NE in juvenile males. This manipulation inhibited the development of quality songs, with some birds producing syllables that were unusually long and/or contained frequencies that were predominantly higher than normal. These results suggest that NE is important for the acquisition of typical song.