Neural auditory selectivity develops in parallel with song.

The zebra finch learns his song by memorizing a tutor's vocalization and then using auditory feedback to match his current vocalization to this memory, or template. The neural song system of adult and young birds responds to auditory stimuli, and exhibits selective tuning to the bird's own song (BOS). We have directly examined the development of neural tuning in the song motor system. We measured song system responses to vocalizations produced at various ages during sleep. We now report that the auditory response of the song motor system and motor output are linked early in song development. During sleep, playback of the current BOS induced a response in the song nucleus HVC during the song practice period, even when the song consisted of little more than repeated begging calls. Halfway through the sensorimotor period when the song was not yet in its final form, the response to BOS already exceeded that to all other auditory stimuli tested. Moreover, responses to previous, plastic versions of BOS decayed over time. This indicates that selective tuning to BOS mirrors the vocalization that the bird is currently producing.