Abstract:


Songbirds are capable of vocal learning and communication and are ideally suited to the study of neural mechanisms of auditory feedback processing. We investigate feedback processing in single auditory forebrain neurons of juvenile zebra finches that are in a late developmental stage of song learning. Overall, we see similarity of spike responses during singing and during playback of the bird’s own song, with song responses commonly leading by a few milliseconds. However, brief time-locked acoustic perturbations of auditory feedback reveal complex sensitivity that cannot be predicted from passive playback responses. Some neurons that respond to playback perturbations do not respond to song perturbations, which is reminiscent of sensory-motor mirror neurons. By contrast, some neurons are highly feedback sensitive in that they respond vigorously to song perturbations, but not to unperturbed songs or perturbed playback. These findings suggest that a computational function of forebrain auditory areas may be to detect errors between actual feedback and mirrored feedback deriving from an internal model of the bird’s own song or that of its tutor. Such feedback-sensitive spikes could constitute the key signals that trigger adaptive motor responses to song disruptions or reinforce exploratory motor gestures for vocal learning.