Gating of auditory responses in the vocal control system of awake songbirds.

Nucleus HVc of the avian song system is a forebrain structure critical in song production, perception and learning. Here we show that most HVc neurons that respond to auditory stimuli under anesthesia show no responses to the same stimulus in the awake, unrestrained bird. This suppression of auditory responses in awake birds does not occur in the forebrain field L complex, which is one of the auditory input stages for HVc. Gating of auditory input at the junction between the auditory and vocal control system may be essential for regulating auditory feedback signals necessary for song learning and maintenance.