RECOVERY OF HEARING AND VOCAL BEHAVIOR AFTER HAIR-CELL REGENERATION

Postmitotic hair-cell regeneration in the inner far of birds provides an opportunity to study the effect of renewed auditory input on audito ry perception, vocal production, and vocal learning in a vertebrate, W e used behavioral conditioning to test both perception and vocal produ ction in a small Australian parrot, the budgerigar. Results show that both auditory perception and vocal production are disrupted when hair cells are damaged or lost but that these behaviors return to near norm al over time. Precision in vocal production completely recovers well b efore recovery of full auditory function. These results may have parti cular relevance for understanding the relation between hearing loss an d human speech production especially where there is consideration of a n auditory prosthetic device, Tile present results show, at least for a bird, that even limited recovery of auditory input soon after deafen ing can support full recovery of vocal precision.