New studies on hair cell regeneration in birds

The discovery of hair cell regeneration in birds a little over a decade ago raises a number of obvious and exciting questions about basic functional and neural plasticity in the vertebrate auditory system. Because many birds must learn the complex, species-specific, acoustic signals they use for communication just as humans must learn the sounds of speech, the finding of hair cell regeneration in birds also raises other interesting questions. One of these questions concerns the relation between hearing loss and vocal production. Another question concerns the effect of full or partial hearing recovery on vocal behavior. The purpose of this paper is to review what is known about the functional (i.e. behavioral) consequences of hair cell loss and subsequent hair cell regeneration in birds, to point out the relevance of this work for human hearing recovery, and to suggest some directions for future research.