TestimonialMy summer as a Grass Fellow (1985) was probably one of the most productive and career-changing three months of my life. My work in collaboration with Jeff Corwin led to the discovery of hair cell bundle reorientation during development and to the eventual discovery of hair cell regeneration in the avian cochlea. Both of these discoveries have radically changed the direction of the entire field of hearing research since then. This seminal work went on to influence a whole new field defining PCP gene pathways in the developing chick and mouse cochlea. Our work on the discovery of hair cell regeneration was published in Science in 1988 and although it doesn't specifically mention support from the Grass Foundation, it probably should have. Most of the ideas and future studies Jeff and I did together on regeneration had their initial formulation that summer in Woods Hole. Well, it turns out I forgot to include the work that Jeff and I did that summer that was actually what we got funded for in the first place by the Grass Foundation! We were able to show that embryonic hair cells developed their correct tonotopic features completely independently of innervation by culturing denervated chick cochlea and tracking the differentiation of their position-specific tonotopic stereocilia morphologies. This work eventually led to the current research on the inherent genetic control of hair cell differentiation within the sensory epithelium that has been such an exciting finding in recent work on hair cell development. Prior to our discovery, the field assumed that the cochlear nerves primarily influenced and regulated the development of hair cells and their tuning characteristics and that the hair cells were just passive recipients of the critical developmental signals.