In the mammalian ear, sounds are encoded as cochlear vibrations that are tonotopically organized, i.e., with high and low frequencies maximally stimulating auditory-nerve fibers at basal and apical sites, respectively. Herman von Helmholtz thought that those vibrations might resemble standing waves such as those of piano or harp strings. This view was superseded after George von Békésy described traveling waves which propagated on the basilar membrane of human cadaver cochleae from base to apex. Traveling waves have been described only at a few sites of healthy cochleae in living animals. We have gleaned some of the missing information by studying the phases of responses to tones of auditory-nerve fibers innervating sites throughout the chinchilla cochlea. Collectively, these response phases provide the first general description of organ of Corti traveling waves as a function of both frequency and cochlear place and also reveal a non-traveling wave form of vibration, reminiscent of Helmholtz’s views

 

Mario Ruggero is well known for his studies of the physiology and biophysics of the mammalian cochlea. he was Hugh Knowles professor of Hearing Sciences at department of Communication Disorders, member of Graduate School Faculty in Northwestern University, USA. He is Fellow of the Acoustical Society of America and the American Association for the Advancement of Science. He was Associate Editor of the Journal of Neuroscience and a member of the editorial Boards of Audiology and Neuro-Otology and the Journal of the Association for Research in Otolaryngology. He has published 73 journal articles, 59 abstracts, 3 book reviews and has co-edited one book.