Laurel Carney is invited by the PDS team in the context of the ANR project INSPECTSYN to present her novel theory about the neural coding of sounds, in particular speech, by the auditory system (Look at the figure: Which neural mechanisms provide the magenta curve from the input spectrum?).

This theory, which fundamentally challenges our "usual" way of thinking about sound, is shaking up not only the auditory neuroscience community, but also many other disciplinary fields, as its implications invite us to reconsider the way audio signal descriptors are designed as well as how hearing aids or cochlear implants algorithms work.

Abstract: This talk will provide examples of how we are using computational models to simulate and test our ideas about how the auditory nervous system functions. For example, the nonlinearities of the inner ear are often considered to be obstacles that the central nervous system has to overcome to decode neural responses to sounds. Using a model that includes these nonlinearities, I will describe how saturation of the inner-hair-cell response and of the IHC-auditory-nerve synapse are actually beneficial to the neural encoding of complex sounds such as speech. These nonlinearities set up contrast in the depth of neural-fluctuations in auditory-nerve responses along the tonotopic axis, referred to as neural fluctuation contrast (NFC). Physiological and psychophysical support for the NFC coding hypothesis will be presented, including model predictions of speech intelligibility in listeners with sensorineural hearing loss. Also, I will present a framework based on the NFC code for understanding how the medial olivocochlear (MOC) efferent system may contribute to the coding of complex sounds by enhancing NFC along the tonotopic axis, enabling robust encoding of complex sounds across a wide range of sound levels and in the presence of background noise.

Biography: Laurel Carney is Professor of Biomedical Engineering and Neuroscience at the University of Rochester since 2007 and director of the auditory neuroscience laboratory. After completing a PhD in electrical engineering at the University of Wisconsin and a postdoctoral fellowship in psychology at the University of Pennsylvania, she took several faculty positions at Boston University and Syracuse University. She has received numerous awards and prizes for her research and teaching. She is a fellow of the Acoustical Society of America and the American Institute of Medicine and Biomedical Engineering.