Mammals and birds rely heavily on audition to localize prey or escape predator. Many studies demonstrated the high degree of precision the auditory system achieves in encoding sound properties present at both ears, and proposed explanations for underlying mechanisms. For instance, brainstem neurons are sensitive to certain stimulus properties, such as the interaural time difference present at both ears (ITD), or to the phase of the input sound. In order to assess this neural sensitivity, such experiments involves the variation of one stimulus parameter, while keeping the others fixed. Our acoustical inputs are nevertheless mutli-dimensional, e.g. a sound with a certain ITD can have different intensities, with the consequence that neural sensitivity to a certain property does not equate with the information contained about this property.
In this project, we propose to study whether the sound encoding capacity of brainstem monaural neurons is robust against changes in stimulus parameters, such as overall intensity and modulation depth. While the few results available on the topic used stationary stimuli, we propose to record and analysis neural responses to non-stationary sounds, both artificial and natural. The use of such non-stationary sounds is crucial for the long-term goal of understanding auditory processing in realistic environments, as they introduce additional constraints for efficient sound encoding. To complement this experimental approach, modeling is used to investigate necessary mechanisms, e.g. dynamical neural threshold, needed to exhibit such invariance of responses to certain input parameters. The outputs of this project will have important consequences, both fundamental and practical, as, for instance, a better understanding of auditory processing of naturalistic stimuli allows refining encoding strategies for auditory prosthetic devices.
Field of science
- /humanities/languages and literature/linguistics/phonetics
Call for proposal
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