Stefan Martignoli

Email:	mstefan@ini.phys.ethz.ch
Work phone:	41 44 635 30 62
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The mammalian auditory system extracts from the arriving soundwaves rich portraits of the auditory environment. To a large extent, this ability is the consequence of the nonlinear signal processing in the cochlea, where the local amplification profiles have been shown to originate from systems close to Hopf bifurcations. Starting from biophysical principles, we have developed and implemented an analog electronic Hopf-cochlea displaying mammalian hearing characteristics (patented). Using this novel sensor, we aim at implementing in this project an autonomous hearing system, supported by an auditory cortico-cochlear feedback loop. In particular, we investigate the role of cochlear processing in assisting a listener to discriminate between different auditory objects in a cocktail-party environment and how much this task can be improved by an efferent tuning of the Hopf-amplifiers.
As a long-term goal, the sensor will be used as a next-generation cochlea implant. In this context, a hardware-bioware interfacing project was recently set up together with specialists in this field.
The Hopf-approach is further used to study how hearing impairment could be mended, to study and model human perception of complex sounds, and to better understand the hearing systems of insects. Finally, the Hopf-cochlea will be embedded within a general theory of Hopf-sensors.