Decoding the hearing: ERC grant for Tobias Moser

Our sense of hearing processes acoustic signals that differ in sound pressure by more than six orders of magnitude. This enables the perception of auditory impressions as different as rustling of leaves and a roaring jet engine. This amazing function of the ear can be compared to trying to measure body temperature and the temperature inside the sun with the same thermometer. While the presynaptic inner hair cells (IHCs) in the cochlea cover the entire dynamic range of audible sound intensities, each downstream spiral ganglion neuron (SGN) encodes only a fraction. The intensity information is then reconstructed by the brain. This so-called "dynamic range problem" of hearing is known for decades, but how sound intensity information is decomposed into different neural pathways remains elusive.

In vivo recordings discovered a wide functional diversity of postsynaptic SGNs that also exhibit distinct molecular profiles. Ensembles of these different neurons collectively encode the intensity for a given sound frequency. The aim of the project is to test the hypothesis that an interplay of synaptic heterogeneity, molecularly distinct subtypes of SGNs, and efferent modulation serves the neuronal decomposition of sound intensity information. Using a multiscale and multidisciplinary research approach, Moser and his team will elucidate the molecular underpinnings of synaptic heterogeneity, decipher the mechanisms establishing such heterogeneity, and relate them to functional SGN diversity. To this end, the scientists combine state-of-the-art multimodal imaging approaches, optogenetics and modeling techniques.

MEDICA-tradefair.com; Source: University Medical Center Göttingen