Dresden 2017 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 54: Statistical Physics of Biological Systems I (Joint Session BP/DY)

BP 54.3: Vortrag

Donnerstag, 23. März 2017, 15:30–15:45, ZEU 250

Statistical description of normalized odor representations — •David Zwicker — Harvard University, Cambridge, USA

Natural odors comprise many molecules at different concentrations and it is unclear how such odors are discriminated by relatively few olfactory receptors. One problem is that the correlations present in natural odors cannot be removed by local computations, like center-surround inhibition in vision. Instead, the global inhibition present in the olfactory system leads to normalized odor representations, where the odor intensity is separated from its identity, encoded by the relative concentrations of the odorant molecules. This separation is useful to robustly identify odors at different intensities, but how such global inhibition influences the neural representations of odors is unclear.

In this presentation, I discuss a simple theoretical model of the olfaction system that focuses on global inhibition. The model leads to sparse odor representations and reveals two generic consequences of global inhibition: (i) odors with many molecular species are more difficult to discriminate and (ii) receptor arrays with heterogeneous sensitivities perform badly. Comparing these predictions to experiments will help us to understand the role of global inhibition in shaping normalized odor representations.