Abstract
The olfactory system faces a hard problem: on the basis of noisy information from olfactory receptor neurons (the neurons that transduce chemicals to neural activity), it must figure out which odors are present in the world. Odors almost never occur in isolation, and different odors excite overlapping populations of olfactory receptor neurons, so the central challenge of the olfactory system is to demix its input. Because of noise and the large number of possible odors, demixing is fundamentally a probabilistic inference task. We propose that the early olfactory system uses approximate Bayesian inference to solve it. The computations involve a dynamical loop between the olfactory bulb and the piriform cortex, with cortex explaining incoming activity from the olfactory receptor neurons in terms of a mixture of odors. The model is compatible with known anatomy and physiology, including pattern decorrelation, and it performs better than other models at demixing odors.
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Acknowledgements
Funding for A.G.-B. and P.E.L. was provided by the Gatsby Charitable Foundation; for Z.F.M. and A.P., by the Human Frontiers Science Programme (RGP0027/2010) and the Simons Foundation (325057); for A.P., by the Swiss National Foundation (31003A_143707).
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A.G.-B., Z.F.M., A.P. and P.E.L conceived the project. A.G.-B., S.B., J.B., A.P. and P.E.L. developed the theory. A.G.-B., S.B., A.P. and P.E.L. wrote the manuscript. A.G.-B. performed the simulations.
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Grabska-Barwińska, A., Barthelmé, S., Beck, J. et al. A probabilistic approach to demixing odors. Nat Neurosci 20, 98–106 (2017). https://doi.org/10.1038/nn.4444
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DOI: https://doi.org/10.1038/nn.4444
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