The olfactory system translates myriad chemical structures into diverse odour perceptions. To gain insight into how this is accomplished, we prepared mice that coexpressed a transneuronal tracer with only one of about 1,000 different odorant receptors. The tracer travelled from nasal neurons expressing that receptor to the olfactory bulb and then to the olfactory cortex, allowing visualization of cortical neurons that receive input from a particular odorant receptor. These studies revealed a stereotyped sensory map in the olfactory cortex in which signals from a particular receptor are targeted to specific clusters of neurons. Inputs from different receptors overlap spatially and could be combined in single neurons, potentially allowing for an integration of the components of an odorant's combinatorial receptor code. Signals from the same receptor are targeted to multiple olfactory cortical areas, permitting the parallel, and perhaps differential, processing of inputs from a single receptor before delivery to the neocortex and limbic system.
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We are grateful to F. Alt for providing training in his laboratory in embryonic stem cell techniques. We would like to thank P. Mombaerts for the pETLpA/LTNL plasmid; Q. Ma for helpful suggestions; and D. Hubel and R. Brent for critically reading the manuscript. We would also like to thank C. Gao for technical assistance, and members of the Buck laboratory for comments and discussions. This work was supported by the Howard Hughes Medical Institute, grants from the National Institutes of Health and the Department of Defense (L.B.B.), a Howard Hughes Predoctoral Fellowship (L.F.H.), the Fyssen Foundation (J.-P.M.) and the Alice and Joseph Brook Fund (J.-P.M.).
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Zou, Z., Horowitz, L., Montmayeur, JP. et al. Genetic tracing reveals a stereotyped sensory map in the olfactory cortex. Nature 414, 173–179 (2001). https://doi.org/10.1038/35102506
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