title: Innate versus learned odour processing in the mouse olfactory bulb.
abstract: The mammalian olfactory system mediates various responses, including aversive behaviours to spoiled foods and fear responses to predator odours. In the olfactory bulb, each glomerulus represents a single species of odorant receptor. Because a single odorant can interact with several different receptor species, the odour information received in the olfactory epithelium is converted to a topographical map of multiple glomeruli activated in distinct areas in the olfactory bulb. To study how the odour map is interpreted in the brain, we generated mutant mice in which olfactory sensory neurons in a specific area of the olfactory epithelium are ablated by targeted expression of the diphtheria toxin gene. Here we show that, in dorsal-zone-depleted mice, the dorsal domain of the olfactory bulb was devoid of glomerular structures, although second-order neurons were present in the vacant areas. The mutant mice lacked innate responses to aversive odorants, even though they were capable of detecting them and could be conditioned for aversion with the remaining glomeruli. These results indicate that, in mice, aversive information is received in the olfactory bulb by separate sets of glomeruli, those dedicated for innate and those for learned responses.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Kobayakawa
authors.forename: Reiko
authors.initials: R
authors.lastname: Kobayakawa
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Oka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imai
authors.forename: Masahito
authors.initials: M
authors.lastname: Ikawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Okabe
authors.forename: Toshio
authors.initials: T
authors.lastname: Ikeda
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Itohara
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kikusui
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakano
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D002087:Butyrates / Q000494:pharmacology; D020869:Gene Expression Profiling; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D009154:Mutation / Q000235:genetics; D009434:Neural Pathways / Q000187:drug effects; D009812:Odorants / Q000032:analysis*; D009830:Olfactory Bulb / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018035:Receptors, Odorant / Q000378:metabolism; D012903:Smell / Q000187:drug effects / Q000502:physiology*; D013844:Thiazoles / Q000494:pharmacology
chemical_list: C451263:2,4,5 trimethylthiazoline; D000447:Aldehydes; D002087:Butyrates; D018035:Receptors, Odorant; D013844:Thiazoles; C046012:pentanal; C019475:2-methylbutanoic acid