title: Architecture of odor information processing in the olfactory system.
abstract: Since the discovery of the superfamily of approximately 1000 odorant receptor genes in rodents, the structural simplicity as well as the complexity of the olfactory system have been revealed. The simple aspects include the one neuron-one receptor rule and the exclusive convergence of projections from receptor neurons expressing the same receptors to one or two glomeruli in the olfactory bulb. Odor decoding in the olfactory cortex or higher cortical areas is likely to be a complicated process that depends on the sequence of signal activation and the relative signal intensities of receptors overlapping for similar but different odors. The aim of the present study was to investigate odor information processing both in receptors and in the olfactory cortex. At the receptor level, the similarity and difference in receptor codes between a pair of chiral odorants were examined using the tissue-printing method for sampling all the epithelial zones. In order to dissect odor-driven signal processing in the olfactory cortex by reducing cross-talk with the non-olfactory activities, such as cyclic respiration or other sensory inputs, an in vitro preparation of isolated whole brain with an attached nose was developed, and the methodologies and resulting hypothesis of receptor-sensitivity-dependent hierarchical odor information coding were reviewed.
authors.affiliation: Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Amagasaki, Hyogo, Japan. taka-sato@aist.go.jp
authors.forename: Takaaki
authors.initials: T
authors.lastname: Sato
authors.forename: Junzo
authors.initials: J
authors.lastname: Hirono
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hamana
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Akira
authors.initials: A
authors.lastname: Shimizu
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takashima
authors.forename: Riichi
authors.initials: R
authors.lastname: Kajiwara
authors.forename: Toshio
authors.initials: T
authors.lastname: Iijima
mesh_terms: D000818:Animals; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D006168:Guinea Pigs; D008297:Male; D009666:Nose / Q000033:anatomy & histology / Q000502:physiology; D009812:Odorants; D009831:Olfactory Mucosa / Q000502:physiology; D009833:Olfactory Pathways / Q000033:anatomy & histology* / Q000502:physiology*; D055696:Olfactory Perception / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000033:anatomy & histology / Q000502:physiology