Architecture of odor information processing in the olfactory system
Article first published online: 25 FEB 2008
© 2008 The Authors. Journal compilation © 2008 Japanese Association of Anatomists
Anatomical Science International
Volume 83, Issue 4, pages 195–206, December 2008
How to Cite
Sato, T., Hirono, J., Hamana, H., Ishikawa, T., Shimizu, A., Takashima, I., Kajiwara, R. and Iijima, T. (2008), Architecture of odor information processing in the olfactory system. Anatomical Science International, 83: 195–206. doi: 10.1111/j.1447-073X.2007.00215.x
- Issue published online: 6 NOV 2008
- Article first published online: 25 FEB 2008
- Received 13 March 2007; accepted 26 October 2007.
- odor coding;
- odor discrimination;
- piriform cortex;
- sensory information processing
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.