The mammalian olfactory system is able to solve two important problems in chemistry. Specifically, it discriminates between closely related odorant chemicals, but it also detects odorants of vastly different chemical structure. The responses of the olfactory bulb to a small number of relatively similar odorants have suggested some potentially fundamental rules for odor coding by the olfactory system. However, the measured responses constitute only a meager sampling of the large number of receptors, ligands, and perceived odors that are involved in normal olfactory function. We are now in a position to test the generality of current hypotheses by assessing glomerular responses to 355 odorants by using a 2-deoxyglucose uptake technique that affords access to the entire structure of the olfactory bulb. These odorants include sets of molecules that differ incrementally along a number of as yet untested molecular dimensions. At the same time, the odorants also include molecules differing very greatly in chemical structure, thereby providing a sample more commensurate with the broad capabilities of the olfactory system. In addition to testing hypotheses that have been advanced previously, this large and varied odorant set should give ample opportunity to uncover novel aspects of odor coding. Finally, we have developed a method to place all of the glomerular activity data in a database that we can use to assess quantitative similarities and differences in patterns either across the entire glomerular layer, or in smaller regions of that lamina. This approach should allow us to extract information about the structural features in odorant molecules that are critical for stimulating specific glomerular areas. The approach also should allow us to make additional quantitative predictions regarding similarities in odor perceptions. We plan to use this informatics approach to extract novel hypotheses regarding the relationships between odorants, glomerular activity and odor perception.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
2R01DC003545-06
Application #
6541184
Study Section
Integrative, Functional and Cognitive Neuroscience 8 (IFCN)
Program Officer
Davis, Barry
Project Start
1998-01-01
Project End
2007-12-31
Budget Start
2003-01-01
Budget End
2003-12-31
Support Year
6
Fiscal Year
2003
Total Cost
$365,338
Indirect Cost
Name
University of California Irvine
Department
Other Basic Sciences
Type
Schools of Arts and Sciences
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Falasconi, Matteo; Gutierrez-Galvez, Agustin; Leon, Michael et al. (2012) Cluster analysis of rat olfactory bulb responses to diverse odorants. Chem Senses 37:639-53
Johnson, Brett A; Woo, Cynthia C; Zeng, Yu et al. (2010) Prolonged stimulus exposure reveals prolonged neurobehavioral response patterns. J Comp Neurol 518:1617-29
Johnson, Brett A; Ong, Joan; Leon, Michael (2010) Glomerular activity patterns evoked by natural odor objects in the rat olfactory bulb are related to patterns evoked by major odorant components. J Comp Neurol 518:1542-55
Leon, Michael; Johnson, Brett A (2009) Is there a space-time continuum in olfaction? Cell Mol Life Sci 66:2135-50
Johnson, Brett A; Xu, Zhe; Ali, Sameera S et al. (2009) Spatial representations of odorants in olfactory bulbs of rats and mice: similarities and differences in chemotopic organization. J Comp Neurol 514:658-73
Johnson, Brett A; Ong, Joan; Lee, Kaman et al. (2007) Effects of double and triple bonds on the spatial representations of odorants in the rat olfactory bulb. J Comp Neurol 500:720-33
Johnson, Brett A; Arguello, Spart; Leon, Michael (2007) Odorants with multiple oxygen-containing functional groups and other odorants with high water solubility preferentially activate posterior olfactory bulb glomeruli. J Comp Neurol 502:468-82
Cleland, Thomas A; Johnson, Brett A; Leon, Michael et al. (2007) Relational representation in the olfactory system. Proc Natl Acad Sci U S A 104:1953-8
Johnson, Brett A; Leon, Michael (2007) Chemotopic odorant coding in a mammalian olfactory system. J Comp Neurol 503:1-34
Woo, Cynthia C; Hingco, Edna E; Johnson, Brett A et al. (2007) Broad activation of the glomerular layer enhances subsequent olfactory responses. Chem Senses 32:51-5

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