The present study has the following specific aims:
1. to provide data on human olfactory detection thresholds for five members of a homologous series of aliphatic aldehydes (C4-C8)
2. to provide data on olfactory discrimination ability of human subjects as a function of stimulus concentration
3. to determine the concentration span between detection and qualitative recognition of aliphatic aldehydes in human subjects
4. to assess odor structure-activity relationships in human subjects and to compare them to those of other species tested previously on the same set of odorants
5. to evaluate the impact of the number of functional olfactory receptor genes on threshold sensitivity and discrimination performance