Processing of Odor Mixtures in the Mammalian Olfactory System

Abstract

Animals rarely encounter odors in isolation, and their olfactory
systems generally operate in the context of complex mixtures of odorants.
Individual objects typically emit a multitude of volatile chemicals
that become their signature for identification. In addition, chemicals emitted
from multiple objects mix in the air before reaching the nose. There
is great interest, therefore, in understanding how mixtures are processed
by the olfactory system to allow perceiving objects and segregating them
from background odors. Studies comparing the neural responses to single
odorants and their mixtures show that it is often not easy to predict
the mixture response from the components, suggesting that cross-odorant
interactions take place at multiple levels of the mammalian olfactory
system. Experiments that relate cross-odorant interactions to perception
may elucidate how mixture processing underlies object identification
and background segregation.