Temporal processing of odor mixtures reveals that identification of components takes precedence over temporal information in olfactory memory.

Temporal processing of binary mixtures results in odorants being perceived in series separated by many hundreds of milliseconds. Since the odorant perceived first is the main suppressor, knowledge of the order of perception of two odorants can allow prediction of interactions in mixtures. The present study investigated the temporal coding of ternary mixtures composed of carvone, coniferan and triethylamine, and citralva, lillial and triethylamine using a specially constructed air-dilution olfactometer. The results indicated that even though each of the components could be readily identified in ternary mixtures, it was very difficult to indicate which odor was perceived first, with chance scores being recorded. The same outcome occurred even when the 'slowest' odorant was delivered 600 ms after the 'fastest' to the nose. It is proposed that olfactory memory gives precedence to identification of the components of mixtures rather than to their order of perception when more than two odorants are in a mixture.