Evidence for the temporal processing of odor mixtures in humans.

The neural mechanisms underlying the perception of complex odor mixtures are largely unknown. The present study investigated the hypothesis that odorants in a mixture are processed and perceived in series. The results indicate that (i) odorants in mixtures are temporally processed with up to several hundred milliseconds separating individual components; (ii) 'fast' odorants are more likely to be a suppressor of 'slow' odorants than the reverse; and (iii) separation times can be altered by changing the concentrations of mixture components. These findings provide a new mechanism to account for the limited ability of humans to identify odorants in mixtures and for odor suppression.