Abstract
Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints.
Highlights
From before birth to death, organisms live in a complex chemical world
We did not apply for ethical approval since the experimental design did not fall into the category of the biomedical research, as any design in which ‘‘all actions are performed and products used in the usual way, without any additional procedure or unusual diagnostic or monitoring’’ (Code de la santepublique lois nu2004-806 du 9 aout 2004 et 2006-450 du 18 avril 2006 Article L1121-1)
The present experiments aimed to study the perception of a complex mixture, the red cordial (RC) mixture, which induces perceptual blending in humans
Summary
From before birth to death, organisms live in a complex chemical world. Organisms can selectively respond to certain odorants in odor mixtures (elemental perception). When a unique odor is perceived at the expense of the components’ odors, the perception is said to be configural. The configural perception is considered to be total when the odors of components cannot be distinguished. It is weak when the odor of the components is perceived together with the specific odor of the configuration [2]. Some mixtures are called ‘‘blending mixtures’’ because they appear to be spontaneously processed, either in a total or in a weak configural way [3,4,5,6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
