Researchers at the Institute of Psychology of the Chinese Academy of Sciences have discovered that scents are created by odor molecules released by various substances and detected by our noses, "Decomposition of an odorant in olfactory perception and neural representation."
When people smell various odors, it entails an analysis of submolecular structural features. In an assessment of more than 400 participants, it showed a breakdown in the unified smell of a compound following substructure adaptation.
Study Abstract
Molecules—the elementary units of substances—are commonly considered the units of processing in olfactory perception, giving rise to undifferentiated odor objects invariant to environmental variations. By selectively perturbing the processing of chemical substructures with adaptation (‘the psychologist’s microelectrode’) in a series of psychophysical and neuroimaging experiments (458 participants), we show that two perceptually distinct odorants sharing part of their structural features become significantly less discernible following adaptation to a third odorant containing their non-shared structural features, in manners independent of olfactory intensity, valence, quality or general olfactory adaptation. The effect is accompanied by reorganizations of ensemble activity patterns in the posterior piriform cortex that parallel subjective odor quality changes, in addition to substructure-based neural adaptations in the anterior piriform cortex and amygdala. Central representations of odor quality and the perceptual outcome thus embed submolecular structural information and are malleable by recent olfactory encounters.
