Aroma mix for the nerves
Clove + Rose=Carnation. Apparently the sense of smell calculates according to this equation, because people smell carnations when they hold the first two scents in the correct mixing ratio under their nose. Nerves calibrated to the special mix seem to be decisive here.
Some people only consciously perceive their nose when it is full. If it is blocked, it is not only difficult to breathe, but food and drink suddenly appear extremely bland - the special aroma that only develops through the typical smell of the food is missing. But the nose not only makes haute cuisine tasty for us, but also opens the door to a rich world of experience: the memory of grandmother's kitchen, when steam from bratwurst with sauerkraut wafts through the apartment, the pleasant shivering of the skin when inhaling the very personal touch of the loved one, the joy of spring after a long winter, when the air suddenly no longer smells of snow but of warm, damp earth - but also the disgusted turning away at the smell of vomit.
In the end, smelling is nothing more than the mundane transmission of chemical information from the nose to the brain: there are receptors in the nasal mucosa that send an electrical signal on their way as soon as certain scents dock with them. This stimulus eventually ends up in the brain and makes us perceive the special smell of the substance that has bound to the receptors. To complicate things a bit, virtually every natural fragrance is a mixture of different individual components and each substance excites several receptors at the same time.
Zhihua Zou from the University of Texas and Linda Buck from the Howard Hughes Medical Institute and Fred Hutchinson Cancer Research Center in Seattle took a closer look at what happens in mice when odors are transmitted from the receptor to the brain.
The scientists let mice sniff out an odor at short intervals, then another and finally the two previously presented scents mixed together and then looked into the mice's olfactory cortex, i.e. the part of the brain where scents are perceived will. The test substances used were: eugenol (cloves) combined with dimethylpyrazine (chocolate), methenyl methyl ether (citrus) combined with methylamine (fishy) and vanillin (vanilla) together with ethyl butyrate (apple).
In their sniffing experiments, the researchers found that most nerve cells in the rodents' olfactory cortex responded to both a single odor and a mixture of the two. However, a smaller proportion of the neurons were only excited by the scent mixture and not by the individual components - so there were special nerve cells for scent mixtures.
The scientists deduce from their observations that when a mixture of two odor notes is perceived, the neurons in the olfactory cortex coming from the nose are connected to special nerve cells in such a way that new combinations of information from the odor receptors in the nasal mucosa are created, which ultimately result in their own fragrance notes. This model could explain why people have the impression of smelling carnations when exposed to a specific combination of eugenol and phenylethyl alcohol (rose).
