A really interesting read, I’d love to have a really acute sense of smell, mix up some of those olfactory nerves!
Brain scans now show that more of the brain is devoted to smell processing than Broca’s anatomical studies would have suggested. And although we may have fewer types of receptor than other mammals, Charles Greer at Yale University has shown that the human nose and brain are unusually well connected, with each group of receptors linking to many more neural regions than is the case in other animals. That should give us a good ability to process incoming scents.
Once researchers began looking, they found the nose to be far more sensitive than its reputation suggested. One study, for example, found that we can detect certain chemicals diluted in water to less than one part per billion. That means that a person can detect just a few drops of a strong odorant like ethyl mercaptan in an Olympic-sized pool.
We are also exceptionally gifted at telling smells apart, even distinguishing between two molecules whose only difference is that their structures are mirror images of one another. “That is fantastic sensitivity,” says George Dodd, a perfumer and researcher at the olfaction group of the University of Warwick, UK.