Sniffing Your Friends
We are all familiar with the unique smells associated with particular places or people. Many homes have a distinct olfactory signature, as do cities away from home. Even our close friends and significant others subtly convey their presence via their individual scents.
Underlying the sense of smell is chemistry: single or sets of molecules interact with receptors in our nose to register their identity. But how is this chemical information conveyed to the brain?
New research reveals that the peptide hormone vasopressin is responsible for integrating olfactory stimuli. Tobin et al. have found a previously unknown population of vasopressin neurons in the olfactory bulb (Nature 464 [18 March 2010], 413–417). Intriguingly, these neurons mediate social recognition among individuals based on olfactory characteristics, and this recognition can be blocked with vasopressin inhibitors.
Alas, the experiments are in rats, and the authors take pains to say that olfaction may not mediate social recognition in humans. Of course, our common experience suggests smelly people are easily recognized, even without visual clues, so the underlying chemistry in rodents may not be as far from our own as cautious scientists would suggest.