The regions of the brain associated with olfaction are more developed in professional perfumers than in the general population. In addition, the quantity of grey matter in the experts' olfactory regions increases in proportion to their experience. [...] Based on anatomical MRI scans of professional perfumers, perfumery students and control subjects, it shows that training and practice make it possible to reverse the age-related grey matter reduction observed in olfactory regions among the general population.

— For the rest of us, these regions of the brain tend to shrink with age. Read more at Experience modifies the perfumer's brain at CNRS. They scanned the brains of perfumer Jean-Claude Ellena and students at the ISIPCA perfumery school, among others.

We all think we know how certain things smell. But to someone else that same bottle of perfume - or piece of cheese, or glass of wine - may smell completely differently. American scientists have discovered that we all experience odours in a completely different way. Their paper, published in the Nature Neuroscience journal, reveals that 30 per cent of smell receptors differ between any two people.

— Read more at Why perfume smells different to each of us: Receptors in the nose vary by 30% in two different people at the Daily Mail.

Preti is an expert on human odors, having studied them for more than 40 years. He has sniffed — both with machines and with his nose — breath, sweat and other secretions in search of answers about why we smell the way we do. This latest project seeks to answer a question others might have never thought to ask: Does ovarian cancer have a smell?

— That's George Preti, of the Monell Chemical Senses Center. Read more at What Does Cancer Smell Like? at the New York Times. Hat tip to HemlockSillage!

It might seem that the range of scents humans can detect is infinite, but scientists have managed to sort them all into 10 basic categories, ranging from peppermint to pungent.

The classifications are meant to be the olfactory equivalent of the five basic tastes (sweet, sour, salty, bitter and umami).

— From Humans can sniff out 10 basic odors, scientists say at the LA Times. Hat tip to Aparatchick!