2004 - Richard Axel and Linda B. Buck

How do we recognize and remember 10,000 different odors?

Axel and Buck revealed a large gene family comprised of 1,000 different genes (3% of our genes), leading to an equivalent number of olfactory receptor types, located on the olfactory receptor cells in the nasal epithelium. While each olfactory receptor cell expresses one and only one odorant receptor gene, it reacts with varying intensity to a limited number of related molecules. Since most odors are composed of multiple odorant molecules, they activate several odorant receptors.

The receptor cells send fibers to the olfactory bulb, also called the primary olfactory area, which projects to other parts of the brain, where the information from several olfactory receptors is combined to form an "odorant pattern". This is the basis for our ability to consciously experience the smell of a lilac flower in the spring, or to recall this olfactory memory at other times.