By Prachiti Dalvi
Nobel Laureate Dr. Richard Axel, who visited Duke on March 14, 2013.
“A good scientist has to have a nose for which field to work in,” cancer researcher Bernard Weinstein once told his mentee Dr. Richard Axel.
It was a saying Axel took quite literally.
He and Linda Buck won the 2004 Nobel Prize in Physiology or Medicine for discovering the cell receptors that run our sensory system for olfaction, or the sense of smell.
Axel first stepped into the research world when he took a job as a glass washer to support himself during his undergraduate years at Columbia University. After a few broken test tubes and dirty beakers, he was fired as a glass washer and, instead, rehired to do research. He went on to publish three papers as an undergraduate, including one where he was senior author.
In 1979, he earned his medical degree from Johns Hopkins University. He then returned to Columbia, and in 1977 he, along with Michael Wigler and Saul Silverstein, discovered a way to insert foreign DNA into a host cell to produce particular proteins.
The finding grew into to the field of molecular cloning and earned Axel a spot in the National Academy of Sciences at 37.
Axel moved on to study how the brain represents the external world. This is a central issue in philosophy, psychology and neuroscience. But unlike, vision and touch, which have at least two dimensions in the external world, information about odors has no dimensionality at all.
So, how is smell represented in the various smell centers of the brain? Axel explained what scientists know about the representations during a March 14 lecture sponsored by the Ruth K. Broad Foundation and the Chancellor’s Lecture Series.
Pathway of odor perception (courtesy of nobelprize.org)
The process starts in the nose, where different kinds of smell-sensing cells line the nasal cavity. Each type of smell-sensing cell expresses only one of about 1400 odor-receptor genes. The cells expressing a given gene are randomly distributed through the nasal tissue and send projections back through the skull into the olfactory bulb.
This bulb is essentially first relay station for sensing smell in the brain. The incoming information gets consolidated in a part of the bulb called the glomerulus. There a given odor receptor activates nerve fibers called glomeruli. They send signals to higher brain regions, which then create a topographic map of incoming odors.
This topographic map is similar, or conserved, in all individuals of a species, Axel said.
His lab at Columbia is now focused on understanding how the sense of smell is established during development, how it may change over time and how certain smells can elicit specific thoughts and behaviors.