ScienCentral News
 
environment general science genetics health and medicine space technology March 30, 2003 
home NOVA News Minutes archive login

is a production of
ScienCentral, Inc.
Making Sense of Science

Also of Interest
Gulf War Syndrome Gene (video)

Brain Pills (video)

Driving Blind (video)

Rainbow X-Ray Vision (video)

Cognitive Behavioral Therapy (video)

West Nile Airplanes (video)

Schizophrenic Brains (video)

Baby Talk (video)

Noisy Brain Signals (video)

Exercise Your Brain (video)

Bloody Teeth Boost Memory (video)

What Sex Is Your Brain (video)

Lysins To Kill (video)

M.D. on a Chip (video)

Anger Gene (video)

NOVA News Minutes
Visit the NOVA News Minutes archive.
ScienCentral News and Nature
Nature genome promo logo
Don’t miss Enter the Genome
our collaboration with Nature.
Best of the Web!
Popular Science Best of the Web 2000
Selected one of Popular Science’s 50 Best of the Web.
Get Email Updates
Write to us and we will send you an email when a new feature appears on the site.
Smart Nose (video)
November 07, 2002

Can't see the movie above??
download realplayer logo
You can choose to either view it with a RealPlayer by clicking here. Or get the free QuickTime player to view the higher-quality video above.

Interviewees: Noam Sobel, University of California - Berkeley; Joel Mainland, UC Berkeley.

Video is 1 min 32 sec long. Please be patient while it loads enough to start playing.

Produced by Brad Kloza

Copyright © ScienCentral, Inc., with additional footage courtesy of Maurizio Corbetta.

Also on ScienCentral News

Brain Bounceback (video) - About 750,000 Americans suffer a stroke each year. In many cases, their ability to understand and use language is severely impaired. Now scientists can see why this ability is not lost for good. (10/18/02)

Mind Control (video) - Brain researchers are turning thoughts into commands. (9/24/02)

Elsewhere on the web

Smells Database - Berkeley

Listen to BORP

Seeing, Hearing, and Smelling the World - Howard Hughes Medical Institute

Neuroscience for kids - smell experiment

Do you smell with your nose or your brain?

Scientists have been wondering that for years. As this ScienCentral News video reports, new tests show it's not the nose, but the brain that knows.


Clearing the air

“What’s that smell?” your friend asks, sniffing into the air and wrinkling his nose. If you couldn’t detect a fulsome odor, you might wonder if he’s imagining things. But actually, the problem could be in your head. Neuroscientists at the University of California Berkeley now believe that for some of us, our brains have to learn to smell certain odors.
About 30 percent of the population does not detect an odor when they sniff androstenone (which functions as a sex pheromone in wild pigs). But Noam Sobel, a professor working in the Berkeley Olfactory Research Project (BORP), can smell it from 30 feet away when it is sealed inside jars (it smells awful--“like dirty laundry,” he says).

At first scientists assumed this was a genetic flaw, something akin to color blindness. But in 1989 researchers at the Monell Chemical Senses Center discovered that, with practice and time, non-detectors could learn to smell androstenone. What was not known, however, was whether this learning was happening in the odor receptors in the nose, or in the olfactory cortex in the brain.

Sobel and grad student Joel Mainland set out to test this by replicating the 1989 study of training non-detectors to smell androstenone. But this time, they blocked one of the subjects’ nostrils, effectively training only one nostril to learn the smell.

“The idea here is simple,” says Sobel. “If the untrained, unexposed nostril learns to detect androstenone, then the learning must have occurred at a higher level, at the brain.”

Their results, published in the journal Nature, revealed that the un-exposed nostrils of non-detectors learned just as well as the exposed ones.

“The message from the peripheral nose to the brain was always the same when the person couldn’t, and later could, detect the odor,” says Sobel. “The brain, over time, learned how to make sense of a previously senseless [message].”

The plastic brain

The ability of the brain to acquire a capability it previously did not have is referred to as “plasticity.” Brain scientists are finding that adult brains are more malleable than previously thought, and understanding plasticity has become a central theme of neuroscience.

“Ideally, if you were to understand the mechanisms underlying this phenomenon you would eventually be able to repair the injured nervous system,” says Sobel. “One of the major goals of neuroscience is to repair an injured nervous system or brain. And in order to do that artificially you would want to first understand how that happens naturally, how the system regenerates on its own.”

Studies like this suggest that it merely takes sustained practice to force the brain to do something we had assumed it could not do. For example, stroke patients who lose the use of one side of their body can often regain the capability by literally tying down the good side and forcing the brain to relearn how to use the bad side.

“Here we have another instance of that,” says Sobel. “If we force the brain to do something it doesn't usually do, it can actually gain capabilities, even in the adult.”

Sobel next hopes to use magnetic resonance imaging to find the location of this plasticity and watch it happen in the brain. His work was funded by the National Institute on Deafness and Other Communication Disorders and the Sense of Smell Institute.



by Brad Kloza


About Search Login Help Webmaster
ScienCentral News is a production of ScienCentral, Inc.
in collaboration with the Center for Science and the Media.
248 West 35th St., 17th Fl., NY, NY 10001 USA (212) 244-9577.
The contents of these WWW sites © ScienCentral, 2000-2003. All rights reserved.
The views expressed in this website are not necessarily those of the NSF.
NOVA News Minutes and NOVA are registered trademarks of WGBH Educational Foundation and are being used under license.