Sniffing out danger

Mar 27, 2008

Each human nose encounters hundreds of thousands of scents in its daily travels perched front and center on our face. Some of these smells are nearly identical, so how do we learn to tell the critical ones apart?

Something bad has to happen. Then the nose becomes a very quick learner.

New research from Northwestern University's Feinberg School of Medicine shows a single negative experience linked to an odor rapidly teaches us to identify that odor and discriminate it from similar ones.

"It's evolutionary," said Wen Li, lead author of the study and a postdoctoral fellow at the Cognitive Neurology and Alzheimer's Disease Center at the Feinberg School. "This helps us to have a very sensitive ability to detect something that is important to our survival from an ocean of environmental information. It warns us that it's dangerous and we have to pay attention to it."

The study will be published March 28 in the journal Science.

In the study, subjects were exposed to a pair of grassy smells which were nearly identical in their chemical makeup and perceptually indistinguishable. The subjects received an electrical shock when they were exposed to one scent, but not when they were exposed to the other similar one.

After being shocked, the subjects learned to discriminate between the two similar smells. This illustrates the tremendous power of the human sense of smell to learn from emotional experience. Odors that once were impossible to tell apart became easy to identify when followed by an aversive event.

Li and her colleagues also found specific changes in how odor information is stored in "primitive" olfactory regions of the brain, enhancing perceptual sensitivity for smells that have a high biological relevance.

Source: Northwestern University

Explore further: Ultrasound enhancement provides clarity to damaged tendons, ligaments

add to favorites email to friend print save as pdf

Related Stories

Mosquito sperm have 'sense of smell'

Feb 03, 2014

Vanderbilt biologists have discovered that mosquito sperm have a "sense of smell" and that some of same chemicals that the mosquito can smell cause the sperm to swim harder.

Odor suppression causes bad wine smell

Sep 17, 2013

(Phys.org) —A bad, musty smell sometimes ruins a bottle of corked wine. Since the 1990s, researchers have known that this unpleasant odor comes from the chemical 2,4,6-trichloroanisole (TCA), which forms ...

Recommended for you

A better way to track emerging cell therapies using MRIs

19 hours ago

Cellular therapeutics – using intact cells to treat and cure disease – is a hugely promising new approach in medicine but it is hindered by the inability of doctors and scientists to effectively track the movements, destination ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

HeRoze
not rated yet Mar 27, 2008
This is interesting. All the extraneous stuff aside, we as humans can actually learn to distinguish 'indistinguishable' objects (smells). This makes me wonder what else we are lumping together that we can separate; Colors, sounds, feelings, tastes. It's also cool that they got to shock the participants < eg >