Nav: Home

Quick! What's that smell? Mammal brains identify type of scent faster than once thought

November 14, 2017

It takes less than one-tenth of a second -- a fraction of the time previously thought -- for the sense of smell to distinguish between one odor and another, new experiments in mice show.

In a study to be published in the journal Nature Communications online Nov. 14, researchers at NYU School of Medicine found that odorants -- chemical particles that trigger the sense of smell -- need only reach a few signaling proteins on the inside lining of the nose for the mice to identify a familiar aroma. Just as significantly, researchers say they also found that the animals' ability to tell odors apart was the same no matter how strong the scent (regardless of odorant concentration).

"Our study lays the groundwork for a new theory about how mammals, including humans, smell: one that is more streamlined than previously thought," says senior study investigator and neurobiologist Dmitry Rinberg, PhD. His team is planning further animal experiments to look for patterns of brain cell activation linked to smell detection and interpretation that could also apply to people.

"Much like human brains only need a few musical notes to name a particular song once a memory of it is formed, our findings demonstrate that a mouse's sense of smell needs only a few nerve signals to determine the kind of scent," says Rinberg, an associate professor at NYU Langone Health and its Neuroscience Institute.

When an odorant initially docks into its olfactory receptor protein on a nerve cell in the nose, the cell sends a signal to the part of the brain that assigns the odor, identifying the smell, says Rinberg.

Key among his team's latest findings was that mice recognize a scent right after activation of the first few olfactory brain receptors, and typically within the first 100 milliseconds of inhaling any odorant.

Previous research in animals had shown that it takes as long as 600 milliseconds for almost all olfactory brain receptors involved in their sense of smell to become fully activated, says Rinberg. However, earlier experiments in mice, which inhale through the nose faster than humans and have a faster sense of smell, showed that the number of activated receptors in their brains peaks after approximately 300 milliseconds.

Earlier scientific investigations had also shown that highly concentrated scents activated more receptors. But Rinberg says that until his team's latest experiments, researchers had not yet outlined the role of concentration in the odor identification process.

For the new study, mice were trained to lick a straw to get a water reward based on whether they smelled orange- or pine-like scents.

Using light-activated fibers inserted into the mouse nose, researchers could turn on individual brain receptors or groups of receptors involved in olfaction to control and track how many receptors were available to smell at any time. The optical technique was developed at NYU Langone.

The team then tested how well the mice performed on water rewards when challenged by different concentrations of each smell, and with more or fewer receptors available for activation. Early activation of too many receptors, the researchers found, impaired odor identification, increasing the number of errors made by trained mice in getting their reward.

Researchers found that early interruptions in sensing smell, less than 50 milliseconds from inhalation, reduced odor identification scores nearly to chance. By contrast, reward scores greatly improved when the mouse sense of smell was interrupted at any point after 50 milliseconds, but these gains fell off after 100 milliseconds.
Note: Video commentary from researchers, as well as b-roll are also available at

Funding support for the study was provided by National Institutes of Health grants R01 DC013797 and R01 DC014366, and a grant from the Whitehall Foundation.

Besides Rinberg, other NYU researchers involved in this study are lead study investigator Christopher Wilson, PhD; and Gabriela Serrano, BS. Additional research support was provided by Alexei Koulakov, PhD, at Cold Spring Harbor Laboratory in Cold Spring, NY.

Media Inquiries:

David March

NYU Langone Health / NYU School of Medicine

Related Brain Articles:

Study describes changes to structural brain networks after radiotherapy for brain tumors
Researchers compared the thickness of brain cortex in patients with brain tumors before and after radiation therapy was applied and found significant dose-dependent changes in the structural properties of cortical neural networks, at both the local and global level.
Blue Brain team discovers a multi-dimensional universe in brain networks
Using a sophisticated type of mathematics in a way that it has never been used before in neuroscience, a team from the Blue Brain Project has uncovered a universe of multi-dimensional geometrical structures and spaces within the networks of the brain.
New brain mapping tool produces higher resolution data during brain surgery
Researchers have developed a new device to map the brain during surgery and distinguish between healthy and diseased tissues.
Newborn baby brain scans will help scientists track brain development
Scientists have today published ground-breaking scans of newborn babies' brains which researchers from all over the world can download and use to study how the human brain develops.
New test may quickly identify mild traumatic brain injury with underlying brain damage
A new test using peripheral vision reaction time could lead to earlier diagnosis and more effective treatment of mild traumatic brain injury, often referred to as a concussion.
This is your brain on God: Spiritual experiences activate brain reward circuits
Religious and spiritual experiences activate the brain reward circuits in much the same way as love, sex, gambling, drugs and music, report researchers at the University of Utah School of Medicine.
Brain scientists at TU Dresden examine brain networks during short-term task learning
'Practice makes perfect' is a common saying. We all have experienced that the initially effortful implementation of novel tasks is becoming rapidly easier and more fluent after only a few repetitions.
Balancing time & space in the brain: New model holds promise for predicting brain dynamics
A team of scientists has extended the balanced network model to provide deep and testable predictions linking brain circuits to brain activity.
New view of brain development: Striking differences between adult and newborn mouse brain
Spikes in neuronal activity in young mice do not spur corresponding boosts in blood flow -- a discovery that stands in stark contrast to the adult mouse brain.
Map of teenage brain provides evidence of link between antisocial behavior and brain development
The brains of teenagers with serious antisocial behavior problems differ significantly in structure to those of their peers, providing the clearest evidence to date that their behavior stems from changes in brain development in early life, according to new research led by the University of Cambridge and the University of Southampton, in collaboration with the University of Rome Tor Vergata in Italy.

Related Brain Reading:

Warning: Invalid argument supplied for foreach() in /home/brightsurfadmin/ on line 836

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Consequences Of Racism
What does it mean to be judged before you walk through the door? What are the consequences? This week, TED speakers delve into the ways racism impacts our lives, from education, to health, to safety. Guests include poet and writer Clint Smith, writer and activist Miriam Zoila Pérez, educator Dena Simmons, and former prosecutor Adam Foss.
Now Playing: Science for the People

#465 How The Nose Knows
We've all got a nose but how does it work? Why do we like some smells and not others, and why can we all agree that some smells are good and some smells are bad, while others are dependant on personal or cultural preferences? We speak with Asifa Majid, Professor of Language, Communication and Cultural Cognition at Radboud University, about the intersection of culture, language, and smell. And we level up on our olfactory neuroscience with University of Pennsylvania Professor Jay Gottfried.