Anxiety boosts sense of smell

March 22, 2012

Anxious people have a heightened sense of smell when it comes to sniffing out a threat, according to a new study by Elizabeth Krusemark and Wen Li from the University of Wisconsin-Madison in the US. Their work¹ is published online in Springer's journal Chemosensory Perception. The study is part of a special issue² of this journal on neuroimaging the chemical senses.

In animals, the is an essential tool to detect, locate and identify predators in the surrounding environment. In fact, the olfactory-mediated defense system is so prominent in animals, that the mere presence of predator odors can evoke potent fear and responses.

Smells also evoke powerful emotional responses in humans. Krusemark and Li hypothesized that in humans, detection of a particular bad smell may signal danger of a noxious airborne substance, or a decaying object that carries disease.

The researchers exposed 14 young adult participants to three types of odors: neutral pure , neutral odor mixture, and negative odor mixture. They asked them to detect the presence or absence of an odor in an MRI scanner. During scanning, the researchers also measured the skin's ability to conduct electricity (a measure of arousal level) and monitored the subjects' breathing patterns. Once the odor detection task was over, and the subjects were still in the scanner, they were asked to rate their current level of anxiety. The authors then analyzed the brain images obtained.

They found that as anxiety levels rose, so did the subjects' ability to discriminate negative odors accurately - suggesting a 'remarkable' olfactory acuity to threat in anxious subjects. The skin conductance results showed that anxiety also heightened emotional arousal to smell-induced threats.

The authors uncovered amplified communication between the sensory and emotional areas of the brain in response to negative odors, particularly in anxiety. This increased connectivity could be responsible for the heightened arousal to threats.

Krusemark and Li conclude: "This enhanced sensory-emotional coupling could serve as a critical mechanism to arouse adequate physiological alertness to potential insults."

Explore further: Researcher finds elderly lose ability to distinguish between odors

More information: 1. Krusemark EA & Li W (2012). Enhanced olfactory sensory perception of threat in anxiety: an event-related fMRI study. Chemosensory Perception. DOI:10.1007/s12078-011-9111-7
2. Chemosensory Perception, Special issue: Neuroimaging the Chemical Senses, Vol. 5, No. 1, March 2012,

Related Stories

Recommended for you

Wiring rules untangle brain circuitry

December 1, 2015

Our brains contain billions of neurons linked through trillions of synaptic connections, and although disentangling this wiring may seem like mission impossible, a research team from Baylor College of Medicine took on the ...

Can physical exercise enhance long-term memory?

November 25, 2015

Exercise can enhance the development of new brain cells in the adult brain, a process called adult neurogenesis. These newborn brain cells play an important role in learning and memory. A new study has determined that mice ...

New insights on how cocaine changes the brain

November 25, 2015

The burst of energy and hyperactivity that comes with a cocaine high is a rather accurate reflection of what's going on in the brain of its users, finds a study published November 25 in Cell Reports. Through experiments conducted ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.