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, www.springerlink.com/content/1936-5802/5/1/

Related Stories

Recommended for you

MRI technique induces strong, enduring visual association

June 30, 2016

Researchers have made two new scientific points with a set of experiments in which they induced people to perceive colors that weren't really there—one concerning how the brain works and the other concerning how to work ...

Erasing unpleasant memories with a genetic switch

June 30, 2016

Researchers from KU Leuven (Belgium) and the Leibniz Institute for Neurobiology (Germany) have managed to erase unpleasant memories in mice using a 'genetic switch'. Their findings were published in Biological Psychiatry.

Motivation to bully is regulated by brain reward circuits

June 29, 2016

Individual differences in the motivation to engage in or to avoid aggressive social interaction (bullying) are mediated by the basal forebrain, lateral habenula circuit in the brain, according to a study conducted at the ...

0 comments

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.