Overcoming Fear: Researchers Use Scents To Manipulate Memory And Treat Anxiety During Sleep
Next time you find yourself paralyzed with fear after seeing that spider scurry under the couch cushion in your living room, try getting some shut eye. At least, that's the idea behind a new study into how people can overcome distressing memories. Scientists from Northwestern University in Chicago have tested a way of manipulating people's fears while they slept and found that it could be possible to unlearn certain anxiety-triggering memories.
Like Us on Facebook
Fear is a kind of emotion that is often cultivated at a young age through observation or experience. "It can take only an instant for fear to take hold in the brain," The Washington Post reports. For example, "a fear of snakes after being bitten by one, or anxiety around bodies of water after witnessing a drowning."
"Across all species, one thing is true: The learning of a fear occurs much more quickly than the fear extinction process," lead researcher and neurologist Katherina K. Hauner told The Washington Post. But the researchers are hoping to speed that process up a bit.
Hauner and her team wanted to find out if they could alleviate people's fears while they slept. To test this theory, they first conditioned 15 "healthy" subjects to fear certain stimuli. They showed the subjects a series of photos depicting faces. For two of the photos the subjects received electric shocks to their feet. After a few rounds of this type of conditioning, the subjects learned to fear the faces for which they received the electric shock. This was measured by the increased levels of sweat, or their skin-conductance response, as well as an MRI scan of their amygdala, the part of the brain associated with fear.
Additionally, for every photo, researchers pumped a certain scent like roses or lemons into the subject's vicinity. That way, both the smell and the sight of the face were associated with the unpleasant electric shock.
After the fear conditioning took place, subjects slept for 40 minutes. Researchers then releases the same smells into the room. They measured the same anxiety responses in the subjects while they slept and found that the smell still triggered a fear response. But the longer the smell lingered, the fear response became less intense.
When the subjects woke up, they were shown the same faces as before. According to New Scientist, the stress measurements were "less pronounced" when the subjects were shown the same faces.
"From a clinical perspective, this can be a new approach to try and treat stressful or traumatic memories," said Jay Gottfried, the senior author of the study.
Their research was published over the weekend in Nature Neuroscience.
Fear extinction is the process of pacifying a person's anxiety response to something that distresses him. As a 2007 study in the journal Molecular Psychiatry notes, extinction is not the same as forgetting. From "Mechanisms of fear extinction:"
Although it is difficult to be sure that forgetting does not occur to some extent in extinction, numerous studies show that extinction cannot fully be explained by forgetting because extinction requires exposure to the CS in the absence of the US as opposed to the simple passage of time. This is especially true with fear extinction because fear memories can last months or even years with little forgetting.
The idea is to disassociate the body's fear response - changes in respiration, increased blood pressure, and emission of ultrasonic distress calls - with certain stimuli. If scientists can do the same with sleep, it could be a novel way to help people overcome debilitating fears. Although it'll have to prove effective in preexisting fears, first.
Read more from iScience Times:
© 2012 iScience Times All rights reserved. Do not reproduce without permission.