Smells that trigger memories could be used to calm fears while you’re asleep.
This is according to a study in Chicago which trained volunteers to associate images, linked to different smells, with fear.
When they were exposed to these smells during sleep, the test subjects woke up less afraid of the image that it was linked to.
Smells that trigger memories could be used to calm fears while you're asleep, according to a new study by researchers in Chicago
The study, published in Nature Neuroscience, could help develop better treatment for phobias and stress-related disorders.
‘It's a novel finding,’ said Katherina Hauner, a postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine and lead author of the study.
‘We showed a small but significant decrease in fear.’
Previous research has shown that memory and motor skills can be improved during sleep.
However, it wasn't previously known that emotions could be manipulated during sleep, according to the researchers.
15 volunteers were trained associate images, linked to different smells, with fear. When they were exposed to these smells during sleep, they woke up less afraid of the image that it was linked to
The study involved 15 test subjects who were each shown two different faces.
They were simultaneously subjected to a mild electric shock and a specific smell including woody, clove, new shoes, lemon or mint.
The volunteers were then monitored in a sleep lab and exposed to the same smell when they were in deep sleep for between five and 40 minutes.
When shown the picture a second time, the test subjects showed changes in the areas linked to memory, such as the hippocampus (in red)
When shown the faces again in the morning, they showed less fear that before they were subjected to the smell while asleep.
Deep sleep, or ‘slow wave’ sleep, is a time when we consolidate new memories and skills.
The effect was strongest for those who slept in deep sleep the longest.
Their response was measured through the amount of sweat on the skin and fMRI (functional magnetic resonance imaging) brain scans.
These revealed changes in the areas linked to memory, such as the hippocampus, and in patterns of brain activity in regions associated with emotion, such as the amygdala.
‘While this particular odorant was being presented during sleep, it was reactivating the memory of that face over and over again which is similar to the process of fear extinction during exposure therapy,’ said Dr Hauner.
‘If it can be extended to pre-existing fear, the bigger picture is that, perhaps, the treatment of phobias can be enhanced during sleep,’ she added.
Read more: http://www.dailymail.co.uk/health/article-2429984/Get-fears-sleep-Study-finds-SMELLING-fear-night-help-tackle-phobias-morning.html#ixzz2fk6dMvu6
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