September 23, 2013
Some Fears May Be Eliminated Just By Going To Sleep
[ Watch the Video: Never Fear! Just Sleep On It! ]
Michael Harper for redOrbit.com - Your Universe Online
Using specific odors, such as woody or floral scents, scientists were able to reduce the reactions of subjects who were trained to fear a pair of faces prior to the study. Going forward, the researchers say this new technique could be used to treat people who suffer from post-traumatic stress disorder (PTSD) or other crippling bouts of terror. The research also dovetails previous research, which shows people can be alleviated of their fears if they’re simply subjected to them directly, such as handling spiders or climbing to the top of a tall building.
“Sleep sort of stamps memories in more strongly,” said Gottfried in an interview with the Washington Post's Meeri Kim. “That’s when a lot of memory formation can take place.”
Gottfried and colleagues gathered 15 healthy participants and trained them to become afraid of a pair of faces. These subjects were shown a series of photos with people’s faces in them. When the subjects saw two specific faces, they were given a mild electric shock to their feet to create a fear reaction. The pair of faces were also accompanied by a specific odor, such as lemon or rose. After several successions of being shocked and smelling a certain odor, the participants showed fear reactions to the faces, evidenced by beads of sweat and confirmed with an fMRI.
Once a fear of the faces was established, the participants were asked to fall asleep. Once they reached a deep phase of sleep, known as slow-wave sleep, the researchers sprayed the associated scent in the room to trigger the memory or fear in their minds. After they awoke, the researchers subjected them to another fMRI scan as they showed the pair of frightful faces. Those who had been subjected to the odors as they slept the longest saw the greatest reduction of fear reactions. To avoid any preconditioning, the subjects did not know the researchers would be spraying the scents as they slept.
“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,” explained Katherina Hauner, a postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine, who helped with the study.
Explaining the research, Gottfried said: “From a clinical perspective, this can be a new approach to try and treat stressful or traumatic memories.”
Fears can be learned in a couple of ways, either from direct experience or observing something traumatic. For instance, being bitten by a dog as a child can create a lifelong fear of canines. Additionally, people who observe a close friend or family member being bitten by a dog can also develop a similar fear. While these fears can be created rather quickly, Gottfried and Hauner say unlearning these fears through a process they call “fear extinction” may take much longer.
“This is a very novel area. I think the process has to be refined,” said Hauner in closing, noting that more research is needed.