Odors Associated With Bad Memories can Eliminate Fears If They are Exposed to People as They Sleep

Exposing people to odors, which they associate with bad memories, as they sleep could help them lose the fear of those memories, a new study has found.

In a study, Katherina Hauner and Jay Gottfried of Northwestern University in Evanston, Illinois, exposed subjects to four pictures of faces and a series of inoffensive smells such as mint, New Scientist reported.

Circadian Rhythm Sleep Disorders - Types, Causes, Health risks, Diagnosis, Treatment, Prognosis
Circadian rhythm (also known as sleep/wake cycle or the body clock) is a biological process that follows an internal cycle of roughly 24 hours.

When one of the faces appeared, the volunteers were given a painful electric shock so that they get scared.

Then the researchers measured the amount of electricity conducted by the subjects' skin - a measure that goes up when afraid, because the sweat produced is a good conductor. The researchers found that conductance spiked whenever the volunteers saw the face associated with the shock.

They then let half the subjects sleep, and exposed this group to variable amounts of the odour that had been presented along with the "painful" face. The next day, these volunteers were much less afraid of the face - and those with the least fear were those that had received the highest exposure to the odour while asleep.

Obstructive Sleep Apnea - Overview
Obstructive sleep apnea should be suspected in overweight middle aged adults who snore loudly and which can cause interruption of breathing for 10 seconds or more and this results in reduced blood o

Brain scans also showed that brain areas associated with fear and with memory were less active after this exposure.

The other group of subjects stayed awake while they received pulses of the odour associated with the "painful" face. Unlike the sleeping group, however, these volunteers became more afraid of the face with greater exposure to the odour.

Sleep - Overview and Definition
Sleep is a behavioral state of restricted physical activity. It is controlled by our internal biological clock.

It is unclear as to why sleep dissociates the fear from the image, rather than reinforcing the connection.

But, according to Hauner, a clue may lie in reports from the awake volunteers, who said they saw the face in their minds every time they smelled the odour.

Sleep Disorder : Restless Legs Syndrome
Restless legs syndrome (RLS) causes - An urge to move, usually due to uncomfortable sensations that occur primarily in the legs.

The technique could eventually enhance treatments for posttraumatic stress disorder by associating images from the traumatic memory with a smell, and then using odour exposure while sleeping, said Hauner.

Hauner's team presented their study at the Society for Neuroscience conference in New Orleans, Louisiana, last week.

Source-ANI