Smells used to calm fears while you sleep

Our sense of smell is attributed to a number of cognitive functions, like when the smell of a fresh apple pie triggers memories of home. What else can our sense of smell do? It may help diminish fear. A new study published in Nature Neuroscience suggests when people are exposed to specific smells while in a deep sleep, it mutes the feelings associated with certain fears.

Researchers at Northwestern University Feinberg School of Medicine tested this method on 15 people who were shown pictures of two different faces while receiving a mild electric shock — to instill anxiety and/or fear — and certain scents, such as lemon, mint and wood. These same smells were then released while the participants slept deeply in a sleep lab. After they woke, the two pictures were shown to them again, without smells or shocks. Participants were less fearful of the face linked to a smell released during their sleep than the other face.

The amount of sweat from the skin and a fMRI were used to measure the level of fear. The fMRI revealed changes in the hippocampus, the area linked to memory, and the amygdala, the area linked to emotion. The experiment worked the best for people who slept longer.

These results show a promising new path for treating phobias. Researchers even suggest it may help to treat Post-Traumatic Stress Disorder, though more research is needed before expanding on this idea.

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Sourced from:, Tackling fears 'while you sleep'