Sleep deprivation leads to intrusive thoughts and reliving bad memories

Sleep deprivation can hamper the brain’s ability to suppress unwanted memories and intrusive thoughts, according to a new study.

Scientists at the University of York and the University of East Anglia have shown that sleep deprivation interferes with the ability of the prefrontal area of the brain to restrict the surfacing of memories that would have otherwise been suppressed.

Dr Scott Cairney from the University of York said: “Memories of unpleasant experiences often intrude into our conscious mind in response to reminders, but tend to be fleeting and can be put out of the mind again, but we have previously shown that the brain's ability to suppress such intrusive memories is contingent on obtaining restful sleep.

“Suppression is a very clever function of the brain as it weakens all of the connecting traces of the memory, thereby inhibiting us from joining up all the dots to retrieve the full picture of the experience when it is triggered by an external stimulus.”

To understand how the brain does this, the team used functional magnetic resonance imaging (fMRI) scans to investigate the brain activity of 85 healthy adults, half of which had experienced a healthy night sleep in the sleep lab, and the other half stayed awake all night.

They were asked to look at faces, which they had previously seen paired with images of scenes, some of which were emotionally negative, such as a picture of a car crash or a fight. For each face they were asked to either recall the scene associated with it, or suppress the memory of the scene.

When attempting to suppress the scene images, the well-rested participants showed more activation in the right dorsolateral prefrontal cortex - a brain region that controls thoughts, actions, and