Sleep recharges us; it gives our bodies a chance to reboot and our brains a chance to clear out some cellular trash. Now research out of Switzerland shows there’s even more going on during shut-eye. While catching our ZZZ’s, we may also be giving our psyches the opportunity to heal negative emotions.

Most of the powerful transformations during sleep take place during the REM or rapid eye movement phase of sleep. This is when we do almost all of our dreaming; it is also the period when we experience the most intense emotions.

When we’re awake, the area of our brain called the prefrontal cortex is in charge of emotions such as fear or fight or flight. On the other hand, when we’re asleep, that part of our brain appears to dream intensely — but not react.

Sleep may give our psyches a chance to heal negative emotions.

Swiss researchers wanted to explore this dichotomy — how the same part of the brain could have such different functions during sleep and waking. “Our goal was to understand the underlying mechanism and the functions of such a surprising phenomenon,” researcher, Antoine Adamantidis, of the Department of Biomedical Research at the University of Bern and Inselspital University Hospital of Bern, both in Switzerland, said in a statement.

Being able to safely process danger is an important part of emotional health — but it’s not always easy to manage. In the United States, for example, it’s estimated that around 12 million people a year are dealing with Post Traumatic Stress Disorder (PTSD), a syndrome that often develops following a traumatic event and is marked by flashbacks to the event and persistent anxiety.

The study offers insights into how the brain reinforces positive emotions and weakens negative or traumatic ones during REM sleep. Using mice in a laboratory setting to explore the phenomena, the research team conditioned some mice to recognize auditory stimuli associated with safety, while other mice were conditioned to associate the stimuli with danger.

The activity of the brain’s neurons in the mice was recorded during their sleep-wake cycles. This enabled scientists to track how emotional memories are transformed during REM sleep. Neurons are made up of a cell body called “soma” which integrates information coming from dendrites where signals are sent off to other neurons.

Being able to safely process danger is an important part of emotional health — but it’s not always easy to manage.

The researchers discovered that during REM sleep cell somas are kept silent, while dendrites are activated. That’s notable. It means that during sleep the brain favors safety versus danger in the dendrites, and prevents an overreaction to emotion, particularly to danger signals. “We hope our findings will not only be of interest to the patients, but also to the broad public,” said Adamantidis.

The findings may also lead to the development of treatments for PTSD and other anxiety disorders.

Meanwhile, there’s no doubt that sleep is an important part of our health and offers benefits that include boosting our immune system, strengthening our hearts, preventing weight gain and just putting us in a better mood.

If you’re having a tough time sleeping, try these techniques:

  • Make exercise a routine, but not too close to bedtime. Morning workouts outdoors are best.
  • Reserve the bedroom for sleep and sex. Make it your refuge for zzz’s.
  • Avoid eating a big meal within 2 to 3 hours of bedtime.
  • Stay away from alcohol and caffeine (including chocolate) in the hours just before bedtime.
  • Discuss medications you’re taking with your doctor. Some may interfere with sleep.

The study is published in Science.