A good night’s sleep and we can take on the world
A GOOD night’s sleep can leave you feeling ready for anything because it reduces the fear factor, scientists have shown.
Better quality sleep makes the brain better equipped to handle potentially traumatic events the next day, according to a study.
The discovery could be used to treat and even prevent posttraumatic stress disorder (PTSD) in military personnel.
It is already known that more time spent in REM (rapid eye movement) slumber, deep sleep that leads to dreams, is linked to a fall in levels of the hormone norepinephrine. Called noradrenalin in the UK, it allows signals to pass between different brain regions.
But too much noradrenalin boosts connectivity between neural regions that control fear.
Brain monitors were attached to young adult volunteers as they slept over the course of a week at Rutgers University in New Jersey.
After waking, the students were given a test in which they had been taught to associate some images with a mild electric shock.
Those who had slept better were less fearful at the prospect of an electric shock during tests the next day. The findings, reported in the Journal Of Neuroscience, suggest deep sleep dampened feelings of fear and could be a future treatment for PTSD.
Study authors Itamar Lerner and Shira Lupkin said: “Students who spent more time in [REM} sleep exhibited weaker modulation of activity in, and connectivity between, their amygdala, hippocampus and ventromedial prefrontal cortex during fear learning.
“The findings are consistent with the idea that REM sleep reduces levels of norepinephrine which may dampen an individual’s sensitivity to fearful stimuli.”