14 DAY TRIAL // No sleep is really bad for your body, the effects ranging from lowered immune system (meaning vulnerability to infections) to memory and cognitive impairment and weight gain.
"Almost all psychiatric disorders show some problems with sleep. But scientists previously believed the psychiatric problems triggered the sleep issues." said psychologist Matthew Walker of the University of California, Berkeley. His team, collaborating with a Harvard Medical School team, has now found the opposite: sleep loss can induce psychological impairments.
26 healthy subjects aged 24 to 31 were investigated after either an all-nighter or a full night's sleep.
14 volunteers spent 35 straight sleepless hours, a time during which the researchers monitored their brain function through 100 functional magnetic resonance imaging (fMRI) photos. The first slides revealed little activity; but they progressively turned extremely active while watching shocking settings, like a tarantula on a person's shoulder or pictures of burn victims.
Amygdala, a brain nucleus controlling emotion had a similar baseline activity when sleep deprived or control subjects were presented innocuous images. When the images turned more gruesome, the activity of amygdalae of the sleep-deprived subjects increased with 60 % more than in the case of normal subjects. Five times more brain cells from the amygdala were activated, sending impulses in the sleep-deprived brains.
"We've never seen a magnitude of increase between two groups that big in any of our studies before. In normal participants, the amygdala seemed to be talking to the medial prefrontal cortex, an outer layer of the brain that helps to contextualize experiences and emotions. But, in the sleep-deprived brain, the amygdala seemed to be "rewired," coupling instead with a brain stem area called the locus coeruleus, which secretes norepinephrine, a precursor of the hormone adrenaline that triggers fight-or-flight type reactions." said Walker.
"Medial prefrontal cortex is the policeman of the emotional brain. It makes us more rational. That top-down, inhibitory connection is severed in the condition of sleep deprivation. ? The amygdala seems to be able to run amok. People in this state seem to experience a pendulum of emotions, going from upset and annoyed to giddy in moments," he added. Studies already connected sleep apnea, correlated to impaired sleep, to attention deficit hyperactivity disorder and depression to insomnia.
"It might be that those medial frontal regions tell the rest of the brain, 'You can chill'. Those circuits become exhausted or altered after a lack of sleep." said Robert Stickgold, an associate professor of psychiatry at Harvard Medical School, not involved in this research.
"I think we may start to think about a new potential function for sleep. It does actually prepare our emotional brains for next-day social and emotional interactions." said Walker.