Sleep-deprivation causes an emotional brain ‘disconnect’.
sleep, the emotional centers of the brain dramatically overreact to
negative experiences, reveals a new brain imaging study in the October
23rd issue of Current Biology, a publication of Cell Press. The reason
for that hyperactive emotional response in sleep-deprived people stems
from a shutdown of the prefrontal lobe—a region that normally keeps
emotions under control.
new study from Harvard Medical School and the University of California,
Berkeley is the first to explain, at the neural level, what seems to be
a universal phenomenon: that sleep loss leads to emotionally irrational
behavior, according to the researchers. The findings might also offer
some insight into the clinical connection between sleep disruptions and
adds to the critical list of sleep’s benefits,” said Matthew Walker,
from the University of California, Berkeley. “Sleep appears to restore
our emotional brain circuits, and in doing so prepares us for the next
day’s challenges and social interactions. Most importantly, this study
demonstrates the dangers of not sleeping enough. Sleep deprivation
fractures the brain mechanisms that regulate key aspects of our mental
health. The bottom line is that sleep is not a luxury that we can
optionally choose to take whenever we like. It is a biological
necessity, and without it, there is only so far the band will stretch
before it snaps, with both cognitive and emotional consequences.”
have known that sleep deprivation impairs a range of bodily functions,
including the immune system and metabolism, as well as brain processes,
such as learning and memory, the researchers explained. Yet, evidence
for the role of sleep in governing our emotional brain state had
remained surprisingly scarce, they noted.
the new study, Walker’s team assigned 26 healthy people to either a
sleep-deprivation group—in which participants were kept awake for about
35 hours—or a normal sleep group. On the following day, the study
subjects’ brains were scanned by functional magnetic resonance imaging
(fMRI), which measures brain activity on the basis of blood flow, while
viewing 100 images. The images were at first emotionally neutral, but
became increasingly aversive over time.
had predicted a potential increase in the emotional reaction from the
brain , but the size of the increase truly
surprised us,” Walker said of the study’s findings. “The emotional
centers of the brain were over 60% more reactive under conditions of
sleep deprivation than in subjects who had obtained a normal night of
sleep. It is almost as though, without sleep, the brain reverts back to
a more primitive pattern of activity, becoming unable to put emotional
experiences into context and produce controlled, appropriate responses.
it is early days,” he added, “clinical evidence has shown that some
form of sleep disruption is present in almost all psychiatric
disorders. These findings may offer new mechanisms as to why, and
provide novel insights into how we can understand and even treat these
disorders at a brain level.