Thursday, 01 December 2011 14:05 While humans spend one-third of
their lives sleeping, there is no scientific consensus on the
function of sleep. During the dream phase of sleep, the body’s
stress chemistry shuts down, taking the edge off difficult
memories. The finding may help explain why people with post-
traumatic stress disorder suffer reoccurring nightmares. “The
dream stage of sleep, based on its unique neurochemical
composition, provides us with a form of overnight therapy, a
soothing balm that removes the sharp edges from the prior day’s
emotional experiences,” said Matthew Walker, associate professor
of psychology and neuroscience at the University of California,
Berkeley. For people with PTSD, such as war veterans, this
overnight therapy may not work effectively, so when a “flashback
is triggered by, say, a car backfiring, they relive the whole
visceral experience once again because the emotion has not been
properly stripped away from the memory during sleep.” Published
in Current Biology, the study