Rapid eye movement sleep can alleviate emotional stress caused by past events, according to a UC Berkeley study.
According to The Daily Californian, the study, which was conducted over a period of one and a half years, is the first to systematically test the effects of sleep on both brain activity and behavioral reactions to emotional stress.
“It’s the first to look at REM sleep in such a sophisticated way,” Els van der Helm, a UC Berkeley doctoral student in psychology and lead author of the study, told the Californian in an email. “It aids therapies not only for (post-traumatic stress disorder) but also mood disorders.”
According to the study, REM sleep creates an ideal environment for the brain to process emotions because it reduces stress-inducing electrical activity patterns and activity of some neurotransmitters.
“We believe this unique brain state helps to put these emotional experiences ‘in perspective’ by integrating them with previous memories while ‘stripping away’ the emotional tone associated with them,” van der Helm also said in the email.
For the study, participants [35 healthy young adults] were shown emotion-invoking images twice, with a 12-hour interval in between. Participants who were allowed to sleep between the two viewings showed a significantly less intense reaction to the images the second time around compared to those who stayed awake.
According to the Californian, the researchers also noticed that the aggressive reactionary forces of the amygdala — the brain’s emotion-processing area — decreased following REM sleep, allowing the rational part of the brain to regain control of the participants’ REM sleep, allowing the rational part of the brain to regain control of the participants’ emotional reactions.
“The finding that REM sleep physiology is associated with … amygdala activity in response to previous emotional experiences … the next day has some very exciting implications for treatment of mood and/or anxiety disorders,” Carrie Bearden, associate professor of psychiatry and biobehavioral sciences and psychology at UCLA, told the Californian in an email. “It’s a very innovative study.”
“This research shows that sleep plays a crucial role in emotional processing and opens up doors for therapeutic avenues,” van der Helm said in the email. Patients with mood disorders such as post-traumatic stress disorder can benefit from improved therapeutic sessions using the findings in the study, he added.
“It would be interesting to conduct a longer-term study to examine cross-lagged effects of changes in amygdala reactivity and subjective emotional reactivity over time,” Bearden said in the email. “The relationship of REM sleep to emotional response is surprisingly under-studied so I think this is a great step in that direction.”
This study was published Nov. 23 in the journal Current Biology
