July 5, 2022 – REM sleep is the darling of the sleep world. short for “rapid eye movement,” REM fascinates us because that’s when we do most of ours i’m dreaming – when all our inner fears, frustrations and passions are supposed to play out.
We already have strong evidence that REM sleep helps us process these emotions, but a new study reveals how.
It turns out that neurons (messenger cells) in the front of the brain may be busy reinforcing positive emotions while suppressing our most negative and traumatic ones, say researchers from the University of Bern and the University Hospital of Bern in Switzerland. It’s a defense mechanism, they think.
How sleep helps us process emotions
The researchers reached their conclusions after studying brain activity in mice during wakefulness, REM and non-REM sleep.
They wanted to understand why the front part of the brain — the prefrontal cortex — actively integrates many emotions when you’re awake, but appears inactive during REM sleep, says lead study author Mattia Eime, a postdoctoral researcher at the Department of Biomedical Research at the University of Bern. . This is a puzzling phenomenon, the authors note in their study in the diary Science.
Neurons have three key parts, Aim explains—dendrites, axons, and the cell body (soma). Dendrites receive information and send it to the cell body. The information is then transferred to axons, which send it to other neurons. So, dendrites retrieve information and axons send it.
But the researchers found that during REM, the emotional content is stored at the dendritic level and the “output” part of the cell stops communicating.
“This means that the dendrites active during REM sleep provide a substrate for consolidation,” says Aim, blocking all outgoing messages associated with danger. Think of it as a game of alley whispering that stops when someone gets a scary or negative whisper and doesn’t pass it on to the next person.
Aime calls the mechanism “bidirectional” because different parts of the neuron (the “input” and “output” parts) behave in opposite ways.
“This is essential for optimizing the consolidation of emotional memories,” says Aim. “Dendrites store information, cell bodies [become] inactive to avoid excessive storage.’
Advances in Sleep Medicine
“The interaction between REM-dependent learning and PTSD is of great interest,” Aim says, noting that when this process is compromised, it can lead to PTSD-like behavior.
REM sleep is also thought to play a role in anxiety and major depressive disorder.
“These findings pave the way to a better understanding of emotion processing during sleep in the mammalian brain and open new perspectives for new therapeutic targets,” he says.