How sleep helps to process emotions

Summary: Research reveals how the brain processes emotions during sleep by reducing the consolidation of negative emotions and consolidating positive emotions. Research could lead to new treatments for PTSD and other disorders associated with negative emotional processes.

A source: University of Bern

Researchers from the Department of Neurology at the University of Bern and the University Hospital in Bern found that the brain distributes emotions during sleep, which reduces the consolidation of negative emotions.

The work expands the importance of sleep in mental health and offers a path to new therapeutic strategies.

Rapid eye movement (REM or paradoxical) sleep is a unique and mysterious state of sleep in which most dreams occur with intense emotional content.

It is unknown how and why these emotions are revived. The prefrontal cortex unites most of these emotions during awakening, but seems paradoxically calm during REM sleep.

“Our goal was to understand the basic mechanism and functions of this amazing phenomenon,” he said. Antoine Adamantidis is from the Department of Biomedical Research (DBMR) at the University of Bern and the Department of Neurology at the University Hospital of Bern.

Emotional processing, especially the distinction between danger and safety, is essential for the survival of animals.

In humans, excessive negative emotions, such as fear reactions and anxiety, can lead to pathological conditions such as post-traumatic stress disorder (PTSD). In Europe, 15% of the population suffers from chronic anxiety and severe mental illness.

A research team led by Antoine Adamantidis is now looking at how the brain can help reinforce positive emotions during REM sleep and weaken strong negative or traumatic emotions.

This study was published in the journal science.

Two mechanisms

For the first time, the researchers allowed mice to recognize safety-related hearing stimuli and other risk-related stimuli (unpleasant stimuli). The activity of neurons in the mice’s brains was then recorded in sleep-wake cycles.

In this way, the researchers were able to map different areas of the cell and determine how emotional memories change during REM sleep.

Neurons consist of the body of a cell that combines information from dendrites and transmits signals to other neurons through its axons. The results showed that when their dendrites were activated, the cell amounts were silent.

“It means the division of two cell divisions, that is, the soma sleeps soundly and the dendrites wake up,” explains Adamantidis.

This disconnection is important because the strong activity of the dendrites allows them to encode both danger and safety emotions, while soma blockers completely block the output of the circuit during REM sleep. In other words, the brain supports security discrimination against danger in dendrites, but blocks excessive reactions to emotions, especially danger.

The advantage of life

According to researchers, the coexistence of two mechanisms is beneficial for the stability and survival of organisms:

“This two-way mechanism is critical to optimizing the discrimination between dangerous and unsafe signals,” said Mattia Eime, the first author of the study, from DBMR. If people do not have this discrimination and develop excessive fear reactions, it can lead to anxiety disorders.

It is unknown how and why these emotions are revived. Image in public domain

Studies have been particularly relevant to pathological conditions such as post-traumatic stress disorder, in which the trauma is excessively concentrated in the prefrontal cortex during daily sleep.

Discovery of sleep medicine

These findings provide a better understanding of the processing of emotions during sleep in humans and open up new perspectives for the treatment of traumatic memory impairment, such as post-traumatic stress disorder (PTSD) and their early sleep-dependent consolidation. .

Additional acute or chronic mental health problems include acute and chronic stress, anxiety, depression, panic, and even inability to feel pleasure, which can lead to this somatodendritic deprivation during sleep.

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Sleep Research and Sleep Medicine has long been the research center of the University of Bern and the Inselspital, Berne University Hospital.

“We hope that our findings will be of interest not only to patients but also to the general public,” says Adamantidis.

News about sleep and emotional processing research on this

Author: Press service
A source: University of Bern
The connection: Press Service – University of Bern
Photo: Image in public domain

Original study: Closed access.
“Paradoxical somatodendritic dissection supports cortical plasticity during REM sleep” Mattia Aime et al. science


Abstract

Paradoxically, somatodendritic dissection supports cortical plasticity during REM sleep

Rapid eye movement (REM) sleep is associated with the consolidation of emotional memories. However, the basic neocortical schemes and synaptic mechanisms remain unclear.

We observed that REM sleep is associated with somatodendritic detachment in pyramidal neurons of the prefrontal cortex.

This discrepancy reflects a change in the inhibitory balance between mediated somatic inhibition of parvalbumin neurons and dendritic dysentibulation of vasoactive intestinal peptide, mainly caused by neurons in the central thalamus.

REM-specific optogenetic suppression of dendritic activity led to a loss of safety discrimination against risk and a lack of synaptic plasticity during associative learning, and an increase in discrimination and synaptic potential in the optogenetic release of somatic inhibition.

Somatodendritic deprivation during REM sleep promotes conflicting synaptic plasticity mechanisms to optimize emotional responses to future behavioral stresses.

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