Scientists identify how the brain sorts emotions during dream sleep | Sciences-Environment

Scientists at department of Neurology from the University of Bern and the University Hospital of Bern has identified how sleep helps in the processing of emotions. The study was published in the journal “Science”.

The work expands the importance of sleep in mental health and opens up new avenues of therapeutic strategies. Rapid eye movement (REM or REM) sleep is a unique and mysterious sleep state in which most dreams occur with intense emotional content. How and why these emotions are reactivated is unclear. The prefrontal cortex integrates many of these emotions during wakefulness but paradoxically appears at rest during REM sleep.

“Our goal was to understand the underlying mechanism and functions of such a surprising phenomenon,” explains Prof. Antoine Adamantidis of the department for Biomedical Research (DBMR) from the University of Bern and department of neurology at the Inselspital, University Hospital of Bern. The processing of emotions, in particular the distinction between danger and safety, is essential to the survival of animals. In humans, excessively negative emotions, such as fear reactions and states of anxiety, lead to disease states such as post-traumatic stress disorder (PTSD). In Europe, about 15% of the population suffers from persistent anxiety and serious mental disorders. The research group led by Antoine Adamantidis is now shedding light on how the brain contributes to reinforcing positive emotions and weakening strongly negative or traumatic emotions during REM sleep.

The researchers first conditioned the mice to recognize auditory stimuli associated with safety and others associated with danger (aversive stimuli). The activity of neurons in the mouse brain was then recorded during sleep-wake cycles. In this way, the researchers were able to map different areas of a cell and determine how emotional memories are processed during REM sleep. Neurons are composed of a cell body (soma) which integrates information from dendrites (inputs) and sends signals to other neurons via their axons (outputs). The results obtained showed that the cell somas are kept silent while their dendrites are activated. “This means a decoupling of the two cellular compartments, in other words, deeply asleep soma and wide-awake dendrites,” says Adamantidis. This decoupling is important because the high activity of dendrites allows the encoding of both danger and safety emotions, while soma inhibitions completely block circuit output during REM sleep. In other words, the brain promotes discrimination of safety versus danger in the dendrites, but blocks over-reaction to emotion, especially danger.

An advantage for survival According to the researchers, the coexistence of the two mechanisms is beneficial to the stability and survival of organisms: “This bidirectional mechanism is essential to optimize the discrimination between dangerous and safe signals”, specifies Mattia Aime of the DBMR, first author of the study. If this discrimination is lacking in humans and excessive fear reactions are generated, this can lead to anxiety disorders. The findings are particularly relevant for pathological conditions such as post-traumatic stress disorder, in which trauma is overconsolidated in the prefrontal cortex day after day during sleep.

Breakthrough for sleep medicine These findings pave the way for a better understanding of the processing of emotions during sleep in humans and open up new prospects for therapeutic targets to treat the maladaptive processing of traumatic memories, such as post stress disorder. -traumatic (PTSD) and their early sleep. – dependent consolidation. Other acute or chronic mental health conditions that may involve this somatodendritic uncoupling during sleep include acute and chronic stress, anxiety, depression, panic, or even anhedonia, the inability to experience pleasure. Sleep research and sleep medicine have long been a focus of research at the University of Bern and the Inselspital, University Hospital of Bern. “We hope that our findings will be of interest not only to patients but also to the general public,” says Adamantidis. (ANI)

(This story has not been edited by the Devdiscourse team and is auto-generated from a syndicated feed.)

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