Researchers at the Department of Neurology of the University of Bern and University Hospital Bern uncovered how the brain triages emotions during dream sleep in order to support the storage of positive emotions while lowering the concentration of negative ones. The study investigates how sleep affects mental health and teaches new methods of therapeutic therapy.
After awakening, the prefrontal cortex integrates many of these emotions during wakefulness but appears paradoxically quiescent during REM sleep. Our goal was to understand the structure and nature of this strange phenomenon, according to Prof. Antoine Adamantidis, the Department of Biomedical Research (DBMR) at the University of Bern.
Extremely negative emotions, such as fear reactions and states of anxiety, are causing pathological states like Post-Traumatic Stress Disorders (PTSD) in humans. In Europe, about 15% of the population is affected by persistent anxiety and severe mental illness. This study has been published in the journalScience.
A Dual mechanism
The researchers conditioned mice to discern auditory stimuli associated with safety and others associated with danger (aversive stimuli). The activity of neurons in the brain of mice was then recorded during sleep-wake cycles. In this way, they were able to map different areas of a cell and determine how emotional memories are altered during REM sleep.
Neurons are formed of a cell body (soma) that integrates information from the dendrites (inputs) and sends signals to other neurons via their axons (inputs). This means a decoupling of the two cellular compartments, in other words soma wide asleep and dendrites wide awake, according to Adamantidis. This means a decoupling of the two cellular compartments, while danger and safety factors are totally blocked, thus the brain
A survival advantage
According to the DBMR, the coexistence of both mechanisms is beneficial to the stability and survival of organisms, and this bi-directional mechanism is essential to reduce the discrimination between dangerous and safe signals. This is especially relevant to post-traumatic stress disorders, in which trauma is over-consolidated in the prefrontal cortex, day after day during sleep.
Breakthrough for sleep medicine
These findings help to better understand the processing of emotions during sleep in humans and provide new perspectives for therapeutic therapeutic solutions to overcome traumatic memories, such as posttraumatic stress disorder (PTSD) and their early sleep-dependent consolidation. Additional acute and chronic mental health difficulties that may be involved in this somatodendritic decoupling during sleep include acute and chronic stress, anxiety, depression, and panic, as well as the incapacitate to feel pleasure. According to Adamantidis, sleep research and sleep medicine have long been a focus of
The Inter-Faculty Collaboration Foundation for Sleep & Health has benefited the University of Bern, the Inselspital University Hospital Bern, the Sinergia Grant on Sleep & stroke from the Swiss National Science Foundation, and the European Research Council. Part of the research includes collaboration with Prof. T. Fellin at the Italian Institute of Technology (IIT), Genoa, Italy.