(Rapid-eye-movement) REM sleep has been an area of interest for researchers but not much is found about why our brain regions appear to be activated during it. At the Inselspital and the University of Bern however, researchers have discovered now that during REM sleep the hypothalamus has activated neurons that help regulate our behavior of eating. In mice, if this activity is suppressed it decreases their appetite.
As we sleep, we move between varied sleep phases, and each of these can contribute to how rested we end up feeling. REM sleep is one such stage and it is also a stage known as paradoxical sleep. This is the phase during which we dream. Although highly active electrical activity occurs during this stage according to brain circuits, its functions however remain mostly unknown.
Areas that are responsible for regulating functions of memory or emotions are most active during REM sleep. A brain part in most mammals called lateral hypothalamus is a tiny structure and it shows major activity taking place during REM sleep. When awake, in this region neurons of the brain lead appetite functions and eating of food. They also regulate motivated behaviors, including addiction.
In the latest study led by Prof. Dr. Antoine Adamantidis of the University of Bern, researchers decided to study the workings of hypothalamic neuron activity of mice when they are in REM sleep. With this research, they aimed to discover how REM sleep can influence our waking daily behavior.
In mice, they found that if the behaviour of such neurons is suppressed, mice appetites were also reduced. This suggests that Rapid-eye-movement sleep Is almost compulsory to have a stable food consumption, says Adamantidis.
Study results have been since then published in a journal of Proceedings of the National Academy of Sciences (PNAS)
Through a practice known as optogenetics, researchers assessed how important these patterns of activity during REM were. As a consequence, they found that the patterns of activity for consumption were altered and animals eat less food when the activity of these neurons is suppressed.
Lukas Oesch is a writer on the study. He says they were quite surprised at how strong the effect is on the behavior of mice just due to a change in neural activity in the lateral hypothalamus. He says the change in behaviour patterns was still noticeable enough to measure after 4 days of normal sleep. This discovery suggests that neuron electrical activity in circuits of the hypothalamus during Rapid-eye-movement sleep is highly important for eating normally in mammals.
These findings are vital for our understanding of how important sleep is. Sleep quantity is not only needed for the betterment of our being but quality of sleep also plays an important role in regulating our behavior of eating normally.
Adamantidis says this is especially relevant today in a society where sleep quantity is decreasing and quality of sleep is being drastically altered by work shifts, adolescent social jet lag, or screen exposure during late hours of the night.
Through the study, they discovered a relationship among the neuron activity during REM sleep and the behavior of eating normally. This may help the making of new therapeutical treatments for the treating of eating disorders. Adamantidis however admits that more factors are still left to be discovered that affect this relationship.