Have you ever been told to just “sleep it off” after a particularly bad day? Or to “sleep on it” when making a tough decision? But why are we told these things? What is it that makes sleep so important to our emotional and mental health?
A new study published in Science suggests the answer has to do with how we process and consolidate emotions. The findings demonstrate how the brain, while in a REM state, sorts through negative and positive emotions differently, collecting the positive ones while dampening the negative ones.
To better understand the mechanisms happening in the brain during REM sleep, researchers first conditioned mice to recognize different sounds and associate them with either safety or danger, to simulate what it would be like for a person to feel anxious and at ease. From there, the activity of the neurons in their brain was analyzed while mice were sleeping as well as awake, which allowed scientists to map out different parts of a cell to determine what happens when we sleep in a dreamy, REM state.
They discovered that mice neurons were made up of a cell body, or the soma. The soma integrates information through different inputs and outputs, known as dendrites and axons. Scientists also noted that when certain dendrites or inputs are activated, the cell somas are kept silent. “This means a decoupling of the two cellular compartments, in other words soma wide asleep and dendrites wide awake,” study co-author Antoine Adamantidis explained in a press release.
The researchers pointed out that this decoupling is significant because it shows preference in the brain toward discriminating between safe and dangerous emotions, while blocking over-reactions to certain emotions like danger.
Adamantidis and Aime suspect the findings translate to humans and help to explain the link between sleep deprivation and anxiety disorders. When we don’t get enough REM sleep, our neurons don’t go through the process of discriminating between safety and danger, so we feel an excessive amount of irrational fear. Per usual, while follow-up research needs to be done, the scientists are hopeful that the current study will improve treatments for conditions like post traumatic stress disorder.
Simply put, there may one day be a way for scientists to intervene during our REM sleep in order to emphasize certain emotional memories, while turning down the volume on more traumatic ones. But for now, the findings underscore the importance of a good night’s rest. Not that you needed to hear it from anyone else.