Healthy sleep always makes us feel better the next day. Find out how a recent discovery may lead to more effective treatments for mood disorders, PTSD and other mental illnesses.
I used to have a job that involved a lot of travel. I’d be flying all over North America. Once I had vital, in-person tasks to complete in LA, Chicago and New York City all in one week.
The trouble I’d have with travel on that scale was crossing time zones. Jet lag interrupts our healthy sleep patterns and other circadian rhythms.
I always found that the stress of those business trips combined with the lack of sleep made me cranky. I’d be more irritable, nervous, dim-witted and generally out of sorts if I lost too much sleep during a road trip.
One-Quarter to One-Third of Our Lives Spent Asleep
We used to think that the the one-quarter to one-third of our lives spent asleep was just downtime. However, starting around the middle of the twentieth century, scientists have come to understand that our brains do a lot of important work while we’re in bed.
We pass through four stages of sleep every night. First is that half-asleep state with which we’re all familiar. Then there’s light sleep.
After that, there are two deep sleep stages. These are the delta stage and the rapid eye movement (REM) stage. There’s some debate as to which of these is the most important, with growing evidence that delta sleep matters most.
Sleep Stages Cycle Throughout the Night
The stages cycle throughout the night. With each cycle, the REM and non-REM stages get longer and longer. A good night’s sleep involves four or five complete cycles.
We dream mainly during the REM stage. The dreams we have during that stage can be emotionally intense as well as freaky. Neurologists have always viewed REM sleep as a mysterious phenomenon.
The journal Science published a paper last week that identified what our brains are doing during REM sleep. Researchers from the University of Bern and the University Hospital Bern have discovered how the brain uses REM sleep to get our emotions sorted.
Brain Boosts Postive Emotions, Diminishes Negative Ones
The human brain boosts how we store positive emotions and diminishes the negative ones. Psychologists have always known that healthy sleep is vital to mental well-being, but these new findings amplify sleep’s significance.
One of the mysteries of REM sleep is how and why it reactivates our most intense emotions from when we’re awake. When we’re awake, neurologists can see the part of our brain called the prefontal cortex integrating our emotions.
Inexplicably, that part of our brains looks completely quiet while we’re sleeping. This riddle puzzled Antoine Adamantidis, a professor of Biomedical Research and his colleagues.
“Mechanism and Functions of Surprising Phenomenon”
He explains, “Our goal was to understand the underlying mechanism and the functions of such a surprising phenomenon.” We all have both a “flight or fight” and a “tend and brefriend” response.
Knowing the difference between risk and security has been vital for human evolution. The trouble is that our negative emotions can get way out of hand.
Too many malignant emotions can lead to anxiety, depression and even Post-Traumatic Stress Disorder (PTSD). Professor Adamantidis and his team want to help us to understand how our brain encourages positive emotions while suppressing negative ones with healthy sleep.
Experiments with Mice, Neural Activity in Brain Cells
The team did experiments with mice. They taught the mice to associate some sounds with safety and other sounds with danger. Then they monitored the neural activity in various brain cells as they slept.
A brain cell (neuron) has a body called the soma. The soma is connected to inputs called dendrites and outputs to other brain cells called axons.
The researchers found that the somas seem to disconnect from the dendrites when the mice are in REM sleep. Professor Adamantidis explained this finding.
Blocks Output of Emotions During REM Sleep
“This means a decoupling of the two cellular compartments, in other words, soma wide asleep and dendrites wide awake.” This decoupling blocks the output of emotions through the brain during REM sleep.
This means that brains encode both fearful and calm emotions, but prevent excessive responses to threats. This keeps animals well adjusted and enables them to survive.
The study’s lead author is Professor Mattia Aime. She interprets the results, saying, “This bi-directional mechanism is essential to optimize the discrimination between dangerous and safe signals.”
“Discrimination Between Dangerous and Safe Signals”
It appears that some human brains don’t have enough of this capacity to discriminate. In those cases, traumatic experiences get too much emphasis in the prefontal cortex, interrupting healthy sleep.
That’s where mood disorders and PTSD come in. This is an important breakthrough for patients and their therapists working to overcome mental illness.
The powerful consciousness of our minds is what makes us human. Yet, we’ve always had difficulty understanding how our thoughts and emotions work inside our brains.
How Our Thoughts and Emotions Work Inside Our Brains
We need a New Story to help each other understand Humanity and its place in Nature. We won’t have that science-based story until we unravel the mystery of our own minds.
Philosophers call it the “hard problem of consciousness.” It deals with how signals in our brain somehow translate into our experience of the world around us.
“The Feeling of What It Is Like to Be Something”
Philosopher Thomas Nagel described experience as, “the feeling of what it is like to be something.” He wrote an influential paper on this called “What Is It Like to Be a Bat?”
This new discovery helps us to understand what it’s like to be a mouse. More importantly, it seems to shed light on what it’s like to be one of us.
The research is a vital step toward healthy sleep therapies that can better treat PTSD and mood disorders. By applying this discovery, we may find ways to keep bad memories from being emphasized while we’re asleep.
Keep Bad Memories From Being Emphasized During Sleep
This is especially important immediately after a distressing experience. If we can help patients’ brains to properly block negative emotions during REM sleep, therapists may be able to prevent mental illnesses before they take hold.
Promoting healthy sleep might also help with related conditions. This could include stress disorders, panic attacks and complete lack of pleasure – what scientists call anhedonia.
Professor Adamantidis shared his final thoughts, saying “We hope that our findings will not only be of interest to the patients, but also to the broad public.”
We always have more to learn if we dare to know.
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