Could dreaming be the cure for Alzeimer’s disease or is it not that simple? | Deveshi
- hederahelixscience
- Jan 11, 2022
- 4 min read
How do we dream?
Most dreaming typically occurs during a process called REM sleep, which stands for ‘Rapid Eye Movement’ sleep. Humans tend to cycle through REM sleep periodically through the night, starting off with non-REM sleep, followed by a shorter period of REM sleep, and then the cycle repeats.
Drifting away into a state of subconscious:
There are three phases of non-REM sleep. Each stage can last from 5 to 15 minutes. You go through all three phases before reaching REM sleep.
Stage 1: It's very easy to wake you up. This phase may last for 5 to 10 minutes.
Stage 2: Light sleep where your heart rate slows and your body temperature drops. Your body is getting ready for deep sleep. This can last for 10-25 minutes.
Stage 3: The deep sleep stage. It's harder to wake you during this stage, and if someone succeeded in waking you up, you would feel disoriented for a few minutes.
Stuck in Dreamland:
According to the National Sleep Foundation, the average person dreams four to six times per night, however, most dreams are quickly forgotten. In fact, people forget 95-99% of their dreams. Also, in a large study conducted by PubMed Central, a highly respected database from the National Institutes of Health, with more than 28,000 people in 2012, it was found that it’s more common for men to forget their dreams than for women, with 79% of men in the study stating they forgot their dreams. The length of a dream can vary; they may last for a few seconds, or approximately 20-30 minutes, but over the course of a night’s sleep, the National Institutes of Health reported you might spend as much as 2 hours in dreamland. Dreams tend to last longer as the night progresses and scientists are certain everyone dreams every time they sleep.
The importance of REM sleep:
During REM sleep, our eyes move around rapidly in a range of directions, but don’t send any visual information to the brain. Experts believe the brainstem generates REM sleep and the forebrain generates dreams. Therefore if the brainstem is injured, patients dream but don’t enter REM sleep, and if the forebrain is injured, patients enter REM sleep but don’t dream. This is evidence that REM sleep is not needed for dreaming to occur, however it is still a very important factor. Sleep studies have also shown that brainwaves are almost as active during REM cycles as they are when we’re awake and since our brain is more active, we are able to have intense dreams during REM sleep. REM is important because it stimulates the areas of the brain that help with learning and is also associated with increased productions of proteins.
Usually, REM sleep happens 90 minutes after you fall asleep, after you go through the three phases of non-REM sleep, talked about earlier on in the article. NREM is equally important, as during the deep stages, the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system. As you get older, you sleep more lightly and get less deep sleep. Aging is also linked to shorter time spans of sleep, although studies show you still need as much sleep as when you are younger.
The first period of REM typically lasts 10 minutes but each later REM stage gets longer, ending on a REM stage that may last up to an hour. On top of that, REM sleep causes numerous other things to occur including: your heart and breathing rate to quicken, your pupils to constrict (perhaps to act as protection against harsh light), you lose muscle tone, which is the amount of tension or resistance to movement in muscles (so you don’t act out your dream and injure yourself) and you can’t regulate your temperature by sweating or shivering and so your body regulates towards the temperature of your room. Babies can actually spend up to 50% of their sleep in the REM stage, compared to only about 20% for adults.
What exactly is Alzheimer's?
Alzheimer's disease is a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. In most people with the disease — those with the late-onset type symptoms first appear in their mid-60s. Symptoms are caused due to the fact Alzeimer’s disease is a result of the destruction of brain cells from a build up of abnormal proteins. As a result, the following symptoms are caused: the inability to remember recent conversations, names etc, misplacing items, repetitively asking questions, finding it hard to make decisions, and being less flexible.
Could it be the cure?
Research led by a team from the University of Tsukuba, found new evidence of brain refreshing that takes place during REM sleep. The team used a technique to directly visualise the movement of red blood cells in the brain capillaries (where nutrients and waste products are exchanged between brain cells and blood) of mice during REM and NREM sleep and to compare the differences in blood flow. They used a dye to make the brain blood vessels visible under fluorescent light, using a technique known as two-photon microscopy.
"We were surprised by the results," explains Professor Hayashi. "There was a massive flow of red blood cells through the brain capillaries during REM sleep, but no difference between non-REM sleep and the awake state, showing that REM sleep is a unique state"
The research team then disrupted the mice's sleep, resulting in "rebound" REM sleep - a stronger form of REM sleep. Blood flow in the brain was further increased during rebound REM sleep, suggesting an association between blood flow and REM sleep strength. However, when the researchers repeated the same experiments in mice without adenosine A2a receptors (the receptors whose blockade makes you feel more awake after drinking coffee), there was less of an increase in blood flow during REM sleep, even during rebound REM sleep, suggesting that adenosine A2a receptors might be partially responsible for this increased blood flow.
Given that reduced blood flow in the brain and decreased REM sleep are correlated with the development of Alzheimer's disease, which involves the buildup of waste products in the brain, it may be interesting to address whether increased blood flow in the brain capillaries during REM sleep is important for waste removal from the brain. This study lays significant groundwork for future investigations into the role of adenosine A2a receptors in this process, which could ultimately lead to the development of new treatments for conditions such as Alzheimer's disease.
By Deveshi Abbott
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