Study Reveals That Sleep Resets Brain Connections


Much research has proved just how important getting the right amount of sleep can be on positively impacting our health.

In another one of our blogs here at Sleepy People, we looked at the long-term health effects of sleep deprivation. The article revealed how sleep is a critical period of time in which your immune system is busily working away to produce protective cytokines and antibodies to fight infection and keep you feeling fit and healthy.

The digestive and cardiovascular system can also be affected by a lack of sleep. This is through the biochemical ghrelin increasing, which then stimulates your appetite causing a craving for junk food. A repetition of sleep deprivation could, therefore, lead to weight gain, and further down the line, may even cause risk to your cardiovascular system.

However, a new study has revealed that sleeplessness can also result in neurons becoming ‘muddled’ with electrical activity, and this finding could be imperative in being able to develop new therapies for mental health disorders including depression.


The correlation between sleep and memory

Researchers of the study found that sleep can help to rearrange the build-up of connectivity in the brain during time which we’re awake. This process has shown to be an essential part in the brain’s ability to learn and retain information.

Even just one evening of poor sleep has proven to be enough to affect the brain’s natural reset mechanism. By not receiving the recommended amount of sleep, this can cause the brain’s neuro system to become ‘over-connected’ and jumbled with electrical activity, meaning that the brain finds it difficult to retain new memories which have been made.

Yet not only was the study important in showing a relation between memory and sleep, but the results could also assist with future treatment for mental health disorders.

Therapeutic sleep deprivation, named as a fundamental therapy for major depression is a therapy which Christopher Nissen, a psychiatrist responsible for leading the research at the University of Freiburg, feels could work through the patient’s brain connectivity.


Why do we sleep?

Why we need to sleep is a big question, but as the results of this and previous research has shown, this is a necessary part of keeping our bodies active and healthy. As highlighted by Nissen in The Guardian’s article discussing the study: “This work shows us that sleep is a highly active brain process and not a waste of time. It’s required for healthy brain function,”.

The results of the study help to confirm what is named the ‘synaptic homeostasis hypothesis of sleep’ (SHY). This notion was first developed by researchers at the University of Wisconsin-Madison in 2003 and clarified why our brains require rest after taking in so much new information throughout the day.

The thought behind the hypothesis is that while we’re awake, the synapses responsible for creating passages between the brain cell are reinforced by the more information we absorb. As this means that the brain has been working hard, sleep is required to help the brain relax, but also to establish the new information which we’ve already absorbed.

Nissen, in the journal Nature Communications, discusses tests undertaken by 11 men and 9 women aged between 19 and 25 after they received a good night’s sleep compared to having no sleep. It states that after a poor night’s sleep, the brain tended to be in a much more excitable state, while it was also hard for the neurons to respond as effectively. This showed that writing memories may be lost due to sleep deprivation.

The tests, therefore, revealed that sleep is critical as it helps to steady the brain’s activity so that memories can be noted down and retained.

However, in terms of being able to help patients with mental health disorders such as depression, Nissen was quoted saying, “If you deprive people with major depression of sleep for one night, about 60% show a substantial improvement in mood, motivation and cognitive function. We think it works by shifting these patients into a more favourable state,”.

While this idea is certainly very interesting, unfortunately, the therapy isn’t entirely effective, as the following night of sleep showed patients to relapse. The tests did, however, display that an individual’s mood could be altered within a matter of hours, and therefore, has been very useful in learning more about how the brain works and helping to potentially progress with new treatments for depression perhaps in years to come.

The study has been successful in demonstrating a link between sleep and being able to absorb new information and retain memories. As Giulio Tononi, a professor of sleep medicine and the first individual to put forward the idea of SHY states, “Sleep is essential, and one main reason is that it allows the brain to learn new things every day while preserving and consolidating the old memories,”.