Neuroscience And Sleep –Ruth McGuire


Without the scientists telling us, most of us are probably well aware of the link between sleep and health. We know for example that a lack of sleep affects our ability to concentrate. However, neuroscientists go beyond the obvious and explore the link between the brain, the nervous systems and sleep. However, it is not all academic. Understanding how sleep affects our brain can help us to prioritise our own sleep and can also help us in our work with parents, children and others that we support.  Dr. Julie Seibt, Lecturer in Sleep and Plasticity at the University of Surrey says: "Our brains are amazing and fascinating organs - they have the ability to change and adapt based on our experiences. It is becoming increasingly clear that sleep plays an important role in these adaptive changes.’

Stages of sleep

Stage 1 This is the stage where we switch from being awake to falling asleep. As we make the switch, our brain waves slow down from their ‘awake’ patterns. 

Stage 2 This is the light sleep that happens as we begin to drift off. During this stage brain wave activity also slows down but ‘is marked by brief bursts of electrical activity.’ 

Stage 3. This is the stage of deep sleep when brain waves slow down even more than previously. At the same time our heartbeats and breathing also slow down.

Stage 4 REM sleep. Most of our dreaming tends to occur during this stage which is a deeper form of sleep. It’s much harder to wake someone up from this stage than from  other stages. As we dream during this stage of the sleep cycle, our arm and legs become temporarily paralysed which is why we don’t get up and act out our dreams. Although there are numerous theories as to why we dream, one theory that sounds credible is that dreams help us to process our emotions. 

Sleep and brain health

Sleep is important to a number of brain functions, including how nerve cells (neurons) communicate with each other. Although we might think that once we go to sleep, our brains shut down, the opposite is true – our brain remains active.  Researchers have found that whilst we sleep, a fluid in the brain called cerebrospinal fluid (CSF) ‘washes’ our brains out by flushing out toxins. Apparently, the process only occurs during sleep – in other words, whilst we sleep, we are quite literally being ‘brainwashed.’ The process of ridding our brains of toxins is believed by some scientists to protect us from conditions such as Alzheimer’s.

Sleep and memory

As we sleep, memories and newly learned skills are moved to more permanent parts of the brain which makes it easier to recall these memories. This is why getting a good night’s sleep before an exam or a test or before any activity where we have to rely on memory, is important. Dr Scott Cairney, from the University of York’s Department of Psychology, explains an experiment that was used to test the link between brain activity and memory. She said: “We asked participants in our study to learn associations between words and pictures of objects or scenes before a nap. Half of the words were then replayed during the nap to trigger the reactivation of the newly learned picture memories. When the participants woke after a good period of sleep, we presented them again with the words and asked them to recall the object and scene pictures. We found that their memory was better for the pictures that were connected to the words that were presented in sleep, compared to those words that weren’t.” Dr Cairney explains the significance of the findings: “When you are awake you learn new things, but when you are asleep you refine them, making it easier to retrieve them and apply them correctly when you need them the most. This is important for how we learn but also for how we might help retain healthy brain functions.” 

Researchers from Harvard University in the USA have found similar links between sleep, learning and memory: “Acquisition and recall occur only during wakefulness, but research suggests that memory consolidation takes place during sleep through the strengthening of the neural connections that form our memories. Although there is no consensus about how sleep makes this process possible, many researchers think that specific characteristics of brainwaves during different stages of sleep are associated with the formation of particular types of memory.”

Sleep deprivation

It stands to reason from the scientific research, that if we are sleep deprived our memory and our capacity to learn will be affected. Apparently, the neurons in our brain do not work property and this affects our ability to access previously learned information. Sleep deprivation may also affect our ability to process information and to make sound judgements. "We discovered that starving the body of sleep also robs neurons of the ability to function properly," said senior author Dr. Itzhak Fried, professor of neurosurgery at the David Geffen School of Medicine at UCLA and Tel Aviv University. He adds: "Inadequate sleep exerts a similar influence on our brain as drinking too much," said Fried. "Yet no legal or medical standards exist for identifying over-tired drivers on the road the same way we target drunk drivers."

Guidance and advice

There is no doubt that our brains and our minds are affected by the quality and amount of our sleep. It is also clear that sleep deprivation can pose a very serious risk not just to our own health and safety but that of others. Reviewing your bedtime routine is a good way to check whether you are giving your brain sufficient time to remove toxins and to learn, recall and process information.

Sleep Council tips for good quality sleep


  •  Keep regular hours. Going to bed and getting up at the same time, all the time, programmes the body to sleep better. Your mind and body loves it!
  • Turn off screens an hour before bedtime. Social media, news, work emails can all stimulate the brain and cause anxious thoughts/feelings.

  • Avoid alcohol. While it may help you fall asleep initially, it will interrupt your sleep later on in the night.

  • Cut down on caffeine – especially in the evening. Have a hot milky drink or herbal tea instead.

  • Try to exercise at least three times a week for 30 minutes. A brisk walk in the Autumn fresh air will do wonders for clearing your mind.

  • Wind down properly before bed. Read a book, have a bath, listen to soothing music or even meditate.

  • Deal with worries or heavy workload but making lists of things to be tackled the next day.

  • Create a sanctuary to sleep in. Messy bedrooms make for a messy mind so declutter. Invest in a comfortable, supportive bed and luxurious bedding.

Further information and advice  (Two-minute video on neuroscience and stages of sleep)