What Happens In Your Brain While You Dream?

Dreams can be enchanting, exciting and even scary. They can wake us up or give us a great story to tell in the morning. But what causes us to dream in the first place? We take a look at what your brain is doing during your dreams.

When do we dream?

During sleep, we go through multiple cycles of 5 stages which are divided into REM (rapid eye movement) and non-REM (NREM) sleep. The first 4 stages are NREM sleep, and are restorative and, mostly, dreamless. Stage 5 is when REM sleep occurs. Medical Daily says that during REM sleep, ‘Our breathing becomes shallow and irregular, and our limb muscles become temporarily paralysed. Our eyes begin to jerk in various directions. This is also the stage where the dreams we actually remember tend to take place.’

It is not known exactly why REM sleep is so important, but the body does take measures to ensure it is not disturbed. For instance, the sound of a phone ringing or people talking may manifest in the dream as something else. Since REM sleep is the final stage of the sleep cycle, you’ll often find that you wake up having just had a dream. Writing down your dreams in a journal can help you decipher what’s on your mind or just have fun looking back on.

The limbic system

The limbic system is a relatively primitive part of the brain where memories and emotions are processed. It is made up of the amygdala, hippocampus and cingulate gyrus:

The amygdala – acts as a link between a stimulus and how you react to that stimulus. It takes information from your senses and reacts in the appropriate way, i.e. if something smells bad, we feel disgust.
The hippocampus – the memory teacher. The hippocampus is responsible for memory consolidation. For example, the first time we touch something hot, it learns the experience and replays it repeatedly to another part of the brain called the cerebral cortex. This creates a long-term memory.
The cingulate gyrus – this structure is partly responsible for your physical reactions to situations. It controls skeletal muscle movement and also recognising which part of the body has been stimulated through touch.

Limbic system

During REM sleep, this part of the brain is highly active. When we see what this part of the brain does, it is easy to relate it to dream production. In our dreams, we often see familiar things in strange settings or jumbled imagery. Interestingly, the part of the brain that deals with logic and self-control – the prefrontal cortex – is a lot less active during REM sleep. This could explain why our dreams often seem so illogical and disorganised!

REM sleep paralysis

As mentioned previously, during REM sleep, the muscles become temporarily paralysed. Sleep paralysis usually occurs either when a person is falling asleep or when waking up. This is when you are passing between stages of being awake and asleep. People who experience this are consciously awake but unable to move or speak, and some find it hard to breathe.

Additionally, people often report hallucinations, which could be a continuation of their dream. It can be a frightening experience that can last for a few seconds or a few minutes.

Sleep paralysis is not uncommon. In fact, WebMD reports that up to 4 in 10 people experience the condition. It can be caused by many different things including lack of sleep, a change in sleep schedule or irregular sleeping pattern and certain medications. The NHS advises good quality sleep, a comfortable sleep environment and healthy lifestyle are the best ways to avoid sleep paralysis.

Boy in bed holding up covers

Active brain

So, while you may think your brain ‘switches off’ when you go asleep, it is actually highly active for part of the night. It is almost as active during REM sleep as when you are awake! During this time, it is thought that your brain also works hard to clean itself up. According to Prevention, research suggests, ‘we sleep to allow time to clear away toxic by-products that would otherwise pile up and cause problems, like the trademark plaques of Alzheimer’s disease’. That’s why it’s vitally important that you have good quality sleep.

Tell us about your strangest dreams or sleep experiences in the comments!