Sleep is something that we spend one third of our lives doing, and nearly everyone is familiar with that feeling of waking up after a vivid dream, but what is really happening in our brains while this goes on? Without enough sleep, the human body stops being able to function properly, making it absolutely essential to our survival – but what really goes on while our brains shut off from the real world and invent ridiculous stories? Is there any meaning behind those terrifying dreams we’ve all had about our teeth falling out, or turning up at school wearing less than you would ideally like?

Put in simple terms, dreams are thoughts, feelings and images that occur while we sleep. Some people dream in colour, while others actually dream in black and white, and on average, most people dream for around two hours a night, although they may not remember the majority of what took place. Dreams occur most commonly and intensely in the rapid-eye movement (REM) stage of our sleep cycle, which first happens around 90 minutes after we fall asleep and gets its name from the way that our eyes move quickly from side to side underneath our eyelids during this stage. Brain wave activity during REM sleep actually appears very similar to brain waves during our waking hours – it shouldn’t come as a surprise that our dreams can become so wild and intense while we are in this stage, then. New Scientist have even suggested that we dream a lot more than we might think, but we actually forget most of it. Tore Nielsen from the University of Montreal explains that dreaming consists of ‘hours and hours of mental experiences,’ of which we remember just minutes after we’ve woken up. 

One of the questions that has plagued scientists for years is whether or not our dreams have any kind of real meaning. Some theories, like the activation-synthesis hypothesis, suggest that dreams actually have no meaning, instead simply resulting from the brain attempting to make sense of neural activity that occurs while we sleep. According to this theory, our brains try to give meaning to random signals that are created when circuits in the brainstem are activated during REM sleep, and this is why we dream. 

Freud would disagree with this theory, though – according to his research on the subject, he believed that dreams were derived from real life and must, therefore, be connected to it. He theorised that our dreams explore our unconscious desires and wishes, particularly ones we are unable to fulfil in reality for various reasons, and that if the symbols in one’s dreams are analysed carefully enough, their underlying emotions can be uncovered and understood. Freud’s theories are certainly taken with a pinch of salt nowadays, though, so it might be best just to trust the modern scientists.

Although sleep might seem like a simple process that we go through every night, there is so much more to it than just closing your eyes and nodding off. From constantly-shifting sleep phases to stimulated brainstem circuits, our brains are anything but dormant throughout the night.

Fancy more Sci&Tech? Check out these stories:

Should Social Media Platforms Censor Vaccine Misinformation?

‘World’s Oldest Map of the Stars’ Coming to the British Museum

Creature Feature: Black-Footed Ferret