The Science of Dreaming



What is the most bizarre dream you have ever had?

For thousands of years, many have written about dreams and a few people have received inspiration from their dreams, including some scientists. Dreaming is universal throughout the animal kingdom but the function of it is however unknown. To understand dreams, we first need to understand sleep.


Stages of Sleep

There are five stages of sleep: the first is light sleep where you can easily be woken up and where muscle activity and eye movements slow down. By the second stage, eye movements’ stop and your brainwaves start to slow down with the odd burst of brainwaves taking place, known as sleep spindles. Deep sleep then takes over in stages 3 and 4 where the third stage sees delta brainwaves occur interspersed with smaller faster ones. Delta brainwaves are one out of four different types of electrical brainwaves of varying oscillating speeds. It is by analysing these different types of brainwaves in different parts of the brain using electroencephalography (EEG) that dreaming and other states can be studied in great detail. By stage 4, the delta brainwaves are exclusive and no eye movement or muscle activity is taking place.
















REM (rapid eye movement) follows on from stage 4 and this is usually where dreams occur, but it isn’t exclusive to this stage. In REM, signals from the base of the brain called the pons send signals to your spine to shut off neurons thereby paralysing you preventing you from acting out your dreams (hopefully anyway!) Your breathing will be rapid and irregular, and your eyes will be jerking in different directions. It is during the REM phase where connections between brain cells (which were strengthened when you were awake) are now weakened as two studies published in Science outline. This supports one out of two theories on the function of sleep: Information processing; which allows for memory consolidation. The other theory is restorative (maintaining repairs and flushing out toxins).


Bright pink elephants

Dreaming in colour is not something everyone does, but one theory behind this is it could be a generational thing. Supposedly, dreaming in black and white is due to watching black and white TV, and therefore dreaming in colour could be linked to when colour TV was introduced. But it is difficult to draw a link between the two. Perhaps instead it could be due to electrical stimulation? An Australian man with a tumour in his right eye underwent radiotherapy and for the first time ever dreamt in colour. His dreams later went back to black and white. It is just a guess, but clearly more studies need to be done to explore this further.


Pinch me!

Knowing when you are dreaming- the lucid dream is a state between consciousness and waking, and psychologists are particularly interested in this state because of what it can mean for therapy. Unlike normal dreams, being lucid involves brain regions associated with memory and higher cognitive functions, and those who lucid dream appear to be more resilient to trauma and more capable of avoiding nightmares. A useful trick that clearly the Dream Warriors in Nightmare on Elm Street 3 make use of! Some psychologists are tapping into techniques that can induce lucidity, send messages into lucid dreams and unbelievably enough, the dreamers can reply back. If you want you can even try to induce lucid dreams yourself either to get rid of your nightmares or just change your dream for the fun of it.


Associated brain regions

Remembering dreams is down to the pre-frontal cortex in your brain. This is the region associated with memory, and high activity here means you are more likely to remember your dream. It was when an American research team discovered this that they found dreaming can also occur in non- REM states as well.

An Italian team discovered that some of the more emotional, strange and vivid dreams are associated with the amygdala and the hippocampus (responsible for emotions and memories respectively). Finally an American team at UC Berkeley found that the brain region, known as the right inferior lingual gyrus associated with the visual cortex is a region where either dreams are generated or are transmitted.













It is starting to appear that dreams maybe helping us to process our emotions, that it is a way of dealing with worry and anxiety. So the next time you have a nightmare, you might want to thank your brain! Or perhaps you can become your own “Dream Warrior” and make yourself lucid.

Danae Dodge

I received my PhD in Scientific Archaeology from the University of Sheffield in 2011 which specialised in ancient DNA and anthropology. For my profile, see my websites: I started getting involved in Science Brainwaves as a volunteer in 2010. I have volunteered at presentations, events (such as the British Science Festival in 2011) and even participated in the Science is Vital protest march in October 2010. My first blog for Science Brainwaves was "Ancient Humans: Who were they? And who got it on?" which was the written version of a talk I gave for the Natural History Society at the University of Sheffield on 5 December 2011. I also have a public engagement page dedicated to ancient DNA, which I encourage both the public and specialists to join: