Sleep isn’t as simple as an on/off switch. There are many stages of sleep in which different parts of the brain are engaged or disengaged. It is known that in different stages of sleep millions of crucial things happen, ranging from regulating emotions, to neutralising the toxicity of your body cells, however, there is still a lot about this strange phenomenon that we don’t quite understand, and one thing remains a huge head-scratcher, as it has for millennia – why do we dream?
There are many theories about the exact purpose(s) of dreaming, but very few have any real scientific background. There is, however, one very logical explanation put forth by California University’s professor of psychology and neuroscience, Matthew Walker, and though there is no conclusive proof to support it, there is a great deal of evidence which is extremely compelling.
This theory is all to do with memory storage in the brain, and so to understand it, we must understand the dynamic nature of long-term memory storage: Every experience we face on a day-to-day basis; every emotion we feel; every face you see of someone walking by on the street; forms a memory in a non-permanent depot of the brain. This memory is composed of many neuron pathways which all link together.
The bulk of the sleep cycle is taken up by deep sleep, where there is no dreaming involved. It is believed that during this stage of the sleep cycle, unimportant and insignificant neurons which have formed in this non-permanent depot throughout the day, are destroyed. Then, during REM (rapid-eye movement), or dream sleep, the neurons that were not sieved out are moved to a permanent bank within the brain’s memory storage and are then linked with related experiences to form complex networks. This movement of the neurons from the non-permanent to the permanent depot of the brain requires them to be destroyed and then completely reformed as exact replicas in the new location.
Therefore, Walker proposes, if experiences are forming neuron pathways, then when an exact replica of this neuron pathway is formed in another part of the brain, you should have to re-experience the same thing again while you sleep. This is a dream.
But that then raises another question – if dreams are exact replicas of the significant memories from throughout the day, then why are they so bizarre and obscure? There is no official theory that I know of which answers this question, but I do personally have an explanation which I believe to be logical: if each memory or experience is composed of many neurons, then perhaps some of them are considered relevant and some are not by the brain, and so the ones which are not will be destroyed during the deep sleep stages of the cycle. Your mind will no longer be able to make sense of the experience as a whole, so it must fabricate parts to fill in the gaps. Perhaps these gaps are occupied in the dream state by completely unrelated unconscious thoughts; perhaps they are stimulated by external forces such as rain coming through your window as you sleep; perhaps the gaps are filled with related memories, lessons, or experiences, which have been networked in the permanent depot of the brain and these connections are being fortified in the dream state. The probability is, it’s a combination of all three, and many more.
What you dream, then, literally is symbolic. Not of deep hidden messages from past lives, but symbols of your recent experiences and how they affected you on every level, from sensory to emotional.
If you’re interested in further reading about the topic, I strongly recommend Professor Matthew Walker’s book, “Why We Sleep”. He goes into great deals of detail, with highly understandable analogies and visual aids to explain everything he has discovered about sleep from his extensive research in the past 30 years.