Dreams are mysterious, and since the time of the Ancient Mesopotamians, human beings have been recording their dreams and trying to figure out what, if anything, they mean.

A large percentage of scientists actually believe that dreams are just random images generated from our brains for no reason at all, serving no purpose whatsoever. But there have been prominent doctors and scientists in many fields and from different areas of expertise who would wholeheartedly disagree. Each theory of dreaming that you just heard about is backed by academic and scientific research and study conducted by some of these doctors and scientists.

Since there's no better place to get more in-depth knowledge about each of these theories than directly from their sources, you should check out these links to learn more:

1. We Dream to Fullfill our Wishes: Sigmund Freud's Interpretation of Dreams
2. We Dream to Remember: Memory, Sleep and Dreaming: Experience Consolidation by Erin J. Wamsley and Robert Stickgold
3. We Dream to Forget: The reverse learning theory of dreaming, by Francis Crick and Graeme Mitchison
4. We Dream to Keep our Brains Working: The Continual Activation Theory of Dreaming by Jie Zhang
5. We Dream to Rehearse: Dreaming and Consciousness: Testing the Threat Simulation Theory of the Function of Dreaming by Antti Revonsuo and Katja Valli
6. We Dream to Heal: Overnight Therapy? The Role of Sleep in Emotional Brain Processing by Els van der Helm and Matthew P. Walker
7. We Dream to Solve Problems: The "Committee of Sleep": A Study of Dream Incubation for Problem Solving by Deirdre Barrett

We all have good dreams and bad dreams, and depending on many other factors like your age and your diet and the stressors in your life at any given time. You may also occasionally experience nightmares. Though most of us associate the feeling of fear with our nightmares, other primary feelings like sadness, confusion, anger, guilt and disgust tend to be prevalent in our nightmares as well. The most common themes in nightmares tend to revolve around physical aggression, interpersonal conflicts and situations where the dreamer feels failure and helplessness. Dr. Antonio Zadra from the University of Montreal's Dream and Nightmare Laboratory shares some of the fascinating work they've done in a short interview with Science World here.

For most people, dreaming can happen anytime they are asleep, though we experience dreams most often while we are in the sleep onset and REM sleep stages of our sleep cycle. We usually have 4 to 6 dreams per night, but the majority of us forget most of them as soon as we wake up. Though you can't choose which dreams you'd like to remember, many people believe that your ability to recall more of your dreams in better detail will improve with the use of a dream journal. Also, there are several sources online that can help you interpret and analyze your dreams once you've recalled them (dream dictionaries are one popular tool to do this).

While many of us would be happy to simply remember more about our dreams, there are people who not only remember their dreams, but gain enough consciousness while they are asleep and dreaming that they know they are experiencing a dream while it happens. This phenomenon is called lucid dreaming and though the reality of it isn't exactly like Christopher Nolan's film Inception (which was in fact, at least partially inspired by his own ability to lucid dream) many researchers today are looking at lucid dreaming for its potential to positively impact the lives of dreamers everywhere. Tim Post speaks about The Emerging Science of Lucid Dreaming it in his excellent TEDx talk here.

Like we said at the beginning of this lesson, dreaming is mysterious. But its mysteriousness is one of the reasons that dreams are so intriguing and such a popular field of study today. There is plethora scientific, academic and popular information and media out there and some excellent sources. Take a look at these links! Nova: What are Dreams, Dream Interpretations- BBC, RadioLab Dreams Podcast they just might wake you up to the amazing world of dreaming.