The science of sleep
I liked the movie, but this blog post is about my pet theory of sleep from an information-theoretic standpoint.
During wakefulness, the brain keeps receiving input from all its senses. It is busy recognizing the input and responding to it. Presumably, this input (and the results of the brain's early processing of it to generate a response) get stored in a memory dedicated to sense data.
But during sleep, the brain is free to create the deeper structures of knowledge that make up its neural graph. For example: moral and emotional assessments, and the much-celebrated "flashes of insight" that have helped so many famous scientists and artists (and normal people too, without a doubt).
The various stages of sleep correspond to the various functions the brain must perform, in order to reach the final, REM stage where dreaming mostly occurs. This stage can occur several times per night, lasting from a few minutes to up to an hour. Dreaming is accompanied with "increased brain activity", and is called "paradoxical sleep" because other body systems are also activated, but muscles are relaxed.
The information processing happening during sleep culminates with the REM stage. But what gets processed? Sense data - new information - acquired during wakefulness must be attached to the existing sub-graphs of information that make up memory. This is a classification an indexing job that involves matching the patterns in the input data to patterns in memory. The search through this data activates each particular sub-graphs, and the act of inserting the new sense data in those structures might be the generator of dreams.
All this is called "the unconscious mind" in popular culture.
Meditation is an interesting phenomenon, because it aims at recreating the connection with the unconscious processes during a special state where consciousness is maintained undiminished. Does this mean one could see his dreams fused with reality? In this case, how much "control" would the meditator have on his environment, while in this dream state that is characterized by reaching into the deeper information structures of the brain? A spectator only, or an agent?