Dreams have been a rich vein to mine since early man relied on the dreams of their shamans and holy men. Writers have quarried their depths. Psychologists and psychiatrists take their interest in dreams straight to the bank.
Though not a shaman or a shrink, I've had an interest in dreams for a long time. One thing is clear. The body communicates within the context of the dream. I can personally attest to this.
I've had migraines since I suffered a head injury at age 17. I probably would have developed them anyway, since they are primarily genetic in origin and they run in my Dad's family. The sick headache they used to call them, as in, "I got up this morning with the sick headache." Sick referring to the nausea, and the sensitivity to light and sound which comes with the throbbing one-sided pain.
The type of migraine I have is preceded by a light show, wildly dancing zig-zags of neon light which fill my visual field. This is called an aura. It is not painful, but can be a problem because you can't see very well. But it's a short-lasting phase, 15 minutes from start to finish. After the aura fades there's a lull and then the hammering starts. If I can get to the pain pills when the aura first begins I can usually stop the migraine from developing, but when it begins while I sleep (as it did last night) I am sunk. Once established my migraines can last for a week.
The interesting thing is that my brain still sees the aura, even when I'm sleeping. In my dreams the aura is translated into brilliant flashing lights. In a dream last night they became enormous flashing Christmas lights, and lights on a helicopter (carrying none other than George Dubbya, of whom I am not a fan.) I will spare you the details, as they were most pedantic, something about a book signing.
But that the aura takes place in the brain, and is not just a visual effect, cannot be more clearly demonstrated.
Another type of dream which demonstrates that the body clearly communicates with the brain during sleep is one I call the frustration dream. I have Hypokalemic Periodic Paralysis (HypoKPP). HypoKPP is also a genetic disorder, another passed to me through my dad, who also had it. In HypoKPP a fall in the level of potassium in the blood causes temporary attacks or episodes of weakness, sometimes to the point of paralysis. Attacks often develop during sleep.
When I have an episode during sleep I get frustration dreams. The most common theme of these is that there's an emergency of some sort. I must summon help, usually by telephone. But though I try to make a call I can't. I can't find the number, can't read the phone directory, can't work the phone. I've often dreamed that the house was on fire. I rush in and carry the children out, only to have them run back into the house as soon as I put them down.
Everyone becomes paralyzed while they dream, in what is called the REM stage of sleep. During REM, the electrical activity of the brain, seen on an electroencephalogram (EEG), looks about the same as the electrical activity that occurs when a person is awake. Although the brain functions much the same way during REM sleep as it does during waking, REM sleep is characterized by temporary muscle paralysis. So, being paralyzed during a dream is absolutely normal, yet the brain can tell the difference between normal REM paralysis and the paralysis of a HypoKPP episode, and (in my case) translates that inability to move into a dream full of frustration and panic.
Another odd consequence of HypoKPP episodes are hypnogogic and hypnopompic hallucinations. These occur as (normal) people are falling asleep or waking. They are the result of parts of the brain falling asleep, or waking, at different rates. A dream, seen through the filter of an awake brain, while the body is still in the REM stage of sleep paralysis, can be mistaken for reality. These hallucinations are extremely vivid and are interpreted as reality by the brain. They are undoubtedly the basis for many an alien abduction experience, legends of "The Old Hag", etc.
A study done by Italian Neurologist Giorgio Buzzi et al. showed that people with periodic paralysis are far more likely to have these brain out-of-sync hallucinations. I've had these since childhood. I remember standing in the window of my childhood home at about age six, bending my knees, spreading my arms and flying out over the back gardens, the creek behind our house and the neighbourhood beyond. My memory says this actually happened. I know it didn't because there was no way I could have stood up on the window sill in that window. It simply was too small. Shame. The ability to fly would be useful.
The brain is amazing in its ability to interpret not only what we experience externally, but also what we experience internally. I am always fascinated, but I remain rooted in reality. If the aliens show up to probe me during a hallucination I'll probably note that their sophisticated instruments have Black and Decker stickers.
One other funny thing is that when I have a migraine it interferes with my ability to frame sentences verbally, but writing actually helps mitigate the pain. Blog post as pain killer. What a concept!