Now I don't know if it's just me and I haven't been under general anesthesia too many times, but it seems like time stands still and it's like the mind quits altogether. You wake up (if you're lucky) and it seems that no time has passed at all.
There are a whole bunch of different kinds of consciousness, unconsciousness and semi-consciousness, to the point where the old expression “wonderment” applies. Here are some unrelated anecdotes:
A popular means of anesthesia these days is called “twilight sleep”, in which people may either be quiet, be almost awake, or act like they have been given ‘truth serum’; they may feel pain, but they don’t remember it or anything else after the fact - amnesia. Some surgeons require their surgery staff to sign non-disclosure statements in case patients babble out something incriminating or embarrassing. And they do.
The prescription sleep aide, Ambien, can take sleepwalking to extraordinary degrees, some people even driving cars for miles before eventually bumping them in to something. Two members of the Kennedy family have been cited for driving under the influence of Ambien. (Which doesn’t say anything about character, for once, as sleepwalking seems to have a genetic component.)
However, Ambien can also do something that is extraordinarily good.
In South Africa, a young man was in a motorcycle accident, suffered brain damage, and went into a persistent coma. After some weeks he was moved into a persistent coma ward with other such people. However, he had a “restless arm”, that would unpredictably spasm. So the doctor decided to give him some Ambien (the generic version), to see if it would settle down his arm spasms.
Two hours later he woke up and was able to communicate for a while before relapsing. So he was given more Ambien, and woke up again, for a longer period of time. Eventually he fully woke up and was conscious and responsive.
So the doctor gave Ambien to all the other patients, and about 70% had some response, many regaining consciousness.
The doctor speculated that when the brain is damaged, it puts out a lot of a chemical called GABA, which “turns off” the damaged part of the brain so that it can heal. When it has healed, GABA levels return to normal. However, in some people, the big rush of GABA sensitizes their brain to GABA, so that even normal levels will keep it in a shut down state.
And Ambien is a GABA blocker.
There is a lot of interest these days in people trying to create unusual brain activity by stimulating their brain with different frequencies of light and sound during sleep. Here is something of a comprehensive list of such things, and what some people think they can get from particular stimulation:
http://www.lunarsight.com/freq.htm
Of course, most of it is hooey and wishful thinking, but there is some reasonable stuff in there as well. But given the complexity of the brain, it’s hard to know which is which.
Some years ago, I knew a top biochemical psychiatrist who would work with patients for a year or more trying to develop just the right pharmaceutical combination for their exotic brain problems.
He really hated drinking alcohol, because he said that the human brain had at least 100 significant neurotransmitters and chemicals, and alcohol was almost unique in that it could foul up every one of them. After working with a patient for months, they would go out on a bender, and he would have to start from scratch because their neurochemistry had changed so much.