An article at New Scientist offers an interesting glimpse into research which attempts figure out exactly what anesthetics do, how they do it, and exactly what goes on in the brain that causes consciousness to be extinguished by them:
The development of general anesthesia has transformed surgery from a horrific ordeal into a gentle slumber. It is one of the commonest medical procedures in the world, yet we still don't know how the drugs work. Perhaps this isn't surprising: we still don't understand consciousness, so how can we comprehend its disappearance?The article does a good job of summarizing how anesthesia research may give us deeper insight into the nexus between the brain and consciousness, but the mystery of exactly what consciousness is and how it is generated by the brain seems no closer to being solved today than it's ever been.
That is starting to change, however, with the development of new techniques for imaging the brain or recording its electrical activity during anesthesia. "In the past five years there has been an explosion of studies, both in terms of consciousness, but also how anesthetics might interrupt consciousness and what they teach us about it," says George Mashour, an anesthetist at the University of Michigan in Ann Arbor. "We're at the dawn of a golden era."
Consciousness has long been one of the great mysteries of life, the universe and everything. It is something experienced by every one of us, yet we cannot even agree on how to define it. How does the small sac of jelly that is our brain take raw data about the world and transform it into the wondrous sensation of being alive? Even our increasingly sophisticated technology for peering inside the brain has, disappointingly, failed to reveal a structure that could be the seat of consciousness.