A possible mechanism for Hypnosis?

I've always been a tentative believer in hypnosis, even though I've never been properly hypnotized. When I was in college, I did go to a "cope from your studies" workshop where they used guided imagery to teach you how to relax by pretending you're on a lovely beach. And I tell you, I was there. I braced myself against the salt air, and felt the sand squishing between my toes. Now here's a mechanism to explain how it happened:

The new experiments, which used brain imaging, found that people who were hypnotized "saw" colors where there were none. Others lost the ability to make simple decisions. Some people looked at common English words and thought that they were gibberish.[snip]

Bundles of nerve cells dedicated to each sense carry sensory information. The surprise is the amount of traffic the other way, from top to bottom, called feedback. There are 10 times as many nerve fibers carrying information down as there are carrying it up.

These extensive feedback circuits mean that consciousness, what people see, hear, feel and believe, is based on what neuroscientists call "top down processing." What you see is not always what you get, because what you see depends on a framework built by experience that stands ready to interpret the raw information - as a flower or a hammer or a face.

The top-down structure explains a lot. If the construction of reality has so much top-down processing, that would make sense of the powers of placebos (a sugar pill will make you feel better), nocebos (a witch doctor will make you ill), talk therapy and meditation. If the top is convinced, the bottom level of data will be overruled.

This brain structure would also explain hypnosis, which is all about creating such formidable top-down processing that suggestions overcome reality.

Does this explain people acting totally out of character under hypnosis and such? I don't know. But the brain imaging suggest that hypnosis is a powerfull piece of evidence that hypnosis is a real phenomenon in some degree, and no something to be reflexively cynical about anymore.
(I have been trying to get back to that beach. I've even downloaded a 'complete relaxation' audio file from the net. But it was embarrasingly cheezy, with the hypnotist speaking in this dramatic faux-whisper and New-aged music in the background. How can I relax when I'm cringing?)
(HT Brad P.)