An article in The New York Times explains some new insights into how hypnosis works:
The same processing stream, from lower to higher regions, exists for sounds, touch and other sensory information. Researchers call this direction of flow feedforward. As raw sensory data is carried to a part of the brain that creates a comprehensible, conscious impression, the data is moving from bottom to top.
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.
The article goes on to mention how hypnotizable subjects were able to overcome the Stroop effect (that is, correctly name the color of a word when the word itself is the name of a different color).
This means, too, that the power of self-suggestion is a powerful tool for change: affirmations and visualizations, cheesy as they may sound, conceivably help reprogram this top-down feedback.
