Imperial College of London psychologist John Gruzelier used hypnosis on 12 patients resistant to hypnosis and 12 susceptible to hypnosis while watching their brains with functional Magnetic Resonance Imaging (fMRI) and gave them orders to follow. The hypnotically suspectible showed a difference in brain activity in the anterior cingulate gyrus and in the left prefrontal cortex of the brain.
But under hypnosis, Gruzelier found that the highly susceptible subjects showed significantly more brain activity in the anterior cingulate gyrus than the weakly susceptible subjects. This area of the brain has been shown to respond to errors and evaluate emotional outcomes.
The highly susceptible group also showed much greater brain activity on the left side of the prefrontal cortex than the weakly susceptible group. This is an area involved with higher level cognitive processing and behaviour.
Gruzelier also suspects that hypnotism may interfere with subjects' evaluation of future emotions such as embarrassment. A region in the brain's medio-frontal cortex, close to the anterior cingulate, governs our perception of how we will feel if we take a certain course of action, he says. If connections between the two regions are impaired, stage volunteers might happily act without thinking.
Professor John Gruzelier, from Imperial College London, said: “We have a magnificent therapeutic tool which is being ignored because there’s no evidence of the mechanism involved. Now we’re getting evidence of the mechanism and we hope people will take it more seriously.”
Last year, Stanford University psychiatric researcher David Spiegel used positron emission tomography (PET) scans to watch changes in brain function in volunteers who were highly hypnotizable.
The hypnotized volunteers were told to see colour. Then, regardless of whether or not the researchers showed them colour, the areas of the visual cortex that registers colour would fire. When the researchers told them to see "grey" objects, the volunteers had less activity in the colour zones of the brain.
Of course the development of greater understanding the mechanisms underlying hypnosis will inevitably lead to the development of more powerful and reliable techniques for invoking hypnotic states even in people who can not now be hypnotized. That, in turn, will inevitably lead to abuses of the techniques. Imagine a police state that brings in its citizens, invokes hypnotic states, and then feeds them with all sorts of suggestions about what they should believe and do. Imagine brain implants that can be used to remotely trigger a hypnotic state. Technology enhances the ability to carry out both good and evil acts.
|Share |||Randall Parker, 2004 September 10 03:42 PM Biological Mind|