Brain Scan Proves Hypnotic Effects

An increasing number of studies using brain scans show a physiological basis to hypnosis: different parts of the brain fire different types of electrical signals and fire off at higher levels when people are hypnotized.

In a study, eight highly suggestible hypnotized volunteers were told they would later be asked to name the color in which a word is written. The task was tricky because the word itself was the name of a different color. For instance, the word blue would be written in red ink, for instance.

He also told the hypnotized volunteers that when they emerged from hypnosis and later heard a cue, such as a cough, they would see the printed words as gibberish and focus only on the color of the ink.

The hypnotized volunteers completed the task 10 percent faster than a control group. Their brain scans also showed less activity in a midsection of the brain used to resolve conflict, known as the anterior cingulate cortex.

The results show that hypnosis has a measurable biological effect, said Raz, who published the study in Proceedings of the National Academy of Science. "What I'm showing is that words being suggested to someone can be very powerful. If practitioners carefully craft their words, and the individual is highly suggestible, they can bring about focal changes in the brain that no drug can produce," he said.

In another study, Stanford University researchers showed brightly colored shapes to eight hypnotizable patients and eight who resisted hypnosis. Then they told the subjects to imagine the shapes being drained of any colors but gray, black and white. They also told them to look at black and white shapes and imagine them as brightly colored.

The researchers found that when the suggestible volunteers were hypnotized and told to imagine color shapes, there was an increase in blood flow in brain regions that process color vision. The results, published in the American Journal of Psychiatry, showed that hypnosis can sometimes override what a hypnotized subject actually sees, the researchers say.

Experts say that hypnosis can be a unique tool, but works best when combined with other forms of treatment, such as psychological counseling or some type of therapy tailored to an individual patient.