Not Getting Sleepy? Not Everyone Can Be Hypnotized
The brains of people who can be easily hypnotized are different than the brains of people who can’t be hypnotized, according to new research from the Stanford University School of Medicine.
The study used data from functional and structural magnetic resonance imaging to identify how the areas of the brain associated with executive control and attention tend to have less activity in people who cannot be put into a hypnotic trance.
“There’s never been a brain signature of being hypnotized, and we’re on the verge of identifying one,” said David Spiegel, MD, the paper’s senior author and a professor of psychiatry and behavioral sciences.
This would help scientists better understand the mechanisms underlying hypnosis and how it can be used more widely and effectively in clinical settings, he added.
The researcher estimates that 25 percent of the patients he sees cannot be hypnotized. He adds that the ability to be hypnotized is not linked with any specific personality trait. “There’s got to be something going on in the brain,” he said.
Hypnosis is a trance-like state in which a person has a heightened focus and concentration. It has been shown to help with brain control over sensation and behavior, and has been used clinically to help patients manage pain, control stress and anxiety and combat phobias, according to the researchers.
Hypnosis works by modulating activity in regions of the brain associated with focused attention.
“Our results provide novel evidence that altered functional connectivity in [the dorsolateral prefrontal cortex] and [the dorsal anterior cingulate cortex] may underlie hypnotizability,” the researchers wrote in their paper.
For the study, Spiegel and his colleagues performed functional and structural MRI scans of the brains of 12 adults with high hypnotizability and 12 adults with low hypnotizability.
They looked at the activity of three different networks in the brain: The default-mode network, used when the brain is idle; the executive-control network, which is involved in making decisions; and the salience network, which is involved in deciding something is more important than something else.
According to Spiegel, the findings were clear: Both groups had an active default-mode network, but highly hypnotizable participants showed greater co-activation between components of the executive-control network and the salience network.
In the brains of the highly hypnotizable group, the left dorsolateral prefrontal cortex, an executive-control region of the brain, appeared to be activated in tandem with the dorsal anterior cingulate cortex, which is part of the salience network and plays a role in focusing of attention.
By contrast, there was little functional connectivity between these two areas of the brain in those with low hypnotizability, Spiegel noted.
“The brain is complicated, people are complicated, and it was surprising we were able to get such a clear signature,” he said.
The work also confirms that hypnotizability is less about personality variables and more about cognitive style, he said.
“Here we’re seeing a neural trait,” he said.
The next step is to explore how these functional networks change during hypnosis, according to Spiegel. The research team has recruited high- and low-hypnotizable patients and will conduct fMRI assessments during hypnotic states.
The current study was published in the Archives of General Psychiatry.
Wood, J. (2012). Not Getting Sleepy? Not Everyone Can Be Hypnotized. Psych Central. Retrieved on October 9, 2015, from http://psychcentral.com/news/2012/10/06/not-getting-sleepy-not-everyone-can-be-hypnotized/45672.html