October 4, 2012
Researchers Hunt For Mechanisms Of Hypnosis To Better Understand How It Works On Some, And Not On Others
Alan McStravick for redOrbit.com - Your Universe Online
From the Greek word hypnos, meaning “sleep”, Hypnotherapists are trained in utilizing exercises necessary in bringing about a sense of deep relaxation and an altered state of consciousness. Once in this state, a patient is typically responsive to an idea or image but the therapist isn´t in control of the patient´s mind or free will. By undergoing hypnosis, the patient can learn how to master their own states of awareness allowing them to have a measurable effect on pathological function and psychological response.
There is a reason that we refer to persons who appear to be in a trance by something they have seen or heard as being "mesmerized." Hypnosis, while having a place throughout history in ancient rituals and religious ceremonies, was first associated in modern times due to the work of Austrian physician Franz Anton Mesmer. Dating to his work in the 1700´s, Mesmer believed illness was caused by magnetic fluids in the body becoming unbalanced. His use of magnets and certain hypnotic techniques were not exactly popular with the medical community of the day, and he was eventually accused of fraud; and his techniques were termed ℠unscientific´.
It wasn´t until the mid 1900´s, through the work of prominent psychiatrist Milton H. Erickson that the use of hypnosis in a therapeutic session came back en vogue.
By 1958, the American Medical Association (AMA) and the American Psychological Association (APA) both officially recognized hypnotherapy as a valid medical procedure. More recently, the National Institutes of Health (NIH) has even recommended hypnotherapy as a treatment for chronic pain.
The original and primary use for hypnotherapy is to disassociate a learned behavior or response that would have taken root due to something that might have happened in the past. A trained therapist attempts to guide the patient to remember the instigating event that led to the first reaction. Through hypnotherapy, not only is the learned behavior separated from the memory but the unhealthy behavior is replaced by a new, healthier one.
Someone who undergoes hypnosis is guided to relax allowing thoughts to become more focused. Hypnosis can lower blood pressure and heart rate and change certain types of brain wave activity. Your conscious mind becomes less alert allowing your subconscious mind to achieve a higher level of focus. One of the aspects of hypnosis that psychotherapists have wrestled with is that some people respond better to hypnotic suggestion than others do. The reason for this, and the underlying pathology for it, has remained a mystery.
Enter a research team from Stanford University. In their study, published in the October issue of Archives of General Psychiatry, they present data from the use of functional and structural magnetic resonance imaging (fMRI, MRI) 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 in 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. Such an advance would enable scientists to better understand the mechanisms underlying hypnosis and how it can be used more widely and effectively in clinical settings, added Spiegel, who also directs the Stanford Center for Integrative Medicine.
In Spiegel´s estimation, nearly one-quarter of the patients he sees in his practice are unable to succumb to hypnosis. He states that a person´s hypnotizability is not linked with any specific personality trait, however. “There´s got to be something going on in the brain.”
Hypnosis, as discussed above, works by modulating activity in brain regions associated with focused attention, and this study offers compelling new details regarding neural capacity for hypnosis.
"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.
Spiegel and his colleagues focused their study on 24 adults, (12 with a high hypnotizability; 12 with a low hypnotizabilty), utilizing both fMRI and MRI scans on the participants.
Once the data was collected, the researchers studied the activity of three different networks in the brain: the default-mode network, used when one´s brain is idle; the executive-control network, which is involved in making decisions; and finally, the salience network, which is involved in deciding something is more important than something else.
The results, according to Spiegel, were very clear. While both groups displayed an active default-mode network, the highly hypnotizable group was better at co-activation between components of the executive-control network and the salience network. In a stark contrast, there was little functional connectivity between those two areas of the brain in those with low hypnotizability.
Spiegel said he was pleased that he and his team found something so clear. "The brain is complicated, people are complicated, and it was surprising we were able to get such a clear signature," he explained.
Spiegel also said the work confirms that hypnotizability is less about personality variables and more about cognitive style. "Here we're seeing a neural trait," he said.
Funding for this initial study was provided by the Nissan Research Center, the Randolph H. Chase, MD Fund II, the Jay and Rose Phillips Family Foundation and the National Institutes of Health.
Moving forward, the researchers want to explore further how these functional networks can change during hypnosis. Another group of participants, in both high- and low-hynotizable categories, have been recruited for a new study.
In this study, with funding provided by the National Center for Complementary and Alternative Medicine, the researchers will focus on assessing fMRI data during the hypnotic states of the participants.