Hypnosis Alters Activity in Several Brain Regions, Study Finds
Researchers at the Stanford University School of Medicine have discovered several ways that brain activity changes while a person is in a hypnotic state. Their findings are published online in Cerebral Cortex.
Hypnosis is proven to be clinically useful, but the specific changes which occur in the brain during hypnosis are not completely understood, the authors wrote.
Previous studies have suggested that hypnosis is associated with decreased activity in the brain’s default mode network (DMN), which includes the medial prefrontal cortex and the posterior cingulate cortex. Research has also associated high hypnotizability with greater functional connectivity between the brain’s executive control network (ECN) and the salience network (SN).
The Stanford study used functional magnetic resonance imaging to examine how hypnosis affected activity and functional connectivity among those three networks.
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The team used two hypnotizability scales to choose 57 of 545 healthy subjects who had either very high or extremely low hypnotizability scores. Brain scans were conducted during rest, memory retrieval, and two different hypnotic experiences, which were similar to hypnosis that might be used to treat anxiety, pain, or trauma. The participants with low hypnotizability were used as controls.
Researchers found three changes that occurred during hypnosis in the brains of the highly hypnotizable group:
- Reduced activity in the dorsal anterior cingulate cortex, part of the SN;
- Increased functional connectivity between the dorsolateral prefrontal cortex in the ECN and the insula in the SN;
- Reduced connectivity between the dorsolateral prefrontal cortex in the ECN and the posterior cingulate cortex in the DMN.
“These changes in neural activity underlie the focused attention, enhanced somatic and emotional control, and lack of self-consciousness that [characterize] hypnosis,” wrote lead author Heidi Jiang, a former Stanford research assistant, and colleagues.
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Senior author David Spiegel, MD, professor and associate chair of psychiatry and behavioral sciences at Stanford, said the findings could have implications for future treatment by hypnosis.
“Now that we know which brain regions are involved, we may be able to use this knowledge to alter someone’s capacity to be hypnotized or the effectiveness of hypnosis for problems like pain control,” he said. “We’re certainly interested in the idea that you can change people’s ability to be hypnotized by stimulating specific areas of the brain.”
Hypnosis has been shown to be effective in easily hypnotizable patients for lessening chronic pain and the pain of childbirth and other medical procedures; treating smoking addiction and posttraumatic stress disorder; and easing anxiety or phobias.
—Terri Airov
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