Study identifies brain areas altered during hypnotic trances

July 28, 2016
Credit: Wikimedia Commons

Your eyelids are getting heavy, your arms are going limp and you feel like you're floating through space. The power of hypnosis to alter your mind and body like this is all thanks to changes in a few specific areas of the brain, researchers at the Stanford University School of Medicine have discovered.

The scientists scanned the brains of 57 people during guided hypnosis sessions similar to those that might be used clinically to treat anxiety, pain or trauma. Distinct sections of the brain have altered activity and connectivity while someone is hypnotized, they report in a study that will be published online July 28 in Cerebral Cortex.

"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," said the study's senior author, David Spiegel, MD, professor and associate chair of psychiatry and behavioral sciences.

A serious science

For some people, hypnosis is associated with loss of control or stage tricks. But doctors like Spiegel know it to be a serious science, revealing the brain's ability to heal medical and psychiatric conditions.

"Hypnosis is the oldest Western form of psychotherapy, but it's been tarred with the brush of dangling watches and purple capes," said Spiegel, who holds the Jack, Samuel and Lulu Willson Professorship in Medicine. "In fact, it's a very powerful means of changing the way we use our minds to control perception and our bodies."

Despite a growing appreciation of the clinical potential of hypnosis, though, little is known about how it works at a physiological level. While researchers have previously scanned the brains of people undergoing hypnosis, those studies have been designed to pinpoint the effects of hypnosis on pain, vision and other forms of perception, and not the state of hypnosis itself.

"There had not been any studies in which the goal was to simply ask what's going on in the brain when you're hypnotized," said Spiegel.

Finding the most susceptible

To study hypnosis itself, researchers first had to find people who could or couldn't be hypnotized. Only about 10 percent of the population is generally categorized as "highly hypnotizable," while others are less able to enter the trancelike state of hypnosis. Spiegel and his colleagues screened 545 healthy participants and found 36 people who consistently scored high on tests of hypnotizability, as well as 21 control subjects who scored on the extreme low end of the scales.

Then, they observed the brains of those 57 participants using functional , which measures by detecting changes in blood flow. Each person was scanned under four different conditions—while resting, while recalling a memory and during two different hypnosis sessions.

"It was important to have the people who aren't able to be hypnotized as controls," said Spiegel. "Otherwise, you might see things happening in the brains of those being hypnotized but you wouldn't be sure whether it was associated with hypnosis or not."

Brain activity and connectivity

Spiegel and his colleagues discovered three hallmarks of the brain under hypnosis. Each change was seen only in the highly hypnotizable group and only while they were undergoing hypnosis.

First, they saw a decrease in activity in an area called the dorsal anterior cingulate, part of the brain's salience network. "In hypnosis, you're so absorbed that you're not worrying about anything else," Spiegel explained.

Secondly, they saw an increase in connections between two other areas of the brain—the dorsolateral prefrontal cortex and the insula. He described this as a brain-body connection that helps the brain process and control what's going on in the body.

Finally, Spiegel's team also observed reduced connections between the and the default mode network, which includes the medial prefrontal and the . This decrease in functional connectivity likely represents a disconnect between someone's actions and their awareness of their actions, Spiegel said. "When you're really engaged in something, you don't really think about doing it—you just do it," he said. During hypnosis, this kind of disassociation between action and reflection allows the person to engage in activities either suggested by a clinician or self-suggested without devoting mental resources to being self-conscious about the activity.

Treating pain and anxiety without pills

In patients who can be easily hypnotized, hypnosis sessions have been shown to be effective in lessening chronic pain, the pain of childbirth and other medical procedures; treating smoking addiction and post-traumatic stress disorder; and easing anxiety or phobias. The new findings about how hypnosis affects the brain might pave the way toward developing treatments for the rest of the population—those who aren't naturally as susceptible to hypnosis.

"We're certainly interested in the idea that you can change people's ability to be hypnotized by stimulating specific areas of the brain," said Spiegel.

A treatment that combines stimulation with hypnosis could improve the known analgesic effects of and potentially replace addictive and side-effect-laden painkillers and anti-anxiety drugs, he said. More research, however, is needed before such a therapy could be implemented.

The study's lead author is Heidi Jiang, a former research assistant at Stanford who is currently a graduate student in neuroscience at Northwestern University.

Explore further: Not getting sleepy? Study explains why hypnosis doesn't work for all

Related Stories

Self-hypnosis training doesn't cut epidural use

May 26, 2015

(HealthDay)—Self-hypnosis training does not reduce women's epidural use during childbirth, according to a study published online May 11 in BJOG: An International Journal of Obstetrics and Gynaecology.

Recommended for you

Chatter in the deep brain spurs empathy in rats

June 23, 2017

It's a classic conundrum: while rushing to get to an important meeting or appointment on time, you spot a stranger in distress. How do you decide whether to stop and help, or continue on your way?

The neural relationship between light and sleep

June 23, 2017

Humans are diurnal animals, meaning that we usually sleep at night and are awake during the day, due at least in part to light or the lack thereof. Light is known to affect sleep indirectly by entraining—modifying the length ...

How pheromones trigger female sexual behavior

June 22, 2017

A study by a group of Japanese scientists showed how a male pheromone in mice enhances sexual behaviors in females—and how it may enhance a different behavior, aggression, in males—by identifying distinct neural circuits ...

Coupling of movement and vision

June 22, 2017

In a study published in Cell, Georg Keller and his group shed light on neural circuits in the cortex that underlie the integration of movement and visual feedback. They identified a mechanism in the visual cortex responsible ...

Forgetting can make you smarter

June 21, 2017

For most people having a good memory means being able to remember more information clearly for long periods of time. For neuroscientists too, the inability to remember was long believed to represent a failure of the brain's ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

dirk_bruere
not rated yet Jul 28, 2016
Now throw in some tDCS

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.