Do couples truly share pain? Studies probe brain, empathy
WASHINGTON (AP) When someone says, "I feel your pain," they really may.
A groundbreaking study shows that some of the same brain regions involved in feeling physical pain become activated when someone empathizes with another's pain.
And when it's time to feel better, thinking that a drug helps can make it so, according to a different brain-scanning study that finally caught the power of placebo in action.
The studies, reported in Friday's edition of the journal Science, provide important new evidence of the power of the mind, said Dr. Jon Levine, a pain specialist at the University of California, San Francisco, who reviewed the research.
"Very likely the same part of the brain which is affected by empathy for pain, and therefore suffering, is the area that also our mind or our expectation has to deal with if we're going to get control of that pain," Levine said.
In the empathy study, British researchers recruited 16 couples. One at a time, the women were put into brain scanners called MRI machines; the men sat nearby. The women could see only their loved one's hand and a computer screen. The women and men got brief electric shocks to the hand. The computer screen flashed who would get the next shock and whether it would be mild or very sharp.
When the women got shocked, the MRI showed how their brain's entire pain network activated, researchers reported. They registered feeling the jolt and how much it stung, from sensory brain regions, as well as how much it made them suffer — the "affective" or emotional regions.
But when the men got shocked, part of the women's pain network sprang into action, too — not sensory regions but emotional ones. They knew when the men were being shocked only by watching the computer screen.
The lead researcher, Tania Singer of University College of London, likened it to vivid feeling when imminent pain is imagined and the heart speeds up before the actual sensation arrives.
Men were not studied for their reaction to how women responded to a shock.
Singer did not tell the couples that she was studying empathy so as not to rig the results. But she later asked the women to describe how they felt when their partner was zapped.
"They indicated it was as unpleasant" when the man got zapped as when they did, Singer said. "What they say matched what I saw in the brain activity."
She also rated their degree of empathy, using questions such as how easily they cry at movies. The more empathetic their nature, the more emotional brain activity there was.
It was not "emotional contagion," like how one person's yawn can set a whole room to yawning, because the women could see only their partner's hand, Singer said. Instead, the women were using the same brain areas that anticipate one's own pain.
In the second study, volunteers put inside MRI machines had either electric shocks or heat applied to the arm. The pain activated all the expected neural pathways, researchers from the University of Michigan and Princeton University reported.
Then, researchers smeared on a cream they said would block the pain. In fact, it was a regular skin lotion.
When the volunteers were zapped again, they reported significantly less pain — and pain circuits in the brain showed they really felt better. Those were the same brain regions that respond to painkilling medication.
Then researchers spread on cream again, this time telling the volunteers it was a placebo — and they hurt all over again.
Doctors long known have known the placebo effect is real. It is one reason that they talk up the benefits of a drug as they write the prescription. But the effect has been assumed to be psychological, Levine said.
The study provides "a novel and important insight into the fact that placebo is in fact due to a physiological attenuation of the pain signal," he said.
As for empathy, Singer now is studying whether people can sense a stranger's suffering as much as a loved one's.
Is empathy a learned trait or a genetic one? Her study suggests it is a completely automatic response that varies merely in its degree, meaning it probably is hard-wired into our brains through evolution.
After all, Singer said, empathy serves two important survival functions: bonding between people, especially mother and child, and the ability to predict others' actions, such as whether someone in pain is a threat.
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