Brain-imaging Study Shows ‘Hot Spot’ that May Explain why African Americans Feel Greater Pain than Non-Hispanic White People and Latinxs


To be Black in America is to literally feel greater pain than non-Hispanic white people and Latinxs do — at least if the pain is being inflicted by a white man wearing a white coat, if it’s happening in a lab, if it follows years of racial discrimination, and if the findings of a sobering study reported on Monday are correct.

Despite the persistence of the slavery-era myth that African Americans are less sensitive to pain than people of other backgrounds (as a large fraction of white laypeople, medical students, and hospital residents in a 2016 study believed), the science is unambiguous. African Americans, and in some studies Latinxs, report more pain from the identical stimulus (being touched with something very hot, for instance) than non-Hispanic white people. Yet somewhat surprisingly, when it seems that every mental and emotional experience has been analyzed with brain imaging, the neurobiological mechanisms for that heightened pain sensitivity have been unclear.

Hoping to remedy that, neuroscientist Elizabeth Losin of the University of Miami set out to examine brain activity when people of different ethnic backgrounds experienced the identical pain-inducing stimulus. She persisted for eight years, through funding denials (the National Institutes of Health said she’d never be able to find enough Black participants), journal rejections (they worried that her study, like others involving race and biology, would spark controversy), and a 2,000-mile move (she started the research at the University of Colorado).

“It’s been an extremely long labor of love,” she said. “But I think it’s important that the findings get out there.”

Losin and co-author Tor Wager of Dartmouth College believe their results, if replicated by others, have implications for clinical care. Doctors have historically undertreated pain in their Black patients, and often dismiss the pain of sickle cell disease patients as exaggerated or even faked. “That’s a striking contrast to what our studies show,” Wager said: “that African Americans are more sensitive to pain, and that it correlates with experiences of discrimination.”

Their findings, published in Nature Human Behaviour, start with how the participants Losin recruited — 28 African Americans, 30 Latinxs, and 30 non-Hispanic white people, all from around Denver — responded to having four spots on their left forearm touched with a device, called a thermode, heated to about 118 degrees F. (Dice-sized thermodes, heated to a precise temperature, are labs’ go-to pain sources.)

Using fMRI to scan the volunteers’ brains, the researchers saw that a circuit called the neurologic pain signature — which neuroscientist Wager found reflects the most basic aspects of pain perception — responded the same way in everyone.

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SOURCE: Stat News, Sharon Begley