MIT researchers study the link between touch stimuli and why it decreases pain: 'We’re interested in this because it’s a common human experience'

Researchers at MIT are digging deeper into why touch stimuli can sometimes decrease pain.

According to a press release, researchers at MIT’s McGovern Institute for Brain Research observed pain-responsive cells in the brains of mice quieting down in response to touch stimuli. This discovery could offer researchers deeper insight into the complicated relationship between pain and touch and could provide insights into chronic pain in humans. 

“We’re interested in this because it’s a common human experience,” says McGovern investigator Fan Wang, according to the press release. “When some part of your body hurts, you rub it, right? We know touch can alleviate pain in this way.” 

The new study along with results of previous studies suggest that touch-induced pain relief may begin in the spinal cord, but there have been hints that the brain is involved, too. This aspect of the response has been largely unexplored because it can be hard to monitor the brain’s response to painful stimuli amidst all the other neural activity happening there, particularly when an animal moves. The team got around this obstacle by focusing on vibrations produced by the movement of the whiskers of mice, which are used to explore and feel out feel out their environment. Researchers observed that these whisker movements affect how mice respond to heat or poking.

“If you look at the brain when an animal is rubbing the face, movement and touch signals completely overwhelm any possible pain signal,” Wang explains, according to the press release. 

According to Wang, the cells that respond to heat and poking are less frequently activated when mice are whisking their whiskers. 

“When there is a pain stimulation, usually the trajectory of the population dynamics quickly moved to wiping. But if you already have whisking, that takes much longer,” Wang says. 

Wang hopes that the discovery might lead to more insight into thalamic pain syndrome, a chronic pain disorder that develops in patients after a stroke affects the brain’s thalamus.