Brain Basis for Why Petting Feels Good

By Breanna Draxler | January 31, 2013 8:37 am




Researchers genetically engineered mice so the MRGPRB4+ neurons would glow when active. Then they inserted a microscope into the mice’s spinal cords to see what happened as they stroked, poked and pinched the mice. Certain neurons responded to unpleasant stimuli like pokes, but the MRGPRB4+ neurons only responded to stroking.

After pinpointing the MRGPRB4+ neurons’ physical stimulus, the researchers then found a chemical that could elicit the same response. When mice were injected with the chemical, the MRGPRB4+ neurons lit up, just as if the mouse was being stroked. The unique neurons were linked specifically to the hair follicles in the mice’s skin, and the nerve-endings were very spread out. Thus, gently stroking their hindquarters would stimulate the mice but poking would not. And it turns out that humans have similar, stroke-sensitive neurons in the hair-covered portions of our skin.

But do mice enjoy massage as much as people? When given a choice between the caress-like chemical and one with no effect, the mice most often chose the one that stimulated the neurons. The mice also showed fewer signs of stress afterward, which led researchers to believe the sensation was both pleasurable and calming.

The results suggest that mammals may have evolved this propensity for caressing to encourage good hygiene through social grooming. It may also explain why certain hair-covered areas of the human body (think armpits, pubic hair) are more sensitive to touch or associated with pleasure.

CATEGORIZED UNDER: Mind & Brain, Top Posts
MORE ABOUT: mice, neurons, petting, stroking
  • Pen

    If the outcome was both pleasurable AND calming, than this should be a standard after-procedure for any experimentation on animals… today we’ll inject you full of needles, but tonight you’ll be massaged until calm … if you survive.

  • Pen

    I’m also curious whether the genetically-bald animal would still respond to stimulus

  • katchan64

    On the contrary, we’re one of the few animals that live in indefinitely large social groups. In other words, we get along with each other better than most mammals.


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