Ever wonder why your pooch will do just about anything for a belly rub? Now, science has an answer for you. A group of American scientists have identified the neural basis for why mammals, from mice to humans, enjoy being stroked. In a paper published in Nature, researchers from the California Institute of Technology, the University of Louisville, and the University of Pittsburgh found that stroking mice stimulated MRGPRB4+, a specific, rare neuron linked to the hair follicles, Discover reports.
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.
While professional mouse-petter may sound like the cutest job in academia, early versions of the experiment were significantly less cuddly. In 2007, a group of researchers tried and failed to stimulate the neurons using a swatch of mouse skin.