The science behind caressing and stroking.

After reading and seeing all these cute animated gifs on this Buzzfeed feature, it made me want to learn more.  

We humans, and our pets all enjoyed being stroked and caressed. It gives us a sense of pleasure or security or calmness but thinking like a scientist, what is the SCIENCE behind that? According to this study from California Institute of Technology, scientists have linked stroking and caressing to a specific class of cells that respond to this gentle touch. 

""We've known a lot about the neurons that detect things that make us hurt or feel pain, but we've known much less about the identity of the neurons that make us feel good when they are stimulated," says David J. Anderson, Seymour Benzer Professor of Biology at Caltech who is also an investigator with the Howard Hughes Medical Institute. "Generally it's a lot easier to study things that are painful because animals have evolved to become much more sensitive to things that hurt or are fearful than to things that feel good. Showing a positive influence of something on an animal model is not that easy.""

Well, breakthrough!

Researchers found that gentle stroking was the only sensation to stimulate a type of neuron called MRGPRB4+. By synthesizing a chemical that also activates MRGPRB4+, the scientists were able to provoke a response in the neurons and observe a reaction. Mice given the neuron-activating chemical were observed to have fewer signs of stress, leading researchers to believe the sensation was both calming and pleasurable.

The researchers also note that we, humans, have similar neurons in the hair-covered portions of our skin.

 

Credit to CalTech. http://www.caltech.edu/content/sorting-out-stroking-sensations

Credit to Buzzfeed. http://www.buzzfeed.com/mvp84/scientists-discover-why-animals-love-being-pet-93le 

Credit to this NatureNeuroscience article. http://www.nature.com/neuro/journal/v10/n8/abs/nn1937.html