Ever feel you watch to scratch when another person scratches their itch? Sometime even mentioning an itch can make people scratch.
Like yawning, scratching is considered kind of a socially contagious behavior.
Well, a study has now shown that itching really is contagious, and it seems the behavior is hardwired into the brain.
In what seems like kind of a fun experiment, they showed mice videos of other mice scratching themselves. Within seconds the mouse watching the video would start to scratch itself.
The study was published in the journal Science.
Mice rely primarily on smell and touch to explore the surroundings. The researchers were not even sure the mice in the experiments would even be able to see the video.
Not only could the see the video, they could tell the mouse in the video was scratching itself.
Contagious Itching is Hardwired in the Brain
The researchers identified an area in the brain called the suprachiasmatic nucleus (SCN). The SCN was highly active after the mouse watched the video of the scratching mouse.
It seems the SCN releases a chemical called GRP (gastrin-releasing peptide). GRP is like a messenger to tell the mice there is an itch that needs scratching.
The researchers concluded, “The next time you scratch or yawn in response to someone else doing it, remember it’s really not a choice nor a psychological response; it’s hardwired into your brain.”
What can you do with this information? Well, have fun, of course.
The next time you’re in, for example, a crowded elevator, start scratching yourself like crazy! Do your own itch experiments and see if you can get the whole elevator of people to start scratching themselves.
Yu YQ, Barry DM, Hao Y, Liu XT, Chen ZF. Molecular and neural basis of contagious itch behavior in mice. Science, 2017. http://dx.doi.org/10.1126/science.aak9748