Itching is a highly contagious behavior. When we see someone scratch, we’re likely to feel itchy, too. A research shows contagious itching is hardwired in the brain.
For this study, Chen’s team put a mouse in an enclosure with a computer screen. The researchers then played a video that showed another mouse scratching.
“Within a few seconds, the mouse in the enclosure would start scratching, too,” Chen said. “This was very surprising because mice are known for their poor vision. They use smell and touch to explore areas, so we didn’t know whether a mouse would notice a video. Not only did it see the video, it could tell that the mouse in the video was scratching”.
Next, the researchers identified a structure called the suprachiasmatic nucleus (SCN), a brain region that controls when animals fall asleep or wake up. The SCN was highly active after the mouse watched the video of the scratching mouse. When the mouse saw other mice scratching – in the video and when placed near scratching littermates – the brain’s SCN would release a chemical substance called GRP (gastrin-releasing peptide). In 2007, Chen’s team identified GRP as a key transmitter of itch signals between the skin and the spinal cord.
“The mouse doesn’t see another mouse scratching and then think it might need to scratch, too,” Chen said. “Instead, its brain begins sending out itch signals using GRP as a messenger”.
Chen’s team also used various methods to block GRP or the receptor it binds to on neurons, while maintaining the ability to scratch normally when exposed to itch-inducing substances. Chen believes the contagious itch behavior the mice engaged in is something the animals can’t control. “It’s an innate behavior and an instinct,” he said. “We’ve been able to show that a single chemical and a single receptor are all that’s necessary to mediate this particular behavior. 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. (1)
So “the brain” sent the signals. Without the mouse even “seeing” (how do we know?) or even “wanting” (how do we know?) to do anything. The brain “sees” (what?!?) the other mouse scratching and decides on its own.
Are we so much loving the idea of the brain controlling what we do that we are ready to believe into a brain which does things on its own without even an optical stimulus? Are we so much intoxicated by the idea of us not having free will, of us being just slaves to matter, that we are ready to attribute abilities of conscious beings to lifeless substances?
We believe into an ever-seeing brain with a “free will” of its own.
And yet we despise the idea of an ever seeing free will spirit.
We are what we want to be.
We were gods.
And we have chosen to be mice.
Now starting to feel a bit itchy…