Sometimes you just have to hear about lice (school) or bedbugs (info) so that the scalp or your arms are starting to peck seriously. Even without beast on the horizon, the desire to scratch arises while you did not think of it 5 minutes before. This very common phenomenon is not imaginary. His name is the “contagious itching “and it is solidly anchored in our brain functioning.
Our brain is able to build these sensations
“The brain is not content to treat reality: it builds it”explains the neurologist Shaheen E. Lakhan at the HuffPost US. In reality, when we evoke creeping or spicy insects, the brain activates the same circuits as if they were really in contact with our skin. This is a so -called simatosensory simulated answer, triggered by an image, a memory or simply a conversation. It is therefore not a hallucination, but a really generated perception of the interior.
Several mechanisms combine to produce this feeling:
- The first is emotional: the simple fact of imagining insects can arouse disgust, anxiety or discomfort. These emotions activate certain regions of the brain, such as amygdal, which amplify the perception of unpleasant bodily sensations;
- Another more social mechanism comes into play: mirror neurons. These brain cells are active as well when we act as when we observe someone else to act. Result: like the contagious yawning, seeing someone scratching or hearing about it is enough to trigger a similar reaction at home.
But why does our brain have fun?
According to the neuroscientist Friederike Fabritius, this reaction has a utility: it is a survival reflex inherited from our evolutionary past. “”Better to scratch for nothing to risk an infestation of parasites “she explains. In other words, our brain prefers to generate a false positive – an unjustified alert – rather than missing out a potential danger. This protective reflex, although sometimes annoying, has undoubtedly contributed to the survival of our ancestors.
Not everyone is also sensitive to this phenomenon. Anxious people, hypervigilant or very attentive to their bodily sensations (what is called interroce) are more prone to it. “”If you are the type to check your legs after hearing about ticks, your brain is probably very reactive “notes Dr. Lakhan.
Reduce his unpleasant sensations
Good news, however: we can alleviate these induced itching. First of all, the simple fact of recognizing that it is not a real signal of the body, but a message from the brain can help reduce the sensation. “This alone allows you to regain control”insists Dr. Lakhan. Simple techniques can also help: focus on the real sensation of your feet on the ground, touch a cold surface or even manipulate a textured object … These sensory stimulation divert the attention of the internal parasitic signals.
In short, the next time a discussion on the bedbugs makes you want to scratch yourself, breathe a good blow: it is not your scalp that has a problem, it is just your brain that plays the sentries.