In the saga Halloween, Michael Myers is the character who does not flinch when a bullet or one stabs. But is that such resistance to pain possible? Or does it come simply to the suspension of disbelief established by the 7th art?

Welcome to this new IRL, which this time will turn around a seasonal theme: Halloween. So to start this horrific week, I invite you into the intricacies of the brain of a subject that concerns us all: the pain.

Pain is defined by science as "an unpleasant sensory and emotional experience associated with tissue damage or potential, or described in terms of such damage." It is a nerve message that is spreading from lesion point (since we are talking here of the case of injury, not chronic pain) to the brain. The latter processes the message in real pain (localized discomfort), and we will have the impression that it comes directly from the injury point. Many scientists have long ago realized that we all have a different perception and sensitivity of pain. If you doubt this, think -for example- to that person in your high school or college, who boasted to extinguish a cigarette lighter with his fingers, while yours were already painful to approach the flame ...

We obviously know there is a disease depriving some people (less than 100 cases reported worldwide) from pain, called congenital insensitivity to pain or congenital analgesia. Far from being a blessing or a utopia, for them, the disease prevents them from feeling any physical pain, small burn to the bone fracture. In fact, pain is a warning signal indicating that something is wrong in our body. Without it, we could walk for weeks on a broken foot without realizing it, or do not feel a serious illness affects us, and the consequences are often disastrous.

But for now, we will assume that Michael Myers (and any other movie hero who is able to take a bullet and continue to run or act for that matter) is a normal human being, not suffering from any genetic pathology. We therefore ask how he can withstand the pain, and especially how the brain responds with that.

First, be aware that all painful message should spend at our spinal cord, where there is what is called the "gate" of pain. A modulator of great importance that, if opened, will broadcast a pain message of great importance, and if it is half open, let go a much smaller message. In other words, the more the door is open, the more pain you feel, if it is closed, you feel less pain. This theory of "gate control" was established in 1965 by Patrick Wall and Ronald Melzack. This can already change our sensitivity to pain because this door is not always open or closed in the same way. This can vary according to our age, our sex, our physical condition, but also our morale!

Then we must consider the fact that, according to the activity that we practice at the time of injury, the brain will receive a message of small or intense sensitivity. Indeed, our body can secrete hormones that act as natural painkillers. For example, endorphins, which are issued by our bodies, but also present in most drug. Thus, a person under the influence of drugs will be less sensitive to pain than a sober person. However, this did not prevent him from being in danger, or seriously injured. But the endorphins are also produced during exercise, like serotonin, dopamine and adrenaline ...! Therefore, a person doing his jogging or lifting weights at the gym will be less sensitive to the pain that a person at rest, and therefore will more be able to overstep his limits. But in the same way, we can assume that a soldier, a serial killer (as Myers) or even a person living an exceptional event, will be much less sensitive to pain, because in extreme situations (or for least, emotionally and physically stimulating), his body will produce adrenaline by mass, and this will act as an anti-pain throughout the action.

Finally, many testimonies speak of the effectiveness of meditation on pain sensitivity. We all know the "powers" of some Tibetan monks, able to withstand extreme cold, slow down their heart rate, or even not flinching facing severe pain. But if it often seems to be mere legends, be aware that an actual experiment was conducted at Wake Forest Baptist Medical Center in North Carolina, by Dr. Fadel Zeidan by. After learning to fifteen healthy people a simple meditation technique, called "focused attention" (which is to focus only on your breathing to let go free thoughts and emotions), the doctor made them have an MRI and noted that their sensitivity to pain was somewhat reduced, with decreases ranging from 11 to 93%. During the experiment, the patients received a little heat on their right leg (about 48 degrees Celsius). Dr. Zeidan therefore noted a reduction in pain intensity by about 40% and a reduction of discomfort generated by this pain by about 60%. He stated at the end of the study: "This is the first study to demonstrate that achieving little more than an hour of meditation training can dramatically reduce the effect of pain and impact on the brain. "

In sum, this gives us a good explanation on pain sensitivity, and good food for thought on the faculties of the brain. But if this does not guarantee the consistency of some movie scenes where the characters bear intense pain, it does give us a good tool for understanding physical phenomena, which are sometimes quite plausible, if not real!