Circumstances of the appearance of chronic pain
It is very interesting to analyze the next data provided by the study of Dr. Jasson. (1) They refer to the "circumstances of onset of declared fibromyalgia", which, as we will see, are in69% of cases related to traumatic events, to situations that gave rise to mourning because a significant loss, physical, psychological or moral had occurred.
The other patients who responded to this study (22%) were unable to give an answer on the event that could have triggered their disease. I allow myself here to make a link withalexithymia, of which it is likely that 22% of patients - or part of this slice - were affected without knowing it, which is why they were unable to identify the event or events that occurred before their fibromyalgia developed. sets off.
In Dr. Jasson's study, the patients questioned attribute the onset of their disease to:
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in 46% of cases (918), emotional stress (mourning, divorce, family problems, job loss, etc.)
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in 23% of cases (465), to physical stress (fall, accident; frequently cited spinal trauma).
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22% of patients did not note any particular event before the onset of the disease, or do not know clearly how to name its origin, or are unaware of it.
A WHO report (2) on physical and sexual violence against women, denounces the following global estimates: 35% of women, or nearly 1 in 3 women, report having been exposed to physical or sexual violence from their intimate partner or someone else in their lifetime.
WHO quotes "Intimate partner violence and sexual violence cause serious short- and long-term physical, mental, sexual and reproductive health problems for victims and their children and therefore have social and high economics. »
Among its consequences on health, the WHO indicates “…These forms of violence can lead to depression, post-traumatic stress states, anxiety disorders, sleep disorders, eating disorders, psychic disorders and attempts to suicide.
Women who have suffered violence from their intimate partner are almost twice as likely to experience problems with depression or alcoholism. This figure is even higher for women who have experienced violence from someone else.The health effects can be headaches, back pain, abdominal pain, fibromyalgia, digestive disorders, reduced mobility and poor general health.
How is pain recorded in neurons?
Nearly one in five adults suffers from chronic pain: backache, headache, unexplained post-surgical pain…caused:a modification of the neural circuit of pain, which is then “memorized” in the neurons.
According to professor of neurophysiology at the Bernard Calvino School of Physics and Industrial Chemistry "a form of memorization also develops at the cell level, in particular the neuron, which sees its electrical activity modified, over the long term. We talk about long term potentiation (or ltp for long term potentiation). However, this process exists all along the neuronal and cerebral circuit of pain. One of the fundamental properties of the central nervous system, namely the brain and the spinal cord, in information processing is its ability to store data through long-term changes, thanks to its plasticity. This form of learning exists all along the pain circuit (3).
The neurons of the so-called nociceptive peripheral sensory nerves, which react to painful stimulation, and those of the spinal cord called the dorsal horn, which then transmit information to the brain, undergo changes in electrical activity associated with pain. But sometimes they amplify the painful messages in an aberrant way, because they have been subject to "electrical and molecular learning", the ltp, similar to that implemented in the neurons of the hippocampus, the seat of memory, during the formation of memories” (2).
Jean Pascal Lefaucheur explained that "during an injury, for example, the nerves transmit to the central nervous system - the brain and the spinal cord - so-called nociceptive information, and these higher cerebral centers then trigger protective reactions and of repair. But sometimes,the activation of these brain centers – and therefore the painful sensation – persists even though the nociceptive stimulation has disappeared.
For what ?
Especially becausepain changes the strength of connections between neurons in certain regions of the central nervous system, in particular the dorsal horn of the spinal cord, where the peripheral nerve fibers arrive. A "memory" of pain is inscribed in these neurons via a mechanism of neuronal plasticity called long-term potentiation: the more the connection between two neurons is stimulated, the more it strengthens and the more it remains active over the long term or is easily activated on subsequent stimulation” (4).
The teacher. Calvino adds "ltp therefore represents a molecular mechanism for the long-term storage of information and is thought to be involved in the capacity of neurons in the spinal cordto maintain the pain and to memorize it. The persistence of this memory trace depends on complex cellular and molecular mechanisms, in particular the synthesis of multiple proteins in neurons” (3).
LTP in the spinal cord increases the response of nociceptive neurons above their baseline physiological response, and represents a key process of central sensitization by which aacute pain progresses to chronic pain. Some mechanisms installed in this way sometimes persist long after the initial cause of the pain has disappeared, several months or even years.
Such long-term plasticity is not limited to the spinal cord… The entire cerebral pain network may be involved. Thus, the team of Frode Willoch and Trine Hjørnevik, from the University of Oslo, highlighted a ltp at the level of the amygdala, and that of Min Zhuo, from the University of Toronto, at the level of the anterior cingulate cortex; these two structures are cerebral relays of thefeeling of pain involved especially in the emotional aspects. This late phase of ltp would function as a cascade amplifier, increasing the pain signal at each synaptic relay (5).
These works are very interesting, they offer a lead that would explain neuronal plasticity also at the level of the amygdala, the main storage area for emotional suffering.
These few neurophysiological explanations have been given to understand that our brain records our painful perceptions, and, by dint of repeating this stimulation, a process of reinforcement of the neural wiring takes place. We have in our body and brain neural mechanisms that allow the maintenance and memorization of pain.
Do these mechanisms activate when the memory of traumatic events suddenly arises in our head, reinforcing again and again the chronicity of the pain?
(1) Jason, Marie-Claire. Better diagnose and know fibromyalgia by studying the clinical symptoms. 2001-2005.
(2) WHO, World Health Organization -. www.who.int. www.who.int. [Online] http://www.who.int/gho/fr/.
(3) Calvino, Bernard. Why does the pain remain in memory. Brain and Pyscho N° 85. February 2017, pp. 40-45.
(4) Lefaucheur, Jean Pascal. Activate neurons to calm pain. Brain and Psycho. February 2017, p. 46.
(5) Zhuo, Frode Willoch - Min. Why pain remains in memory. Brain and Psycho. February 2017, pp. 40-45.
