Why do we remember the pain?

Like many other great findings about science, the discovery of why we remember pain was a fluke. From these first discoveries have been realized different investigations on the pain and the suffering as well as on the memory of the pain and the chronic pain .

In 1954, two researchers from McGill University in Canada discovered accidentally how humans learn to repeat behavior that is beneficial to our survival. An electrode implanted in the brain of a rat had slipped from its intended location and stopped in the medial beam of the anterior brain , a group of nerve cells that reaches from the depths of the brain to the prefrontal cortex. After receiving a series of electric shocks , the rat showed great interest in the area in which he had been exploring when he received the first shake.

At first, researchers, James Olds and Peter Milner, believed they had found the region of the brain responsible for ruling curiosity. But after further research, Olds and Milner realized that what they had discovered was the reward center of the brain , a system of regions associated with delivering a sense of pleasure in exchange for certain behaviors such as eating and mating. This discovery not only implied a revolution, but showed that animals, including humans, are prepared to learn through motivation .

But motivation goes both ways, and both animals and humans can also be motivated not to repeat behavior. In this pain is a good teacher.

Preliminary research on the nature of pain seemed a rather simple concept. The nociceptors are free nerve endings of primary sensory neurons and their specialized nerve pain receptors , detect potential damage tissue through stimuli such as laceration, increase or decrease in temperature, excess pressure or other modes of injury. This sensation translates into an electrical impulse that travels to the brain where it is experienced as pain. In forming memories of these sensations we remember that we should not do certain things, such as touching a hot stove, playing with a knife or going out in the winter without shelter. That is, we remember the pain to learn to avoid harmful and / or dangerous behaviors.

However, the pain is not so simple. The experience of pain is not only physical , it also involves the presence of an emotional and psychological pain, which is what is known as suffering. In this sense, other research has found that the pathways used by the pain impulses excite not only areas of the brain that experience physical sensation but also those related to emotion and cognition. Thus, pain is not only a physical experience and the association of cognition and emotion are united in the meaning of the experience of pain. These additional pain traits seem to help humans create more refined memories of a painful experience , which may help them not repeat certain actions in the future.

However, the cognitive mind is not only involved in the formation of memories of pain. Research on the nervous system has found that pain memories can also form , which can persist even after removal of tissue. This is what happens in the so-called phantom limb phenomenon, which shows how the mind can retain its ability to experience pain, even after the nociceptors are no longer present. Studies show that patients who have undergone amputation tend to experience phantom limbs more often than people who lack a limb from birth. In fact, recent studies have found that persistent memory pain can lead to a restructuring of the function of the nervous system. This change can lead to chronic pain and the feeling of pain in a healthy person.
Therefore, persistence of pain memory, which may last beyond its beneficial function to learn, has led to research ways to relieve chronic pain . Research has shown that the best way to avoid chronic pain is to prevent the formation of memories of pain.

In this sense, anesthesia prevents the formation of memories of pain in the conscious mind during an intentional injury such as surgery. However, the nervous system may still form its own memories of pain . Medical professionals are discovering that painkillers given to patients prior to surgery help prevent chronic pain memory formation, which slows the development of chronic pain later on.