Effect of acute pain on the plastic potential of the sensorimotor cortex

疼痛是一种令人不快的感觉，但它是我们身体防御系统的重要组成部分，对健康生存起着至关重要的作用。疼痛是一种强烈的动机，促使人们从潜在的破坏性情况中退出，并避免在未来发生这种情况，因此，它是一种非常有效的刺激，可以在行为层面上诱导学习。在神经系统层面，有人认为，强烈痛苦刺激后神经元中发生的变化反映了潜在的学习和记忆变化。正因为如此，有人提出，当我们在疼痛时，我们神经元修改其连接的能力(一种称为可塑性的现象)可能会改变。这种可塑性是神经系统的一个关键特征，它允许学习新的能力，适应不同的环境，在某种程度上，还可以在受伤后恢复。我的研究计划的主要目标是调查剧烈疼痛是否以及如何改变我们大脑区域的可塑性潜力，这些区域涉及我们的行动控制和对我们自己身体的感知。为了回答这个问题，我们将在健康志愿者身上诱导实验性的暂时性疼痛，并研究他们的大脑在不同情况下的反应，与他们没有疼痛时的反应相比。这些情况包括：1-肢体受到实验性的“损伤”(由缺血引起，这是一种安全且可逆的模拟神经损伤的方式)；2-进行新的运动任务训练；3-接受非侵入性脑刺激(一种导致大脑活动暂时改变的技术，用于治疗一些神经问题)；4-暴露在导致身体变化的错觉中(因为我们知道，慢性疼痛的人通常会改变对自己身体的感知，只要想想你的手指比你用锤子击打他们时感觉到的更大)。由于运动和感觉水平的学习伴随着各种环境中的疼痛，从接受康复治疗的患者对非常简单的日常手势的重新学习到精英运动员获得高技能动作，疼痛对可塑性和学习的诱导的潜在影响是一个重要的问题，但科学关注的非常有限。

Pain is an unpleasant sensation, but is an essential part of our body defense system and plays a vital role in healthy survival. Pain act as a strong motivator to withdraw from potentially damaging situations and to avoid those situation in the future, and is therefore a very potent stimulus to induce learning at the behavioral level. At the nervous system level, it has been suggested that the changes occurring in the neurons after intense painful stimulation mirrors the changes underlying learning and memory. Because of that, it has been suggested that the ability of our neurons modify their connections (a phenomenon called plasticity) might be altered when we are in pain. This plasticity is a key feature of the nervous system that allows learning of new abilities, adaptation to different environments and, to some extent, recovery following injury. The main objective of my research program is to investigate whether and how acute pain alters the plastic potential of the regions of our brain that are involved in the control of our movements and in the perception of our own body. To answer that question, we will induce experimental temporary pain in healthy volunteers and study how their brain reacts to different situations compared to when they are not in pain. Those situations include: 1- sustaining an experimental "injury" to a limb (induced by ischemia, a safe and reversible way of simulating a nerve lesion); 2- training in a new motor task; 3- receiving non invasive brain stimulation (a technique inducing temporary changes in brain activity that is used in the treatment of some neurological problem); 4- being exposed to a procedure that cause the illusion of a change in the body (as we know that people with chronic pain often have altered perception of their own body, just think of how your finger feel larger than they are when you just hit them with an hammer). As learning at the motor and sensory levels is accompanied by pain in a variety of contexts, from the relearning of very simple everyday gestures in patients undergoing rehabilitation to the acquisition of highly skilled movement in elite athletes, the potential effect of pain on the induction of plasticity and learning is an important question that has received very limited scientific attention.****