Glogan Eveliina, Gatzounis Rena, Vandael Kristof, Franssen Mathijs, Vlaeyen Johan W S, Meulders Ann
Experimental Health Psychology, Maastricht University; Research Group Health Psychology, KU Leuven.
Experimental Health Psychology, Maastricht University.
J Vis Exp. 2020 Oct 3(164). doi: 10.3791/61717.
Avoidance behavior is a key contributor to the transition from acute pain to chronic pain disability. Yet, there has been a lack of ecologically valid paradigms to experimentally investigate pain-related avoidance. To fill this gap, we developed a paradigm (the robotic arm-reaching paradigm) to investigate the mechanisms underlying the development of pain-related avoidance behavior. Existing avoidance paradigms (mostly in the context of anxiety research) have often operationalized avoidance as an experimenter-instructed, low-cost response, superimposed on stimuli associated with threat during a Pavlovian fear conditioning procedure. In contrast, the current method offers increased ecological validity in terms of instrumental learning (acquisition) of avoidance, and by adding a cost to the avoidance response. In the paradigm, participants perform arm-reaching movements from a starting point to a target using a robotic arm, and freely choose between three different movement trajectories to do so. The movement trajectories differ in probability of being paired with a painful electrocutaneous stimulus, and in required effort in terms of deviation and resistance. Specifically, the painful stimulus can be (partly) avoided at the cost of performing movements requiring increased effort. Avoidance behavior is operationalized as the maximal deviation from the shortest trajectory on each trial. In addition to explaining how the new paradigm can help understand the acquisition of avoidance, we describe adaptations of the robotic arm-reaching paradigm for (1) examining the spread of avoidance to other stimuli (generalization), (2) modeling clinical treatment in the lab (extinction of avoidance using response prevention), as well as (3) modeling relapse, and return of avoidance following extinction (spontaneous recovery). Given the increased ecological validity, and numerous possibilities for extensions and/or adaptations, the robotic arm-reaching paradigm offers a promising tool to facilitate the investigation of avoidance behavior and to further our understanding of its underlying processes.
回避行为是导致急性疼痛向慢性疼痛残疾转变的关键因素。然而，一直缺乏能够在生态环境中有效研究与疼痛相关回避行为的范式。为填补这一空白，我们开发了一种范式（机器人手臂伸展范式）来研究与疼痛相关回避行为发展背后的机制。现有的回避范式（大多用于焦虑研究）通常将回避操作化为实验者指导的低成本反应，叠加在巴甫洛夫恐惧条件反射过程中与威胁相关的刺激上。相比之下，当前的方法在回避的工具性学习（习得）方面以及通过给回避反应增加成本，提高了生态效度。在该范式中，参与者使用机器人手臂从起始点向目标进行手臂伸展动作，并可在三种不同的运动轨迹中自由选择来完成。这些运动轨迹在与疼痛性皮肤电刺激配对的概率以及在偏差和阻力方面所需的努力程度上有所不同。具体而言，通过付出更多努力来执行动作的代价，可以（部分）避免疼痛刺激。回避行为被定义为每次试验中与最短轨迹的最大偏差。除了解释新范式如何有助于理解回避行为的习得，我们还描述了机器人手臂伸展范式的一些改编形式，用于（1）研究回避行为向其他刺激的扩散（泛化），（2）在实验室中模拟临床治疗（使用反应预防来消除回避行为），以及（3）模拟复发和消退后回避行为的恢复（自发恢复）。鉴于其生态效度的提高以及众多扩展和/或改编的可能性，机器人手臂伸展范式为促进对回避行为的研究以及加深我们对其潜在过程的理解提供了一个很有前景的工具。
