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自我强化预期对疼痛的影响:行为和大脑机制

Self-reinforcing expectancy effects on pain: Behavioral and brain mechanisms
课程网址: http://videolectures.net/rldm2015_jepma_expectancy_effects/  
主讲教师: Marieke Jepma
开课单位: 莱顿大学
开课时间: 2015-07-28
课程语种: 英语
中文简介:
通过经典条件作用与疼痛或疼痛缓解相关的线索可以深刻地改变对随后有害事件的反应。与条件性恐惧不同,条件性疼痛调制可以抵抗消失,甚至在缺乏强化的情况下随着时间的推移而增长。对这种“自我强化”效应的一种解释是,先前的信念会偏向学习,因为相对于不确认事件,它会增强从预期确认中学习的能力。如果是这样的话,在期望和体验之间可能存在正反馈循环,从而产生“自我实现的预言”。在两个实验中(N=26和34),我们研究了疼痛期望和疼痛体验之间相互作用的行为和大脑机制。参与者首先完成一个调节阶段,在这个阶段中,线索被反复与低或高热量水平配对。在随后的“消失”阶段,所有线索都伴随着相同的有害热量,我们测量了预期、疼痛体验、自主反应和(实验2)功能磁共振成像活动的试验间动态。对疼痛事件的主观、自主和神经反应在高疼痛提示下比在低疼痛提示下更强,这些效应由自我报告的疼痛预期介导。这些影响并没有随着时间的推移而消失。对学习动力的分析表明,在确认预期的结果之后,参与者更新疼痛预期的次数多于不确认预期的结果,这表明确认偏差在没有强化的情况下维持了线索对疼痛的影响。这种确认偏倚强度的个体差异与前扣带皮质激活与预期确认与不确认结果相关,表明扣带在作为先前信念功能的学习率调节中起着关键作用。这些结果有助于解释为什么即使在缺乏确凿证据的情况下,许多领域的信念也会产生持久的影响。
课程简介: Cues associated with pain or pain relief through classical conditioning can profoundly modify responses to subsequent noxious events. Unlike conditioned fear, conditioned pain modulation can be resistant to extinction or even grow over time in the absence of reinforcement. One explanation for such ‘self-reinforcing’ effects is that prior beliefs bias learning, by enhancing learning from expectancyconfirming relative to disconfirming events. If so, there is the potential for positive feedback loops between expectations and experiences that create ‘self-fulfilling prophecies.’ In two experiments (N=26 and 34), we examined the behavioral and brain mechanisms underlying interactions between pain expectations and pain experiences. Participants first completed a conditioning phase, in which cues were repeatedly paired with either low or high heat levels. In a subsequent ‘extinction’ phase, all cues were followed by identical noxious heat, and we measured trial-to-trial dynamics in expectations, pain experience, autonomic responses, and (in Experiment 2) fMRI activity. Subjective, autonomic and neural responses to painful events were stronger following high- than low-pain cues, and these effects were mediated by self-reported pain expectancies. These effects did not extinguish over time. Analyses of learning dynamics revealed that participants updated pain expectancies more following outcomes that confirmed expectations than those that disconfirmed them, indicating a confirmation bias that maintained the cues’ effects on pain in the absence of reinforcement. Individual differences in the strength of this confirmation bias correlated with anterior cingulate cortex activation to expectancy-confirming vs. -disconfirming outcomes, suggesting a key role for the cingulate in the regulation of learning rate as a function of prior beliefs. These results can help explain why beliefs in many domains can have persistent effects even in the absence of confirming evidence.
关 键 词: 条件性疼痛; 自我强化; 行为和大脑机制
课程来源: 视频讲座网
数据采集: 2021-11-27:zkj
最后编审: 2021-11-27:zkj
阅读次数: 53