Geuter Stephan, Boll Sabrina, Eippert Falk, Büchel Christian
Department of Systems Neuroscience, University Medical Center Hamburg Eppendorf, Hamburg, Germany.
Institute of Cognitive Science, University of Colorado Boulder, Boulder, United States.
Elife. 2017 May 19;6:e24770. doi: 10.7554/eLife.24770.
The computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these beliefs against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors.
大脑从伤害感受中产生疼痛体验的计算原理仍然未知。经典理论分别表明，皮层区域要么反映刺激强度，要么反映强度与预期的累加效应。相比之下，预测编码理论提供了一个统一的框架，解释了感知是如何通过将关于世界的信念与这些信念与感觉输入比较产生的不匹配进行整合而形成的。在概率性热痛范式中使用功能磁共振成像，我们研究了哪些计算构成疼痛感知的基础。皮肤电导、瞳孔扩张和前岛叶对提示性疼痛刺激的反应严格遵循预测编码模型假设的反应模式，而后岛叶编码刺激强度。岛叶内这种疼痛处理的新功能分离以及先前观察到的慢性疼痛变化，为异常疼痛处理提供了一种新的解释，即预测和预测误差的加权受到干扰。
