Hauck Michael, Lorenz Jürgen, Zimmermann Roger, Debener Stefan, Scharein Eckehard, Engel Andreas K
Department of Neurophysiology and Pathophysiology, University Medical Center Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
Exp Brain Res. 2007 Jun;180(2):205-15. doi: 10.1007/s00221-007-0863-x. Epub 2007 Feb 8.
Expectation of pain is an important adaptive process enabling individuals to avoid bodily harm. It reflects the linking of past experience and environmental cues with imminent threat. In the present study, we examined changes in perceived pain contingent upon variation of the interval between an auditory cue and a subsequent painful laser stimulus. The duration of the cue-to-stimulus delay was systematically varied between 2, 4 and 6 s. Pain intensity and evoked brain responses measured by EEG and MEG recordings were analysed. Pain ratings from 15 subjects increased with longer cue-to-pain delays, accompanied by an increase in activity of the midcingulate cortex (MCC), as modelled from evoked EEG potential maps. On the other hand, MEG-based source activity in secondary somatosensory (SII) cortex remained unaffected by manipulation of the cue-to-stimulus interval. We conclude that activity in limbic structures such as MCC play a key role in the temporal dynamics of recruitment of expectation towards pain. Although this reaction is adaptive if the individual is able to avoid the stimulus, it is maladaptive if such opportunity is not present.
对疼痛的预期是一个重要的适应性过程，能使个体避免身体伤害。它反映了过去的经验和环境线索与即将到来的威胁之间的联系。在本研究中，我们研究了根据听觉线索与随后的疼痛激光刺激之间的间隔变化而产生的疼痛感知变化。线索到刺激的延迟时间在2秒、4秒和6秒之间系统地变化。分析了通过脑电图（EEG）和脑磁图（MEG）记录测量的疼痛强度和诱发的脑反应。15名受试者的疼痛评分随着线索到疼痛延迟时间的延长而增加，同时，根据诱发的脑电图电位图建模，扣带前回中部（MCC）的活动也增加。另一方面，基于脑磁图的次级体感皮层（SII）的源活动不受线索到刺激间隔操纵的影响。我们得出结论，诸如扣带前回中部等边缘结构的活动在对疼痛预期的募集的时间动态中起关键作用。如果个体能够避免刺激，这种反应是适应性的；但如果没有这样的机会，它就是适应不良的。
