Lautenbacher Stefan, Horn-Hofmann Claudia, Kunz Miriam
Bamberger Living Lab Dementia (BamLiD), University of Bamberg, Bamberg, Germany.
Medical Psychology and Sociology, Medical Faculty, University of Augsburg, Augsburg, Germany.
Somatosens Mot Res. 2025 Jun;42(2):69-77. doi: 10.1080/08990220.2024.2395809. Epub 2024 Sep 13.
Conditioned pain modulation (CPM) allows to investigate endogenous pain modulation and its clinical outcomes. Although co-activation of emotions has been shown to affect CPM, the impact of 'threat,' which may accompany CPM stimulation itself, has been mostly neglected. A critical factor for the threat level of the conditioning stimulus (CS) may be its predictability.
38 healthy participants (18 female) took part in a CPM study with pressure stimulation on the leg (blood-pressure cuff) serving as CS and heat stimulation on the forearm (contact thermode; CHEPS) serving as test stimulus (TS). While CS varied in intensity and -as operationalisation of threat- in temporary predictability, TS was kept constant. CPM effects were studied by EEG parameters (N2P2) and pain ratings.
We found a significant CPM effect when considering N2P2, with low CS predictability augmenting CPM inhibition; in contrast, a surprisingly facilitatory CPM effect occurred in pain ratings (in the high CS predictability condition). The threat manipulation was only partially successful because CS intensity increased the threat ratings but not -as intended- CS predictability. Correlations between subjective and psychophysiological CPM responses were low.
The differing CPM effects in subjective and psychophysiological responses, with both inhibitory and facilitatory effects, is puzzling but has already been observed earlier. The consideration of the CPM stimulation as major threat that is emotionally active is theoretically clearly justifiable but the operationalisation by means of different levels of CS predictability as in the present study might not have been ideal. Thus, further attempts of experimental verification are warranted.
条件性疼痛调制（CPM）有助于研究内源性疼痛调制及其临床结果。尽管已表明情绪的共同激活会影响CPM，但与CPM刺激本身可能伴随的“威胁”影响大多被忽视了。条件刺激（CS）威胁水平的一个关键因素可能是其可预测性。
38名健康参与者（18名女性）参与了一项CPM研究，以腿部压力刺激（血压袖带）作为CS，前臂热刺激（接触式热刺激仪；CHEPS）作为测试刺激（TS）。虽然CS在强度以及作为威胁的操作化方面在临时可预测性上有所不同，但TS保持不变。通过脑电图参数（N2P2）和疼痛评分研究CPM效应。
在考虑N2P2时，我们发现了显著的CPM效应，低CS可预测性增强了CPM抑制；相反，在疼痛评分中出现了令人惊讶的促进性CPM效应（在高CS可预测性条件下）。威胁操纵仅部分成功，因为CS强度增加了威胁评分，但未如预期那样增加CS可预测性。主观和心理生理CPM反应之间的相关性较低。
主观和心理生理反应中不同的CPM效应，既有抑制作用又有促进作用，令人困惑，但此前已经观察到。从理论上讲，将CPM刺激视为情绪活跃的主要威胁是合理的，但如本研究中通过不同水平的CS可预测性进行操作化可能并不理想。因此，有必要进行进一步的实验验证尝试。
