心理所王锦琰副研究员与罗非研究员等人最近的一项关于痛觉预期的研究显示，痛觉预期能够显著增强伤害性刺激引起的神经元放电以及痛觉内、外侧通路中的脑区内及脑区间神经活动的相关性，说明内侧和外侧痛觉系统对伤害性信息的加工都受到预期的调节。
无论是人还是动物，预期是痛觉的一个有效调节因素。已有研究证实，伤害性神经元受到个体对于疼痛预期的调节。然而，还没有研究考察痛觉预期对伤害性神经元活动以及中枢痛觉神经网络中功能联结的影响。因此，该研究着重考察了痛觉神经网络中某些脑区内与脑区间神经元活动的关系及信息流动。研究使用声音——激光条件化范式来建立大鼠的痛觉预期，同时采用多通道记录技术记录了前扣带回（ACC），丘脑背内侧核（MD）和初级躯体感觉皮层（S1）区的神经元活动。利用交互相关和偏定向相干分析方法来分析各记录区域内以及它们之间的功能联结。结果表明，在有预期的条件下，上述三个记录脑区对伤害性刺激的反应都有所增加，而只有ACC神经元对声音信号的反应增强。与没有预期的条件相比，预期条件下各记录脑区内以及它们之间的神经元活动的相关性显著增强，表明痛觉神经网络中神经活动的同步性增强。此外，从内侧痛觉传导通路（ACC和MD）到外侧痛觉传导通路（S1）的信息流增加，表明痛觉传导过程中与情绪有关的神经活动可能会调节躯体感觉通路的神经活动。本研究为探索预期调节痛觉的脑机制提供了有力证据。
该研究已发表于《分子疼痛》（Molecular Pain）杂志上。（生物谷Bioon.com）
生物谷推荐原始出处：
Molecular Pain，2008, 4:34，Wang JY，Luo F
Anticipation of pain enhances the nociceptive transmission and functional connectivity within pain network in rats
Jin-Yan Wang1 , Han-Ti Zhang2 , Jing-Yu Chang3 , Donald J Woodward3 , Luiz A Baccalá4 and Fei Luo1
1Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, PR China
2Neuroscience Research Institute, Peking University, Beijing, PR China
3Neuroscience Research Institute of North Carolina, Winston-Salem, NC, USA
4Telecommunications and Control Engineering, Escola Politecnica, University of Sao Paulo, Brazil
Background
Expectation is a very potent pain modulator in both humans and animals. There is evidence that pain transmission neurons are modulated by expectation preceding painful stimuli. Nonetheless, few studies have examined the influence of pain expectation on the pain-related neuronal activity and the functional connectivity within the central nociceptive network.
Results
This study used a tone-laser conditioning paradigm to establish the pain expectation in rats, and simultaneously recorded the anterior cingulate cortex (ACC), the medial dorsal thalamus (MD), and the primary somatosensory cortex (SI) to investigate the effect of pain expectation on laser-induced neuronal responses. Cross-correlation and partial directed coherence analysis were used to determine the functional interactions within and between the recorded areas during nociceptive transmission. The results showed that under anticipation condition, the neuronal activity to the auditory cue was significantly increased in the ACC area, whereas those to actual noxious stimuli were enhanced in all the recorded areas. Furthermore, neuronal correlations within and between these areas were significantly increased under conditions of expectation compared to those under non-expectation conditions, indicating an enhanced synchronization of neural activity within the pain network. In addition, information flow from the medial (ACC and MD) to the lateral (SI cortex) pain pathway increased, suggesting that the emotion-related neural circuits may modulate the neuronal activity in the somatosensory pathway during nociceptive transmission.
Conclusion
These results demonstrate that the nociceptive processing in both medial and lateral pain systems is modulated by the expectation of pain.
