Wang Gang, Erpelding Nathalie, Davis Karen D
Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, Toronto, ON, Canada Institute of Medical Science, University of Toronto, Toronto, ON, Canada Department of Surgery, University of Toronto, Toronto, ON, Canada.
Pain. 2014 Apr;155(4):755-763. doi: 10.1016/j.pain.2014.01.005. Epub 2014 Jan 13.
We previously reported that women exhibit greater heat pain adaptation to a prolonged painful stimulus and greater habituation to repeated painful stimuli than men. The neural mechanism underlying this sex difference is unknown. However, Bingel et al. (2007) have shown that pain habituation after 8 days of daily pain testing is associated with an increase in pain-evoked activity of the subgenual anterior cingulate cortex (sgACC), suggesting that pain habituation may be mediated via connectivity between the sgACC and the descending pain antinociceptive system. Therefore, we investigated whether women have stronger functional connectivity (FC) and greater structural connectivity (SC) compared to men between the sgACC and the descending antinociceptive system. Our analyses revealed that (1) women exhibited greater FC between the sgACC and the periaqueductal gray (PAG), raphe nucleus, medial thalamus, and anterior midcingulate cortex (aMCC) than men; (2) men had stronger sgACC FC with the anterior insula and temporoparietal junction than women; (3) women and men exhibited comparable SC of the sgACC with the PAG, thalamus, aMCC, anterior insula, and amygdala; and (4) men have stronger sgACC SC with the hypothalamus than women. These data indicate that brain circuitry in women may provide for greater engagement of the descending modulation system mediating pain habituation. In contrast, in men, the salience network may be more engaged, which could support greater sustained attention to pain, thereby preventing pain habituation. Furthermore, the hypothalamus findings suggest a more powerful stress and endorphin-based system at play in men than women.
我们之前报道过，与男性相比，女性对长时间疼痛刺激表现出更强的热痛适应性，对重复疼痛刺激表现出更强的习惯化。这种性别差异背后的神经机制尚不清楚。然而，宾格尔等人（2007年）已经表明，在每天进行疼痛测试8天后的疼痛习惯化与膝下前扣带回皮质（sgACC）疼痛诱发活动的增加有关，这表明疼痛习惯化可能是通过sgACC与下行疼痛抗伤害系统之间的连接介导的。因此，我们研究了与男性相比，女性在sgACC与下行抗伤害系统之间是否具有更强的功能连接（FC）和更大的结构连接（SC）。我们的分析表明：（1）与男性相比，女性在sgACC与导水管周围灰质（PAG）、中缝核、内侧丘脑和前扣带回中部皮质（aMCC）之间表现出更强的FC；（2）男性与女性相比，sgACC与前岛叶和颞顶叶交界处的FC更强；（3）女性和男性在sgACC与PAG、丘脑、aMCC、前岛叶和杏仁核之间表现出相当的SC；（4）男性与女性相比，sgACC与下丘脑的SC更强。这些数据表明，女性的脑回路可能使介导疼痛习惯化的下行调节系统有更大的参与度。相比之下，在男性中，突显网络可能参与度更高，这可能支持对疼痛有更强的持续注意力，从而防止疼痛习惯化。此外，下丘脑的研究结果表明，男性中基于压力和内啡肽的系统比女性更强大。
