Koning Elena, Powers Jocelyn M, Ioachim Gabriela, Stroman Patrick W
Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
Brain Sci. 2023 May 9;13(5):777. doi: 10.3390/brainsci13050777.
The somatosensory system is multidimensional and processes important information for survival, including the experience of pain. The brainstem and spinal cord serve pivotal roles in both transmitting and modulating pain signals from the periphery; although, they are studied less frequently with neuroimaging when compared to the brain. In addition, imaging studies of pain often lack a sensory control condition, failing to differentiate the neural processes associated with pain versus innocuous sensations. The purpose of this study was to investigate neural connectivity between key regions involved in descending modulation of pain in response to a hot, noxious stimulus as compared to a warm, innocuous stimulus. This was achieved with functional magnetic resonance imaging (fMRI) of the brainstem and spinal cord in 20 healthy men and women. Functional connectivity was observed to vary between specific regions across painful and innocuous conditions. However, the same variations were not observed in the period of anticipation prior to the onset of stimulation. Specific connections varied with individual pain scores only during the noxious stimulation condition, indicating a significant role of individual differences in the experience of pain which are distinct from that of innocuous sensation. The results also illustrate significant differences in descending modulation before and during stimulation in both conditions. These findings contribute to a deeper understanding of the mechanisms underlying pain processing at the level of the brainstem and spinal cord, and how pain is modulated.
体感系统是多维的，它处理对生存至关重要的信息，包括疼痛体验。脑干和脊髓在传递和调节来自外周的疼痛信号方面发挥着关键作用；然而，与大脑相比，它们在神经成像研究中较少被关注。此外，疼痛的成像研究往往缺乏感觉对照条件，无法区分与疼痛和无害感觉相关的神经过程。本研究的目的是调查与温暖的无害刺激相比，在热的有害刺激下，参与疼痛下行调制的关键区域之间的神经连接。这是通过对20名健康男性和女性的脑干和脊髓进行功能磁共振成像（fMRI）来实现的。观察到在疼痛和无害条件下，特定区域之间的功能连接有所不同。然而，在刺激开始前的预期期间未观察到相同的变化。仅在有害刺激条件下，特定连接随个体疼痛评分而变化，这表明个体差异在疼痛体验中发挥了重要作用，与无害感觉不同。结果还表明，在两种条件下，刺激前和刺激期间的下行调制存在显著差异。这些发现有助于更深入地理解脑干和脊髓水平上疼痛处理的潜在机制，以及疼痛是如何被调制的。
