Department of Psychology, University of Alabama at Birmingham, University Boulevard, Birmingham, Alabama.
Spine (Phila Pa 1976). 2018 Jun 15;43(12):E697-E702. doi: 10.1097/BRS.0000000000002472.
An experimental study.
This study aimed to investigate task-dependent changes in fractional anisotropy (FA) within the spinal cord during painful stimulation.
Earlier experiments by Mandl et al (2008, 2013) used non-invasive functional diffusion tensor imaging (fDTI) to detect white matter fibers that were active during functional tasks. In two studies, it was observed that FA of involved white matter tracts exhibited repeatable task-related increases. In this study, we attempted to extend the fDTI work in the spinal cord.
Twenty-three healthy, right-handed men (mean age 22 yrs, standard deviation [SD] = 4) were invited to participate in this study. Diffusion-weighted images were collected over spinal levels C2 to T4 during a painful thermal stimulus applied to the left thenar eminence. In order to investigate task-related activity, FA values within the contralateral (right) spinothalamic tract were analyzed using a generalized estimating equations (GEE) procedure. As a control, we also examined activity in the ipsilateral and contralateral corticospinal tracts, which are not considered to be involved in nociception.
Significant task-related decreases in FA were observed in the right spinothalamic tract at vertebral levels C2-C5 (Wald X(1) = 17.754, P < 0.001). There was no change in control regions at levels C7-T2 of the same tract, which are located below the level of input from dermatome C6, Wald X(1) = 0.185, P = 0.667. Results in all other regions assessed, that is, the left spinothalamic tract and bilateral corticospinal tract, were also not significant (P > 0.05).
The current findings suggest that task-related changes in FA associated with the transmission of pain signals along the spinal cord can be detected using fDTI. We observed decreased FA values in the contralateral (right) spinothalamic tract following painful stimulation, while no such activity was apparent in control regions.
实验研究。
本研究旨在探究在疼痛刺激期间脊髓内与任务相关的各向异性分数（FA）的变化。
Mandl 等人（2008 年、2013 年）的早期实验使用非侵入性功能扩散张量成像（fDTI）来检测在功能任务期间活跃的白质纤维。在两项研究中，观察到涉及的白质束的 FA 表现出可重复的与任务相关的增加。在这项研究中，我们试图扩展脊髓中的 fDTI 工作。
邀请 23 名健康、右利手的男性（平均年龄 22 岁，标准差 [SD] = 4）参与本研究。在将热刺激施加到左手鱼际时，在 C2 至 T4 的脊髓水平采集扩散加权图像。为了研究与任务相关的活动，使用广义估计方程（GEE）程序分析对侧（右侧）脊髓丘脑束内的 FA 值。作为对照，我们还检查了不被认为参与痛觉的同侧和对侧皮质脊髓束的活动。
在 C2-C5 的右侧脊髓丘脑束中观察到与任务相关的 FA 显著下降（Wald X(1) = 17.754，P < 0.001）。在同一束的 C7-T2 的对照区域没有变化，该区域位于 C6 皮节输入水平以下，Wald X(1) = 0.185，P = 0.667。评估的所有其他区域，即左侧脊髓丘脑束和双侧皮质脊髓束的结果也没有统计学意义（P > 0.05）。
目前的研究结果表明，使用 fDTI 可以检测到与脊髓内疼痛信号传递相关的 FA 与任务相关的变化。我们观察到在疼痛刺激后对侧（右侧）脊髓丘脑束中 FA 值降低，而在对照区域则没有明显的活动。
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