Department of Biomedical Sciences of Cells and Systems and University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Department of Rehabilitation Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
J Neurotrauma. 2021 Nov 1;38(21):2988-2998. doi: 10.1089/neu.2021.0140. Epub 2021 Sep 2.
Incomplete spinal cord injury (SCI) may result in muscle weakness and difficulties with force gradation. Although these impairments arise from the injury and subsequent changes at spinal levels, changes have also been demonstrated in the brain. Blood-oxygen-level dependent (BOLD) imaging was used to investigate these changes in brain activation in the context of unimanual contractions with the first dorsal interosseous muscle. BOLD- and force data were obtained in 19 individuals with SCI (AISA Impairment Scale [AIS] C/D, level C4-C8) and 24 able-bodied controls during maximal voluntary contractions (MVCs). To assess force modulation, participants performed 12 submaximal contractions with each hand (at 10, 30, 50, and 70% MVC) by matching their force level to a visual target. MVCs were weaker in the SCI group (both hands < 0.001), but BOLD activation did not differ between SCI and control groups. For the submaximal contractions, force (as %MVC) was similar across groups. However, SCI participants showed increased activity of the ipsilateral motor cortex and contralateral cerebellum across all contractions, with no differential effect of force level. Activity of ipsilateral M1 was best explained by force of the target hand (vs. the non-target hand). In conclusion, the data suggest that after incomplete cervical SCI, individuals remain capable of producing maximal supraspinal drive and are able to modulate this drive adequately. Activity of the ipsilateral motor network appears to be task related, although it remains uncertain how this activity contributes to task performance and whether this effect could potentially be harnessed to improve motor functioning.
不完全性脊髓损伤（SCI）可能导致肌肉无力和力量分级困难。尽管这些损伤是由脊髓水平的损伤和随后的变化引起的，但大脑也发生了变化。使用血氧水平依赖（BOLD）成像来研究第一背侧骨间肌单收缩时大脑激活的这些变化。在 19 名不完全性 SCI 患者（AISA 损伤量表 [AIS] C/D，C4-C8 节段）和 24 名健康对照者中获得了 BOLD 和力数据，在最大自主收缩（MVC）期间。为了评估力调制，参与者用双手进行了 12 次次最大收缩（用 10%、30%、50%和 70%MVC 匹配力水平），通过将力水平与视觉目标相匹配。SCI 组的 MVC 较弱（双手均 < 0.001），但 SCI 和对照组之间的 BOLD 激活没有差异。对于次最大收缩，各组之间的力（作为 %MVC）相似。然而，SCI 参与者在所有收缩中同侧运动皮层和对侧小脑的活动增加，而力水平没有差异影响。同侧 M1 的活动最好用目标手的力来解释（与非目标手相比）。总之，数据表明，不完全性颈 SCI 后，个体仍然能够产生最大的皮质上驱动，并能够充分调节这种驱动。同侧运动网络的活动似乎与任务有关，尽管尚不清楚这种活动如何有助于任务表现，以及这种效应是否可以被利用来改善运动功能。
