Altered corticospinal function during movement preparation in humans with spinal cord injury
Altered corticospinal function during movement preparation in humans with spinal cord injury
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DOI：
10.1113/jp272266
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发表时间：
2017-01-01
影响因子：
5.5
通讯作者：
Perez, Monica A.
中科院分区：
文献类型：
--
作者：
Federico, Paolo;Perez, Monica A.
在人类即将到来的运动的准备阶段，皮质脊髓输出以任务依赖的方式进行调制。这种能力是否在脊髓损伤（SCI）后保留尚不清楚。在这项研究中，我们研究了运动诱发电位引起的皮质（MEP）和皮质下（CMEP）刺激的皮质脊髓轴突和短时间间隔内皮层抑制在第一背侧骨间肌的反应时间任务的准备阶段，慢性不完全性颈椎脊髓损伤和年龄匹配的控制需要抑制（NOGO）或启动（GO）弹道食指等长自主收缩。与对照组相比，SCI参与者的反应时间延长，每组在运动开始前提供刺激约90 ms。在NOGO试验期间，与SCI参与者的基线相比，MEP和CMEP保持不变，但在对照受试者中受到抑制。值得注意的是，在GO试验期间，两组的MEP增加到相似的程度，但CMEP仅在对照组中增加。在NOGO试验中，对照组的短间隔皮质内抑制的幅度增加，但SCI受试者没有增加，而在GO试验中，两组的短间隔皮质内抑制的幅度都减少。这些新的观察结果表明，不完全性颈椎脊髓损伤的人在运动准备过程中，当需要抑制但不执行即将到来的快速手指运动时，调节皮质脊髓兴奋性的能力改变，这可能与皮质和脊髓水平的传输受损有关。因此，人类SCI后皮质脊髓传递的缺陷延伸到即将到来的运动的准备阶段。
Corticospinal output is modulated in a task-dependent manner during the preparatory phase of upcoming movements in humans. Whether this ability is preserved after spinal cord injury (SCI) is unknown. In this study, we examined motor evoked potentials elicited by cortical (MEPs) and subcortical (CMEPs) stimulation of corticospinal axons and short-interval intracortical inhibition in the first dorsal interosseous muscle in the preparatory phase of a reaction time task where individuals with chronic incomplete cervical SCI and age-matched controls needed to suppress (NOGO) or initiate (GO) ballistic index finger isometric voluntary contractions. Reaction times were prolonged in SCI participants compared with control subjects and stimulation was provided approximate to 90ms prior to movement onset in each group. During NOGO trials, both MEPs and CMEPs remained unchanged compared to baseline in SCI participants but were suppressed in control subjects. Notably, during GO trials, MEPs increased to a similar extent in both groups but CMEPs increased only in controls. The magnitude of short-interval intracortical inhibition increased in controls but not in SCI subjects during NOGO trials and decreased in both groups in GO trials. These novel observations reveal that humans with incomplete cervical SCI have an altered ability to modulate corticospinal excitability during movement preparation when there is a need to suppress but not to execute upcoming rapid finger movements, which is probably related to impaired transmission at a cortical and spinal level. Thus, deficits in corticospinal transmission after human SCI extend to the preparatory phase of upcoming movements.