Remote limb ischemic preconditioning (RIPC) has shown to improve dynamic postural control in humans. However, studies on the underlying adaptations of spinal cord networks have never been performed. The present work addresses this issue by investigating parameters from the soleus H-reflex recruitment curve (RC), presynaptic mechanisms of reflex modulation (presynaptic inhibition-PSI, and post activation depression-PAD), and the excursion of the center of pressure (CP) recorded during 1 min in upright stance over a compliant surface. A sham ischemic protocol (partial obstruction of blood flow) was applied to the contralateral thigh along four consecutive days. The same procedure was repeated with full obstruction (RIPC) three days after ending the sham protocol. Data were collected before and after both sham and RIPC protocols. The follow-up data were collected five days after the last ischemic intervention. Significant reduction was detected for both the fast oscillations of the CP (higher frequency components) and the parameter estimated from the RC corresponding to the high amplitude H-reflexes (p < 0.05). Even though the magnitude of effects was similar, it was washed out within three days after sham, but persisted for at least five days after RIPC. No significant differences were found for PSI and PAD levels across conditions. These findings indicate that RIPC leads to enduring changes in spinal cord excitability for the latest reflexively recruited motoneurons, along with improvement in balance control. However, these adaptations were not mediated by the presynaptic mechanisms currently assessed.

中文翻译：

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健康年轻人中远端肢体缺血预处理对脊髓兴奋性的调节作用。

远端肢体缺血预处理（RIPC）已显示可改善人体动态姿势控制。但是，从未对脊髓网络的基础适应性进行研究。本研究通过研究比目鱼H反射募集曲线（RC），突触调制前突触机制（突触前抑制-PSI和活化后抑郁-PAD）以及压力中心偏移（CP）来解决此问题。 ）在1分钟内以直立姿势记录在顺应性表面上。连续四天对对侧大腿应用假性缺血方案（部分血流阻塞）。假手术方案结束三天后，完全阻塞（RIPC）重复相同的步骤。假和RIPC协议之前和之后均收集数据。在最后一次缺血干预后五天收集随访数据。检测到CP的快速振荡（高频分量）和从RC估计的与高振幅H反射相对应的参数均显着降低（p <0.05）。尽管影响的程度相似，但在伪造后的三天内将其冲洗掉，但在RIPC后至少持续了五天。在所有条件下，PSI和PAD含量均无显着差异。这些发现表明，RIPC导致最新自发募集的运动神经元的脊髓兴奋性发生持久变化，并且平衡控制得到改善。但是，这些适应不是由目前评估的突触前机制介导的。检测到CP的快速振荡（高频分量）和从RC估计的与高振幅H反射相对应的参数均显着降低（p <0.05）。尽管影响的程度相似，但在伪造后的三天内将其冲洗掉，但在RIPC后至少持续了五天。在所有条件下，PSI和PAD含量均无显着差异。这些发现表明，RIPC导致最新自发募集的运动神经元的脊髓兴奋性发生持久变化，并且平衡控制得到改善。但是，这些适应不是由目前评估的突触前机制介导的。检测到CP的快速振荡（高频分量）和从RC估计的与高振幅H反射相对应的参数均显着降低（p <0.05）。尽管影响的程度相似，但在伪造后的三天内将其冲洗掉，但在RIPC后至少持续了五天。在所有条件下，PSI和PAD含量均无显着差异。这些发现表明，RIPC导致最新自发募集的运动神经元的脊髓兴奋性发生持久变化，并且平衡控制得到改善。但是，这些适应不是由目前评估的突触前机制介导的。