Interlimb neural interactions in corticospinal and spinal reflex circuits during preparation and execution of isometric elbow flexion
Interlimb neural interactions in corticospinal and spinal reflex circuits during preparation and execution of isometric elbow flexion
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准备和执行等距肘屈曲过程中皮质脊髓和脊髓反射回路的肢体间神经相互作用
DOI：
10.1152/jn.00705.2019
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发表时间：
2020
影响因子：
2.5
通讯作者：
Matija Milosevic and Kimitaka Nakazawa
中科院分区：
文献类型：
--
作者：
Atsushi Sasaki;Naotsugu Kaneko;Yohei Masugi;Matija Milosevic and Kimitaka Nakazawa
虽然协调和同时运动的上肢和下肢肌肉的日常生活活动所需的，肢体间的神经相互作用机制和它们的性质尚未完全阐明。本研究的目的是探讨运动准备和执行同侧，对侧，双侧上肢肌肉收缩对皮质脊髓和脊髓反射回路的下肢肌肉兴奋性的影响。每项研究招募了14名身体健全的个体。本实验采用经颅磁刺激初级运动皮层诱发运动诱发电位（MEP）和经皮脊髓刺激腰胸段诱发脊髓反射的方法，研究了皮层脊髓兴奋性和脊髓反射兴奋性。在1）同侧（右），2）对侧（左）和3）双侧（右和左）肘屈曲过程中同时记录多个右下肢肌肉的测量值。结果表明，在准备和执行屈肘时，下肢肌肉的MEP都得到了促进，而脊髓反射只在运动执行时得到了促进。此外，右，左，双侧收缩之间的促进程度没有差异。总之，上肢肌肉收缩的运动准备并不影响脊髓回路，但似乎会影响控制下肢肌肉的脊髓上网络。然而，需要上肢肌肉的实际收缩（运动执行）来促进控制下肢肌肉的脊髓反射回路。此外，肢体间的远程促进皮质脊髓和脊髓反射电路不依赖于是否对侧或同侧的手收缩或如果他们收缩bilateral.NEW &值得注意的是，我们发现，上肢肌肉收缩促进皮质脊髓回路控制下肢肌肉，即使在运动准备，而运动执行的任务，以促进脊髓回路。我们还发现，促进并不依赖于是否对侧或同侧的手收缩，或者如果他们收缩双边。总的来说，这些研究结果表明，未受影响的上肢的训练可能是有用的，以提高促进受影响的下肢截瘫患者。
Although coordinated and simultaneous movement of upper and lower limb muscles is required for activities of daily living, interlimb neural interaction mechanisms and their nature are yet to be fully elucidated. The purpose of this study was to investigate effects of motor preparation and execution of ipsilateral, contralateral, and bilateral upper limb muscle contractions on the excitability of corticospinal and spinal reflex circuits of the lower limb muscles. Fourteen able-bodied individuals were recruited in each study. Experiments were conducted to investigate1) corticospinal excitability with transcranial magnetic stimulation applied on the primary motor cortex to evoke motor evoked potentials (MEPs) and2) spinal reflex excitability with transcutaneous spinal cord stimulation applied at the lumbothoracic level to evoke spinal reflexes. Measurements were recorded from multiple right lower limb muscles simultaneously during1) ipsilateral (right),2) contralateral (left), and3) bilateral (right and left) elbow flexion. The results indicate that MEPs in lower limb muscles were facilitated during both preparation and execution of elbow flexion, whereas spinal reflexes were facilitated only during motor execution. Moreover, the extent of facilitation did not differ between right, left, and bilateral contractions. In conclusion, motor preparation for upper limb muscle contractions did not affect spinal circuits but seemed to affect the supraspinal networks controlling lower limb muscles. However, actual contraction (motor execution) of upper limb muscles is required to facilitate spinal reflex circuits controlling the lower limb muscles. Moreover, interlimb remote facilitation in corticospinal and spinal reflex circuits did not depend on whether contralateral or ipsilateral hands were contracted or if they were contracted bilaterally.NEW & NOTEWORTHYWe found that upper limb muscle contractions facilitated corticospinal circuits controlling lower limb muscles even during motor preparation, whereas motor execution of the task was required to facilitate spinal circuits. We also found that facilitation did not depend on whether contralateral or ipsilateral hands were contracted or if they were contracted bilaterally. Overall, these findings suggest that training of unaffected upper limbs may be useful to enhance facilitation of affected lower limbs in paraplegic individuals.