Changes in the Spinal Neural Circuits are Dependent on the Movement Speed of the Visuomotor Task.
Changes in the Spinal Neural Circuits are Dependent on the Movement Speed of the Visuomotor Task.
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DOI：
10.3389/fnhum.2015.00667
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发表时间：
2015
影响因子：
2.9
通讯作者：
Funase K
中科院分区：
文献类型：
--
作者：
Kubota S;Hirano M;Koizume Y;Tanabe S;Funase K
先前的研究表明，脊髓神经回路受到运动技能训练的调节。然而，任务运动速度对脊髓神经回路变化的影响尚未明确。这项研究的目的是调查脊髓神经回路是否受到任务运动速度的影响。三十八名健康受试者参与了这项研究。在实验1中，检查了任务运动速度对脊髓神经回路的影响。十八名受试者执行涉及踝关节肌肉慢速（九名受试者）或快速（九名受试者）运动速度的视觉运动任务。另外九名受试者以快速运动速度执行非视觉运动任务（控制）。运动任务训练持续20分钟。使用 H-relfex 条件测试范式测量 D1 抑制和倒数 Ia 抑制的量，并在训练前、训练后 5、15 和 30 分钟进行记录。在实验2中，使用经颅磁刺激（TMS），在执行视觉运动（八名受试者）或控制任务（八名受试者）之前和之后检查皮质脊髓下行输入对突触前抑制通路的影响。所有测量均在休息条件下进行。无论运动速度如何，视觉运动任务后 D1 抑制量都会增加（P < 0.01）。 Ia 相互抑制量随着快速运动速度调节而增加（P < 0.01），但随着慢速运动速度调节而没有变化。训练结束后，这些变化在 D1 抑制中持续长达 15 分钟，在相反的 Ia 抑制中持续 5 分钟。对照任务不会引起 D1 抑制和 Ia 相互抑制的变化。视觉运动任务后，突触前抑制通路的 TMS 条件抑制作用降低（P < 0.01）。在整个实验中，测试 H 反射的大小几乎相同。结果表明，控制关节运动的脊髓上下行输入是造成脊髓神经回路变化的原因，而任务运动速度是诱导 Ia 相互抑制可塑性变化的关键因素之一。
Previous studies have shown that spinal neural circuits are modulated by motor skill training. However, the effects of task movement speed on changes in spinal neural circuits have not been clarified. The aim of this research was to investigate whether spinal neural circuits were affected by task movement speed. Thirty-eight healthy subjects participated in this study. In experiment 1, the effects of task movement speed on the spinal neural circuits were examined. Eighteen subjects performed a visuomotor task involving ankle muscle slow (nine subjects) or fast (nine subjects) movement speed. Another nine subjects performed a non-visuomotor task (controls) in fast movement speed. The motor task training lasted for 20 min. The amounts of D1 inhibition and reciprocal Ia inhibition were measured using H-relfex condition-test paradigm and recorded before, and at 5, 15, and 30 min after the training session. In experiment 2, using transcranial magnetic stimulation (TMS), the effects of corticospinal descending inputs on the presynaptic inhibitory pathway were examined before and after performing either a visuomotor (eight subjects) or a control task (eight subjects). All measurements were taken under resting conditions. The amount of D1 inhibition increased after the visuomotor task irrespective of movement speed (P < 0.01). The amount of reciprocal Ia inhibition increased with fast movement speed conditioning (P < 0.01), but was unchanged by slow movement speed conditioning. These changes lasted up to 15 min in D1 inhibition and 5 min in reciprocal Ia inhibition after the training session. The control task did not induce changes in D1 inhibition and reciprocal Ia inhibition. The TMS conditioned inhibitory effects of presynaptic inhibitory pathways decreased following visuomotor tasks (P < 0.01). The size of test H-reflex was almost the same size throughout experiments. The results suggest that supraspinal descending inputs for controlling joint movement are responsible for changes in the spinal neural circuits, and that task movement speed is one of the critical factors for inducing plastic changes in reciprocal Ia inhibition.