Changes in motor cortex excitability during ipsilateral hand muscle activation in humans
Changes in motor cortex excitability during ipsilateral hand muscle activation in humans
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DOI：
10.1016/s1388-2457(99)00243-6
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发表时间：
2000-02-01
影响因子：
4.7
通讯作者：
Hallett, M
中科院分区：
文献类型：
--
作者：
Muellbacher, W;Facchini, S;Hallett, M
目的：探讨单侧手部肌肉激活是否与同侧初级运动皮层（M1）兴奋性变化有关。方法：采用右半球单脉冲和双脉冲经颅磁刺激（TMS）诱发静息左短拇外展肌（APB）运动诱发电位（MEPs）。我们监测运动阈值（MT）、MEP募集、皮质内抑制（ICI）和皮质内促进（ICF）的变化，而同侧右侧APE处于静止或主动激活状态。使用f波记录程序评估脊髓运动神经元的兴奋性。结果：同侧APE的随意肌激活显著促进了对侧APE记录的mep和f波。当肌肉激活>达到最大自主力的50%，刺激强度>高于个体静息运动阈值20%时，观察到促进作用。同侧M1的皮质内抑制显著降低，而在此过程中皮质内促进没有显著变化。结论：单侧手肌激活改变了同侧M1和对侧脊髓同位手肌表征的兴奋性。虽然大部分MEP促进很可能发生在脊髓水平，但同侧半球的参与可能有助于磁反应的扩大。(C) 2000爱思唯尔科学爱尔兰有限公司版权所有。
Objectives: To test whether unilateral hand muscle activation involves changes in ipsilateral primary motor cortex (M1) excitability.Methods: Single- and paired-pulse transcranial magnetic stimulation (TMS) of the right hemisphere was used to evoke motor evoked potentials (MEPs) from the resting left abductor pollicis brevis (APB) in 9 normal volunteers. We monitored changes in motor threshold (MT), MEP recruitment, intracortical inhibition (ICI) and intracortical facilitation (ICF) while the ipsilateral right APE was either at rest or voluntarily activated. Spinal motoneuron excitability was assessed using F-wave recording procedures.Results: Voluntary muscle activation of the ipsilateral APE significantly facilitated the MEPs and F-waves recorded from the contralateral APE. Facilitation was observed with muscle activation >50% of the maximum voluntary force and with stimulus intensities >20% above the individual resting motor threshold. Intracortical inhibition significantly decreased in the ipsilateral M1, while there was no significant change in intracortical facilitation during this maneuver.Conclusions: Unilateral hand muscle activation changes the excitability of homotopic hand muscle representations in both the ipsilateral M1 and the contralateral spinal cord. While the large proportion of MEP facilitation most likely occurred at a spinal level, involvement of the ipsilateral hemisphere may have contributed to the enlargement of magnetic responses. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.