Bilateral responses of upper limb muscles to transcranial magnetic stimulation in human subjects
Bilateral responses of upper limb muscles to transcranial magnetic stimulation in human subjects
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DOI：
10.1007/s00221-004-2031-x
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发表时间：
2004-10-01
影响因子：
2
通讯作者：
Gross, PA
中科院分区：
文献类型：
--
作者：
Bawa, P;Hamm, JD;Gross, PA
对灵长类动物的解剖学和行为学研究表明，轴向和近端四肢肌肉的双侧神经支配，以及远端四肢肌肉的对侧控制。接下来的研究检查了在对侧或双侧控制的上肢远端和近端肌肉之间是否存在明显的边界。刺激代表上肢的右侧运动皮质区，同时记录静息和阶段性自主收缩时双侧上肢肌肉的表面肌电信号。测量双侧各肌运动诱发电位(MEP)峰间波幅。计算7对肌肉的R=(同侧MEP：对侧MEP)。对于七对受试者中的每一对，R都小于1.0，这意味着对于每一块肌肉和受试者，对侧控制更强。R从几乎为零变化到明显可测量的量值的边界取决于受试者。几乎所有受试者的斜方肌和胸肌的同侧MEP均可记录到轻微的背景收缩；另一方面，在三角肌和二头肌，同侧MEP只有双手相收缩。一般来说，前臂和手部肌肉没有显示任何同侧MEP。受试者之间的主要区别在于有或没有同侧的二头肌和三角肌的MEP，但没有明确界定近端和远端肌肉之间的界限。
Anatomical and behavioural work on primates has shown bilateral innervation of axial and proximal limb muscles, and contralateral control of distal limb muscles. The following study examined if a clear boundary exists between the distal and proximal upper limb muscles that are controlled contralaterally or bilaterally. The right motor cortical area representing the upper limb was stimulated, while surface EMG was recorded bilaterally from various upper limb muscles during rest and phasic voluntary contractions. Peak-to-peak amplitude of motor evoked potential (MEP) was measured for each muscle on both sides. The ratio R = (ipsilateral MEP: contralateral MEP) was calculated for seven pairs of muscles. For each of the seven pairs, R was less than 1.0, implying that for each muscle and subject, the contralateral control is stronger. The boundary where R changed from almost zero to a clearly measurable magnitude depended on the subject. Ipsilateral MEPs from trapezius and pectoralis could be recorded with a small background contraction from almost all subjects; on the other hand, in deltoid and biceps brachii, ipsilateral MEPs were observed only with bimanual phasic contractions. The forearm and hand muscles, in general, did not show any ipsilateral MEPs. Major differences between subjects lay in the presence or the absence of ipsilateral MEPs in biceps brachii and deltoid, without defining a sharp boundary between proximal and distal muscles.