Excitability changes in resting forearm muscles during voluntary foot movements depend on hand position: a neural substrate for hand-foot isodirectional coupling
Excitability changes in resting forearm muscles during voluntary foot movements depend on hand position: a neural substrate for hand-foot isodirectional coupling
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DOI：
10.1016/j.brainres.2004.07.003
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发表时间：
2004-10-01
期刊：
影响因子：
2.9
通讯作者：
Baldissera, F
中科院分区：
文献类型：
--
作者：
Borroni, P;Cerri, G;Baldissera, F
当关联手部和脚部的自主摆动时，无论手部位置如何(俯卧或仰卧)，最好采用等向耦合。为了研究这种耦合模式的神经相关性，在同侧足部周期性自愿屈伸的过程中，测试了支配静息前臂的运动投射的兴奋性。在一些实验中，经颅磁刺激(TMS)促进的H反射和复合肌肉动作电位(CMAPs)在足部运动周期中的5个间隔被诱发在桡侧腕屈肌(FCR)和桡侧腕伸肌(ECR)。在俯卧位时，腕屈伸肌的兴奋性呈正弦变化，但相位相反：FCR在足底屈曲时兴奋性增加，背屈时兴奋性降低，而ECR则相反。在两个拮抗剂中同时诱发的CMAP的兴奋性调制证实了这种相互作用。当手掌后仰时，H反射调制发生反转，即足背屈时FCR兴奋性增强，足底屈时FCR兴奋性降低。在所测试的肌肉和手位置中，当脚部惯性负荷增加肌肉到运动的相位延迟时，H反射兴奋性调节仍然与肌肉收缩有关，而不是与运动有关。综上所述，这些结果表明，手部运动者的潜意识兴奋性调制与脚部运动者的平行显性激活具有共同的中枢起源，是相互组织的，并且不依赖于肌肉。因此，它可能代表手(俯卧或仰卧)与脚等向耦合的神经底物。(C)2004爱思唯尔B.V保留所有权利。
When associating hand and foot voluntary oscillations, isodirectional coupling is preferred irrespective of hand position (prone or supine). To investigate the neural correlates of this coupling modality, excitability of the motor projections innervating the resting forearm was tested during cyclic voluntary flexion-extensions of the ipsilateral foot. H-reflexes, in some experiments facilitated by subliminal Transcranial Magnetic Stimulation (TMS), and Compound Muscle Action Potentials (CMAPs), evoked by supraliminal TMS, were elicited in Flexor Carpi Radialis (FCR) and Extensor Carpi Radialis (ECR) muscles at five intervals during the foot movement cycle. With the hand prone, a sinusoidal excitability modulation was observed in wrist flexors and extensors, but reversed in phase: in FCR, excitability increased during plantar-flexion and decreased during dorsiflexion, while in ECR the opposite occurred. This reciprocal organisation was confirmed by the excitability modulation of CMAPs evoked simultaneously in the two antagonists. When the hand was supinated, the H-reflex modulation reversed in phase, i.e., FCR excitability increased during foot dorsiflexion and decreased during plantar-flexion. In both muscles and hand positions tested, when the muscle-to-movement phase-lag was increased by inertial loading of the foot, H-reflex excitability modulations remained phase linked to muscular contractions, not to movement. Together, these results suggest that the subliminal excitability modulation of hand movers has a common central origin with the parallel overt activation of foot movers, is reciprocally organised, and is direction- not muscle-dependent. It may therefore represent the neural substrate for isodirectional coupling of hand (prone or supine) with the foot. (C) 2004 Elsevier B.V All rights reserved.