Afferent-induced facilitation of primary motor cortex excitability in the region controlling hand muscles in humans
Afferent-induced facilitation of primary motor cortex excitability in the region controlling hand muscles in humans
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DOI：
10.1111/j.1460-9568.2009.06815.x
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发表时间：
2009-08-01
影响因子：
3.4
通讯作者：
Cassim, F.
中科院分区：
文献类型：
--
作者：
Devanne, H.;Degardin, A.;Cassim, F.
已知来自皮肤和肢体受体的感觉输入会影响运动皮层网络的兴奋性。尽管最近的大多数研究都集中在传入输入对经颅磁刺激（TMS）引起的手臂运动反应的抑制影响，但很少考虑促进效应。在目前的工作中，我们试图确定本体感觉感觉输入如何调节控制某些手部和腕部肌肉的初级运动皮层区域的兴奋性。阈上 TMS 脉冲之前是正中神经刺激 (MNS) 或食指刺激，刺激间隔 (ISI) 范围为 20 至 200 毫秒（特别关注 40-80 毫秒）。拇短展肌 (APB)、第一骨间背肌和桡侧腕伸肌中记录的运动诱发电位受到 MNS 的强烈促进（高达 150%），ISI 约为 60 ms，而手指刺激的效果较弱。与 TMS 相比，当在引起最佳促进效果的时间间隔内给予 MNS 时，H 反射幅度保持不变，并且经颅电刺激引起的 APB 运动反应没有增加。传入诱导的促进和短潜伏期皮质内抑制（SICI）和皮质内促进（ICF）机制可能在皮质回路中相互作用，正如当 MNS 与 ICF 同时递送时观察到的强促进以及 MNS 后 SICI 的减少所表明的那样。我们得出的结论是，传入诱导的促进是一种可能涉及肌梭传入的机制，在研究健康和疾病情况下的感觉运动整合机制时应予以考虑。
Sensory inputs from cutaneous and limb receptors are known to influence motor cortex network excitability. Although most recent studies have focused on the inhibitory influences of afferent inputs on arm motor responses evoked by transcranial magnetic stimulation (TMS), facilitatory effects are rarely considered. In the present work, we sought to establish how proprioceptive sensory inputs modulate the excitability of the primary motor cortex region controlling certain hand and wrist muscles. Suprathreshold TMS pulses were preceded either by median nerve stimulation (MNS) or index finger stimulation with interstimulus intervals (ISIs) ranging from 20 to 200 ms (with particular focus on 40-80 ms). Motor-evoked potentials recorded in the abductor pollicis brevis (APB), first dorsalis interosseus and extensor carpi radialis muscles were strongly facilitated (by up to 150%) by MNS with ISIs of around 60 ms, whereas digit stimulation had only a weak effect. When MNS was delivered at the interval that evoked the optimal facilitatory effect, the H-reflex amplitude remained unchanged and APB motor responses evoked with transcranial electric stimulation were not increased as compared with TMS. Afferent-induced facilitation and short-latency intracortical inhibition (SICI) and intracortical facilitation (ICF) mechanisms are likely to interact in cortical circuits, as suggested by the strong facilitation observed when MNS was delivered concurrently with ICF and the reduction of SICI following MNS. We conclude that afferent-induced facilitation is a mechanism which probably involves muscle spindle afferents and should be considered when studying sensorimotor integration mechanisms in healthy and disease situations.