This paper addresses the issue of the central correlates of the "Kohnstamm phenomenon", i.e. the long-lasting involuntary muscle contraction which develops after a prolonged isometric voluntary contraction. Although this phenomenon was described as early as 1915, the mechanisms underlying these post-effects are not yet understood. It was therefore proposed to investigate whether specific brain areas may be involved in the motor post-effects induced by either wrist muscle contraction or vibration using the fMRI method. For this purpose, experiments were carried out on the right wrist of 11 healthy subjects. Muscle activity (EMG) and regional cerebral blood flow were recorded during isometric voluntary muscle contraction and muscle vibration, as well as during the subsequent involuntary contractions (the post-effects) which occurred under both conditions. Brain activations were found to occur during the post-contraction and post-vibration periods, which were very similar under both conditions. Brain activation involved motor-related areas usually responsible for voluntary motor command (primary sensory and motor cortices, premotor cortex, anterior and posterior cingulate gyrus) and sensorimotor integration structures such as the posterior parietal cortex. Comparisons between the patterns of brain activation associated with the involuntary post-effects and those accompanying voluntary contraction showed that cerebellar vermis was activated during the post-effect periods whereas the supplementary motor area was activated only during the induction periods. Although post-effects originate from asymmetric proprioceptive inputs, they might also involve a central network where the motor and somatosensory areas and the cerebellum play a key role. In functional terms, they might result from the adaptive recalibration of the postural reference frame altered by the sustained proprioceptive inputs elicited by muscle contraction and vibration.

译文

本文讨论了 “Kohnstamm现象” 的中心相关性问题,即在长时间的等距自愿收缩后发展的长期非自愿肌肉收缩。尽管早在1915年就描述了这种现象,但尚不了解这些后效的机制。因此,建议使用fMRI方法研究特定的大脑区域是否可能参与腕部肌肉收缩或振动引起的运动后效应。为此,在11名健康受试者的右手腕上进行了实验。在等距自愿肌肉收缩和肌肉振动期间以及在两种情况下发生的随后的非自愿收缩 (后效) 期间记录了肌肉活动 (EMG) 和局部脑血流量。发现大脑激活发生在收缩后和振动后时期,在两种情况下都非常相似。大脑激活涉及通常负责自愿运动命令的运动相关区域 (主要感觉和运动皮层,运动前皮层,前扣带回和后扣带回) 和感觉运动整合结构,例如后顶叶皮层。与非自愿后效应相关的大脑激活模式与伴随自愿收缩的大脑激活模式之间的比较表明,小脑ver在后效应期间被激活,而辅助运动区仅在诱导期被激活。尽管后效应源于不对称的本体感受输入,但它们也可能涉及中央网络,其中运动和体感区域以及小脑起着关键作用。从功能上讲,它们可能是由于姿势参考系的适应性重新校准而导致的,该姿势参考系被肌肉收缩和振动引起的持续的本体感受输入所改变。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录