Mühlbeier Andreas, Puta Christian, Boström Kim J, Wagner Heiko
Department of Movement Science, University of MünsterMünster, Germany.
Center for Interdisciplinary Prevention of Diseases Related to Professional Activities, Friedrich Schiller University JenaJena, Germany.
Front Hum Neurosci. 2017 Jun 7;11:296. doi: 10.3389/fnhum.2017.00296. eCollection 2017.
Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood. In this study, we applied unilateral and bilateral sudden external perturbations to the trunk of healthy subjects and measured the muscular activity and the movement onset of the trunk. We found that the onset of the trunk muscle activity is prior to, or coincident with, the onset of the trunk movement. Additionally, the results of our experiments imply that the muscular response mechanism integrates distant sensory information from both sides of the body. These findings rule out a simple monosynaptic stretch reflex in favor of a more complex polysynaptic postural reflex mechanism to compensate postural perturbations. Moreover, the previously predicted negative correlation between reflex delay and reflex gain was also confirmed for bilateral perturbations.
姿势反射对于运动和姿势稳定性至关重要，并且可能在慢性背痛的病因中起重要作用。最近在理论上已经预测到，并且借助于对躯干的单侧扰动在实验上得到证实，即感觉运动控制必须降低反射幅度以增加反射延迟来维持脊柱稳定性。然而，姿势扰动补偿的潜在神经肌肉机制尚未完全理解。在本研究中，我们对健康受试者的躯干施加单侧和双侧突然的外部扰动，并测量肌肉活动和躯干的运动起始。我们发现躯干肌肉活动的起始先于或与躯干运动的起始同时发生。此外，我们的实验结果表明，肌肉反应机制整合了来自身体两侧的远距离感觉信息。这些发现排除了简单的单突触牵张反射，支持更复杂的多突触姿势反射机制来补偿姿势扰动。此外，对于双侧扰动，先前预测的反射延迟和反射增益之间的负相关也得到了证实。
