De Nunzio A M, Yavuz U S, Martinez-Valdes E, Farina D, Falla D
Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK.
Institute of Applied Mechanics, University of Stuttgart, Stuttgart, Germany.
Exp Brain Res. 2018 May;236(5):1471-1478. doi: 10.1007/s00221-018-5229-z. Epub 2018 Mar 16.
Sensory information conveyed along afferent fibers from muscle and joint proprioceptors play an important role in the control of posture and gait in humans. In particular, proprioceptive information from the neck is fundamental in supplying the central nervous system with information about the orientation and movement of the head relative to the rest of the body. The previous studies have confirmed that proprioceptive afferences originating from the neck region, evoked via muscle vibration, lead to strong body-orienting effects during static conditions (e.g., leaning of the body forwards or backwards, depending on location of vibration). However, it is not yet certain in humans, whether the somatosensory receptors located in the deep skin (cutaneous mechanoreceptors) have a substantive contribution to postural control, as vibratory stimulation encompasses the receptive field of all the somatosensory receptors from the skin to the muscles. The aim of this study was to investigate the postural effect of cutaneous mechanoreceptor afferences using electro-tactile stimulation applied to the neck. Ten healthy volunteers (8M, 2F) were evaluated. The average position of their centre of foot pressure (CoP) was acquired before, during, and after a subtle electro-tactile stimulation over their posterior neck (mean ± SD = 5.1 ± 2.3 mA at 100 Hz-140% of the perception threshold) during upright stance with their eyes closed. The electro-tactile stimulation led to a body-orienting effect with the subjects consistently leaning forward. An average shift of the CoP of 12.1 ± 11.9 mm (mean ± SD) was reported, which significantly (p < 0.05) differed from its average position under a control condition (no stimulation). These results indicate that cutaneous mechanoreceptive inflow from the neck is integrated to control stance. The findings are relevant for the exploitation of electro-tactile stimulation for rehabilitation interventions where induced anteropulsion of the body is desired.
沿传入纤维从肌肉和关节本体感受器传来的感觉信息在人类姿势和步态控制中发挥着重要作用。特别是，来自颈部的本体感受信息对于向中枢神经系统提供有关头部相对于身体其他部位的方位和运动的信息至关重要。先前的研究已经证实，通过肌肉振动诱发的源自颈部区域的本体感受传入，在静态条件下会导致强烈的身体定向效应（例如，身体向前或向后倾斜，取决于振动的位置）。然而，在人类中尚不确定位于深层皮肤的躯体感觉感受器（皮肤机械感受器）对姿势控制是否有实质性贡献，因为振动刺激涵盖了从皮肤到肌肉的所有躯体感觉感受器的感受野。本研究的目的是使用施加于颈部的电触觉刺激来研究皮肤机械感受器传入的姿势效应。对10名健康志愿者（8名男性，2名女性）进行了评估。在他们闭眼直立站立期间，对其颈部后部进行轻微电触觉刺激（100Hz时平均±标准差 = 5.1±2.3 mA，为感知阈值的140%）之前、期间和之后，获取他们的足底压力中心（CoP）的平均位置。电触觉刺激导致了身体定向效应，受试者持续向前倾斜。报告的CoP平均偏移为12.1±11.9 mm（平均±标准差），与对照条件（无刺激）下的平均位置相比有显著差异（p < 0.05）。这些结果表明，来自颈部的皮肤机械感受性传入被整合以控制站立姿势。这些发现对于利用电触觉刺激进行需要诱发身体前冲的康复干预具有重要意义。
