Bove M, Bonzano L, Trompetto C, Abbruzzese G, Schieppati M
Department of Experimental Medicine, Section of Human Physiology, University of Genoa, Viale Benedetto XV 3, I-16132 Genoa, Italy.
Neuroscience. 2006 Dec 28;143(4):1095-103. doi: 10.1016/j.neuroscience.2006.08.038. Epub 2006 Oct 30.
The aim of this study was to investigate whether the standing body spatial disorientation, induced by neck muscle vibration, and the related post-effects can be suppressed by light finger touch (LFT) of a stationary surface. Continuous (60 s) vibration of dorsal neck or sternocleidomastoid muscle was administered with eyes closed. The center of foot pressure (CFP) displacement, measured by a stabilometric platform, indicated the degree of vibration-induced body tilt. We also investigated whether sensory information from LFT itself was necessary or anticipation of a more secure posture was enough for reducing vibration effects. To this aim, we administered a vibration pulse (5 s) to dorsal neck or sternocleidomastoid muscle and during reaching to the stationary surface. CFP was recorded during both vibration and post-vibration condition and during the aiming task. Neck vibration induced significant CFP displacement in the direction opposite to vibration site. Post-vibration, CFP slowly returned to control values with ample oscillations. LFT during vibration reduced body tilt. LFT was more effective when fingertip contact was in the plane of the greatest tilt. LFT applied during either vibration or post-vibration period reduced post-vibration effects. Reaching toward the stationary surface was enough for reducing vibration-induced body tilt to values close to those observed during actual LFT. The novel conclusions of this study are: 1) LFT is able to relieve the effects of vibration-induced abnormal proprioceptive input from the neck, a segment central to postural control and orientation; 2) LFT during vibration also attenuates vibration post-effects, further suggesting that its action is not merely mechanical; 3) the intention to stabilize the body generates a new postural 'set' sufficient for diminishing body tilt.
本研究的目的是调查颈部肌肉振动引起的站立身体空间定向障碍及其相关的后效应是否可以通过轻触静止表面来抑制。在闭眼状态下，对颈部背侧或胸锁乳突肌进行持续60秒的振动。通过稳定测力平台测量的足底压力中心（CFP）位移表明了振动引起的身体倾斜程度。我们还研究了轻触本身的感觉信息是否必要，或者对更稳定姿势的预期是否足以减少振动影响。为此，我们在触及静止表面的过程中，对颈部背侧或胸锁乳突肌施加一个5秒的振动脉冲。在振动和振动后状态以及瞄准任务期间记录CFP。颈部振动在与振动部位相反的方向上引起了显著的CFP位移。振动后，CFP伴随着大量振荡缓慢恢复到对照值。振动期间的轻触减少了身体倾斜。当指尖接触在最大倾斜平面时，轻触更有效。在振动或振动后期间施加轻触可减少振动后效应。向静止表面伸手就足以将振动引起的身体倾斜减少到接近实际轻触时观察到的值。本研究的新结论是：1）轻触能够减轻颈部振动引起的异常本体感觉输入的影响，颈部是姿势控制和定向的关键部位；2）振动期间的轻触也减弱了振动后效应，进一步表明其作用不仅仅是机械性的；3）稳定身体的意图产生了一种新的姿势“定势”，足以减少身体倾斜。
