Voluntary control of human jaw stiffness.
Voluntary control of human jaw stiffness.
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自愿控制人类下巴僵硬。
DOI：
10.1152/jn.00164.2005
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Ostry,DavidJ
中科院分区：
文献类型：
--
作者：
Shiller,DouglasM;Houle,Guillaume;Ostry,DavidJ
最近对人类手臂运动的研究表明，刚度的控制可能对保持稳定性和实现运动精度的差异都很重要。在目前的研究中，我们已经检查了在三维人体颌位刚度的自愿控制。目标是解决刚度控制在稳定颌骨和实现语音的不同精度要求中的可能作用。我们以前的研究表明，语言的运动变化模式与颌骨的刚度有系统的关系。如果神经系统使用刚度控制作为一种手段来调节语言的运动变化，那么也应该有可能表明受试者可以自愿地改变下颌刚度。使用一个机器人装置，一系列的力脉冲被施加到颚上，引起刚度的变化，以抵抗位移。测试了三个正交方向和三个大小的力。在所有条件下，受试者增加下颌刚度的大小来抵抗施加的力的影响。除了水平方向外，当施加更大的力时，观察到刚度增加更大。此外，受试者沿垂直轴增加下颌刚度以抵消该方向的干扰。在不同方向上观察到的刚度大小的变化表明有能力控制下巴的刚度模式。结果被解释为证据，颚刚度可以自动调节，因此可能在稳定颌骨和控制运动变化在口面部系统中发挥作用。
Recent studies of human arm movement have suggested that the control of stiffness may be important both for maintaining stability and for achieving differences in movement accuracy. In the present study, we have examined the voluntary control of postural stiffness in 3D in the human jaw. The goal is to address the possible role of stiffness control in both stabilizing the jaw and in achieving the differential precision requirements of speech sounds. We previously showed that patterns of kinematic variability in speech are systematically related to the stiffness of the jaw. If the nervous system uses stiffness control as a means to regulate kinematic variation in speech, it should also be possible to show that subjects can voluntarily modify jaw stiffness. Using a robotic device, a series of force pulses was applied to the jaw to elicit changes in stiffness to resist displacement. Three orthogonal directions and three magnitudes of forces were tested. In all conditions, subjects increased the magnitude of jaw stiffness to resist the effects of the applied forces. Apart from the horizontal direction, greater increases in stiffness were observed when larger forces were applied. Moreover, subjects differentially increased jaw stiffness along a vertical axis to counteract disturbances in this direction. The observed changes in the magnitude of stiffness in different directions suggest an ability to control the pattern of stiffness of the jaw. The results are interpreted as evidence that jaw stiffness can be adjusted voluntarily, and thus may play a role in stabilizing the jaw and in controlling movement variation in the orofacial system.