STABLE HUMAN STANDING WITH LOWER-LIMB MUSCLE AFFERENTS PROVIDING THE ONLY SENSORY INPUT
STABLE HUMAN STANDING WITH LOWER-LIMB MUSCLE AFFERENTS PROVIDING THE ONLY SENSORY INPUT
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DOI：
10.1113/jphysiol.1994.sp020369
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发表时间：
1994-10-15
影响因子：
5.5
通讯作者：
MCCLOSKEY, DI
中科院分区：
文献类型：
--
作者：
FITZPATRICK, R;ROGERS, DK;MCCLOSKEY, DI
1. 本研究调查了正常受试者站立能力所依赖的感觉信息来源。2． “等效身体”用于模拟每个受试者站立时身体的物理特性。在直立位置支撑等效身体所需的脚踝扭矩调节与站立时支撑受试者自己的身体所需的扭矩调节类似。然而，当平衡等效身体时，前庭输入被排除在指导脚踝扭矩的适当变化之外。因此，可以通过前庭输入（正常姿势）和不使用（平衡等效身体）调节来研究姿势的稳定性。闭上眼睛可以排除视力。来自脚和脚踝的感觉输入可以通过局部麻醉来消除，因为长时间缺血是通过脚踝上方的充气袖带阻塞血流引起的。由于前庭、视觉和周围感觉输入被否定，站立只能依赖于剩余的感觉输入，尤其是来自腿部肌肉中的感觉感受器的输入。3。与人体不同，用于否定前庭输入的等效身体不是分段的。因此，分段身体对稳定性的影响是通过在站立时用夹板固定受试者来确定的，以便仅允许踝关节运动。这是在存在和不存在视觉稳定的情况下完成的。4。对于每项实验任务，无论是站立还是平衡同等身体，在姿势不受干扰的情况下记录摇摆。采用摇摆幅度均方根值和功率谱进行条件比较。 5．当闭眼和双脚麻醉时，每个受试者都能以稳定的方式平衡等效身体。因此，他们可以执行相当于站立的任务，但只有来自腿部肌肉的感觉信息可用于检测摇摆。然而，尽管受试者很稳定，但摇摆程度比他们在所有感官输入可用的情况下正常站立时更大。6．在所有情况下，当闭上眼睛或用夹板阻止脚踝以上身体部位运动时，摇摆都会显着增加。相比之下，当排除脚和脚踝的感觉输入时，摇摆略有增加。身体夹板站立（可用前庭输入）和平衡等效身体（排除前庭输入）的摇摆相似。7。结论是，对于正常受试者：（i）来自腿部肌肉受体的本体感觉信号足以保持稳定的直立姿势； (ii) 视觉输入对于最大稳定性是必要的； (iii)分段体的作用是显着提高稳定性； (iv) 来自足部和脚踝的感觉信息对稳定性的影响较小但显着； (v) 在正常站立期间，前庭输入不负责调节腿部肌肉的活动以帮助保持稳定性。
1. This study investigated the sources of sensory information upon which normal subjects' ability to stand depends.2. An 'equivalent body' was used to simulate the physical properties of each subject's body during standing. The modulation of ankle torque required to support the equivalent body in an upright position was similar to that required to support the subject's own body when standing. However, when balancing the equivalent body, vestibular inputs were excluded from directing the appropriate changes in ankle torque. Thus, stability of stance could be studied with (normal stance) and without (balancing equivalent body) modulation by vestibular inputs. Vision could be excluded by closing the eyes. Sensory input from the feet and ankles could be removed by local anaesthesia from prolonged ischaemia, induced by occluding blood flow with inflated pneumatic cuffs just above the ankles. With vestibular, visual and peripheral sensory inputs negated, standing could rely only upon remaining sensory inputs, notably those from sensory receptors in the leg muscles.3. Unlike the human body, the equivalent body used to negate vestibular inputs is not segmented. Therefore, the effects on stability of having a segmented body were determined by splinting subjects during standing so that only ankle movement was possible. This was done in the presence and absence of visual stabilization.4. For each experimental task, either standing or balancing the equivalent body, sway was recorded while posture was unperturbed. Root mean square values of sway amplitude and power spectra were used to compare conditions.5. Every subject could balance the equivalent body in a stable way when the eyes were closed, and when the feet were anaesthetized. Therefore, they could perform a task that was equivalent to standing but when only sensory information from the leg muscles was available to detect the sway. However, although subjects were stable, sway was greater than when they were standing normally with all sensory inputs available.6. In all situations, sway increased significantly when the eyes were shut, or when splinting prevented the movement of body segments above the ankles. In contrast, there was a small increase in sway when sensory inputs from the feet and ankles were excluded. Sway was similar for standing with the body splinted (vestibular inputs available) and for balancing the equivalent body (vestibular inputs excluded).7. It is concluded that, for normal subjects: (i) proprioceptive signals from receptors in the leg muscles are sufficient to maintain a stable upright stance; (ii) visual inputs are necessary for maximal stability; (iii) the effect of the segmented body is to significantly improve stability; (iv) sensory information from the feet and ankles has a smaller but significant effect on stability; and (v) during normal standing, vestibular inputs are not responsible for modulating activity in the leg muscles to assist stability.