Honeine Jean-Louis, Crisafulli Oscar, Sozzi Stefania, Schieppati Marco
Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy; and Centro Studi Attività Motorie (CSAM), Fondazione Salvatore Maugeri (IRCSS), Pavia, Italy.
Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy; and.
J Neurophysiol. 2015 Dec;114(6):3097-110. doi: 10.1152/jn.00618.2015. Epub 2015 Sep 2.
We investigated the integration time of haptic and visual input and their interaction during stance stabilization. Eleven subjects performed four tandem-stance conditions (60 trials each). Vision, touch, and both vision and touch were added and withdrawn. Furthermore, vision was replaced with touch and vice versa. Body sway, tibialis anterior, and peroneus longus activity were measured. Following addition or withdrawal of vision or touch, an integration time period elapsed before the earliest changes in sway were observed. Thereafter, sway varied exponentially to a new steady-state while reweighting occurred. Latencies of sway changes on sensory addition ranged from 0.6 to 1.5 s across subjects, consistently longer for touch than vision, and were regularly preceded by changes in muscle activity. Addition of vision and touch simultaneously shortened the latencies with respect to vision or touch separately, suggesting cooperation between sensory modalities. Latencies following withdrawal of vision or touch or both simultaneously were shorter than following addition. When vision was replaced with touch or vice versa, adding one modality did not interfere with the effect of withdrawal of the other, suggesting that integration of withdrawal and addition were performed in parallel. The time course of the reweighting process to reach the new steady-state was also shorter on withdrawal than addition. The effects of different sensory inputs on posture stabilization illustrate the operation of a time-consuming, possibly supraspinal process that integrates and fuses modalities for accurate balance control. This study also shows the facilitatory interaction of visual and haptic inputs in integration and reweighting of stance-stabilizing inputs.
我们研究了触觉和视觉输入的整合时间及其在姿势稳定过程中的相互作用。11名受试者进行了四种串联站立条件（每种条件60次试验）。分别添加和撤去视觉、触觉以及视觉和触觉两者。此外，视觉与触觉相互替换。测量身体摆动、胫骨前肌和腓骨长肌的活动。在添加或撤去视觉或触觉后，在观察到摆动最早变化之前有一个整合时间段。此后，摆动呈指数变化至新的稳态，同时进行重新加权。感觉添加时摆动变化的潜伏期在受试者中为0.6至1.5秒，触觉的潜伏期始终比视觉的长，并且肌肉活动变化通常先于摆动变化。同时添加视觉和触觉相对于单独添加视觉或触觉缩短了潜伏期，表明感觉模态之间存在协同作用。撤去视觉或触觉或两者同时撤去后的潜伏期比添加后的短。当视觉被触觉替换或反之亦然时，添加一种模态不会干扰撤去另一种模态的效果，表明撤去和添加的整合是并行进行的。撤去时达到新稳态的重新加权过程的时间进程也比添加时短。不同感觉输入对姿势稳定的影响说明了一个耗时的、可能是脊髓以上的过程的运作，该过程整合和融合各种模态以实现精确的平衡控制。这项研究还显示了视觉和触觉输入在姿势稳定输入的整合和重新加权中的促进性相互作用。
