Opsomer Laurent, Delhaye Benoit P, Théate Vincent, Thonnard Jean-Louis, Lefèvre Philippe
Institute of Neuroscience, Université catholique de Louvain, 1200 Brussels, Belgium.
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
iScience. 2023 Jun 28;26(7):107246. doi: 10.1016/j.isci.2023.107246. eCollection 2023 Jul 21.
Human dexterity requires very fine and efficient control of fingertip forces, which relies on the integration of cutaneous and proprioceptive feedback. Here, we examined the influence of gravity on isometric force control. We trained participants to reproduce isometric vertical forces on a dynamometer held between the thumb and the index finger in normal gravity and tested them during parabolic flight creating phases of microgravity and hypergravity, thereby strongly influencing the motor commands and the proprioceptive feedback. We found that gravity creates the illusion that upward forces are larger than downward forces of the same magnitude. The illusion increased under hypergravity and was abolished under microgravity. Gravity also affected the control of the grip force employed to secure the grasp. These findings suggest that gravity biases the haptic estimation of forces, which has implications for the design of haptic devices to be used during flight or space activities.
人类的灵巧性需要对指尖力量进行非常精细和高效的控制，这依赖于皮肤感觉反馈和本体感觉反馈的整合。在此，我们研究了重力对等长力控制的影响。我们训练参与者在正常重力条件下，用拇指和食指握住测力计，重现垂直等长力，并在抛物线飞行过程中对他们进行测试，抛物线飞行会产生微重力和超重力阶段，从而强烈影响运动指令和本体感觉反馈。我们发现，重力会造成一种错觉，即相同大小的向上力比向下力更大。这种错觉在超重力条件下增强，在微重力条件下消失。重力还影响了用于确保抓握的握力控制。这些发现表明，重力会使力的触觉估计产生偏差，这对飞行或太空活动中使用的触觉设备的设计具有启示意义。
