Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
Sci Adv. 2024 Jan 19;10(3):eadh9344. doi: 10.1126/sciadv.adh9344. Epub 2024 Jan 17.
During object manipulation, humans adjust the grip force to friction, such that slippery objects are squeezed more firmly than sticky ones. This essential mechanism to keep a stable grasp relies on feedback from tactile afferents innervating the fingertips, that are sensitive to local skin strains. To test if this feedback originates from the skin-object interface, we asked participants to perform a grip-lift task with an instrumented object able to monitor skin strains at the contact through transparent plates of different frictions. We observed that, following an unbeknown change in plate across trials, participants adapted their grip force to friction. After switching from high to low friction, we found a significant increase in strain inside the contact arising ~100 ms before the modulation of grip force, suggesting that differences in strain patterns before lift-off are used by the nervous system to quickly adjust the force to the frictional properties of manipulated objects.
在物体操作过程中，人类会根据摩擦力调整握持力，从而使光滑的物体比粘性物体被紧握得更紧。这种保持稳定抓握的基本机制依赖于从指尖传入的触觉传入神经的反馈，这些传入神经对手指皮肤的局部应变敏感。为了测试这种反馈是否来自皮肤-物体界面，我们要求参与者使用一种可通过不同摩擦系数的透明板监测接触处皮肤应变的仪器化物体进行握持-提起任务。我们观察到，在未知的试验间盘子变化后，参与者根据摩擦力调整了握持力。在从高摩擦切换到低摩擦后，我们发现接触处的应变显著增加，大约在握持力调制之前 100 毫秒，这表明在提起之前，应变模式的差异被神经系统用来快速调整力以适应所操作物体的摩擦特性。
