Delevoye-Turrell Y N, Li F-X, Wing A M
JE2375 CNRS, Lille, France and University of Birmingham, Birmingham, UK.
Q J Exp Psychol A. 2003 Oct;56(7):1113-28. doi: 10.1080/02724980245000025.
During object manipulation, both predictive feedforward and reactive feedback mechanisms are available to adjust grip force (GF) levels to compensate for the destabilizing effects of load force changes. During collisions, load force increases impulsively (< 20 ms). Thus, only predictive control of GF can be used to ensure grasp stabilization. A collision paradigm is here used to investigate the effects of practice and vision on the efficiency of the predictive control of GF. Subjects actively produced or received an imposed collision with a pendulum. Subjects were more efficient (used smaller GF for identical loads) when producing than when receiving the collisions. Effects of practice were evident in the active producing task only, with GF levels reducing over repetitions, suggesting that sensorimotor memory for the task was used to adjust GF more efficiently. With imposed collisions, GF levels did not reduce with repetition, which suggests that a direct relation between motor action and sensory feedback may be necessary to improve efficiency. Nevertheless, in this condition GF was lower with visual feedback, indicating potential for more efficient grip possibly associated with subjects degree of confidence. We discuss the implications of these results for accounts of the predictive and the reactive control of movement.
在物体操作过程中，预测性前馈和反应性反馈机制均可用于调整握力（GF）水平，以补偿负载力变化的不稳定影响。在碰撞过程中，负载力会瞬间增加（<20毫秒）。因此，只有GF的预测性控制可用于确保抓握稳定。这里使用碰撞范式来研究练习和视觉对GF预测性控制效率的影响。受试者主动产生或接受与摆锤的碰撞。与接受碰撞相比，受试者在产生碰撞时效率更高（对于相同负载使用较小的GF）。练习的效果仅在主动产生任务中明显，随着重复次数的增加，GF水平降低，这表明该任务的感觉运动记忆被用于更有效地调整GF。在施加碰撞的情况下，GF水平不会随着重复次数而降低，这表明运动动作和感觉反馈之间的直接关系可能是提高效率所必需的。然而，在这种情况下，有视觉反馈时GF较低，表明可能与受试者的信心程度相关的更有效抓握的潜力。我们讨论了这些结果对运动预测性和反应性控制解释的意义。
