We used a finger force matching task to explore the role of efferent signals in force perception. Healthy, young participants performed accurate force production tasks at different force levels with the index and middle fingers of one hand (task-hand). They received visual feedback during an early part of each trial only. After the feedback was turned off, the force drifted toward lower magnitudes. After 5 s of the drift, the participants matched the force with the same finger pair of the other hand (match-hand). The match-hand consistently overshot the task-hand force by a magnitude invariant over the initial force levels. During force matching, both hands were lifted and lowered smoothly to estimate their referent coordinate (RC) and apparent stiffness values. These trials were performed without muscle vibration and under vibration applied to the finger/hand flexors or extensors of the task-hand or match-hand. Effects of vibration were seen in the match-hand only; they were the same during vibration of flexors and extensors. We interpret the vibration-induced effects as consequences of using distorted copies of the central commands to the task-hand during force matching. In particular, using distorted copies of the RC for the antagonist muscle group could account for the differences between the task-hand and match-hand. We conclude that efferent signals may be distorted before their participation in the perceptual process. Such distortions emerge spontaneously and may be amplified by the response of sensory endings to muscle vibration combined over both agonist and antagonist muscle groups.

我们使用手指力匹配任务来探索传出信号在力感知中的作用。健康，年轻的参与者用一只手（任务手）的食指和中指在不同的力量水平上执行了精确的力量生产任务。他们仅在每个试验的早期阶段就收到了视觉反馈。关闭反馈后，力向较低的方向漂移。漂移5秒钟后，参与者用另一只手的同一根手指（匹配手）使力匹配。火柴手始终超过任务手的力量，幅度超过初始力量水平。在力匹配过程中，两只手平稳地抬起和放下，以估计其参考坐标（RC）和表观刚度值。这些试验在没有肌肉振动的情况下进行，并且在施加于任务手或火柴手的手指/手屈肌或伸肌的振动下进行。振动的影响只出现在火柴上。在屈肌和伸肌振动期间它们是相同的。我们将振动引起的影响解释为在力匹配过程中使用扭曲的中央命令副本到任务手的后果。特别是，使用变形的RC副本来对抗肌群可以解释任务手和匹配手之间的差异。我们得出结论，传出信号在参与感知过程之前可能会失真。这样的扭曲自发地出现，并且可以通过在激动剂和拮抗肌群上组合的肌肉振动的感觉末端的响应而被放大。