Cuadra Cristian, Corey Jacob, Latash Mark L
Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA; Escuela Kinesiología, Facultad de Ciencias de la Rehabilitación, Universidad Andres Bello, Calle Quillota 980, Viña del Mar, Chile.
Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
Neuroscience. 2021 Mar 1;457:139-154. doi: 10.1016/j.neuroscience.2021.01.006. Epub 2021 Jan 17.
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.
我们使用手指力量匹配任务来探究传出信号在力量感知中的作用。健康的年轻参与者用一只手（任务手）的食指和中指在不同力量水平下执行精确的力量产生任务。他们仅在每个试验的早期阶段接受视觉反馈。反馈关闭后，力量向较低幅度漂移。漂移5秒后，参与者用另一只手（匹配手）的同一对手指来匹配力量。匹配手始终比任务手的力量超出一个幅度，该幅度在初始力量水平上保持不变。在力量匹配过程中，双手平稳地抬起和放下，以估计它们的参照坐标（RC）和表观刚度值。这些试验在没有肌肉振动的情况下进行，以及在对任务手或匹配手的手指/手部屈肌或伸肌施加振动的情况下进行。振动的影响仅在匹配手中观察到；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量匹配过程中使用了发送到任务手的中央指令的失真副本的结果。特别是，使用拮抗肌组的RC的失真副本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。这种失真会自发出现，并且可能会因感觉末梢对激动剂和拮抗剂肌肉组的肌肉振动的反应而放大。
