The Influence of Recent Actions and Anticipated Actions on the Stability of Finger Forces During a Tracking Task

摘要

The authors examined how the stability of the current total isometric force (F-T) produced by four fingers is influenced by previous and expected voluntary changes in F-T. The authors employed the synergy index obtained from the across-trial uncontrolled manifold analysis to quantify the stability of F-T. The authors compared two tasks with similar histories of F-T changes; one in which participants expected changes in F-T in the future, and one in which they expected no changes in F-T. The stability of F-T was lower in the former task, indicating the existence of a novel type of anticipatory synergy adjustment. Disparate histories of F-T changes yield inconsistent changes in stability, driven by individual differences in the covariation in the finger forces that leave F-T invariant. Future research should focus on exploring these individual differences to better understand how previous and expected behavior changes influence the stability of the current motor behavior.