We explored changes in finger forces and in an index of unintentional finger force production (enslaving) under a variety of visual feedback conditions and positional finger perturbations. In particular, we tested a hypothesis that enslaving would show a consistent increase with time at characteristic times of about 1–2 s. Young healthy subjects performed accurate force production tasks under visual feedback on the total force of the instructed fingers (index and ring) or enslaved fingers (middle and little). Finger feedback was covertly alternated between master and enslaved fingers in a random fashion. The feedback could be presented over the first 5 s of the trial only or over the whole trial duration (21 s). After 5 s, the fingers were lifted by 1 cm, and after 15 s, the fingers were lowered to the initial position. The force of the instructed fingers drifted toward lower magnitudes in all conditions except the one with continuous feedback on that force. The force of enslaved fingers showed variable behavior across conditions. In all conditions, the index of enslaving showed a consistent increase with the time constant varying between 1 and 3 s. We interpret the results as pointing at the spread of excitation to enslaved fingers (possibly, in the cortical M1 areas). The relatively fast changes in enslaving under positional finger perturbations suggest that quick changes of the input into M1 from pre-M1 areas can accelerate the hypothesized spread of cortical excitation.

我们探讨了在各种视觉反馈条件和手指位置扰动下，手指力的变化以及无意识手指力产生（奴役）的指数。尤其是，我们检验了一个假设，即在大约1-2 s的特征时间内，奴役将随时间不断增加。年轻健康的受试者在对指示的手指（食指和无名指）或从动手指（中，小）的总力的视觉反馈下执行了精确的力产生任务。手指反馈以随机方式在主手指和从属手指之间秘密地交替。反馈只能在试验的前5 s或整个试验持续时间内（21 s）提出。5秒钟后，将手指抬起1厘米，15秒钟后，将手指放低至初始位置。所指示的手指的力在所有情况下都向较低的幅度漂移，除了对该力具有连续反馈的手指。被奴役的手指的力量在各种情况下都表现出可变的行为。在所有条件下，奴隶指数均随时间常数在1到3 s之间变化而持续增加。我们将结果解释为指向激发到被奴役手指的传播（可能在皮层M1区域）。在位置手指扰动下奴隶制的相对快速变化表明，从M1之前的区域到M1的输入的快速变化可以加速假设的皮层兴奋扩散。在所有条件下，奴隶指数均随时间常数在1到3 s之间变化而持续增加。我们将结果解释为指向激发到被奴役手指的传播（可能在皮层M1区域）。在位置手指扰动下奴隶制的相对快速变化表明，从M1之前的区域到M1的输入的快速变化可以加速假设的皮层兴奋扩散。在所有条件下，奴隶指数均随时间常数在1到3 s之间变化而持续增加。我们将结果解释为指向激发到被奴役手指的传播（可能在皮层M1区域）。在位置手指扰动下奴隶制的相对快速变化表明，从M1之前的区域到M1的输入的快速变化可以加速假设的皮层兴奋扩散。