Henningsen H, Knecht S, Ende-Henningsen B
Department of Neurology, University of Wisconsin, Waisman Center, Madison 53705, USA.
Exp Brain Res. 1997 Feb;113(2):207-13. doi: 10.1007/BF02450319.
The influence of afferent feedback on isometric fine force resolution was studied in humans. Subjects performed the smallest possible isometric flexion force increments with the index finger while visual, cutaneous, and muscle spindle feedback conditions were varied. In the control conditions with visual feedback, isometric force resolution was finest and independent of cutaneous or muscle spindle feedback. In the absence of visual cues, force resolution was significantly coarser. When agonist muscle spindles were vibrated (100 Hz and 150 Hz), fine force resolution capabilities declined further. Diminution of cutaneous feedback per se did not affect fine force resolution. However, the effect of agonist vibration was attenuated when full cutaneous feedback was available. We conclude that in voluntary isometric contractions the degree of fine force resolution depends on the type of afferent feedback available for calibrating central motor commands. Visual feedback is more powerful than spindle feedback, which is more efficient than cutaneous feedback. The extent to which the central motor command itself contributes to the sensation of force is indirectly implied by reproducible, yet coarser force resolution levels when peripheral information is minimized.
在人类中研究了传入反馈对等长精细力量分辨的影响。受试者用食指进行尽可能小的等长屈曲力量增量，同时改变视觉、皮肤和肌梭反馈条件。在有视觉反馈的对照条件下，等长力量分辨最精细，且与皮肤或肌梭反馈无关。在没有视觉线索的情况下，力量分辨明显更粗糙。当对主动肌肌梭进行振动（100赫兹和150赫兹）时，精细力量分辨能力进一步下降。皮肤反馈本身的减少并不影响精细力量分辨。然而，当有完整的皮肤反馈时，主动肌振动的影响会减弱。我们得出结论，在自主等长收缩中，精细力量分辨的程度取决于可用于校准中枢运动指令的传入反馈类型。视觉反馈比肌梭反馈更有效，而肌梭反馈比皮肤反馈更有效。当外周信息减至最少时，可重复但更粗糙的力量分辨水平间接暗示了中枢运动指令本身对力量感觉的贡献程度。
