Importance of cutaneous feedback in maintaining a secure grip during manipulation of hand-held objects
Importance of cutaneous feedback in maintaining a secure grip during manipulation of hand-held objects
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DOI：
10.1152/jn.00249.2002
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发表时间：
2003-02-01
影响因子：
2.5
通讯作者：
Thonnard, JL
中科院分区：
文献类型：
--
作者：
Augurelle, AS;Smith, AM;Thonnard, JL
先前的研究表明，在操纵手持物体的过程中，抓握力和负载力同时被调制。这种紧密的时间耦合表明，这两种力都是由CNS内的内部模型控制的，该模型预测了手指上切向力的变化。本研究的目的是检查内部模型将如何补偿通过局部麻醉的食指和拇指的皮肤感觉的损失。要求10名健康成年受试者（5男5女，年龄20-57岁）抓握、举起并保持静止，250 g物体20 s。接下来，受试者被要求以1.0 Hz的频率在20 cm的距离上进行垂直振荡运动30 s。11项试验是在感觉完整的情况下进行的，11项试验是在用布比卡因（5 mg/ml）对食指和拇指进行局部环形阻滞麻醉后进行的。在静态保持过程中，皮肤感觉的丧失使安全范围显著增加。然而，在20秒的静态保持期间，握力显著下降。在摆动手臂的运动，抓地力和负载力不断调制在一起的预测方式所建议的弗拉纳根和翼。同样，握力在30秒的运动中下降，7/10的受试者至少有一次掉落物体。在感觉完整的情况下，物体不会掉落;但在手指被麻醉的情况下，有36%的实验中物体会掉落，还有12%的实验中发生了明显的滑动。所有受试者的握力和负荷力之间的平均相关性从感觉完整的0.71恶化到手指麻醉后的0.48。然而，计算出的抓握力和负载力之间的互相关表明，无论是否有手指麻醉，相位滞后都近似为零。两者合计，从本研究的数据表明，皮肤传入需要设置和维持的背景水平的握力，除了他们的相位滑检测功能和他们的作用，在适应的握力/负载力比的摩擦与物体的初始接触。最后，在更理论的层面上，他们纠正和维护手持物体物理特性的内部模型。
Previous research has shown that grip and load forces are modulated simultaneously during manipulation of a hand-held object. This close temporal coupling suggested that both forces are controlled by an internal model within the CNS that predicts the changes in tangential force on the fingers. The objective of the present study was to examine how the internal model would compensate for the loss of cutaneous sensation through local anesthesia of the index and thumb. Ten healthy adult subjects (5 men and 5 women aged 20-57 yr) were asked to grasp, lift, and hold stationary, a 250 g object for 20 s. Next, the subjects were asked to perform vertical oscillatory movements over a distance of 20 cm at a rate of 1.0 Hz for 30 s. Eleven trials were performed with intact sensation, and 11 trials after a local ring-block anesthesia of the index and thumb with bupivacain (5 mg/ml). During static holding, loss of cutaneous sensation produced a significant increase in the safety margin. However, the grip force declined significantly over the 20-s static hold period. During oscillatory arm movements, grip and load forces were continuously modulated together in a predictive manner as suggested by Flanagan and Wing. Again, the grip force declined over the 30-s movement, and 7/10 subjects dropped the object at least once. With intact sensation, the object was never dropped; but with the fingers anesthetized, it was dropped on 36% of the trials, and a significant slip occurred on a further 12%. The mean correlation between the grip and load forces for all subjects deteriorated from 0.71 with intact sensation to 0.48 after digital anesthesia. However, a cross-correlation calculated between the grip and load forces indicated that the phase lag was approximately zero both with and without digital anesthesia. Taken together, the data from the present study suggest that cutaneous afferents are required for setting and maintaining the background level of the grip force in addition to their phasic slip-detection function and their role in adapting the grip force/load force ratio to the friction on initial contact with an object. Finally, at a more theoretical level, they correct and maintain an internal model of the physical properties of hand-held objects.