Limb position drift: Implications for control of posture and movement
Limb position drift: Implications for control of posture and movement
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DOI：
10.1152/jn.00013.2003
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发表时间：
2003-11-01
影响因子：
2.5
通讯作者：
Sainburg, RL
中科院分区：
文献类型：
--
作者：
Brown, LE;Rosenbaum, DA;Sainburg, RL
在没有视觉反馈的情况下，受试者报告的手的位置往往随着时间的推移漂移。这种漂移已被归因于信号肢体位置的本体感觉的有用性逐渐减少。如果这个解释是正确的，漂移应该会降低在没有视觉反馈的情况下进行的一系列移动的移动距离和方向的准确性。为了验证这一假设，我们要求参与者从一个可见的开始位置到一个可见的目标进行六个系列的75次重复运动，并及时发出有规律的声音。在该系列的前五次试验中，指尖位置反馈由光标给出。然后删除反馈，参与者将继续进行接下来的70次试验。从三个起始位置（初始肩关节角度为30度、40度、50度，初始肘关节角度为90度）的每个位置在两个方向（30度和120度）上进行运动。在70次试验中，每个动作的起始位置平均偏离初始起始位置8厘米。这种漂移随运动方向而系统地变化，表明漂移与运动产生有关。然而，尽管手的位置和关节结构发生了这些巨大的变化，运动距离和方向仍然相对恒定。逆动力学分析表明，运动保存伴随着关节肌肉扭矩的大幅修改。这些结果表明，本体感觉仍然是一个可靠的来源肢体位置信息后，长时间没有视觉，但这种信息是不同的用于保持肢体位置和指定运动轨迹。
In the absence of visual feedback, subject reports of hand location tend to drift over time. Such drift has been attributed to a gradual reduction in the usefulness of proprioception to signal limb position. If this account is correct, drift should degrade the accuracy of movement distance and direction over a series of movements made without visual feedback. To test this hypothesis, we asked participants to perform six series of 75 repetitive movements from a visible start location to a visible target, in time with a regular, audible tone. Fingertip position feedback was given by a cursor during the first five trials in the series. Feedback was then removed, and participants were to continue on pace for the next 70 trials. Movements were made in two directions (30degrees and 120degrees) from each of three start locations (initial shoulder angles of 30degrees, 40degrees, 50degrees, and initial elbow angles of 90degrees). Over the 70 trials, the start location of each movement drifted, on average, 8 cm away from the initial start location. This drift varied systematically with movement direction, indicating that drift is related to movement production. However, despite these dramatic changes in hand position and joint configuration, movement distance and direction remained relatively constant. Inverse dynamics analysis revealed that movement preservation was accompanied by substantial modification of joint muscle torque. These results suggest that proprioception continues to be a reliable source of limb position information after prolonged time without vision, but that this information is used differently for maintaining limb position and for specifying movement trajectory.