Université de Bourgogne, Unité de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives, Dijon, France.
PLoS One. 2013 Aug 29;8(8):e73042. doi: 10.1371/journal.pone.0073042. eCollection 2013.
Motor imagery, i.e., a mental state during which an individual internally represents an action without any overt motor output, is a potential tool to investigate action representation during development. Here, we took advantage of the inertial anisotropy phenomenon to investigate whether children can generate accurate motor predictions for movements with varying dynamics. Children (9 and 11 years), adolescents (14 years) and young adults (21 years) carried-out actual and mental arm movements in two different directions in the horizontal plane: rightwards (low inertia) and leftwards (high inertia). We recorded and compared actual and mental movement times. We found that actual movement times were greater for leftward than rightward arm movements in all groups. For mental movements, differences between leftward versus rightward movements were observed in the adults and adolescents, but not among the children. Furthermore, significant differences between actual and mental times were found at 9 and 11 years of age in the leftward direction. The ratio R/L (rightward direction/leftward direction), which indicates temporal differences between low inertia and high inertia movements, was inferior to 1 at all ages, except for the mental movements at 9 years of age, indicating than actual and mental movements were shorter for the rightward than leftward direction. Interestingly, while the ratio R/L of actual movements was constant across ages, it gradually decreased with age for mental movements. The ratio A/M (actual movement/mental movement), which indicates temporal differences between actual and mental movements, was near to 1 in the adults' groups, denoting accurate mental timing. In children and adolescents, an underestimation of mental movement times appeared for the leftward movements only. However, this overestimation gradually decreased with age. Our results showed a refinement in the motor imagery ability during development. Action representation reached maturation at adolescence, during which mental actions were tightly related to their actual production.
运动想象，即个体在没有任何明显运动输出的情况下内部表现出的一种动作的心理状态，是研究发展过程中动作表现的一种潜在工具。在这里，我们利用惯性各向异性现象来研究儿童是否能够针对具有不同动力学特性的运动产生准确的运动预测。儿童（9 岁和 11 岁）、青少年（14 岁）和年轻成年人（21 岁）在水平面上以两个不同的方向进行实际和心理手臂运动：向右（低惯性）和向左（高惯性）。我们记录并比较了实际和心理运动的时间。我们发现，在所有组中，左向手臂运动的实际运动时间都大于右向手臂运动。对于心理运动，在成年人和青少年中观察到了左向与右向运动之间的差异，但在儿童中没有。此外，在左向方向上，9 岁和 11 岁时发现了实际和心理时间之间的显著差异。比率 R/L（右向方向/左向方向），表示低惯性和高惯性运动之间的时间差异，除了 9 岁时的心理运动外，在所有年龄都低于 1，表明实际和心理运动对于右向比左向方向更短。有趣的是，虽然实际运动的比率 R/L 在所有年龄段都保持不变，但对于心理运动，它随着年龄的增长而逐渐减小。比率 A/M（实际运动/心理运动），表示实际运动和心理运动之间的时间差异，在成年人组中接近 1，表明心理计时准确。在儿童和青少年中，仅对于左向运动，出现了对心理运动时间的低估。然而，这种高估随着年龄的增长逐渐减小。我们的结果表明，运动想象能力在发展过程中得到了提高。运动表现到青春期达到成熟，在此期间，心理动作与实际产生紧密相关。
