Laboratoire de Neurosciences Cognitives (LNC-UMR 7291), Centre National de la Recherche Scientifique, Marseille, France.
PLoS One. 2013;8(2):e56313. doi: 10.1371/journal.pone.0056313. Epub 2013 Feb 7.
Although there is suggestive evidence that a link exists between independent walking and the ability to establish anticipatory strategy to stabilize posture, the extent to which this skill facilitates the development of anticipatory postural control remains largely unknown. Here, we examined the role of independent walking on the infants' ability to anticipate predictable external perturbations. Non-walking infants, walking infants and adults were sitting on a platform that produced continuous rotation in the frontal plane. Surface electromyography (EMG) of neck and lower back muscles and the positions of markers located on the platform, the upper body and the head were recorded. Results from cross-correlation analysis between rectified and filtered EMGs and platform movement indicated that although muscle activation already occurred before platform movement in non-walking infants, only walking infants demonstrated an adult-like ability for anticipation. Moreover, results from further cross-correlation analysis between segmental angular displacement and platform movement together with measures of balance control at the end-points of rotation of the platform evidenced two sorts of behaviour. The adults behaved as a non-rigid non-inverted pendulum, rather stabilizing head in space, while both the walking and non-walking infants followed the platform, behaving as a rigid inverted pendulum. These results suggest that the acquisition of independent walking plays a role in the development of anticipatory postural control, likely improving the internal model for the sensorimotor control of posture. However, despite such improvement, integrating the dynamics of an external object, here the platform, within the model to maintain balance still remains challenging in infants.
尽管有迹象表明独立行走与建立姿势稳定的预期策略能力之间存在联系，但这种技能在多大程度上促进了预期姿势控制的发展在很大程度上仍然未知。在这里，我们研究了独立行走对婴儿预测外部干扰能力的作用。非行走婴儿、行走婴儿和成人坐在一个平台上，该平台在额状面产生连续旋转。记录颈和下背部肌肉的表面肌电图（EMG）以及位于平台、上半身和头部的标记的位置。对校正和滤波后的 EMG 与平台运动之间的互相关分析的结果表明，尽管非行走婴儿在平台运动之前已经发生了肌肉激活，但只有行走婴儿表现出类似于成人的预期能力。此外，进一步对节段角位移与平台运动之间的互相关分析以及平台旋转终点处平衡控制的测量结果表明存在两种行为。成年人的行为就像一个非刚性不倒翁，而是在空间中稳定头部，而行走和非行走的婴儿都跟随平台，表现为刚性倒摆。这些结果表明，独立行走的获得在预期姿势控制的发展中起着作用，可能改善了姿势的感觉运动控制的内部模型。然而，尽管有了这种改进，在婴儿中，将外部物体（此处为平台）的动力学整合到模型中以保持平衡仍然具有挑战性。
