Bioengineering Department, University of Pittsburgh, Pittsburgh, PA 15260.
Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15213.
eNeuro. 2022 Apr 19;9(2). doi: 10.1523/ENEURO.0369-21.2022. Print 2022 Mar-Apr.
Humans can perform complex movements with speed and agility in the face of constantly changing task demands. To accomplish this, motor plans are adapted to account for errors in our movements because of changes in our body (e.g., growth or injury) or in the environment (e.g., walking on sand vs ice). It has been suggested that adaptation that occurs in response to changes in the state of our body will generalize across different movement contexts and environments, whereas adaptation that occurs with alterations in the external environment will be context-specific. Here, we asked whether the ability to form generalizable versus context-specific motor memories develops during childhood. We performed a cross-sectional study of context-specific locomotor adaptation in 35 children (3-18 years old) and 7 adults (19-31 years old). Subjects first adapted their gait and learned a new walking pattern on a split-belt treadmill, which has two belts that move each leg at a different speed. Then, subjects walked overground to assess the generalization of the adapted walking pattern across different environments. Our results show that the generalization of treadmill after-effects to overground walking decreases as subjects' age increases, indicating that age and experience are critical factors regulating the specificity of motor learning. Our results suggest that although basic locomotor patterns are established by two years of age, brain networks required for context-specific locomotor learning are still being developed throughout youth.
人类能够在面对不断变化的任务需求时，以速度和敏捷性执行复杂的动作。为了实现这一目标，运动计划会根据我们身体（例如生长或受伤）或环境（例如在沙地上行走与冰面上行走）的变化而进行调整，以弥补运动中的错误。有观点认为，针对身体状态变化而产生的适应将在不同的运动环境和背景中具有通用性，而针对外部环境改变而产生的适应则具有特定于环境的特征。在这里，我们探讨了在儿童时期是否能够形成具有通用性和特定于环境的运动记忆的能力。我们对 35 名儿童（3-18 岁）和 7 名成年人（19-31 岁）进行了特定于环境的运动适应性的横断面研究。研究对象首先在跑步机上调整他们的步态并学习新的行走模式，跑步机有两条带，每条带以不同的速度移动一条腿。然后，研究对象在实地行走以评估适应的行走模式在不同环境中的通用性。我们的结果表明，随着研究对象年龄的增长，跑步机后效对实地行走的通用性会降低，这表明年龄和经验是调节运动学习特异性的关键因素。我们的研究结果表明，尽管基本的运动模式在两岁时就已建立，但在整个青少年时期，仍在不断发展用于特定于环境的运动学习的大脑网络。
