Roberts James W, Wood Greg, Wakefield Caroline J
Psychology, Action and Learning of Movement (PALM) Laboratory, School of Health Sciences, Liverpool Hope University, Hope Park, Liverpool, L16 9JD, UK.
Brain and Behaviour Laboratory, Research Institute of Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Tom Reilly Building, Liverpool, L3 5AF, UK.
Exp Brain Res. 2020 Dec;238(12):2983-2992. doi: 10.1007/s00221-020-05939-z. Epub 2020 Oct 21.
Motor imagery is suggested to be functionally equivalent to physical execution as they each utilise a common neural representation. The present study examined whether motor imagery correspondingly reflects the spatial characteristics of physically executed movements, including the signal-dependent noise that typically manifests in more variable end locations (as indicated by effective target width; W). Participants executed or imagined a single, upper-limb target-directed aim in the horizontal medio-lateral direction. The start and end of the imagined movements were indexed by the lifting and lowering of the limb over the home position, respectively. Following each imagined movement, participants had to additionally estimate their imagined end location relative to the target. All the movements had to be completed at a pre-specified criterion time (400 ms, 600 ms, 800 ms). The results indicated that the W increased following a decrease in movement time for execution, but not imagery. Moreover, the total error of imagined movements was greater than the actual error of executed movements. While motor imagery may comprise a neural representation that also contributes to the execution of movements, it is unable to closely reflect the random sources of variability. This limitation of motor imagery may be attributed to the comparatively limited efferent motor signals.
运动想象被认为在功能上等同于实际执行，因为它们都利用共同的神经表征。本研究考察了运动想象是否相应地反映了实际执行运动的空间特征，包括通常在更多可变终点位置表现出的信号相关噪声（如有效目标宽度；W所示）。参与者在水平中外侧方向上执行或想象一个单一的上肢目标导向动作。想象运动的开始和结束分别通过肢体在起始位置上方的抬起和放下进行标记。在每次想象运动之后，参与者还必须估计相对于目标的想象终点位置。所有运动都必须在预先指定的标准时间（400毫秒、600毫秒、800毫秒）内完成。结果表明，执行运动时，随着运动时间的减少，W增加，但想象运动时并非如此。此外，想象运动的总误差大于实际执行运动的误差。虽然运动想象可能包含一种也有助于运动执行的神经表征，但它无法紧密反映变异性的随机来源。运动想象的这种局限性可能归因于相对有限的传出运动信号。
