Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden.
Nat Commun. 2018 Apr 24;9(1):1617. doi: 10.1038/s41467-018-03989-0.
Research on motor imagery has identified many similarities between imagined and executed actions at the behavioral, physiological and neural levels, thus supporting their "functional equivalence". In contrast, little is known about their possible "computational equivalence"-specifically, whether the brain's internal forward models predict the sensory consequences of imagined movements as they do for overt movements. Here, we address this question by assessing whether imagined self-generated touch produces an attenuation of real tactile sensations. Previous studies have shown that self-touch feels less intense compared with touch of external origin because the forward models predict the tactile feedback based on a copy of the motor command. Our results demonstrate that imagined self-touch is attenuated just as real self-touch is and that the imagery-induced attenuation follows the same spatiotemporal principles as does the attenuation elicited by overt movements. We conclude that motor imagery recruits the forward models to predict the sensory consequences of imagined movements.
运动想象研究在行为、生理和神经水平上发现了想象动作和执行动作之间的许多相似之处，从而支持了它们的“功能等同性”。相比之下，对于它们可能的“计算等同性”——具体来说，即大脑内部的前向模型是否像预测显性运动的感觉后果一样预测想象运动的感觉后果，我们知之甚少。在这里，我们通过评估想象中的自我产生的触摸是否会减弱真实触觉来解决这个问题。先前的研究表明，与来自外部的触摸相比，自我触摸感觉不那么强烈，因为前向模型根据运动指令的副本预测触觉反馈。我们的结果表明，想象中的自我触摸会像真实的自我触摸一样减弱，并且图像诱发的衰减遵循与显性运动引起的衰减相同的时空原则。我们的结论是，运动想象招募了前向模型来预测想象运动的感觉后果。
