School of Engineering, Computing and Mathematics, University of Plymouth, Plymouth PL4 8AA, United Kingdom
Neuromuscular Diagnostics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich, 80992 Munich, Bavaria, Germany.
J Neurosci. 2024 Nov 20;44(47):e0359242024. doi: 10.1523/JNEUROSCI.0359-24.2024.
In daily life, we coordinate both simultaneous and sequential bimanual movements to manipulate objects. Our ability to rapidly account for different object dynamics suggests there are neural mechanisms to quickly deal with them. Here we investigate how actions of one arm can serve as a contextual cue for the other arm and facilitate adaptation. Specifically, we examine the temporal characteristics that underlie motor memory formation and recall, by testing the contextual effects of prior, simultaneous, and post contralateral arm movements in both male and female human participants. To do so, we measure their temporal generalization in three bimanual interference tasks. Importantly, the timing context of the learned action plays a pivotal role in the temporal generalization. While motor memories trained with post adaptation contextual movements generalize broadly, motor memories trained with prior contextual movements exhibit limited generalization, and motor memories trained with simultaneous contextual movements do not generalize to prior or post contextual timings. This highlights temporal tuning in sensorimotor plasticity: different training conditions yield substantially different temporal generalization characteristics. Since these generalizations extend far beyond any variability in training times, we suggest that the observed differences may stem from inherent differences in the use of prior, current, and post adaptation contextual information in the generation of natural behavior. This would imply differences in the underlying neural circuitry involved in learning and executing the corresponding coordinated bimanual movements.
在日常生活中，我们协调双手同时和顺序进行动作，以操纵物体。我们能够快速适应不同物体的动态，这表明存在神经机制来快速应对这些动态。在这里，我们研究了一只手臂的动作如何成为另一只手臂的上下文提示，并促进适应。具体来说，我们通过测试男性和女性人类参与者在先前、同时和对侧手臂运动中的上下文效应对运动记忆形成和回忆的时间特征进行了检查。为此，我们在三个双手干扰任务中测量了它们的时间泛化。重要的是，所学动作的时间上下文在时间泛化中起着关键作用。虽然用适应后的上下文运动训练的运动记忆广泛地泛化，但用先前的上下文运动训练的运动记忆表现出有限的泛化，而用同时的上下文运动训练的运动记忆不会泛化到先前或适应后的上下文时间。这突出了感觉运动可塑性中的时间调谐：不同的训练条件产生了截然不同的时间泛化特征。由于这些泛化远远超出了训练时间的任何变化，因此我们认为观察到的差异可能源于在生成自然行为中对先前、当前和适应后上下文信息的使用存在固有差异。这意味着在学习和执行相应的协调双手运动时涉及的潜在神经回路存在差异。
