Programme de Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
CIAMS (Complexité, Innovation, Activités, Motrices, et Sportives), Université Paris-Saclay, 91405 Orsay, France.
J Neurosci. 2023 Jul 12;43(28):5264-5275. doi: 10.1523/JNEUROSCI.0213-23.2023. Epub 2023 Jun 20.
Although premovement beta-band event-related desynchronization (β-ERD; 13-30 Hz) from sensorimotor regions is modulated by movement speed, current evidence does not support a strict monotonic association between the two. Given that β-ERD is thought to increase information encoding capacity, we tested the hypothesis that it might be related to the expected neurocomputational cost of movement, here referred to as action cost. Critically, action cost is greater both for slow and fast movements compared with a medium or "preferred" speed. Thirty-one right-handed participants performed a speed-controlled reaching task while recording their EEG. Results revealed potent modulations of beta power as a function of speed, with β-ERD being significantly greater both for movements performed at high and low speeds compared with medium speed. Interestingly, medium-speed movements were more often chosen by participants than low-speed and high-speed movements, suggesting that they were evaluated as less costly. In line with this, modeling of action cost revealed a pattern of modulation across speed conditions that strikingly resembled the one found for β-ERD. Indeed, linear mixed models showed that estimated action cost predicted variations of β-ERD significantly better than speed. This relationship with action cost was specific to beta power, as it was not found when averaging activity in the mu band (8-12 Hz) and gamma band (31-49 Hz) bands. These results demonstrate that increasing β-ERD may not merely speed up movements, but instead facilitate the preparation of high-speed and low-speed movements through the allocation of additional neural resources, thereby enabling flexible motor control. Heightened beta activity has been associated with movement slowing in Parkinson's disease, and modulations of beta activity are commonly used to decode movement parameters in brain-computer interfaces. Here we show that premovement beta activity is better explained by the neurocomputational cost of the action rather than its speed. Instead of being interpreted as a mere reflection of changes in movement speed, premovement changes in beta activity might therefore be used to infer the amount of neural resources that are allocated for motor planning.
尽管运动前感觉运动区域的β 波段事件相关去同步化（β-ERD；13-30 Hz）受到运动速度的调节，但目前的证据并不支持两者之间存在严格的单调关联。鉴于β-ERD 被认为可以增加信息编码能力，我们测试了这样一种假设，即它可能与运动的预期神经计算成本有关，我们将其称为动作成本。关键是，与中速或“偏好”速度相比，无论是慢速还是快速运动，动作成本都更高。31 名右利手参与者在执行速度控制的伸展任务时记录他们的 EEG。结果显示，β 功率作为速度的函数呈现出强烈的调制，与中速相比，高速和低速运动的β-ERD 明显更大。有趣的是，参与者更多地选择中速运动，而不是低速和高速运动，这表明它们被评估为成本较低。与此一致，动作成本的建模显示，在速度条件下的调制模式与β-ERD 的模式非常相似。事实上，线性混合模型表明，估计的动作成本比速度更能显著预测β-ERD 的变化。这种与动作成本的关系是β 功率特有的，因为在平均 mu 波段（8-12 Hz）和伽马波段（31-49 Hz）活动时没有发现这种关系。这些结果表明，增加β-ERD 可能不仅会加速运动，还会通过分配额外的神经资源来促进高速和低速运动的准备，从而实现灵活的运动控制。帕金森病中与运动减速相关的β 活动增加，β 活动的调制通常用于解码脑机接口中的运动参数。在这里，我们表明，运动前的β 活动更多地由动作的神经计算成本来解释，而不是运动的速度。因此，运动前β 活动的变化可能不是运动速度变化的简单反映，而是可以用来推断为运动规划分配的神经资源量。
