Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada.
McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Canada; Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain; Biomedical Image Technologies, Universidad Politécnica de Madrid and CIBER-BBN, Madrid, Spain.
Neuroimage. 2019 Nov 1;201:116037. doi: 10.1016/j.neuroimage.2019.116037. Epub 2019 Jul 19.
Muscle contractions are associated with a decrease in beta oscillatory activity, known as movement-related beta desynchronization (MRBD). Older adults exhibit a MRBD of greater amplitude compared to their younger counterparts, even though their beta power remains higher both at rest and during muscle contractions. Further, a modulation in MRBD has been observed during sustained and dynamic pinch contractions, whereby beta activity during periods of steady contraction following a dynamic contraction is elevated. However, how the modulation of MRBD is affected by aging has remained an open question. In the present work, we investigated the effect of aging on the modulation of beta oscillations and their putative link with motor performance. We collected magnetoencephalography (MEG) data from younger and older adults during a resting-state period and motor handgrip paradigms, which included sustained and dynamic contractions, to quantify spontaneous and motor-related beta oscillatory activity. Beta power at rest was found to be significantly increased in the motor cortex of older adults. During dynamic hand contractions, MRBD was more pronounced in older participants in frontal, premotor and motor brain regions. These brain areas also exhibited age-related decreases in cortical thickness; however, the magnitude of MRBD and cortical thickness were not found to be associated after controlling for age. During sustained hand contractions, MRBD exhibited a decrease in magnitude compared to dynamic contraction periods in both groups and did not show age-related differences. This suggests that the amplitude change in MRBD between dynamic and sustained contractions is larger in older compared to younger adults. We further probed for a relationship between beta oscillations and motor behaviour and found that greater MRBD in primary motor cortices was related to degraded motor performance beyond age, but our results suggested that age-related differences in beta oscillations were not predictive of motor performance.
肌肉收缩伴随着β振荡活动的减少，这种现象被称为运动相关的β去同步化（MRBD）。与年轻个体相比，老年人的 MRBD 振幅更大，尽管他们在休息和肌肉收缩时的β功率仍然更高。此外，在持续和动态捏合收缩期间观察到了 MRBD 的调制，其中在动态收缩后的稳定收缩期间，β活动升高。然而，MRBD 的调制如何受到年龄的影响仍然是一个悬而未决的问题。在本工作中，我们研究了衰老对β振荡调制的影响及其与运动表现的潜在联系。我们在静息状态期间和运动手抓握范式期间从年轻和老年成年人收集了脑磁图（MEG）数据，这些范式包括持续和动态收缩，以量化自发和运动相关的β振荡活动。在老年个体的运动皮层中，休息时的β功率明显增加。在动态手收缩期间，老年参与者在前额、运动前和运动脑区的 MRBD 更为明显。这些脑区也表现出与年龄相关的皮质厚度减少；然而，在控制年龄后，MRBD 的幅度和皮质厚度之间没有发现相关性。在持续手收缩期间，与动态收缩期相比，MRBD 的幅度在两组中都有所减小，并且没有表现出与年龄相关的差异。这表明，与年轻人相比，老年人在动态和持续收缩之间的 MRBD 幅度变化更大。我们进一步探讨了β振荡与运动行为之间的关系，并发现初级运动皮层中的更大的 MRBD 与运动表现的恶化有关，而与年龄无关，但我们的结果表明，β振荡的年龄相关差异不能预测运动表现。
