Amsterdam Movement Science Institute (AMS) and Institute for Brain and Behaviour Amsterdam (iBBA), Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.
Hum Brain Mapp. 2019 Apr 15;40(6):1799-1813. doi: 10.1002/hbm.24491. Epub 2018 Dec 26.
We studied the relationship between age-related differences in inter- and intra-hemispheric structural and functional connectivity in the bilateral motor network. Our focus was on the correlation between connectivity and declined motor performance in older adults. Structural and functional connectivity were estimated using diffusion weighted imaging and resting-state electro-encephalography, respectively. A total of 48 young and older healthy participants were measured. In addition, motor performances were assessed using bimanual coordination tasks. To pre-select regions-of-interest (ROIs), a neural model was adopted that accounts for intra-hemispheric functional connectivity between dorsal premotor area (PMd) and primary motor cortex (M1) and inter-hemispheric connections between left and right M1 (M1 and M1 ). Functional connectivity was determined via the weighted phase-lag index (wPLI) in the source-reconstructed beta activity during rest. We quantified structural connectivity using kurtosis anisotropy (KA) values of tracts derived from diffusion tensor-based fiber tractography between the aforementioned areas. In the group of older adults, wPLI values between M1 -M1 were negatively associated with the quality of bimanual motor performance. The additional association between wPLI values of PMd --M1 and PMd -M1 supports that functional connectivity with the left hemisphere mediated (bimanual) motor control in older adults. The correlational analysis between the selected structural and functional connections revealed a strong association between wPLI values in the left intra-hemispheric PMd -M1 pathway and KA values in M1 -M1 and PMd -M1 pathways in the group of older adults. This suggests that weaker structural connections in older adults correlate with stronger functional connectivity and, hence, poorer motor performance.
我们研究了双侧运动网络中与年龄相关的半球间和半球内结构和功能连接的差异。我们关注的是连接与老年人运动能力下降之间的相关性。使用扩散加权成像和静息状态脑电图分别估计结构和功能连接。共有 48 名年轻和老年健康参与者接受了测量。此外，还使用双手协调任务评估了运动表现。为了预选感兴趣区域（ROI），采用了一种神经模型，该模型考虑了背侧运动前区（PMd）和初级运动皮层（M1）之间的半球内功能连接以及左、右 M1 之间的半球间连接（M1 和 M1）。在静息状态下，通过源重建的β活动中的加权相位滞后指数（wPLI）确定功能连接。我们使用基于扩散张量的纤维束追踪技术，在上述区域之间衍生的轨迹的峰度各向异性（KA）值来量化结构连接。在老年组中，M1-M1 之间的 wPLI 值与双手运动表现的质量呈负相关。PMd--M1 和 PMd--M1 之间的 wPLI 值之间的额外关联表明，与左侧大脑半球的功能连接介导了老年人的（双手）运动控制。所选结构和功能连接之间的相关分析显示，老年组左侧半球内 PMd-M1 通路中的 wPLI 值与 M1-M1 和 PMd-M1 通路中的 KA 值之间存在很强的关联。这表明老年人较弱的结构连接与较强的功能连接相关，进而与较差的运动表现相关。
