School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Australia.
Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.
Neurobiol Aging. 2018 Apr;64:85-91. doi: 10.1016/j.neurobiolaging.2017.12.016. Epub 2017 Dec 29.
Growing evidence implicates a decline in white matter integrity in the age-related decline in motor control. Functional neuroimaging studies show significant associations between functional connectivity in the cortical motor network, including the supplementary motor area (SMA), and motor performance. Dual-coil transcranial magnetic stimulation studies show facilitatory connections between SMA and the primary motor cortex (M1) in younger adults. Here, we investigated whether SMA-M1 facilitation is affected by age and whether the strength of SMA-M1 facilitation is associated with bilateral motor control. Dual-coil transcranial magnetic stimulation was used to measure SMA-M1 connectivity in younger (N = 20) and older adults (N = 18), and bilateral motor control was measured with the assembly subtest of the Purdue Pegboard and clinical measures of dynamic balance. SMA-M1 facilitation was seen in younger but not older adults, and a significant positive association was found between SMA-M1 facilitation and bimanual performance. These results show that SMA-M1 facilitation is reduced in older adults compared to younger adults and provide evidence of the functional importance of SMA-M1 facilitation.
越来越多的证据表明，大脑白质完整性的下降与运动控制的年龄相关下降有关。功能神经影像学研究表明，皮质运动网络（包括辅助运动区[SMA]）的功能连接与运动表现之间存在显著关联。双线圈经颅磁刺激研究表明，年轻成年人的 SMA 和初级运动皮层（M1）之间存在促进性连接。在这里，我们研究了 SMA-M1 促进作用是否受到年龄的影响，以及 SMA-M1 促进作用的强度是否与双侧运动控制有关。使用双线圈经颅磁刺激来测量年轻成年人（N=20）和老年成年人（N=18）的 SMA-M1 连接，并用 Purdue 钉板装配子测试和动态平衡的临床测量来测量双侧运动控制。在年轻成年人中观察到 SMA-M1 促进作用，但在老年成年人中没有观察到，并且发现 SMA-M1 促进作用与双手表现之间存在显著正相关。这些结果表明，与年轻成年人相比，老年成年人的 SMA-M1 促进作用减少，并提供了 SMA-M1 促进作用的功能重要性的证据。
