Godde Ben, Voelcker-Rehage Claudia
Neuroscience and Human Performance, Jacobs Center on Lifelong Learning, Jacobs University Bremen, Germany.
Front Aging Neurosci. 2010 Sep 1;2. doi: 10.3389/fnagi.2010.00139. eCollection 2010.
Using motor imagery, we investigated brain activation in simple and complex walking tasks (walking forward and backward on a treadmill) and analyzed if the motor status of older adults influenced these activation patterns. Fifty-one older adults (64-79 years of age) were trained in motor execution and imagery and then performed the imagination task and two control tasks (standing, counting backward) in a horizontal position within a 3T MRI scanner (first-person perspective, eyes closed). Walking backward as compared to walking forward required larger activations in the primary motor cortex, supplementary motor area, parietal cortex, thalamus, putamen, and caudatum, but less activation in the cerebellum and brainstem. Motor high-fit individuals showed more activations and larger BOLD signals in motor-related areas compared to low-fit participants but demonstrated lower activity in the dorsolateral prefrontal cortex. Moreover, parietal activation in high-fit participants remained stable throughout the movement period whereas low-fit participants revealed an early drop in activity in this area accompanied by increasing activity in frontal brain regions. Overall, walking forward seemed to be more automated (more activation in cerebellum and brainstem), whereas walking backward required more resources, e.g., for visual-spatial processing and sensorimotor control. Low-fit subjects in particular seemed to require more cognitive resources for planning and controlling. High-fit subjects, on the contrary, revealed more movement automation and a higher "attention span." Our results support the hypothesis that high fitness corresponds with more automation and less cognitive control of complex motor tasks, which might help to free up cognitive resources.
我们运用运动想象，研究了简单和复杂步行任务（在跑步机上向前和向后行走）中的大脑激活情况，并分析了老年人的运动状态是否会影响这些激活模式。51名老年人（64 - 79岁）接受了运动执行和想象训练，然后在3T磁共振成像扫描仪中以水平姿势（第一人称视角，闭眼）执行想象任务和两项对照任务（站立、倒数）。与向前行走相比，向后行走在初级运动皮层、辅助运动区、顶叶皮层、丘脑、壳核和尾状核中需要更大的激活，但在小脑和脑干中的激活较少。与低健康水平参与者相比，运动高健康水平个体在运动相关区域表现出更多的激活和更大的血氧水平依赖信号，但在背外侧前额叶皮层的活动较低。此外，高健康水平参与者在整个运动期间顶叶的激活保持稳定，而低健康水平参与者在该区域的活动早期下降，同时额叶区域的活动增加。总体而言，向前行走似乎更自动化（小脑和脑干激活更多），而向后行走需要更多资源，例如用于视觉空间处理和感觉运动控制。特别是低健康水平的受试者似乎在计划和控制方面需要更多认知资源。相反，高健康水平的受试者表现出更多的运动自动化和更高的“注意力持续时间”。我们的结果支持这样的假设，即高健康水平与复杂运动任务中更多的自动化和更少的认知控制相对应，这可能有助于释放认知资源。
