Competition for limited neural resources in older adults leads to greater asymmetry of bilateral movements than in young adults.
Competition for limited neural resources in older adults leads to greater asymmetry of bilateral movements than in young adults.
复制标题
与年轻人相比，老年人对有限神经资源的竞争导致双边运动更加不对称。
DOI：
10.1152/jn.00405.2019
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发表时间：
2020
影响因子：
2.5
通讯作者：
Whitall,Jill
中科院分区：
文献类型：
--
作者：
Woytowicz,ElizabethJ;Sainburg,RobertL;Westlake,KellyP;Whitall,Jill
我们以前证明了预测和阻抗机制的神经控制的偏侧化反映了双侧任务控制的肢体间差异。老化已被证明减少偏侧在单侧性能，可能是由于更多的招聘同侧半球。我们现在假设，年龄相关的神经资源效率的降低，应该会在双侧动作中产生更大的行为不对称性，这是因为同时控制优势臂和非优势臂的功能，应该会引起对半球特定资源的竞争。为了验证这一假设，我们现在研究老化（年轻，n= 20;老年，n= 20）对机械耦合任务的性能的影响，其中一只手臂伸向目标，而另一只手臂稳定在连接两个手臂的弹簧上。结果表明，更好的优势臂达到性能和更好的非优势臂稳定性能为两组。最值得注意的是，优势臂的肢体和关节顺应性较低，导致优势臂在稳定性能方面的缺陷。组分析表明，老年人表现出更大的不对称性，在稳定对弹簧负载比年轻的成年人。我们建议，在老年人有限的神经资源的竞争是与右半球机制的贡献减少右优势臂稳定性能，从而更大的不对称的performance.NEW &值得注意的是，我们提供的证据更大的不对称的interlimb差异在双边协调稳定和保存的不对称性达到老化。这些结果提供了第一个证据增加偏侧化与老化的背景下，一个互补的双边任务。
We previously demonstrated that lateralization in the neural control of predictive and impedance mechanisms is reflected by interlimb differences in control of bilateral tasks. Aging has been shown to reduce lateralization during unilateral performance, presumably due to greater recruitment of the ipsilateral hemisphere. We now hypothesize that aging-related reduction in the efficiency of neural resources should produce greater behavioral asymmetry during bilateral actions that require hemispheric specialization for each arm. This is because simultaneous control of dominant and nondominant arm function should induce competition for hemisphere-specific resources. To test this hypothesis, we now examine the effect of aging (young,n= 20; old,n= 20) on performance of a mechanically coupled task, in which one arm reaches toward targets while the other arm stabilizes against a spring that connects the two arms. Results indicate better dominant arm reaching performance and better nondominant arm stabilizing performance for both groups. Most notably, limb and joint compliance was lower in the dominant arm, leading to dominant arm deficits in stabilizing performance. Group analysis indicated that older adults showed substantially greater asymmetry in stabilizing against the spring load than did the younger adults. We propose that competition for limited neural resources in older adults is associated with reduced contributions of right hemisphere mechanisms to right-dominant arm stabilizing performance, and thus to greater asymmetry of performance.NEW & NOTEWORTHYWe provide evidence for greater asymmetry of interlimb differences in bilateral coordination for stabilizing and preserved asymmetry of reaching with aging. These results provide the first evidence for increased lateralization with aging within the context of a complementary bilateral task.
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