Multimodal imaging of brain activity to investigate walking and mobility decline in older adults

项目简介：老年人的行动能力障碍降低了生活质量，并与高 社会和经济负担。美国国家卫生研究院RFA-AG-18-019征集申请“…对中枢神经的研究 老年人的活动控制…使用创新和尖端的方法。当前的研究方法 行走的神经控制受到行走过程中无法测量人的限制(功能性的 磁共振成像，功能磁共振成像)或无法测量皮质以下的活动(功能性近 红外光谱，fNIRS)。我们断言，对行走的神经控制有充分和准确的理解 在老年人中，需要实时测量实际行走过程中整个大脑的活跃区域。我们 将通过使用高密度脑电(EEG)的创新移动大脑成像来实现这一点。 这种方法依赖于创新的硬件和软件来提供Active的三维本地化 步行过程中具有高空间和时间分辨率的皮质和皮质下脑区。结果是 对行走的神经控制的前所未有的洞察。在这里，我们的首要目标是确定 通过收集步行时的脑电并将这些发现关联起来，对老年人的活动进行中枢神经控制 具有一套全面的不同移动结果(基于诊所的步行、复杂步行和社区 流动性措施)。我们的第一个目标是评估实际行走过程中大脑活动的程度 机动性下降。在横截面和纵向设计中，我们将确定步行能力较差 绩效和更陡峭的下降轨迹与补偿相关的利用率有关 神经回路假说(嘎嘎)。Crunch是一个得到充分支持的大脑活动模式模型，它是 当年纪较大的人执行日益复杂的任务时可以看到。Crunch描述的是过度招聘 与年轻人相比，老年人表现出额顶脑网络的特征，即使在低水平的 任务复杂性。Crunch还描述了老年人大脑中可用的有限储备资源。这些 因素导致老年人在执行增加的任务时大脑资源迅速达到上限 复杂性。当达到上限时，业绩就会受到影响。RFA还呼吁提出以下建议 操作和协调用于量化动态步态和运动的成像协议和技术 功能“。根据这一呼吁，我们的第二个目标是描述和协调高密度脑电 在行走过程中，使用fNIRS(在实际行走和成像行走期间)和fMRI(在想象行走期间)。这将是 使我们能够通过神经成像识别大脑活动的最强健的与嘎嘎声相关的特征 这将加强我们的结论，并使我们的结论能够得到广泛应用。我们的 第三个目的是研究与行走时嘎吱作响有关的机制。因此，我们的项目将解决 NIH RFA-AG-18-019中的大多数目标，并将确定老年人行走的神经相关性 导致对行动能力下降和功能障碍的前所未有的洞察。

Project Description: Mobility impairments in older adults decrease quality of life and are associated with high societal and economic burden. NIH RFA-AG-18-019 solicits applications “…to investigate the central neural control of mobility in older adults…using innovative and cutting-edge methods.” Current approaches to study the neural control of walking are limited by either the inability to measure people during walking (functional magnetic resonance imaging, fMRI) or the inability to measure activity below the cortex (functional near- infrared spectroscopy, fNIRS). We assert that a full and accurate understanding of the neural control of walking in older adults requires real time measurement of active regions throughout the brain during actual walking. We will achieve this by using innovative mobile brain imaging with high-density electroencephalography (EEG). This approach relies upon innovative hardware and software to deliver three-dimensional localization of active cortical and subcortical brain regions with high spatial and temporal resolution during walking. The result is unprecedented insight into the neural control of walking. Here, our overarching objective is to determine the central neural control of mobility in older adults by collecting EEG during walking and correlating these findings with a comprehensive set of diverse mobility outcomes (clinic-based walking, complex walking and community mobility measures). Our first aim is to evaluate the extent to which brain activity during actual walking explains mobility decline. In both cross sectional and longitudinal designs, we will determine whether poorer walking performance and steeper trajectories of decline are associated with the Compensation Related Utilization of Neural Circuits Hypothesis (CRUNCH). CRUNCH is a well-supported model of brain activity patterns that are seen when older individuals perform tasks of increasing complexity. CRUNCH describes the over-recruitment of frontoparietal brain networks that older adults exhibit in comparison to young adults, even at low levels of task complexity. CRUNCH also describes the limited reserve resources available in the older brain. These factors cause older adults to quickly reach a ceiling in brain resources when performing tasks of increasing complexity. When the ceiling is reached, performance suffers. The RFA also calls for proposals to “Operationalize and harmonize imaging protocols and techniques for quantifying dynamic gait and motor functions”. In accordance with this call, our second aim is to characterize and harmonize high-density EEG during walking with fNIRS (during actual and imaged walking) and fMRI (during imagined walking). This will allow us to identify the most robust CRUNCH-related hallmarks of brain activity across neuroimaging modalities, which will strengthen our conclusions and allow for widespread application of our findings. Our third aim is to study the mechanisms related to CRUNCH during walking. Thus, our project will address a majority of the objectives in NIH RFA-AG-18-019 and will identify the neural correlates of walking in older adults, leading to unprecedented insight into mobility declines and dysfunction.