Gait is an excellent indicator of physical, emotional, and mental health. Previous studies have shown that gait impairments in ageing are common, but the neural basis of these impairments are unclear. Existing methodologies are suboptimal and novel paradigms capable of capturing neural activation related to real walking are needed. In this study, we used a hybrid PET/MR system and measured glucose metabolism related to both walking and standing with a dual-injection paradigm in a single study session For this study, 15 healthy older adults (10 females, age range: 60.5-70.7 years) with normal cognition were recruited from the community. Each participant received an intravenous injection of [F]-2-fluoro-2-deoxyglucose (FDG) before engaging in two distinct tasks, a static postural control task (standing) and a walking task. After each task, participants were imaged. To discern independent neural functions related to walking compared to standing, we applied a bespoke dose correction to remove the residual F signal of the first scan (PET) from the second scan (PET) and proportional scaling to the global mean, cerebellum, or white matter (WM). Whole-brain differences in walking-elicited neural activity measured with FDG-PET were assessed using a one-sample t-test. In this study, we show that a dual-injection paradigm in healthy older adults is feasible with biologically valid findings. Our results with a dose correction and scaling to the global mean showed that walking, compared to standing, increased glucose consumption in the cuneus ( = 7.03), the temporal gyrus ( = 6.91) and the orbital frontal cortex ( = 6.71). Subcortically, we observed increased glucose metabolism in the supraspinal locomotor network including the thalamus ( = 6.55), cerebellar vermis and the brainstem (pedunculopontine/mesencephalic locomotor region). Exploratory analyses using proportional scaling to the cerebellum and WM returned similar findings. Here, we have established the feasibility and tolerability of a novel method capable of capturing neural activations related to actual walking and extended previous knowledge including the recruitment of brain regions involved in sensory processing. Our paradigm could be used to explore pathological alterations in various gait disorders.

中文翻译：

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开发一种新型双注射 FDG-PET 成像方法来研究步态的功能神经解剖学

步态是身体、情绪和心理健康的一个很好的指标。先前的研究表明，衰老过程中的步态障碍很常见，但这些障碍的神经基础尚不清楚。现有的方法不是最理想的，需要能够捕获与真实行走相关的神经激活的新范例。在这项研究中，我们使用了混合 PET/MR 系统，并在一次研究中使用双注射范例测量了与行走和站立相关的葡萄糖代谢。在这项研究中，15 名健康老年人（10 名女性，年龄范围：60.5- 70.7岁）从社区招募具有正常认知能力的人。每个参与者在参与两项不同的任务（静态姿势控制任务（站立）和步行任务）之前接受静脉注射[F]-2-氟-2-脱氧葡萄糖（FDG）。每项任务结束后，参与者都会被拍照。为了辨别与站立相比与行走相关的独立神经功能，我们应用了定制剂量校正，从第二次扫描 (PET) 中去除第一次扫描 (PET) 的残留 F 信号，并按比例缩放到全局平均值、小脑或白细胞物质（WM）。使用单样本 t 检验评估使用 FDG-PET 测量的步行引起的神经活动的全脑差异。在这项研究中，我们证明了健康老年人的双重注射模式是可行的，并且具有生物学上有效的发现。我们的剂量校正和全球平均值缩放结果表明，与站立相比，步行增加了楔叶 (= 7.03)、颞回 (= 6.91) 和眶额皮质 (= 6.71) 的葡萄糖消耗。在皮质下，我们观察到脊髓上运动网络中的葡萄糖代谢增加，包括丘脑 (= 6.55)、小脑蚓部和脑干（桥脚/中脑运动区域）。使用小脑和 WM 比例缩放的探索性分析得出了类似的结果。在这里，我们建立了一种新方法的可行性和耐受性，该方法能够捕获与实际行走相关的神经激活，并扩展先前的知识，包括招募参与感觉处理的大脑区域。我们的范例可用于探索各种步态障碍的病理改变。