Department of Neurology, Albert Einstein College of Medicine, Bronx, New York.
Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, New York.
J Gerontol A Biol Sci Med Sci. 2019 Jun 18;74(7):1076-1083. doi: 10.1093/gerona/gly181.
Neural trajectories of gait are not well established. We determined two distinct, clinically relevant neural trajectories, operationalized via functional near-infrared spectroscopy (fNIRS) HbO2 measures in the prefrontal cortex (PFC), under Single-Task-Walk (STW), and Dual-Task-Walk (DTW) conditions. Course trajectory assessed neural activity associated with attention during the course of a walking task; the second trajectory assessed neural activity associated with learning over repeated walking trials. Improved neural efficiency was defined as reduced PFC HbO2 after practice.
Walking was assessed under STW and DTW conditions. fNIRS was utilized to quantify HbO2 in the PFC while walking. Burst measurement included three repeated trials for each experimental condition. The course of each walking task consisted of six consecutive segments.
Eighty-three nondemented participants (mean age = 78.05 ± 6.37 years; %female = 49.5) were included. Stride velocity (estimate = -0.5259 cm/s, p = <.0001) and the rate of correct letter generation (log estimate of rate ratio = -0.0377, p < .0001) declined during the course of DTW. In contrast, stride velocity (estimate = 1.4577 cm/s, p < .0001) and the rate of correct letter generation (log estimate of rate ratio = 0.0578, p < .0001) improved over repeated DTW trials. Course and trial effects were not significant in STW. HbO2 increased during the course of DTW (estimate = 0.0454 μM, p < .0001) but declined over repeated trials (estimate = -0.1786 μM, p < .0001). HbO2 declined during the course of STW (estimate = -.0542 μM, p < .0001) but did not change significantly over repeated trials.
We provided evidence for distinct attention (course) and learning (repeated trials) trajectories and their corresponding PFC activity. Findings suggest that learning and improved PFC efficiency were demonstrated in one experimental session involving repeated DTW trials.
步态的神经轨迹尚未得到很好的确定。我们通过前额叶皮层（PFC）的功能近红外光谱（fNIRS）HbO2 测量，在单任务行走（STW）和双任务行走（DTW）条件下，确定了两个截然不同的、具有临床意义的神经轨迹。路线轨迹评估了在行走任务过程中与注意力相关的神经活动；第二个轨迹评估了在多次行走试验中与学习相关的神经活动。神经效率的提高定义为练习后 PFC HbO2 的减少。
在 STW 和 DTW 条件下评估行走。fNIRS 用于量化行走时 PFC 中的 HbO2。突发测量包括每个实验条件的三个重复试验。每个行走任务的过程由六个连续的阶段组成。
纳入了 83 名非痴呆参与者（平均年龄=78.05±6.37 岁；女性比例=49.5%）。步速（估计值=-0.5259cm/s，p<.0001）和正确字母生成率（对数估计率比= -0.0377，p<.0001）在 DTW 过程中下降。相比之下，步速（估计值=1.4577cm/s，p<.0001）和正确字母生成率（对数估计率比=0.0578，p<.0001）在重复的 DTW 试验中提高。在 STW 中，路线和试验效应不显著。HbO2 在 DTW 过程中增加（估计值=0.0454μM，p<.0001），但在重复试验中减少（估计值=-0.1786μM，p<.0001）。HbO2 在 STW 过程中下降（估计值=-0.0542μM，p<.0001），但在重复试验中没有明显变化。
我们提供了注意力（路线）和学习（重复试验）轨迹及其对应的 PFC 活动的证据。研究结果表明，在一次涉及重复 DTW 试验的实验会议中，学习和改善的 PFC 效率得到了证明。
