Dual tasking, a defined facet of executive control processes, is subserved, in part, by the prefrontal cortex (PFC). Previous functional near-infrared spectroscopy (fNIRS) studies revealed elevated PFC oxygenated hemoglobin (HbO₂) under Dual-Task-Walk (DTW) compared to Single-Task Walk (STW) conditions. Based on the concept of neural inefficiency (i.e., greater activation coupled with similar or worse performance), we hypothesized that decreased cortical thickness across multiple brain regions would be associated with greater HbO₂ increases from STW to DTW. Participants were 55 healthy community-dwelling older adults, whose cortical thickness was measured via MRI. HbO₂ levels in the PFC, measured via fNIRS, were assessed during active walking under STW and DTW conditions. Statistical analyses were adjusted for demographics and behavioral performance. Linear mixed-effects models revealed that the increase in HbO₂ from STW to DTW was moderated by cortical thickness in several regions. Specifically, thinner cortex in specific regions of the frontal, parietal, temporal, and occipital lobes, cingulate cortex, and insula was associated with greater increases in HbO₂ levels from single to dual-task walking. In conclusion, participants with thinner cortex in regions implicated in higher order control of walking employed greater neural resources, as measured by increased HbO₂, in the PFC during DTW, without demonstrating benefits to behavioral performance. To our knowledge, this is the first study to examine cortical thickness as a marker of neural inefficiency during active walking.

双重任务是执行控制过程的一个明确方面，它在一定程度上受到前额皮质 (PFC) 的促进。之前的功能性近红外光谱 (fNIRS) 研究表明，与单任务步行 (STW) 条件相比，双任务步行 (DTW) 条件下PFC 氧合血红蛋白 (HbO _{2 ) 升高。}基于神经效率低下的概念（即更大的激活与相似或更差的表现相结合），我们假设多个大脑区域的皮质厚度减少与从 STW 到 DTW 的HbO _{2更大增加有关。}参与者是 55 名居住在社区的健康老年人，通过 MRI 测量其皮质厚度。通过 fNIRS 测量 PFC 中的HbO _{2水平，并在 STW 和 DTW 条件下主动行走期间进行评估。}统计分析根据人口统计和行为表现进行了调整。线性混合效应模型显示，HbO ₂从 STW 到 DTW 的增加受到多个区域皮质厚度的调节。具体而言，额叶、顶叶、颞叶、枕叶、扣带皮层和岛叶等特定区域的皮质较薄，与从单任务步行到双任务步行时HbO ₂水平的更大增加有关。总之，在DTW 期间，与行走高级控制相关的区域皮质较薄的参与者在 PFC 中使用了更多的神经资源（通过增加的 HbO _{2来衡量），但没有表现出对行为表现的益处。}据我们所知，这是第一项检查皮质厚度作为主动步行过程中神经效率低下标志的研究。