Dual task (DT) is a commonly used paradigm indicative of executive functions. Brain activities during DT walking is usually measured by portable functional near infrared spectroscopy (fNIRS). Previous studies focused on cortical activation in prefrontal cortex and overlooked other brain regions such as sensorimotor cortices. This study is aimed at investigating the modulations of cortical activation and brain network efficiency in multiple brain regions from single to dual tasks with different complexities and their relationships with DT performance. Forty-two healthy adults [12 males; mean age: 27.7 (SD=6.5) years] participated in this study. Participants performed behavioral tasks with portable fNIRS simultaneous recording. There were three parts of behavioral tasks: cognitive tasks while standing (serial subtraction of 3′s and 7′s), walking alone and DT (walk while subtraction, including serial subtraction of 3′s and 7′s). Cognitive cost, walking cost and cost sum (i.e., sum of cognitive and walking costs) were calculated for DT. Cortical activation, local and global network efficiency were calculated for each task. The cognitive cost was greater and the walking cost was less during DT with subtraction 3′s compared with 7′s (’s = 0.032 and 0.019, respectively). Cortical activation and network efficiency were differentially modulated among single and dual tasks ( < 0.05). Prefrontal activation during DT was positively correlated with DT costs, while network efficiency was negatively correlated with DT costs ( < 0.05). Our results revealed prefrontal over-activation and reduced network efficiency in individuals with poor DT performance. Our findings suggest that reduced network efficiency could be a possible mechanism contributing to poor DT performance, which is accompanied by compensatory prefrontal over-activation.

中文翻译：

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双重任务期间的皮质激活和大脑网络效率：一项 fNIRS 研究

双重任务（DT）是表示执行功能的常用范式。DT 行走期间的大脑活动通常通过便携式功能近红外光谱 (fNIRS) 来测量。之前的研究主要集中在前额叶皮层的皮层激活，而忽略了其他大脑区域，例如感觉运动皮层。本研究旨在研究不同复杂性的单任务到双任务中多个大脑区域的皮质激活和大脑网络效率的调节及其与 DT 表现的关系。42 名健康成年人 [12 名男性；平均年龄：27.7（SD=6.5）岁]参与了这项研究。参与者使用便携式 fNIRS 同步记录执行行为任务。行为任务分为三部分：站立认知任务（3和7的连续减法）、独自行走和DT（边走边减法，包括3和7的连续减法）。计算DT的认知成本、步行成本和成本总和（即认知成本和步行成本之和）。计算每项任务的皮质激活、局部和全局网络效率。与减 7 相比，减 3 的 DT 期间认知成本更高，步行成本更低（分别 = 0.032 和 0.019）。皮层激活和网络效率在单任务和双任务之间存在差异调节（<0.05）。DT期间前额叶激活与DT成本正相关，而网络效率与DT成本负相关（<0.05）。我们的结果显示，DT 表现不佳的个体前额叶过度激活，网络效率降低。我们的研究结果表明，网络效率降低可能是导致 DT 表现不佳的一个可能机制，并伴有补偿性前额叶过度激活。