Dual Mechanisms of Control in Cognitive and Motor Aging

执行功能包括复杂活动中涉及的各种认知控制过程，如多任务和协调行动。因此，EFS可以影响老年人日常生活活动的成败。双重控制机制(DMC)理论(Braver等人，2007)假设了两种认知控制模式。在主动模式下，与目标相关的信息被主动地保存在工作记忆中，以偏向注意力以防止干扰。在反应式模式中，当没有可用的与任务相关的提示时，在即时的基础上招募控制。DMC框架假设，虽然反应性控制在老年时保持不变，但主动控制会下降。目前，对这些假设的支持主要基于简单的键盘反应时间任务(AX-CPT、Stroop、Fanker)。鉴于认知控制在复杂任务表现中的普遍性和重要性，合乎逻辑的下一步是在更接近日常活动的任务中测试DMC模型。因此，建议的研究计划的主要目标是检验DMC理论及其在一系列认知、视觉-手册和粗大运动EF范式中的应用。利用我目前持有的NSERC基金，我的实验室在年轻人和老年人的广泛的认知和运动范式(更新、任务转换、运动双重任务)中研究了EFS的作用。到目前为止，我们只在认知背景下测试了DMC框架的假设。因此，我们的目标是调整我们现有的视觉-手动和姿势控制范例，以系统地改变这些新环境中的主动和反应性控制需求。我们预计，年轻人将灵活地部署反应性和主动性控制。相反，老年人会使用反应性控制，当只能使用主动控制时，他们的任务表现将受到影响。总而言之，计划中的研究有望促进目前对DMC理论的理解，并制定出其在更广泛的EF背景下适用的限制。对DMC原理在精细和粗大运动控制领域的评估是全新的。识别主动控制能力下降使老年人处于危险之中的环境，将有助于设计训练方案和辅助设备，以改善老年人的日常功能。

Executive functions (EFs) encompass a variety of cognitive control processes implicated in complex activities such as multitasking and coordinated action. As such, EFs can influence the success or failure of activities of daily living in old age. The Dual Mechanisms of Control (DMC) theory (Braver et al., 2007) postulates two modes of cognitive control. In the Proactive mode, goal-relevant information is actively maintained in working memory, biasing attention to prevent interference. In the Reactive mode, when no task-relevant cues are available, control is recruited on a just-in-time basis. The DMC framework assumes that whereas reactive control is maintained in old age, proactive control declines. Presently, support for these assumptions is largely based upon simple keyboard reaction time tasks (AX-CPT, Stroop, Flanker). Given the ubiquity and importance of cognitive control in complex task performance, a logical next step is to test the DMC model in tasks that better approximate everyday activities. The major objective of the proposed research program is, therefore, to examine the DMC theory and its applications across a range of cognitive, visuo-manual, and gross motor EF paradigms.Using my currently held NSERC funds, my lab has examined the role of EFs in a broad variety of cognitive and motor paradigms (updating, task switching, motor dual tasking), in young and older adults. To date, we have tested the assumptions of the DMC framework only in a cognitive context. We therefore aim to adapt our existing visual-manual and postural control paradigms to systematically vary the proactive and reactive control demands in these new contexts. We anticipate that young adults will flexibly deploy reactive and proactive control. In contrast, older adults will employ reactive control, and their task performance will suffer when only proactive control can be used. Together, the planned research is expected to advance current understanding of DMC theory and map out the limits of its applicability across a broader range of EF contexts. Evaluation of the DMC principles in the domains of fine and gross motor control is entirely novel. Identifying contexts in which declining proactive control puts elders at risk will inform the design of training protocols and assistive devices to improve the everyday functioning of older adults.