Motor-cognitive dual task performance: a multidimensional approach

在双重任务条件下，随着年龄的增长，姿势不稳定和摔倒的风险增加。在这方面，工作记忆(WM)任务尤其苛刻。姿势控制和WM操作之间的双重任务干扰可能是由于注意焦点必须以时间关键的方式在WM中的维护和处理操作与用于调整直立姿势的控制操作之间频繁和重复地切换的事实。因此，处理速度以及注意焦点的大小(短期存储容量)的差异可能代表在双重任务条件下引起干扰的关键限制。本研究涉及以下几个问题：(1)双重任务成本是否取决于对工作记忆操作的需求，以及这种需求与姿势控制的需求是如何相互作用的？(2)加工速度或注意焦点的大小是这方面的关键限制因素吗？(3)潜在的大脑机制是什么？(4)提高双重任务绩效的训练策略是什么？为了揭示双重任务干扰的神经认知机制，我们改变了对工作记忆操作的需求和对姿势控制的需求，并比较了这些差异在健康青年和老年被试之间的交互效果。我们将这些影响与基于视觉注意理论(TVA)的个体处理速度和短期存储容量的定量估计联系起来。应用功能磁共振成像、脑磁图和脑电分析，研究了静息状态和任务相关的脑网络，以揭示加工能力和双重任务干扰背后的脑动力学。我们特别感兴趣的是一个功能大脑网络对另一个功能大脑网络的影响，以及这种影响如何随着双重任务成本的变化而变化。对轻度认知障碍(MCI)患者和恐惧性眩晕患者的评估将允许比较两种类型的中央加工限制的病理影响：结构性(对于MCI)和策略性(对于恐惧性眩晕)。两组之间大脑连接模式的比较将提供关于可能的结构瓶颈、有限的处理能力和潜在的可修改的战略瓶颈的网络基础的信息。我们的建议以一种跨学科的方法将运动科学、认知心理学、脑成像和临床神经学结合在一起。预期的结果不仅将提高我们对运动-认知双重任务要求下人类表现的神经认知框架的理解。它们还可以支持对姿势不稳定和衰老的新的预防性干预策略的开发和理解。

With increasing age, postural instability and risk to fall increase under dual task conditions. Working memory (WM) tasks are particularly demanding in this regard. Dual task interference between postural control and WM manipulation may result from the fact that the attentional focus has to be frequently and repeatedly switched, in a time-critical manner, between maintenance and processing operations in WM, and control operations for adjusting upright posture. Therefore, differences in processing speed but also the size of the attentional focus (short-term storage capacity) may represent critical limitations causing interference under dual task conditions.Four critical questions arise, which are addressed by the proposed project: (1) Do dual task costs depend on the demand on WM manipulation and how does this demand interact with the demand on postural control? (2) Is processing speed or the size of the attentional focus the crucially limiting factor in this regard? (3) What are the underlying brain mechanisms? (4) What are appropriate training strategies to enhance dual task performance?To reveal the neuro-cognitive mechanisms responsible for dual task interference, we vary the demand on WM manipulation and the demand on postural control, and compare the interactive effects of these variations between healthy young and elderly subjects. We relate these effects to quantitative estimates, based on a theory of visual attention (TVA), of the individual processing speed and short-term storage capacity. Applying fMRI, MEG, and EEG analyses, resting state and task related brain networks are investigated to reveal the cerebral dynamics underlying processing capacity and dual task interference. We are particularly interested in the influences that one functional brain network exerts over another and how this influence changes with the variation of the dual task costs. Assessment of patients with mild cognitive impairment (MCI) and of patients with phobic vertigo will allow to compare the pathological effects of two types of central processing limitations: structural (in the case of MCI) versus strategic (in the case of phobic vertigo). A comparison of the cerebral connectivity patterns between both groups will provide information about the network basis of a possible structural bottleneck, limiting processing capacity, and of a potentially modifiable strategic bottleneck.Our proposal brings together movement science, cognitive psychology, brain imaging and clinical neurology in an interdisciplinary approach. The expected results will not only improve our understanding of the neuro-cognitive framework of human performance under motor-cognitive dual task requirements. They can also support the development and understanding of new preventive intervention strategies in postural instability and aging.