Lugtmeijer Selma, Geerligs Linda, Tsvetanov Kamen A, Mitchell Daniel J, Campbell Karen L
Department of Psychology, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada.
Radboud University, Thomas van Aquinostraat 4, 6525 GD, Nijmegen, the Netherlands.
Neuroimage. 2023 Apr 15;270:119982. doi: 10.1016/j.neuroimage.2023.119982. Epub 2023 Feb 26.
Working memory is critical to higher-order executive processes and declines throughout the adult lifespan. However, our understanding of the neural mechanisms underlying this decline is limited. Recent work suggests that functional connectivity between frontal control and posterior visual regions may be critical, but examinations of age differences therein have been limited to a small set of brain regions and extreme group designs (i.e., comparing young and older adults). In this study, we build on previous research by using a lifespan cohort and a whole-brain approach to investigate working memory load-modulated functional connectivity in relation to age and performance. The article reports on analysis of the Cambridge center for Ageing and Neuroscience (Cam-CAN) data. Participants from a population-based lifespan cohort (N = 101, age 23-86) performed a visual short-term memory task during functional magnetic resonance imaging. Visual short-term memory was measured with a delayed recall task for visual motion with three different loads. Whole-brain load-modulated functional connectivity was estimated using psychophysiological interactions in a hundred regions of interest, sorted into seven networks (Schaefer et al., 2018, Yeo et al., 2011). Results showed that load-modulated functional connectivity was strongest within the dorsal attention and visual networks during encoding and maintenance. With increasing age, load-modulated functional connectivity strength decreased throughout the cortex. Whole-brain analyses for the relation between connectivity and behavior were non-significant. Our results give additional support to the sensory recruitment model of working memory. We also demonstrate the widespread negative impact of age on the modulation of functional connectivity by working memory load. Older adults might already be close to ceiling in terms of their neural resources at the lowest load and therefore less able to further increase connectivity with increasing task demands.
工作记忆对高阶执行过程至关重要，且在整个成年期都会衰退。然而，我们对这种衰退背后的神经机制的理解有限。最近的研究表明，额叶控制区域与后部视觉区域之间的功能连接可能至关重要，但对其中年龄差异的研究仅限于一小部分脑区和极端组设计（即比较年轻人和老年人）。在本研究中，我们基于先前的研究，采用毕生队列和全脑方法来研究与年龄和表现相关的工作记忆负荷调制功能连接。本文报告了对剑桥衰老与神经科学中心（Cam-CAN）数据的分析。来自一个基于人群的毕生队列（N = 101，年龄23 - 86岁）的参与者在功能磁共振成像期间执行了一项视觉短期记忆任务。通过对视觉运动的延迟回忆任务，使用三种不同负荷来测量视觉短期记忆。使用心理生理交互作用在一百个感兴趣区域估计全脑负荷调制功能连接，这些区域被分类为七个网络（Schaefer等人，2018年，Yeo等人，2011年）。结果表明，在编码和维持期间，负荷调制功能连接在背侧注意和视觉网络中最强。随着年龄的增长，整个皮层的负荷调制功能连接强度下降。关于连接性与行为之间关系的全脑分析无显著意义。我们的结果为工作记忆的感觉募集模型提供了额外支持。我们还证明了年龄对工作记忆负荷对功能连接调制的广泛负面影响。老年人在最低负荷时其神经资源可能已经接近上限，因此随着任务需求增加，他们进一步增加连接性的能力较弱。
