Institute of Psychology I, University of Lübeck, 23562 Lübeck, Germany, and
Computational Memory Lab, Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
J Neurosci. 2019 May 29;39(22):4344-4352. doi: 10.1523/JNEUROSCI.2791-18.2019. Epub 2019 Mar 22.
The retrieval (or testing) of information leads to better memory performance compared with reencoding. This phenomenon is known as "testing effect" or "retrieval practice effect" and has been primarily described in behavioral studies with healthy young subjects. However, possible age-related changes and their associated underlying neural processes, in particular neural oscillations, remain unclear. To address this issue, we used a previously established paradigm in healthy young ( = 27) and elderly ( = 28) male and female human adults while their brain activity was being recorded using EEG. Subjects viewed prefamiliarized scene images intermixed with new scenes and classified them as indoor versus outdoor (encoding task) or old versus new (retrieval task). Subsequently, subjects performed a recognition memory task 10 min and 24 h after encoding. Behaviorally, both age groups showed the testing effect at both time points but, importantly, it was less pronounced in the elderly. At the neural level, the retrieval compared with the encoding task was accompanied by power decreases in the alpha (9-12 Hz) and beta bands (13-30 Hz), possibly reflecting task demands, and this difference was more pronounced in the elderly. Finally, a correlation analysis revealed that those elderly who displayed a more pronounced testing effect exhibited a neural pattern that was more similar to the younger subjects. These findings provide evidence that the testing effect decreases across the life span, and they suggest that changes in alpha-beta oscillations play a direct role. Learning new and retrieving old information is part of everyday human life. Understanding how learning processes can be optimized therefore has direct applications in the realm of educational and rehabilitative contexts. Here, we show that retrieval practice is a strategy to optimize encoding into long-term memory in both young and elderly humans. Importantly, retrieval practice was significantly reduced in the elderly and closely related to changes in alpha (9-13 Hz) and beta band (13-30 Hz) oscillations. Our findings suggest that decreased retrieval practice effects across the life span contribute to, and may reflect, age-related declines in memory performance. They further provide new insights into the underlying neural mechanisms and point toward future avenues for neuro-modulatory interventions.
信息检索（或测试）比重新编码更能提高记忆表现。这种现象被称为“测试效应”或“检索练习效应”，主要在健康的年轻受试者的行为研究中进行了描述。然而，可能的年龄相关变化及其相关的潜在神经过程，特别是神经振荡，仍然不清楚。为了解决这个问题，我们使用了一个先前在健康的年轻（= 27）和老年（= 28）男性和女性成年人体内建立的范式，同时使用 EEG 记录他们的大脑活动。在编码任务中，被试观看预先熟悉的场景图像与新场景图像混合，并将其分类为室内或室外；在检索任务中，被试将场景图像分类为旧或新。随后，在编码后 10 分钟和 24 小时，被试进行了识别记忆任务。行为上，两个年龄组在两个时间点都表现出了测试效应，但重要的是，老年组的效应较小。在神经水平上，与编码任务相比，检索任务伴随着 alpha（9-12 Hz）和 beta 频段（13-30 Hz）的功率下降，这可能反映了任务的要求，而这种差异在老年人中更为明显。最后，相关分析表明，那些表现出更明显测试效应的老年人，其神经模式与年轻受试者更为相似。这些发现提供了证据表明，测试效应随着生命周期的延长而降低，并且表明 alpha-beta 振荡的变化直接起作用。学习新信息和检索旧信息是人类日常生活的一部分。因此，了解如何优化学习过程具有直接的教育和康复应用。在这里，我们表明检索练习是一种在年轻和老年人群中优化编码到长期记忆的策略。重要的是，检索练习在老年人中显著减少，并且与 alpha（9-13 Hz）和 beta 频段（13-30 Hz）振荡的变化密切相关。我们的发现表明，整个生命周期中检索练习效应的降低导致并可能反映了与年龄相关的记忆表现下降。它们进一步提供了对潜在神经机制的新见解，并指向未来的神经调节干预途径。
