School of Psychology, Georgia Institute of Technology, 654 Cherry Street, Atlanta, GA 30332-0170, USA.
Brain Res. 2013 Mar 15;1500:55-71. doi: 10.1016/j.brainres.2013.01.018. Epub 2013 Jan 21.
Neuroimaging evidence suggests that older adults exhibit deficits in frontally-mediated strategic retrieval processes, such as post-retrieval monitoring. Behavioral research suggests that explicitly directing attention toward source features during encoding may improve source memory for both young and older adults and alleviate age-related source memory impairments, in part, by reducing demands on post-retrieval monitoring. We investigated this hypothesis in the present event-related potential (ERP) study. Young and older adults attended to either objects and their presented color (source) or to the object alone during study and made color source memory decisions at test. We attempted to match performance between groups by halving the memory load for older adults. Behavioral results showed that, while direction of attention to object and color improved source memory for both groups, older adults benefited less than the young. ERPs revealed that demands on late right frontal effects, indicative of post-retrieval monitoring, were similarly reduced by directed attention at encoding for both groups. However, older adults showed reduced ERP correlates of recollection (parietal old-new effect), as well as a sustained widespread negativity, potentially indicative of memory searches for perceptual details in the face of impaired recollection. These results suggest that older adults, like the young, can engage in post-retrieval monitoring when source details are difficult to recover. However, impaired recollection may underlie persistent age-related source memory deficits, even when encoding is supported via directed attention.
神经影像学证据表明，老年人在额叶介导的策略检索过程中存在缺陷，例如检索后监测。行为研究表明，在编码过程中明确将注意力引导到源特征上，可以改善年轻和老年人的源记忆，并在一定程度上减轻与年龄相关的源记忆损伤，部分原因是减少了对检索后监测的需求。我们在本事件相关电位（ERP）研究中检验了这一假设。年轻和老年人在学习时可以关注对象及其呈现的颜色（源），也可以只关注对象，然后在测试时做出颜色源记忆决策。我们试图通过将老年人的记忆负荷减半来使两组的表现相匹配。行为结果表明，尽管将注意力指向物体和颜色的方向提高了两组的源记忆，但老年人的受益不如年轻人。ERP 揭示，对于两组来说，在编码时引导注意力都可以相似地减少后期右侧额叶效应的需求，这表明检索后监测。然而，老年人的回忆（顶叶新旧效应）的 ERP 相关物减少，以及持续的广泛负性，可能表明在回忆受损的情况下，对感知细节的记忆搜索。这些结果表明，老年人和年轻人一样，当难以恢复源细节时，可以进行检索后监测。然而，即使通过引导注意力来支持编码，回忆受损也可能是与年龄相关的源记忆缺陷持续存在的原因。
