Leshikar Eric D, Duarte Audrey
School of Psychology, Center for Advanced Brain Imaging, Georgia Institute of Technology, JS Coon Building 654 Cherry Street, Atlanta, GA, 30332, USA,
Cogn Affect Behav Neurosci. 2014 Mar;14(1):236-52. doi: 10.3758/s13415-013-0198-y.
Behavioral evidence suggests that young and older adults show a benefit in source memory accuracy when processing materials in reference to the self. In the young, activity within the medial prefrontal cortex supports this source memory benefit at study. In this investigation, we examined whether the same neural regions support this memory benefit in both age groups. Using fMRI, we scanned participants while they studied and retrieved pictures of objects paired with one of three scenes (source) under self-reference and other-reference conditions. At the time of study, half of the items were presented once and half twice, allowing us to match behavioral performance between the groups. Both groups showed equivalent source accuracy benefits for objects encoded self-referentially. Activity in the left dorsal medial prefrontal cortex supported subsequent source memory in both age groups for the self-referenced relative to the other-referenced items. At the time of test, source accuracy for both the self- and other-referenced items was supported by a network of regions including the precuneus in both age groups. At both study and test, little in the way of age differences emerged, suggesting that when they are matched on behavioral performance, young and older adults engage similar regions in support of source memory when processing materials in reference to the self; however, when we did not match performance, age differences in functional recruitment were prevalent. These results suggest that by capitalizing on preserved processes (self-referential encoding), older adults can show improvement in memory for source details that they would typically not remember well, relative to the young.
行为证据表明，年轻人和老年人在参照自我处理材料时，源记忆准确性会有所提高。对于年轻人而言，内侧前额叶皮质内的活动在学习时支持这种源记忆优势。在本研究中，我们考察了相同的神经区域是否在两个年龄组中均支持这种记忆优势。我们使用功能磁共振成像（fMRI）技术，在参与者于自我参照和他人参照条件下学习并回忆与三个场景（源）之一配对的物体图片时对他们进行扫描。在学习阶段，一半的物品呈现一次，另一半呈现两次，这样我们能够使两组在行为表现上相匹配。两组在自我参照编码的物体上均表现出相当的源准确性优势。相对于他人参照的物品，左侧背内侧前额叶皮质的活动在两个年龄组中均支持随后的源记忆。在测试阶段，自我参照和他人参照物品的源准确性在两个年龄组中均由包括楔前叶在内的一系列区域支持。在学习和测试阶段，年龄差异均不明显，这表明当两组在行为表现上相匹配时，年轻人和老年人在参照自我处理材料时会激活相似的区域来支持源记忆；然而，当我们不匹配表现时，功能募集方面的年龄差异则很普遍。这些结果表明，通过利用保留的过程（自我参照编码），相对于年轻人，老年人在源细节记忆方面能够表现出改善，而这些细节他们通常记不太好。
