Previous studies have shown that the vividness of autobiographical memory decreases over time, and older adults often retrieve fewer details than young adults. However, the age-by-temporal distance (i.e., recent versus remote events) effect on autobiographical memory and underlying neural mechanisms are less understood. We recruited 25 young adults and 27 older adults to perform an fMRI-adapted autobiographical memory task with different temporal distances. The results showed that older adults’ vividness ratings were generally higher than that of young adults, but were less sensitive to temporal distances. For neural imaging, an age-by-temporal distance effect was found in the left precuneus, manifested as young adults had more activation for recent events than for remote events, whereas no temporal distance effect was found in older adults. Interestingly, for older adults, the temporal distance effect was reflected by functional connectivity within the default mode network (DMN), with a stronger anterior DMN-posterior DMN coupling for remote events than for recent events, whereas no temporal distance difference on functional connectivity was found in young adults. The results suggest that older adults exhibit age-related neural differences in both activation and functional connectivity during the processing of autobiographical memory with different temporal distances, shedding new light for the understanding of the relationship between the DMN, autobiographical memory, and aging.

先前的研究表明，自传体记忆的生动性会随着时间的推移而降低，老年人通常比年轻人检索的细节更少。然而，对自传体记忆和潜在神经机制的年龄-时间距离（即，近期事件与远距离事件）的影响知之甚少。我们招募了 25 名年轻人和 27 名老年人来执行具有不同时间距离的 fMRI 适应自传体记忆任务。结果表明，老年人的生动性评分普遍高于年轻人，但对时间距离的敏感度较低。对于神经成像，在左侧楔前叶中发现了年龄-时间距离效应，表现为年轻人对近期事件的激活比对远程事件的激活要多，而在老年人中没有发现时间距离效应。有趣的是，对于老年人，默认模式网络 (DMN) 内的功能连接性反映了时间距离效应，远程事件的前 DMN-后 DMN 耦合比近期事件更强，而功能连接的时间距离差异没有见于年轻人。结果表明，老年人在处理具有不同时间距离的自传体记忆过程中，在激活和功能连接方面表现出与年龄相关的神经差异，为理解 DMN、自传体记忆和衰老之间的关系提供了新的思路。与近期事件相比，远程事件的前 DMN-后 DMN 耦合更强，而在年轻人中没有发现功能连接的时间距离差异。结果表明，老年人在处理具有不同时间距离的自传体记忆过程中，在激活和功能连接方面表现出与年龄相关的神经差异，为理解 DMN、自传体记忆和衰老之间的关系提供了新的思路。与近期事件相比，远程事件的前 DMN-后 DMN 耦合更强，而在年轻人中没有发现功能连接的时间距离差异。结果表明，老年人在处理具有不同时间距离的自传体记忆过程中，在激活和功能连接方面表现出与年龄相关的神经差异，为理解 DMN、自传体记忆和衰老之间的关系提供了新的思路。