When encountering unexpected event changes, memories of relevant past experiences must be updated to form new representations. Current models of memory updating propose that people must first generate memory-based predictions to detect and register that features of the environment have changed, then encode the new event features and integrate them with relevant memories of past experiences to form configural memory representations. Each of these steps may be impaired in older adults. Using functional MRI, we investigated these mechanisms in healthy young and older adults. In the scanner, participants first watched a movie depicting everyday activities in a day of an actor’s life. They next watched a second nearly identical movie in which some scenes ended differently. Crucially, before watching the last part of each activity, the second movie stopped, and participants were asked to mentally replay how the activity previously ended. Three days later, participants were asked to recall the activities. Neural activity pattern reinstatement in medial temporal lobe (MTL) during the replay phase of the second movie was associated with detecting changes and with better memory for the original activity features. Reinstatements in posterior medial cortex (PMC) additionally predicted better memory for changed features. Compared to young adults, older adults showed a reduced ability to detect and remember changes and weaker associations between reinstatement and memory performance. These findings suggest that PMC and MTL contribute to change processing by reinstating previous event features, and that older adults are less able to use reinstatement to update memory for changed features.

当遇到意外事件更改时，必须更新对过去相关经验的记忆，以形成新的表示形式。当前的内存更新模型提出，人们必须首先生成基于内存的预测，以检测和注册环境特征已发生变化，然后对新的事件特征进行编码，并将其与过去的经验相关的内存进行集成，以形成配置内存表示。这些步骤中的每一个都可能在老年人中受损。使用功能性MRI，我们研究了健康的年轻人和老年人的这些机制。在扫描仪中，参与者首先观看了一部电影，描绘了演员一整天的日常活动。接下来，他们观看了第二部几乎相同的电影，其中某些场景以不同的方式结束。至关重要的是，在观看每个活动的最后一部分之前，第二部电影停了下来，参与者被要求重新播放之前活动的结局。三天后，要求参与者回忆活动。在第二部电影的重播阶段，内侧颞叶（MTL）中神经活动模式的恢复与检测变化和对原始活动特征的更好记忆有关。后内侧皮质（PMC）的恢复还预测更好的记忆为变化的功能。与年轻人相比，老年人显示出检测和记忆变化的能力降低，恢复和记忆能力之间的关联较弱。这些发现表明，PMC和MTL通过恢复以前的事件功能来促进变更处理，